EPA 815-Z-06-002
T:
             Wednesday,

             January 4, 2006
             Part H



             Environmental

             Protection Agency

             40 CFR Parts 9, 141, and 142
             National Primary Drinking Water
             Regulations: Stage 2 Disinfectants and
             Disinfection Byproducts Rule; Final Rule

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4644
Corrections
                                      Federal Register

                                      Vol. 71, No. 18

                                      Friday, January 27, 2006
This section of the FEDERAL REGISTER
contains editorial corrections of previously
published Presidential, Rule, Proposed Rule,
and Notice documents. These corrections are
prepared by the Office of the Federal
Register. Agency prepared corrections are
issued as signed documents and appear in
the appropriate document categories
elsewhere in the issue.
DEPARTMENT OF EDUCATION

Office of Postsecondary Education;
Overview Information; Developing
Hispanic-Serving Institutions (HSI)
Program; Notice Inviting Applications
for New Awards for Fiscal Year (FY)
2006

Corrections

  In notice document E6—829 beginning
on page 3830 in the issue of Tuesday,
January 24, 2006, make the following
corrections:
  1. On page 3830, in the first column,
under the heading DATES, in the third
paragraph, under Deadline for
Intergovernmental Review: "March 27,
2006" should read " May 9, 2006".
  2. On page 3832, in the first column,
in the fourth paragraph, under Deadline
for Intergovernmental Review: "March
27,  2006" should read "May 9, 2006".

[FR Doc. Z6-829 Filed 1-26-06; 8:45 ami
BILLING CODE 1505-01-D
ENVIRONMENTAL PROTECTION
AGENCY

40 CFR Parts 9,141, and 142

[EPA-HQ-OW-2002-0043; FRL-8012-1]

RIN 2040-AD38

National Primary Drinking Water
Regulations: Stage 2 Disinfectants and
Disinfection Byproducts Rule

Correction
  In rule document 06-3 beginning on
page 388 in the issue of Wednesday,
January 4, 2006, make the following
corrections:^
  1. On page 424, in the third column,
in the last paragraph, in the second line,
"complete" should read "completing".
  2. On the same page, in the same
column, in the same paragraph, in the
12th line, "complete" should read
"completing".
  3. On page 426, the table is corrected
to read as set forth below:
                         TABLE IV.G-1.—IDSE MONITORING FREQUENCIES AND LOCATIONS
Source water
type
Subpart H


Ground
Water

Population size category
<500 consecutive sys-
tems.
<500 non-consecutive
systems.
500-3,300 non-consecu-
tive systems.
500-3,300 consecutive
systems.
3301-9,999

10000-49,999
50 000-249 999 	
250 000-999 999
1 000,000-4 999 999 ..
>5,000,000 	

<500 consecutive sys-
tems
<500 non-consecutive
systems.
500-9,999 	
1 0 000-99 999
1 00 000-499 999
>500 000

Monitoring periods and
frequency of sampling
one (during peak histor-
ical month)2.

four (every 90 days) 	


six (every 60 days) 	




one (during peak histor-
ical month)2.

four (every 90 days) 	



Distribution system monitoring locations 1
Total per
monitoring
period
2
2
2
2
4
8
16
24
32
40
2
2
2
6
8
12
Near entry
points
1

1


1
3
4
6
8
1


1
1
2
Average
residence
time





1
2
4
6
8
10




1
1
2
High TTHM
locations
1
1
1
1
2
3
5
8
10
12
1
1
1
2
3
4
High HAAS
locations
1

1
1
2
4
6
8
10

1
1
2
3
4
  1A dual sample set (i.e., a TTHM and an HAAS sample) must be taken at each monitoring location during each monitoring period.
  2 The peak historical month is the month with the highest TTHM or HAAS levels or the warmest water temperature

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                   Federal  Register/Vol.  71, No. 18/Friday, January  27,  2006/Corrections
                                                                     4645
  4. On page 433, in the second column,  and seventh lines, "2xlO/b 2xlO~4,
in the third full paragraph, in the sixth    W~4 and 10~6" should read "2xlO~4".
                                        5. On pages 434 and 435, Table IV.K-
                                      1 is corrected to read as set forth below:
   TABLE IV.K-1.—TECHNOLOGIES CONSIDERED AND PREDICTED To BE USED IN COMPLIANCE FORECAST FOR SMALL
                                                    SYSTEMS
SW Water Plants
Switching to chloramines as a residual disinfectant
Chlorine dioxide (not for systems serving fewer than 100 people) 	
UV
Ozone (not for systems serving fewer than 100 people)
Micro-filtration/Ultra-filtration 	 	 	
GAC20.
GAC20 + Advanced disinfectants.
integrated Membranes.






GW Water Plants
Switching to chloramines as a residual disinfectant
UV
Ozone (not for systems serving fewer than 100 people)
GAC20
Nanofiltration

  Note: Italicized technologies are those predicted to be used in the compliance forecast
  Source: Exhibits 5.11b and 5.14b, USEPA 2005a.
  6. On page 435, in Table IV.K-2, in
column H, in the second line, "9"
should read "0".
  7. On page 464, in Table VI.K-1, in
the "Notes:", in the third line,
"established exposure" should read
"established between exposure".
§ 9.1  [Corrected]

  8. On page 477, in § 9.1, in the third
column, in the table National Primary
Drinking Water Regulations
Implementation, under "OMB control
No.", in the first line, "2040-0265"
should read "2040-0205".
§141.620  [Corrected]
  9. On page 489, in § 141.620(c), in the
table, in the first column, in entry (4),
"System serving > 10,000" should read
"System serving < 10,000".
|FR Doc. C6-3 Filed 1-26-06; 8:45 am]
BILLING CODE 1505-01-D

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 388
Federal  Register/Vol. 71, No. 2/Wednesday,  January 4, 2006/Rules  and Regulations
 ENVIRONMENTAL PROTECTION
 AGENCY

 40 CFR Parts 9,141, and 142
 [EPA-HQ-OW-2002-0043; FRL-8012-1]
 BIN 2040-AD38

 National Primary Drinking Water
 Regulations: Stage 2 Disinfectants and
 Disinfection Byproducts Rule

 AGENCY: Environmental Protection
 Agency (EPA).
 ACTION: Final rule.

 SUMMARY: The Environmental Protection
 Agency (EPA) is promulgating today's
 final rule, the Stage 2 Disinfectants and
 Disinfection Byproducts Rule (DBPR), to
 provide for increased protection against
 the potential risks for cancer and
 reproductive and  developmental health
 effects associated  with disinfection
 byproducts (DBFs). The final Stage 2
 DBPR contains maximum contaminant
 level goals for chloroform,
 monochloroacetic acid  and
 trichloroacetic acid; National Primary
 Drinking Water Regulations, which
 consist of maximum contaminant levels
 (MCLs) and monitoring, reporting, and
 public notification requirements for
 total trihalomethanes (TTHM) and
 haloacetic acids (HAAS); and revisions
 to the reduced monitoring requirements
 for bromate. This  document also
 specifies the best available technologies
 for the final MCLs. EPA is also
 approving additional analytical methods
 for the determination of disinfectants
 and DBFs in drinking water. EPA
 believes the Stage 2 DBPR will reduce
 the potential risks of cancer and
 reproductive and  developmental health
 effects associated  with DBFs by
                          reducing peak and average levels of
                          DBFs in drinking water supplies.
                            The Stage 2 DBPR applies to public
                          water systems (PWSs) that are
                          community water systems (CWSs) or
                          nontransient noncommunity water
                          systems (NTNCWs) that add a primary
                          or residual disinfectant other than
                          ultraviolet light or deliver water that has
                          been treated with a primary or residual
                          disinfectant other than ultraviolet light.
                            This rule also makes minor
                          corrections to drinking water
                          regulations, specifically the Public
                          Notification tables. New endnotes were
                          added to these tables in recent
                          rulemakings; however, the
                          corresponding footnote numbering in
                          the tables was not changed. In addition,
                          this rule makes a  minor correction to the
                          Stage 1 Disinfectants and Disinfection
                          Byproducts Rule by replacing a sentence
                          that was inadvertently removed.
                          DATES: This final  rule is effective on
                          March 6, 2006.  For judicial review
                          purposes, this final rule is promulgated
                          as January 4, 2006. The incorporation by
                          reference of certain publications listed
                          in the rule is approved by the Director
                          of the Federal Register as of March 6,
                          2006.
                          ADDRESSES: EPA has established a
                          docket for this action under Docket ID
                          No. EPA-HQ-OW-2002-0043. All
                          documents in the docket are listed on
                          the http://www.regulations.gov Web
                          site.
                            Although listed in the index, some
                          information is not publicly available,
                          e.g., CBI or other information whose
                          disclosure is restricted by statute.
                          Certain other material, such as
                          copyrighted material, is not placed on
                          the Internet and will be publicly
                          available only in hard copy form.
  Publicly available docket materials
are available either electronically
through http://www.regulations.gov or
in hard copy at the Water Docket, EPA/
DC, EPA West, Room B102, 1301
Constitution Ave., NW., Washington,
DC. The Public Reading Room is open
from 10 a.m. to 4 p.m., Monday through
Friday, excluding legal holidays. The
telephone number for the Public
Reading Room is (202) 566-1744, and
the telephone  number for the Water
Docket is (202) 566-2426.

FOR FURTHER INFORMATION CONTACT: For
technical inquiries, contact Tom
Grubbs, Standards and Risk
Management Division, Office of Ground
Water  and Drinking Water (MC 4607M),
Environmental Protection Agency, 1200
Pennsylvania Ave., NW., Washington,
DC 20460; telephone number; (202)
564-5262; fax  number: (202) 564-3767;
e-mail  address: grubbs.thomas@epa.gov.
For general information, contact the
Safe Drinking  Water Hotline, Telephone
(800) 426-4791. The Safe Drinking
Water  Hotline  is open Monday through
Friday, excluding legal holidays, from
10 a.m. to 4  p.m. Eastern Time.

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does This Action Apply to Me?

  Entities potentially regulated by the
Stage 2 DBPR are community and
nontransient noncommunity water
systems that add a primary or residual
disinfectant  other than ultraviolet light
or deliver water that has been treated
with a  primary or  residual disinfectant
other than ultraviolet light. Regulated
categories and entities are identified  in
the following chart.

Industry
State, Local,
Category

Tribal, or Federal Governments ....
Examples of regulated entities
Community and nontransient noncommunity water systems that use a primary or residual dis-
infectant other than ultraviolet light or deliver water that has been treated with a primary or
residual disinfectant other than ultraviolet light.
Community and nontransient noncommunity water systems that use a primary or residual dis-
infectant other than ultraviolet light or deliver water that has been treated with a primary or
residual disinfectant other than ultraviolet light.
  This table is not intended to be
exhaustive, but rather provides a guide
for readers regarding entities likely to be
regulated by this action. This table lists
the types of entities that EPA is now
aware could potentially be regulated by
this action. Other types of entities not
listed in the table could also be
regulated. To determine whether your
facility is regulated by this action, you
should carefully examine the definition
of "public water system" in § 141.2 and
                         the section entitled "coverage" (§ 141.3)
                         in Title 40 of the Code of Federal
                         Regulations and applicability criteria in
                         § 141.600 and 141.620 of today's
                         proposal. If you have questions
                         regarding the applicability of this action
                         to a particular entity, contact the person
                         listed in the preceding FOR FURTHER
                         INFORMATION CONTACT section.
B. How Can I Get Copies of This
Document and Other Related
Information?

  See the ADDRESSES section for
information on how to receive a copy of
this document and related information.
Regional contacts:
I. Kevin Reilly, Water Supply Section,
    JFK Federal Bldg., Room 203,
    Boston, MA 02203, (617) 565-3616.
II. Michael Lowy,  Water Supply Section,
    290 Broadway, 24th Floor, New

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             Federal  Register/Vol.  71, No. 2/Wednesday,  January 4, 2006/Rules and  Regulations
                                                                       389
    York, NY 10007-1866, (212) 637-
    3830.
III. Jason Gambatese, Drinking Water
    Section (3WM41), 1650 Arch Street,
    Philadelphia, PA 19103-2029, (215)
    814-5759.
IV. Robert Burns, Drinking Water
    Section, 61 Forsyth Street SW.,
    Atlanta, GA 30303, (404) 562-9456.
V. Miguel Del Toral, Water Supply
    Section, 77 W. Jackson Blvd.,
    Chicago, IL 60604, (312) 886-5253.
VI. Blake L. Atkins, Drinking Water
    Section, 1445 Ross Avenue, Dallas,
    TX 75202, (214) 665-2297.
VII. Douglas J. Bmne, Drinking Water
    Management Branch, 901 North 5th
    Street, Kansas City, KS 66101, (800)
    233-0425.
VIII. Bob Clement, Public Water Supply
    Section (8P2-W-MS), 999 18th
    Street, Suite 500, Denver, CO
    80202-2466,(303) 312-6653.
IX. Bruce Macler,  Water Supply Section,
    75 Hawthorne Street, San
    Francisco, CA 94105, (415) 972-
    3569.
X. Wendy Marshall, Drinking Water
    Unit, 1200 Sixth Avenue (OW-136),
    Seattle, WA 98101, (206) 553-1890.

Abbreviations Used in This Document
ASDWA Association of State Drinking
  Water Administrators
ASTM  American Society for Testing
  and Materials
AWWA  American Water Works
  Association
AwwaRF American Water Works
  Association Research Foundation
BAT  Best available technology
BCAA  Bromochloroacetic acid
BDCM  Bromodichloromethane
CDBG  Community Development Block
  Grant
CWS   Community water system
DBAA  Dibromoacetic acid
DBCM  Dibromochloromethane
DBF  Disinfection byproduct
DBPR  Disinfectants and Disinfection
  Byproducts Rule
DCAA  Dichloroacetic acid
EA  Economic analysis
EC  Enhanced coagulation
EDA  Ethylenediamine
EPA  United States Environmental
  Protection Agency
ESWTR  Enhanced Surface Water
  Treatment Rule
FACA  Federal Advisory Committee
  Act
GAC   Granular activated carbon
GC/ECD  Gas chromatography using
  electron capture detection
GWR  Ground Water Rule
GWUDI  Ground water under the direct
  influence of surface water
HAAS  Haloacetic acids (five) (sum of
  monochloroacetic acid, dichloroacetic
  acid, trichloroacetic acid,
  monobromoacetic acid, and
  dibromoacetic acid)
HAN  Haloacetonitriles
  (trichloroacetonitrile,
  dichloroacetonitrile,
  bromochloroacetonitrile, and
  dibromoacetonitrile)
1C  Ion chromatograph
IC/ICP-MS  Ion chromatograph
  coupled to an inductively coupled
  plasma mass spectrometer
IDSE  Initial distribution system
  evaluation
ILSI  International Life Sciences
  Institute
IESWTR   Interim Enhanced Surface
  Water Treatment Rule
IPCS  International Programme on
  Chemical Safety
IRIS  Integrated Risk Information
  System (EPA)
LOAEL  Lowest observed adverse effect
  level
LRAA Locational running annual
  average
LTlESTWR  Long Term 1 Enhanced
  Surface Water Treatment Rule
LT2ESTWR  Long Term 2 Enhanced
  Surface Water Treatment Rule
MBAA  Monobromoacetic acid
MCAA  Monochloroacetic acid
MCL  Maximum contaminant level
MCLG  Maximum contaminant level
  goal
M-DBP  Microbial and disinfection
  byproducts mg/L Milligram per liter
MRL  Minimum reporting level
MRDL  Maximum residual disinfectant
  level
MRDLG  Maximum residual
  disinfectant level goal
NDMA  N-nitrosodimethylamine
NDWAC  National Drinking Water
  Advisory Council
NF  Nanofiltration
NOAEL  No Observed Adverse Effect
  Level
NODA  Notice of data availability
NPDWR   National primary drinking
  water regulation
NRWA  National Rural Water
  Association
NTNCWS  Nontransient
  noncommunity  water system
NTP  National Toxicology Program
NTTAA  National Technology Transfer
  and Advancement Act
OMB  Office of Management and
  Budget
PAR  Population attributable risk
PE   Performance  evaluation
PWS  Public water system
RAA  Running annual average
RFA  Regulatory  Flexibility Act
RiD  Reference dose
RSC  Relative source contribution
RUS  Rural Utility Service
SAB  Science Advisory Board
SBAR  Small Business Advisory
  Review
SBREFA   Small Business Regulatory
  Enforcement Fairness Act
SDWA  Safe Drinking Water Act, or the
  "Act,"  as amended in 1996
SER  Small Entity Representative
SGA  Small for gestational age
SUVA Specific ultraviolet absorbance
SWAT  Surface Water Analytical Tool
SWTR Surface Water Treatment Rule
TC  Total coliforms
TCAA Trichloroacetic acid
TCR  Total Coliform Rule
THM Trihalomethane
TOG  Total organic carbon
TTHM  Total trihalomethanes (sum of
  four THMs: chloroform,
  bromodichloromethane,
  dibromochloromethane, and
  bromoform)
TWG Technical work group
UMRA  Unfunded Mandates Reform
  Act
UV 254 Ultraviolet absorption at 254
  nm
VSL  Value of Statistical Life
WTP Willingness To Pay

Table of Contents
I. General Information
  A. Does  This Action Apply to Me?
  B. How Can I Get Copies of This Document
    and Other Related Information?
II. Summary of the Final Rule
  A. Why  is EPA Promulgating the. Stage 2
    DBPR?
  B. What Does the Stage 2 DBPR  Require?
  1. Initial Distribution  System Evaluation
  2. Compliance and monitoring
    requirements
  3. Operational Evaluation Levels
  4. Consecutive systems
  C. Correction of § 141.132
III. Background
  A. Statutory Requirements and Legal
    Authority
  B. What is the Regulatory History of the
    Stage 2 DBPR and How Were
    Stakeholders Involved?
  1. Total Trihalomethanes Rule
  2. Stage 1 Disinfectants and  Disinfection
    Byproducts Rule
  3. Stakeholder involvement
  a. Federal Advisory Committee process
  b. Other outreach processes
  C. Public Health Concerns to be Addressed
  1. What are DBFs?
  2. DBP Health Effects
  a. Cancer health effects
  i. Epidemiology
  ii. Toxicology
  b. Reproductive and developmental health
    effects
  i. Epidemiology
  ii. Toxicology
  c. Conclusions
  D. DBP Occurrence and  DBP Control
  1. Occurrence
  2. Treatment
  E. Conclusions for Regulatory Action
IV. Explanation of Today's Action
  A. MCLGs

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390
Federal Register/Vol. 71, No. 2/Wednesday, January  4,  2006/Rules and Regulations
  \. Chloroform MCLG
  a. Today's rule
  b. Background and analysis
  c. Summary of major comments
  2. HAA MCLGs: TCAA and MCAA
  a. Today's rule
  b. Background and analysis
  c. Summary of major comments
  B. Consecutive Systems
  I1. Today's Rule
  2. Background and analysis
  3. Summary of major comments
  C. LRAA MCLs for TTHM and HAAS
  1. Today's rule
  2. Background and analysis
  3. Summary of major comments
  D. BAT for TTHM and HAAS
  1. Today's rule
  2. Background and analysis
  3. Summary of major comments
  E. Compliance Schedules
  1. Today's rule
  2. Background and analysis
  3. Summary of major comments
  F. Initial Distribution System Evaluation
    (IDSE)
  1. Today's rule
  a. Applicability
  b. Data collection
  i. Standard monitoring
  ii. System specific study
  iii. 40/30 certification
  c. Implementation
  2. Background and analysis
  a. Standard monitoring
  b. Very small system waivers
  c. 40/30 certifications
  d. System specific studies
  e. Distribution System Schematics
  3. Summary  of major comments
  G. Monitoring Requirements and
   Compliance Determination for TTHM
   and HAAS MCLs
  1. Today's Rule
  a. IDSE Monitoring
  b. Routine Stage 2 Compliance Monitoring
  i. Reduced monitoring
  ii. Compliance determination
  2. Background and Analysis
  3. Summary  of Major Comments
  H. Operational Evaluation Requirements
   initiated by TTHM and HAAS Levels
  1. Today's rule
  2. Background and analysis
  3. Summary  of major comments
  I. MCL, BAT, and Monitoring for Bromate
  1. Today's rule
  2. Background and analysis
  a. Bromate MCL
  b. Criterion for reduced bromate
   monitoring
  3. Summary  of major comments
  J. Public Notice Requirements
  1. Today's rule
  2. Background and analysis
  3. Summary  of major comments
  K. Variances and Exemptions
  1. Today's Rule
  2. Background and Analysis
  a. Variances
  b. Affordable Treatment Technologies for
   Small Systems
  c. Exemptions
  3. Summary  of major comments
  L. Requirements for Systems to Use
   Qualified Operators
                              M. System Reporting and Recordkeeping
                                Requirements
                              1. Today's rule
                              2. Summary of major comments
                              N. Approval of Additional Analytical
                                Methods
                              1. Today's Rule
                              2. Background and Analysis
                              O. Laboratory Certification and Approval
                              1. PE acceptance criteria
                              a. Today's rule
                              b. Background and analysis
                              c. Summary of major comments
                              2. Minimum reporting limits
                              a. Today's rule
                              b. Background and analysis
                              c. Summary of major comments
                              P. Other regulatory changes
                            V. State Implementation
                              A. Today's rule
                              1. State Primacy Requirements for
                                Implementation Flexibility
                              2. State recordkeeping requirements
                              3. State reporting requirements
                              4. Interim primacy
                              5. IDSE implementation
                              B. Background and Analysis
                              C. Summary of Major Comments
                            VI. Economic Analysis
                              A. Regulatory Alternatives Considered
                              B. Analyses that Support Today's Final
                                Rule '
                              1. Predicting water quality and treatment
                                changes
                              2. Estimating benefits
                              3. Estimating costs
                              4. Comparing regulatory alternatives
                              C. Benefits of the Stage'2 DBPR
                              1. Nonqualified benefits
                              2. Quantified benefits
                              3. Timing of benefits accrual
                              D. Costs of the Stage 2 DBPR
                              1. Total annualized present value costs
                              2. PWS costs
                              a. IDSE costs
                              b. PWS treatment costs
                              c. Monitoring costs
                              3. State/Primacy agency costs
                             4. Non-quantified costs
                             E. Household Costs of the Stage 2 DBPR
                              F. Incremental Costs and Benefits of the
                                Stage 2 DBPR
                             G. Benefits From the Reduction of Co-
                                occurring Contaminants
                              H. Potential Risks From Other
                               Contaminants
                              1. Emerging DBFs
                             2. N-nitrosamines
                             3. Other DBPs
                             I. Effects of the Contaminant on the.
                               General Population and Groups within
                               the General Population that are
                               Identified as Likely To Be at Greater Risk
                               of Adverse Health Effects
                             ]. Uncertainties in the Risk, Benefit, and
                               Cost Estimates for the Stage 2 DBPR
                             K. Benefit/Cost Determination for the Stage
                               2 DBPR
                             L. Summary of Major Comments
                             1. Interpretation of health effects studies
                             2. Derivation of benefits
                             3. Use of SWAT
                             5. Unanticipated risk issues
                             6. Valuation of cancer cases avoided
                           VII. Statutory and Executive Order Reviews
                             A. Executive Order 12866: Regulatory
                               Planning and Review
  B. Paperwork Reduction Act
  C. Regulatory Flexibility Act
  D. Unfunded Mandates Reform Act
  E. Executive Order 13132: Federalism
  F. Executive Order 13175: Consultation
    and Coordination With Indian Tribal
    Governments
  G. Executive Order 13045: Protection of
    Children from Environmental Health
    Risks and Safety Risks
  H. Executive Order 13211: Actions
    Concerning Regulations That
    Significantly Affect Energy Supply,
    Distribution, or Use
  I. National Technology Transfer and
    Advancement Act
  J. Executive Order 12898: Federal Actions
    to Address Environmental Justice in
    Minority Populations or Low-Income
    Populations
  K. Consultations with the Science
    Advisory Board, National Drinking
    Water Advisory Council, and the
    Secretary of Health and Human Services
  L. Plain Language
  M. Analysis of the Likely Effect of
    Compliance With the Stage 2 DBPR on
    the Technical, Managerial, and Financial
    Capacity of Public Water Systems
  N. Congressional Review Act
VIII. References

II. Summary of the Final Rule

A. Why is EPA Promulgating the Stage
2DBPR?
  The Environmental Protection Agency
is finalizing the Stage 2  Disinfectants
and Disinfection Byproduct Rule
(DBPR) to reduce potential cancer risks
and address concerns with potential
reproductive and developmental risks
from DBPs. The Agency is committed to
ensuring that all public  water systems
provide  clean and safe drinking water.
Disinfectants are an essential element of
drinking water treatment because of the
barrier they provide against harmful
waterborne microbial pathogens.
However, disinfectants react with
naturally occurring organic and
inorganic matter in source water and
distribution systems to form
disinfection byproducts (DBPs) that may
pose health risks. The Stage 2 DBPR is
designed to reduce the level of exposure
from DBPs without undermining the
control of microbial pathogens. The
Long Term 2 Enhanced Surface Water
Treatment Rule (LT2ESWTR) is being
finalized and implemented
simultaneously with the Stage 2 DBPR
to ensure that drinking water is
microbiologically safe at the limits set
for DBPs.
  Congress required EPA to promulgate
the Stage 2 DBPR as part of the 1996
Safe Drinking Water Act (SOWA)
Amendments (section 1412(b)(2)(Q).
The Stage 2 DBPR augments the Stage
1 DBPR that was finalized in 1998 (63
FR 69390, December 16, 1998) (USEPA

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             Federal  Register/Vol. 71, No.  2/Wednesday, January 4,  2006/Rules and Regulations
                                                                       391
1998a). The goal of the Stage 2 DBPR is
to target the highest risk systems for
changes beyond those required for Stage
1 DBPR. Today's rule reflects consensus
recommendations from the Stage 2
Microbial/Disinfection Byproducts (M-
DBP) Federal Advisory Committee (the
Advisory Committee) as well as public
comments.
  New information on health effects,
occurrence, and treatment has become
available since the Stage 1 DBPR that
supports the need for the Stage 2 DBPR.
EPA has completed a more extensive
analysis of health  effects, particularly
reproductive and developmental
endpoints, associated with DBFs since
the Stage 1 DBPR. Some recent studies
on both human epidemiology and
animal toxicology have shown possible
associations between chlorinated
drinking water and reproductive and
developmental endpoints such as
spontaneous abortion, stillbirth, neural
tube and other birth defects, intrauterine
growth retardation, and low birth
weight. While results of these studies
have been mixed,  EPA believes they
support a potential hazard concern.
New epidemiology and toxicology
studies evaluating bladder, colon, and
rectal cancers have increased the weight
of evidence linking these health effects
to DBP exposure. The large number of
people (more than 260 million
Americans) exposed to DBFs and the
potential cancer, reproductive, and
developmental risks have played a
significant role in EPA's decision to
move forward with regulatory changes
that target lowering DBP exposures
beyond the requirements of the Stage 1
DBPR.
  While the Stage 1 DBPR is predicted
to provide a major reduction in DBP
exposure, national survey data suggest
that some customers may receive
drinking water with elevated, or peak,
DBP concentrations even when their
distribution system is in compliance
with the Stage 1 DBPR.  Some of these
peak concentrations are substantially
greater than the Stage 1 DBPR maximum
contaminant levels (MCLs) and some
customers receive these elevated levels
of DBFs on a consistent basis. The new
survey results also show that Stage 1
DBPR monitoring sites may not be
representative of higher DBF
concentrations that occur in distribution
systems. In addition, new studies
indicate that cost-effective technologies
including ultraviolet light (UV) and
granular activated carbon (GAG) may be
very effective at lowering DBP levels.
EPA's analysis of this new occurrence
and treatment information indicates that
significant public  health benefits may be
achieved through  further, cost-effective
reductions of DBFs in distribution
systems.
  The Stage 2 DBPR presents a risk-
targeting approach to reduce risks from
DBFs. The new requirements provide
for more consistent, equitable protection
from DBFs across the entire distribution
system and the reduction of DBP peaks.
New risk-targeting provisions require
systems to first identify their  risk level;
then, only those systems with the
greatest risk will need to make
operational or treatment changes. The
Stage 2 DBPR,  in conjunction with the
LT2ESWTR, will help public water
systems deliver safer water to
Americans with the benefits of
disinfection to control pathogens and
with fewer risks from DBFs.

B. What Does the Stage  2 DBPR Require?
  The risk-targeting components of the
Stage 2 DBPR focus the  greatest amount
of change where the greatest amount of
risk may exist. Therefore, the provisions
of the Stage 2 DBPR focus first on
identifying the higher risks through the
Initial Distribution System Evaluation
(IDSE). The rule then addresses
reducing exposure and lowering  DBP
peaks in distribution systems by  using
a new method  to determine MCL
compliance (locational running annual
average (LRAA)), defining operational
evaluation levels, and regulating
consecutive systems. This section
briefly describes the requirements of
this final rule.  More detailed
information on the regulatory
requirements for this rule can be found
in Section IV.

1. Initial Distribution System Evaluation
  The first provision, designed to
identify higher risk systems, is the
Initial Distribution System  Evaluation
(IDSE). The purpose of the IDSE  is to
identify Stage 2 DBPR compliance
monitoring sites that represent each
system's highest levels of DBFs. Because
Stage 2 DBPR compliance will be
determined at these new monitoring
sites, only those systems that identify
elevated concentrations of TTHM and
HAAS will need to make treatment or
process changes to bring the system into
compliance with the Stage  2 DBPR. By
identifying compliance monitoring sites
with the highest concentrations of
TTHM and HAAS in each system's
distribution system, the IDSE will offer
increased assurance that MCLs are being
met across the distribution  system and
that customers are receiving more
equitable public health protection. Both
treatment changes and awareness of
TTHM and HAAS levels resulting from
the IDSE will allow systems to better
control for distribution  system peaks.
  The IDSE is designed to offer
flexibility to public water systems. The
IDSE requires TTHM and HAA5
monitoring for one year on a regular
schedule that is determined by source
water type and system size.
Alternatively, systems have the option
of performing a site-specific study based
on historical data, water distribution
system models, or other data; and
waivers are available under certain
circumstances. The IDSE requirements
are discussed in Sections IV.E, IV.F.,
and IV.G of this preamble and in
subpart U of the rule language.

2. Compliance and Monitoring
Requirements
  As in Stage 1, the Stage 2 DBPR
focuses on monitoring for and reducing
concentrations of two classes of DBFs:
total trihalomethanes (TTHM) and
haloacetic acids (HAAS). These two
groups of DBFs act as indicators for the
various byproducts that are present in
water disinfected with chlorine or
chloramine. This means that
concentrations of TTHM and HAA5 are
monitored for compliance, but their
presence in drinking water is
representative of many other
chlorination DBFs that may also occur
in the water; thus, a reduction in TTHM
and HAAS generally indicates an overall
reduction of DBFs.
  The second provision of the Stage 2
DBPR is designed to address spatial
variations in DBP exposure through a
new compliance calculation (referred to
as locational running annual average)
for TTHM and HAA5 MCLs. The MCL
values  remain the same as in the Stage
1. The  Stage 1 DBPR running annual
average (RAA) calculation allowed some
locations within a distribution system to
have higher DBP annual averages than
others as long as the system-wide
average was below the MCL. The Stage
2 DBPR bases compliance on  a
locational running annual average
(LRAA) calculation, where the annual
average at each sampling location in the
distribution system will be used to
determine compliance with the MCLs of
0.080 mg/L and 0.060 mg/L for TTHM
and HAAS, respectively. The LRAA will
reduce exposures to high DBP
concentrations by ensuring that each
monitoring site is in compliance with
the MCLs as an annual average, while
providing all customers drinking water
that more consistently meets the MCLs.
A more detailed discussion of Stage 2
DBPR MCL requirements can be found
in Sections IV.C, IV.E, and IV.G of this
preamble and in § 141.64(b)(2) and (3)
and subpart V of the rule language.
  The number of compliance
monitoring sites is based on the

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 population served and the source water
 type. EPA believes that population-
 based monitoring provides better risk-
 targeting and is easier to implement.
 Section IV.G describes population-based
 monitoring and how it affects systems
 complying with this rule.
   The Stage 2 DBPR includes new
 MCLGs for chloroform,
 monochloroacetic acid, and
 trichloroacetic acid, but these new
 MCLGs do not affect the MCLs for
 TTHM or HAA5.

 3. Operational Evaluation Levels
   The IDSE and LRAA calculation will
 lead to lower DBF concentrations
 overall and reduce short term exposures
 to high DBF concentrations in certain
 areas, but this strengthened approach to
 regulating DBFs will still allow
 individual DBF samples above the MCL
 even when systems are in compliance
 with the Stage 2 DBPR. Today's rule
 requires systems that exceed operational
 evaluation levels (referred to as
 significant excursions in the  proposed
 rule) to evaluate system operational
 practices and identify opportunities to
 reduce DBF concentrations in the
 distribution system. This provision will
 curtail peaks by providing systems with
 a proactive approach to remain in
 compliance. Operational evaluation
 requirements are discussed in greater
 detail in Section IV.H.

 4. Consecutive Systems
   The Stage 2  DBPR also contains
 provisions for regulating consecutive
 systems, defined in the Stage 2 DBPR as
 public water systems that buy or
 otherwise receive some or all of their
 finished water from another public
 water system.  Uniform regulation of
 consecutive systems provided by the
 Stage 2 DBPR will  ensure that
 consecutive systems deliver drinking
 water that meets applicable DBF
 standards, thereby providing better,
 more equitable public health protection.
 More information on regulation of
 consecutive systems can be found in
 Sections IV.B,  IV.E, and IV.G.
 C. Correction of §141,132
  Section 553  of the Administrative
 Procedure Act, 5 U.S.C. 553(b)(B),
 provides that,  when an agency for good
 cause finds that notice and public
 procedure are  impracticable,
 unnecessary, or contrary to the public
 interest, the agency may issue a rule
 without providing  prior notice and an
 opportunity for public comment.  In
 addition to promulgating the Stage 2
regulations, this rule also makes a minor
correction to the National Primary
Drinking Water Regulations, specifically
                          the Stage 1 Disinfection Byproducts
                          Rule. This rule corrects a technical error
                          made in the January 16, 2001, Federal
                          Register Notice (66 FR 3769) (see page
                          3770). This rule restores the following
                          sentence that was inadvertently
                          removed from § 141.132 (b)(l)(iii),
                          "Systems on a reduced monitoring
                          schedule may remain on that reduced
                          schedule as long as the average of all
                          samples taken in  the year (for systems
                          which must monitor quarterly) or the
                          result of the sample (for systems which
                          must monitor no more frequently than
                          annually) is no more than 0.060 mg/L
                          and 0.045 mg/L for TTHMs and HAAS,
                          respectively." This text had been part of
                          the original regulation when it was
                          codified in the  CFR on December 16,
                          1998. However, as a result of a
                          subsequent amendment to that
                          regulatory text, the text discussed today
                          was removed. EPA recognized the error
                          only after publication of the new
                          amendment, and is now correcting the
                          error. EPA is merely restoring to the
                          CFR language that EPA had
                          promulgated on December 16, 1998.
                          EPA is not creating any new rights or
                          obligations by this technical correction.
                          Thus, additional notice and public
                          comment is not necessary. EPA finds
                          that this constitutes "good cause" under
                          5 U.S.C. 553(b)(B).

                          III. Background
                           A combination  of factors  influenced
                          the development of the Stage 2 DBPR.
                          These include the initial 1992-1994
                          Microbial and Disinfection Byproduct
                          (M-DBP) stakeholder deliberations and
                          EPA's Stage 1 DBPR proposal (USEPA
                          1994); the 1996 Safe Drinking Water Act
                          (SDWA) Amendments; the 1996
                          Information Collection Rule; the 1998
                          Stage 1 DBPR; new data, research, and
                          analysis on disinfection byproduct
                          (DBF) occurrence, treatment, and health
                          effects since the Stage 1 DBPR; and the
                          Stage 2 DBPR Microbial and
                          Disinfection Byproducts Federal
                          Advisory Committee. The following
                          sections provide summary background
                          information  on  these subjects. For
                          additional information, see  the
                          proposed Stage 2 DBPR and supporting
                          technical material where cited (68 FR
                          49548, August 18, 2003) (USEPA
                          2003a).

                          A. Statutory Requirements and Legal
                          Authority
                           The SDWA, as amended in 1996,
                          authorizes EPA to promulgate a national
                          primary drinking water regulation
                          (NPDWR) and publish a maximum
                          contaminant level goal (MCLG) for any
                          contaminant the Administrator
                          determines "may have an adverse effect
 on the health of persons," is "known to
 occur or there is a substantial likelihood
 that the contaminant will occur in
 public water systems with a frequency
 and at levels of public health concern,"
 and for which "in the sole judgement of
 the Administrator, regulation of such
 contaminant presents a meaningful
 opportunity for health risk reduction for
 persons served by public water
 systems" (SDWA section 1412(b)(l)(A)).
 MCLGs are non-enforceable health goals
 set at a level at which "no known or
 anticipated adverse effects on the health
 of persons occur and which allows an
 adequate margin of safety." These
 health goals are published at the same
 time as the NPDWR (SDWA sections
 1412(b)(4) and 1412(a)(3)).
  SDWA also requires each NPDWR for
 which an MCLG is established to
 specify an MCL that is as close to the
 MCLG as is feasible (sections 1412(b)(4)
 and  1401(1)(C)). The Agency may also
 consider additional health risks from
 other contaminants and establish an
 MCL "at a level other than the feasible
 level, if the technology, treatment
 techniques, and other means used to
 determine the feasible level would
 result in an increase in the health risk
 from drinking water by—(i) increasing
 the concentration of other contaminants
 in drinking water; or (ii) interfering with
 the efficacy of drinking water treatment
 techniques or processes that are used to
 comply with other national  primary
 drinking water regulations" (section
 1412(b)(5)(A)). When establishing an
 MCL or treatment technique under this
 authority, "the level or levels or
 treatment techniques shall minimize the
 overall risk of adverse health effects by
 balancing the risk from the contaminant
 and the risk from other contaminants
 the concentrations of which may be
 affected by the use of a treatment
 technique or process that would be
 employed to attain the maximum
 contaminant level or levels" (section
 1412(b)(5)(B)). In today's rule, the
 Agency is establishing MCLGs and
 MCLs for certain DBFs, as described in
 Section IV.
  Finally, section 1412(b)(2)(C) of the
 Act requires EPA to promulgate a Stage
 2 DBPR. Consistent with statutory
 provisions for risk balancing (section
 1412(b)(5)(B)), EPA is finalizing the
 LT2ESWTR concurrently with the Stage
 2 DBPR to ensure simultaneous
 protection from microbial and DBF
risks.

B. What is the Regulatory History of the
 Stage 2 DBPR and How Were
Stakeholders Involved?
  This section first summarizes the
existing regulations aimed at controlling

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levels of DBFs in drinking water. The
Stage 2 DBPR establishes regulatory
requirements beyond these rules that
target high risk systems and provide for
more equitable protection from DBFs
across the entire distribution system.
Next, this section summarizes the
extensive stakeholder involvement in
the development of the Stage 2 DBPR.
1. Total Trihalomethanes Rule
  The first rule to regulate DBFs was
promulgated on November 29, 1979.
The Total Trihalomethanes Rule (44 FR
68624, November 29, 1979) (USEPA
1979) set an MCL of 0.10 mg/L for total
trihalomethanes (TTHM). Compliance
was based on the running annual
average (RAA) of quarterly averages of
all samples collected throughout the
distribution system. This TTHM
standard applied only to community
water systems using surface water and/
or ground water that served at least
10,000 people and added a disinfectant
to the drinking water during any part of
the treatment process.
2.  Stage 1 Disinfectants and Disinfection
Byproducts Rule
  The Stage 1 DBPR, finalized in 1998
(USEPA 1998a), applies to all
community and nontransient
noncommunity water systems that add
a chemical disinfectant to water. The
rule  established maximum residual
disinfectant level goals (MRDLGs) and
enforceable maximum residual
disinfectant level (MRDL) standards for
three chemical disinfectants—chlorine,
chloramine, and chlorine dioxide;
maximum contaminant level goals
(MCLGs) for three trihalomethanes
(THMs), two haloacetic acids (HAAs),
bromate, and chlorite;  and enforceable
maximum contaminant level (MCL)
standards for TTHM, five haloacetic
acids (HAA5), bromate (calculated as
running annual averages (RAAs)), and
chlorite (based on daily and monthly
sampling). The Stage 1 DBPR uses
TTHM and HAAS as indicators of the
various DBFs that are present in
disinfected water. Under the Stage 1
DBPR, water systems that use surface
water or ground water under the direct
influence of surface water and use
conventional filtration treatment are
required to remove specified
percentages of organic materials,
measured as total organic carbon (TOG),
that  may react with disinfectants to form
DBFs. Removal is achieved through
enhanced coagulation  or enhanced
softening, unless a system meets one or
more alternative compliance criteria.
   The  Stage 1 DBPR was one of the first
rules to be promulgated under the 1996
SDWA Amendments (USEPA 1998a).
EPA finalized the Interim Enhanced
Surface Water Treatment Rule (63 FR
69477, December 16, 1998) (USEPA
1998b) at the same time as the Stage 1
DBPR to ensure simultaneous
compliance and address risk tradeoff
issues. Both rules were products of
extensive Federal Advisory Committee
deliberations and final consensus
recommendations in 1997.
3. Stakeholder Involvement
  a. Federal Advisory Committee
process. EPA reconvened the M-DBP
Advisory Committee in  March 1999 to
develop recommendations on issues
pertaining to the Stage 2 DBPR and
LT2ESWTR. The Stage 2 M-DBP
Advisory Committee consisted of 21
organizational members representing
EPA, State and local public health and
regulatory agencies, local elected
officials, Native American Tribes, large
and small drinking water suppliers,
chemical and equipment manufacturers,
environmental groups, and other
stakeholders. Technical support for the
Advisory Committee's discussions was
provided by a technical working group
established by the Advisory Committee.
The Advisory Committee held ten
meetings from September 1999 to July
2000, which were open  to the public,
with an opportunity for public comment
at each meeting.
  The Advisory Committee carefully
considered extensive new data on the
occurrence and health effects of DBFs,
as well as costs and potential impacts
on public water systems. In addition,
they considered risk tradeoffs associated
with treatment changes. Based upon this
detailed technical evaluation, the
committee concluded that a targeted
protective public health approach
should be taken to address exposure to
DBFs beyond the requirements of the
Stage 1 DBPR. While there had been
substantial research to date, the
Advisory Committee also concluded
that significant uncertainty remained
regarding the risk associated with DBFs
in drinking water. After reaching these
conclusions, the Advisory Committee
developed an Agreement in Principle
(65 FR 83015, December 29,  2000)
(USEPA 2000a) that laid out their
consensus recommendations on how to
further control DBFs in  public water
systems, which are reflected in today's
final rule.
  In the Agreement in Principle, the
Advisory Committee recommended
maintaining the MCLs for TTHM and
HAAS at 0.080 mg/L and 0.060 mg/L,
respectively, but changing the
compliance calculation in two phases to
facilitate systems moving from the
running annual average (RAA)
calculation to a locational running
annual average (LRAA) calculation. In
the first phase, systems would continue
to comply with the Stage 1 DBPR MCLs
as RAAs and, at the same time, comply
with MCLs of 0.120 mg/L for TTHM and
0.100 mg/L for HAAS calculated as
LRAAs. RAA calculations average all
samples collected within a distribution
system over a one-year period, but
LRAA calculations average all samples
taken at each individual sampling
location in a distribution system during
a one-year period. Systems would also
carry out an Initial Distribution System
Evaluation (IDSE) to select compliance
monitoring sites that reflect higher
TTHM and HAA5 levels occurring in
the distribution system. The second
phase of compliance would require
MCLs of 0.080 mg/L for TTHM and
0.060 mg/L for HAAS, calculated as
LRAAs at individual monitoring sites
identified through the IDSE. The first
phase has been dropped in the final
rule, as discussed in section IV.C.
  The Agreement in Principle also
provided recommendations for
simultaneous compliance with the
LT2ESWTR so that the reduction of
DBFs does not compromise microbial
protection. The complete text of the
Agreement in Principle (USEPA 2000a)
can be found online at
www.regulations.gov.
  b. Other outreach processes. EPA
worked with stakeholders to develop
the Stage 2 DBPR through various
outreach activities other than the M-
DBP Federal Advisory Committee
process. The Agency consulted with
State, local, and Tribal governments; the
National Drinking Water Advisory
Committee (NDWAC); the Science
Advisory Board (SAB); and Small Entity
Representatives (SERs) and small
system operators (as part of an Agency
outreach initiative under the Regulatory
Flexibility Act). Section VII includes a
complete description of the many
stakeholder activities which contributed
to the development of the Stage 2  DBPR.
  Additionally, EPA posted a pre-
proposal draft of the Stage 2 DBPR
preamble and regulatory language on an
EPA Internet site on October 17, 2001.
This public review period allowed
readers to comment on the Stage 2
DBPR's consistency with the Agreement
in Principle of the Stage 2 M-DBP
Advisory Committee. EPA received
important suggestions on this pre-
proposal draft from 14 commenters,
which included public water systems,
State governments, laboratories, and
other stakeholders.

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 C. Public Health Concerns to be
 Addressed
   EPA is promulgating the Stage 2 rule
 to reduce the potential risks of cancer
 and reproductive and developmental
 health effects from DBFs. In addition,
 the provisions of the Stage 2 DBPR
 provide for more equitable public health
 protection. Sections C and D describe
 the general basis for this public health
 concern through reviewing information
 in the following areas: the health effects
 associated with DBFs, DBF occurrence,
 and the control of DBFs.

 1. What Are DBFs?
   Chlorine has been widely used to kill
 disease-causing microbes in drinking
 water. The addition of chlorine in PWSs
 across the U.S. to kill microbial
 pathogens in the water supply has been
 cited as one of the greatest public health
 advances of the twentieth century
 (Okun 2003). For example, during the
 decade 1880-1890, American cities
 experienced an average mortality rate of
 58 per 100,000 from typhoid, which was
 commonly transmitted through
 contaminated water. By 1938, this rate
 had fallen to 0.67 deaths per 100,000,
 largely due to improved treatment of
 drinking water (Blake 1956).
   During the disinfection process,
 organic and inorganic material  in source
 waters can combine with chlorine and
 certain other chemical disinfectants to
 form DBFs. More than 260 million
 people in the U.S. are exposed to
 disinfected water and DBFs (USEPA
 2005a). Although chlorine is the most
 commonly applied disinfectant, other
 disinfectants, including ozone, chlorine
 dioxide, chloramine, and ultraviolet
 radiation, are in use. In combination
 with these, all surface water systems
 must also use either chlorine or
 chloramine to maintain a disinfectant
 residual in their distribution system.
 The kind of disinfectant used can
 produce different types and levels of
 disinfectant byproducts in the drinking
 water.
  Many factors affect the amount and
 kinds of DBFs in drinking water. Areas
 in the distribution system that have had
 longer contact time with chemical
 disinfectants tend to have higher levels
 of DBFs, such as sites farther from the
treatment plant, dead ends in the
 system, and small diameter pipes. The
makeup and source of the water also
affect DBF formation. Different  types of
organic and inorganic material will form
different types and levels of DBFs. Other
factors, such as water temperature,
season, pH, and location within the
water purification process where
disinfectants are added, can affect DBF
                          formation within and between water
                          systems.
                            THMs and HAAs are widely occurring
                          classes of DBFs formed during
                          disinfection with chlorine and
                          chloramine. The four THMs (TTHM)
                          and five HAAs (HAAS) measured and
                          regulated in the Stage 2 DBPR act as
                          indicators for DBF occurrence. There are
                          other known DBFs in addition to a
                          variety of unidentified DBFs present in
                          disinfected water. THMs and HAAs
                          typically occur at higher levels than
                          other known and unidentified DBFs
                          (McGuire et al. 2002; Weinberg et al.
                          2002). The presence of TTHM and
                          HAAS is representative of the
                          occurrence of many other chlorination
                          DBFs; thus, a reduction in the TTHM
                          and HAAS generally indicates an overall
                          reduction of DBFs.

                          2. DBF Health Effects
                            Since the mid 1980's, epidemiological
                          studies have  supported a potential
                          association between bladder cancer and
                          chlorinated water and possibly also
                          with colon and rectal cancers. In
                          addition, more recent health studies
                          have reported potential associations
                          between chlorinated drinking water and
                          reproductive and developmental health
                          effects.
                            Based on a collective evaluation of
                          both the human epidemiology and
                          animal toxicology data on cancer and
                          reproductive and developmental health
                          effects discussed below and in
                          consideration of the large number of
                          people exposed to chlorinated
                          byproducts in drinking water (more
                          than 260 million), EPA concludes that
                          (1) new cancer data since Stage 1
                          strengthen the evidence of a potential
                          association of chlorinated water with
                          bladder cancer and suggests an
                          association for colon and rectal cancers,
                          (2) current reproductive and
                          developmental health effects data do not
                          support a conclusion at this time as to
                          whether exposure to chlorinated
                          drinking water or disinfection
                          byproducts causes adverse
                          developmental or reproductive health
                          effects, but do support a potential health
                          concern, and  (3) the combined health
                          data indicate  a need for public health
                          protection beyond that provided by the
                          Stage 1 DBPR.
                           This section summarizes the key
                          information in the areas of cancer,
                          reproductive, and developmental health
                          studies that EPA used to arrive at these
                          conclusions. Throughout this writeup,
                          EPA uses  'weight of evidence,'
                          'causality,' and  'hazard' as follows:
                           • A 'weight of evidence' evaluation is
                          a collective evaluation of all pertinent
                          information. Judgement about the
 weight of evidence involves
 considerations of the quality and
 adequacy of data and consistency of
 responses. These factors are not scored
 mechanically by adding pluses and
 minuses; they are judged in
 combination.
   •  Criteria for determining 'causality'
 include consistency, strength, and
 specificity of association, a temporal
 relationship, a biological gradient (dose-
 response relationship), biological
 plausibility, coherence with multiple
 lines of evidence, evidence from human
 populations, and information on agent's
 structural analogues (USEPA 20051).
 Additional considerations for individual
 study findings include reliable exposure
 data, statistical power and significance,
 and freedom from bias and
 confounding.
   •  The term 'hazard' describes not a
 definitive-conclusion, but the possibility
 that a health effect may be attributed to
 a certain exposure, in this case
 chlorinated water. Analyses done for the
 Stage 2 DBPR follow the 1999 EPA
 Proposed  Guidelines for Carcinogenic
 Risk Assessment (USEPA 1999a). In
 March 2005, EPA updated and finalized
 the Cancer Guidelines and a
 Supplementary Children's Guidance,
 which include new considerations on
 mode of action for cancer risk
 determination and additional potential
 risks due to early childhood exposure
 (USEPA 2005i; USEPA 2005J).
 Conducting the cancer evaluation using
 the 2005 Cancer Guidelines would not
 result in any change from the existing
 analysis. With the exception of
 chloroform, no mode of action has been
 established for other specific regulated
 DBFs. Although some of the DBFs have
 given mixed mutagenicity and
 genotoxicity results, having a positive
 mutagenicity study does not necessarily
 mean that a chemical has a mutagenic
 mode of action. The extra factor of
 safety for children's health protection
 does not apply because the new
 Supplementary Children's Guidance
 requires application of the children's
 factor only when a mutagenic mode of
 action has been identified.
  a. Cancer health effects. The following
 section briefly discusses cancer
 epidemiology and toxicology
 information EPA analyzed and  some
 conclusions of these studies and reports.
Further discussion of these studies and
EPA's conclusions can be found in the
proposed Stage 2 DBPR (USEPA 2003a)
and the Economic Analysis for the Final
 Stage 2 Disinfectants and Disinfection
Byproducts Rule (Economic Analysis
 (EA)) (USEPA 2005a).
  Human epidemiology studies and
animal toxicology studies have

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examined associations between
chlorinated drinking water or DBFs and
cancer. While EPA cannot conclude
there is a causal link between exposure
to chlorinated surface water and cancer,
EPA believes that the available research
indicates a potential association
between bladder cancer and exposure to
chlorinated drinking water or DBFs.
EPA also believes the available research
suggests a possible association between
rectal and colon cancers and exposure
to chlorinated drinking water or DBFs.
This is based on EPA's evaluation of all
available cancer studies. The next two
sections focus on studies published
since the Stage 1 DBPR. Conclusions are
based on the research as a whole.
  i. Epidemiology. A number of
epidemiological studies have been
conducted to investigate the
relationship between exposure to
chlorinated drinking water and  various
cancers. These studies contribute to the
overall evidence on potential human
health hazards from exposure to
chlorinated drinking water.
  Epidemiology studies provide useful
health effects information because they
reflect human exposure to a drinking
water DBF mixture through multiple
routes of intake such as ingestion,
inhalation and dermal absorption. The
greatest difficulty with conducting
cancer epidemiology studies is the
length of time between exposure and
effect. Higher quality studies have
adequately controlled for confounding
and have limited the potential for
exposure misclassification, for example,
using DBF levels in drinking water as
the exposure metric as opposed to type
of source water. Study design
considerations for interpreting cancer
epidemiology data include sufficient
follow-up time to detect disease
occurrence, adequate sample  size, valid
                         ascertainment of cause of the cancer,
                         and reduction of potential selection bias
                         in case-control and cohort studies (by
                         having comparable cases and controls
                         and by limiting loss to follow-up).
                         Epidemiology studies provide extremely
                         useful information on human exposure
                         to chlorinated water, which
                         complement single chemical, high dose
                         animal data.
                           In the Stage 1 DBPR, EPA concluded
                         that the epidemiological evidence
                         suggested a potential increased risk for
                         bladder cancer. Some key studies EPA
                         considered for Stage 1 include Cantor et
                         al. (1998), Doyle et al. (1997), Freedman
                         et al. (1997), King and Marrett (1996),
                         McGeehin et al. (1993), Cantor et al.
                         (1987), and Cantor et al. (1985). Several
                         studies published since the Stage 1
                         DBPR continue to support an
                         association between increased risk of
                         bladder cancer and exposure to
                         chlorinated surface water (Chevrier et
                         al. 2004; Koivusalo et al. 1998; Yang et
                         al. 1998). One study found no effects on
                         a biomarker of genotoxicity in urinary
                         bladder cells from TTHM exposure
                         (Ranmuthugala et al. 2003).
                         Epidemiological reviews and meta-
                         analyses generally support the
                         possibility of an association between
                         chlorinated water or THMs and bladder
                         cancer (Villanueva et al. 2004;
                         Villanueva et al. 2003; Villanueva et al.
                         2001; Mills et  al. 1998). The  World
                         Health Organization (WHO 2000) found
                         data inconclusive or insufficient  to
                         determine causality between
                         chlorinated water and any health
                         endpoint, although they concluded that
                         the evidence is better for bladder cancer
                         than for other  cancers.
                           In the Stage 1 DBPR, EPA concluded
                         that early studies suggested a small
                         possible increase in rectal and colon
                         cancers from exposure to chlorinated
                                                   surface waters. The database of studies
                                                   on colon and rectal cancers continues to
                                                   support a possible association, but
                                                   evidence remains mixed. For colon
                                                   cancer, one newer study supports the
                                                   evidence of an association (King et al.
                                                   2000a) while others showed
                                                   inconsistent findings (Hildesheim et al.
                                                   1998; Yang et al. 1998). Rectal cancer
                                                   studies are also mixed. Hildesheim et al.
                                                   (1998) and Yang et al. (1998) support an
                                                   association with rectal cancer while
                                                   King et al. (2000a) did not. A review of
                                                   colon and rectal cancer concluded
                                                   evidence was inconclusive but that
                                                   there was a stronger association for
                                                   rectal cancer and chlorination DBFs
                                                   than for colon cancer (Mills  et al. 1998).
                                                   The WHO (2000) review reported that
                                                   studies showed weak to moderate
                                                   associations with colon and rectal
                                                   cancers and chlorinated surface water or
                                                   THMs but that evidence is inadequate to
                                                   evaluate these associations.
                                                     Recent studies on kidney, brain, and
                                                   lung cancers and DBF exposure support
                                                   a possible association (kidney: Yang et
                                                   al. 1998, Koivusalo et al. 1998; brain:
                                                   Cantor et al. 1999; lung: Yang et al.
                                                   1998). However, so few studies have
                                                   examined these endpoints that
                                                   definitive conclusions cannot be made.
                                                   Studies on leukemia found little or no
                                                   association with DBFs (Infante-Rivard et
                                                   al. 2002; Infante-Rivard et al. 2001). A
                                                   recent study did not find an association
                                                   between pancreatic cancer and DBFs
                                                   (Do  et al. 2005). A study researching
                                                   multiple cancer endpoints found an
                                                   association between THM exposure and
                                                   all cancers when grouped together
                                                   (Vinceti et al. 2004). More details on the
                                                   cancer epidemiology studies since the
                                                   Stage 1 DBPR are outlined in Table II.D-
                                                   1.
             TABLE II.D-1.—SUMMARY OF CANCER EPIDEMIOLOGY STUDIES REVIEWED FOR STAGE 2 DBPR
                Study type
                  Exposure(s) studied
                           Outcome(s)
                            measured
                                   Findings
   Author(s)
Do et al. 2005
Chevrier et al.
  2004..
Case-control
  study in
  Canada,
  1994-1997.
Case-control
  study in
  France,
  1985-1987.
Estimated chlorinated DBPs,
  chloroform, BDCM con-
  centrations.

Compared THM levels, dura-
  tion of exposure, and 3
  types of water treatment
  (ozonation, chlorination,
  ozonation/chlorination).
Pancreatic can-
  cer.
                                                      Bladder cancer
No association was found between pancreatic cancer and
  exposure to chlorinated DBPs, chloroform, or BDCM.
               A statistically significant decreased risk of bladder cancer
                 was found as duration of exposure to ozonated water in-
                 creased. This was evident with and without adjustment
                 for other  exposure measures. A small association was
                 detected for increased bladder cancer risk and duration
                 of exposure to chlorinated surface water and with the es-
                 timated THM content of the water,  achieving statistical
                 significance only when adjusted for duration of ozonated
                 water exposures.  Effect  modification by gender was
                 noted in the adjusted analyses.

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        TABLE II.D-1.—SUMMARY OF CANCER EPIDEMIOLOGY STUDIES REVIEWED FOR STAGE 2 DBPR—Continued
                  Study type
                     Exposure(s) studied
                               Outcome(s)
                                measured
                                       Findings
 Vinceti et al.
   2004.
 Ranmuthugala
   et al. 2003.
 Infante-Rivard
  et al 2002.
 Infante-Rivard
   et al. 2001.
 King et al.
  2000a.
Cantor et al
  1999.
Cantor et al.
  1998.
Hildesheim et
  al. 1998.
Koivusalo et
  al  1998.
 Retrospective
   cohort study
   in Italy,
   1987-1999.
 Cohort study
   in 3 Aus-
   tralian com-
   munities,
   1997.
 Population-
   based case-
   control study
   in Quebec,
   1980-1993.
 Population-
   based case-
   control study
   in Quebec,
   1980-1993
 Population-
   based case-
   control study
   in southern
   Ontario,
   1992-1994

 Population-
   based case-
   control study
   in Iowa,
   1984-1987.
 Population-
   based case-
   control study
   in Iowa,
   1986-1989.
 Population-
   based case-
   control study
   in Iowa,
   1986-1989.
 Population-
   based case-
   control study
   in Finland,
   1991-1992
Standardized mortality ratios
  from all causes vs. cancer
  for consumers drinking
  water with high THMs
Estimated dose of TTHM,
  chloroform, and bromoform
  from routinely-collected
  THM measurements and
  fluid intake diary.
Estimated prenatal and post-
  natal exposure to THMs
  and polymorphisms in two
  genes.

Compared water chlormation
  (never, sometimes, always)
  and exposure to TTHMs,
  metals, and nitrates.
Compared source of drinking
  water and chlormation sta-
  tus. Estimated TTHM lev-
  els, duration of exposure,
  and tap water consumption
Compared level and duration
  of THM exposure (cumu-
  lative and average), source
  of water, chlorination, and
  water consumption.
Compared level and duration
  of THM exposure (cumu-
  lative and average), source
  of water, chlorination, and
  water consumption.
Compared level and duration
  of THM exposure (cumu-
  lative and average), source
  of water, chlorination, and
  water consumption.
Estimated residential duration
  of exposure and level of
  drinking water mutagenicity.
 15 cancers in-
  cluding colon,
  rectum, and
  bladder
Frequency of
  micronuclei in
  urinary blad-
  der epithelial
  cells.
Acute
  lymphoblastic
  leukemia.
Acute
  lymphoblastic
  leukemia.
Colon and rec-
  tal cancer.
Brain cancer ....
Bladder cancer
Colon and rec-
  tal cancer.
Bladder and
  kidney cancer.
 Mortality ratio from all cancers showed a statistically signifi-
  cant small increase for males consuming drinking water
  with high THMs. For females, an increased mortality ratio
  for all cancers was seen but was not statistically signifi-
  cant.  Stomach  cancer in  men  was the only individual
  cancer in which a statistically significant excess in mor-
  tality was detected for consumption of drinking water with
  high THMs.
 Relative risk estimates for DNA damage to bladder cells for
  THM dose metrics were  near 1.0. The study provides no
  evidence that THMs are  associated with DNA damage to
  bladder epithelial cells, and dose-response patterns were
  not detected.
 Data are suggestive, but  imprecise,  linking DNA variants
  with risk of acute  lymphoblastic leukemia associated with
  drinking water DBPs. The number of genotyped subjects
  for GSTT1 and  CYP2E1  genes was too small to be con-
  clusive.
 No increased risk  for lymphoblastic leukemia was observed
  for prenatal  exposure  at average levels of TTHMs, met-
  als or nitrates  However,  a non-statistically significant,
  small  increased risk was seen for postnatal cumulative
  exposure to TTHMs and chloroform (both at above the
  95th exposure percentile of the distribution for cases and
  controls), for zinc, cadmium, and  arsenic, but not other
  metals or nitrates.
 Colon cancer  risk was statistically associated with cumu-
  lative  long term exposure  to THMs, chlorinated surface
  water, and tap water consumption metrics among males
  only. Exposure-response relationships were  evident  for
  exposure measures combining duration and  THM levels.
  Associations between the exposure measures and rectal
  cancer were not observed for either gender.
 Among males,  a  statistically significant increased risk of
  brain  cancer was detected for duration  of  chlorinated
  versus non-chlorinated source  water, especially among
  high-level  consumers of  tap water. An increased risk of
  brain cancer for  high water intake level  was  found in
  men. No associations  were found for women for any of
  the exposure metrics examined.
 A statistically significant positive  association between risk
  of bladder cancer  and exposure to chlorinated ground-
  water or surface water reported for men and for smokers,
  but no association found for male/female non-smokers,
  or for women overall. Limited evidence was found for an
  association between tapwater consumption and bladder
  cancer risk. Suggestive evidence existed for exposure-re-
  sponse effects  of chlorinated  water  and lifetime THM
  measures on bladder cancer risk.
 Increased risks of rectal  cancer was associated with dura-
  tion of exposure  to chlorinated surface water and any
  chlorinated water, with  evidence  of  an exposure-re-
  sponse relationship Risk of rectal cancer is  statistically
  significant increased with >60 years lifetime exposure to
  THMs in drinking water, and risk increased for individuals
  with low dietary fiber  intake. Risks were similar for men
  and women  and no effects were observed for tapwater
  measures. No associations were detected for water ex-
  posure measures and risk of colon cancer.
Drinking water mutagenicity was  associated with  a small,
  statistically significant,  exposure-related  excess risk for
  kidney and bladder cancers among men;  weaker asso-
  ciations were detected for mutagenic water and bladder
  or kidney cancer among women. The effect of  mutage-
  nicity on bladder cancer was modified by smoking status,
  with an increased risk among non-smokers.

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                                                                                                             397
       TABLE II.D-1.—SUMMARY OF CANCER EPIDEMIOLOGY STUDIES REVIEWED FOR STAGE 2 DBPR—Continued
                  Study type
                    Exposure(s) studied
                               Outcome(s)
                               measured
                                       Findings
Yang et al.
  1998.
Doyle et al
  1997.
Freedman et
  al. 1997.
King and
  Marrett 1996.
McGeehin et
  al. 1993.
Cantor et al.
  1987 (and
  Cantor et al.
  1985).
 Reviews/Meta-
   analyses
 Villanueva et
  al. 2004.
Villanueva et
  al. 2003
  (and Goebell
  et al. 2004).
Cross-sec-
  tional study
  in Taiwan,
  1982-1991.
Prospective
  cohort study
  in Iowa,
  1987-1993.
Population-
  based case-
  control study
  in Maryland,
  1975-1992.
Case-control
  study in On-
  tario, Can-
  ada, 1992-
  1994.
Population-
  based case-
  control study
  in Colorado,
  1990-1991.
Population-
  based case-
  control study
  in 10 areas
  of the U.S ,
  1977-1978.
Review and
  meta-anal-
  ysis of 6
  case-control
  studies.

Review and
  meta-anal-
  ysis of 6
  case-control
  studies and
  2 cohort
  studies.
Examined residence in
  chlorinated (mainly surface
  water sources) relative to
  non-chlorinated (mainly pri-
  vate well) water.
Examined chloroform levels
  and source of drinking
  water.
Estimated duration of expo-
  sure to chlorinated water.
  Compared exposure to
  chlorinated municipal water
  (yes/no)
Compared source of drinking
  water and chlormation sta-
  tus. Estimated TTHM lev-
  els, duration of exposure,
  and tap water consumption.
Compared source of drinking
  water, water treatment, and
  tap water versus bottled
  water. Estimated duration
  of exposure to TTHMs and
  levels of TTHMs, nitrates,
  and residual chlorine.
Compared source of drinking
  water. Estimated total bev-
  erage and tap water con-
  sumption and duration of
  exposure.
Individual-based exposure
  estimates to THMs and
  water consumption over a
  40-year period.
Compared source of water
  and estimated duration of
  exposure to chlorinated
  drinking water.
Cancer of rec-
  tum, lung,
  bladder, kid-
  ney, colon,
  and 11 others.
Colon, rectum,
  bladder, and
  8 other can-
  cers in
  women.
                                                            Bladder cancer
                                                            Bladder cancer
                                                            Bladder cancer
                                                            Bladder cancer
                                            Bladder cancer
                                                            Bladder cancer
Residence   in   chlorinating   municipalities   (vs.  non-
  chlorinating) was statistically significantly associated with
  the following types of cancer in both males and females:
  rectal,  lung, bladder, and kidney cancer.  Liver cancer
  and all cancers  were also  statistically  significantly ele-
  vated  in chlorinated towns for males only.  Mortality rates
  for cancers of the esophagus, stomach,  colon, pancreas,
  prostate, brain, breast, cervix uteri and uterus, and  ovary
  were comparable for chlorinated and non-chlorinated res-
  idence.
Statistically  significant  increased  risk  of colon  cancer,
  breast  cancer and all cancers  combined was observed
  for women exposed to chloroform in drinking  water, with
  evidence of exposure-response effects.  No associations
  were detected between chloroform and  bladder, rectum,
  kidney,  upper  digestive organs,  lung,  ovary,  endo-
  metrium,  or breast cancers, or for melanomas  or non-
  Hodgkin's  lymphoma. Surface water exposure (compared
  to ground  water users) was  also a significant predictor of
  colon and  breast cancer risk.
There was a weak association between bladder cancer risk
  and duration of exposure to  municipal water for male cig-
  arette smokers, as well  as  an exposure-response rela-
  tionship. No association was seen for those with no his-
  tory of smoking,  suggesting that  smoking  may modify a
  possible effect of chlorinated surface water on the risk of
  bladder cancer.
Statistically significant associations were detected for blad-
  der cancer and  chlorinated surface  water, duration  or
  concentration  of THM levels and  tap water consumption
  metrics. Population attributable risks  were estimated  at
  14 to 16 percent. An exposure-response relationship was
  observed  for estimated duration of high THM  exposures
  and risk of bladder cancer.
Statistically significant associations were detected for blad-
  der cancer and  duration of  exposure to chlorinated sur-
  face water. The  risk  was similar  for males and females
  and among nonsmokers  and smokers.  The  attributable
  risk was estimated at 14.9 percent. High tap water intake
  was associated with  risk of bladder cancer  in a  expo-
  sure-response  fashion. No  associations were detected
  between bladder cancer and levels  of TTHMs; nitrates,
  and residual chlorine.
Bladder cancer was statistically associated with duration of
  exposure  to chlorinated  surface  water  for women and
  nonsmokers of both sexes.  The largest  risks were seen
  when  both exposure  duration and level  of tap water in-
  gestion were combined.  No association  was seen for
  total beverage consumption.
                 The meta-analysis suggests that risk of bladder cancer in
                   men  increases with  long-term exposure to TTHMs. An
                   exposure-response  pattern was observed  among men
                   exposed to TTHMs, with  statistically significant risk seen
                   at exposures  higher than 50  ug/L. No association be-
                   tween TTHMs and bladder cancer was seen for women.
                 The meta-analysis findings showed a moderate excess risk
                   of bladder cancer attributable  to long-term  consumption
                   of chlorinated drinking water for  both  genders, particu-
                   larly in men. Statistically significance seen with men and
                   combined both sexes. The risk was  higher when expo-
                   sure exceeded 40 years.

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      TABLE 11. D-1.—SUMMARY OF CANCER EPIDEMIOLOGY STUDIES REVIEWED FOR STAGE 2 DBPR—Continued

Villanueva et
al. 2001.






WHO 2000 . ..









Mills et al.
1998.




Study type
Qualitative re-
view of 31
cancer stud-
ies




Qualitative re-
- views of var-
ious studies
in Finland,
U.S., and
Canada




Qualitative re-
view of 22
studies.



Exposure(s) studied
Compared exposure to TTHM
levels, mutagenic drinking
water, water consumption,
source water, types of dis-
infection (chlorination and
chloramination), and resi-
dence times.

Various exposures to THMs.









Examined TTHM levels and
water consumption. Com-
pared source of water and
2 types of water treatment
(chlorination and
chloramination).
Outcome(s)
measured
Cancer of blad-
der, colon,
rectum, and 5
other can-
cers..



Various cancers









Cancer of
colon, rec-
tum, and
bladder.


Findings
Review found that although results for cancer studies var-
ied and were not always statistically significant, evidence
for bladder cancer is strongest, and all 1 0 of the bladder
cancer studies showed increased cancer risks with in-
gestion of chlorinated water. The authors felt associa-
tions with chlorinated water and cancer of the colon, rec-
tum, pancreas, esophagus, brain, and other cancers
were inconsistent.
Studies reviewed reported weak to moderate increased rel-
ative risks of bladder, colon, rectal, pancreatic, breast,
brain or lung cancer associated with long-term exposure
to chlorinated drinking water. The authors felt evidence is
inconclusive for an association between colon cancer
and long-term exposure to THMs; that evidence is insuffi-
cient to evaluate a causal relationship between THMs
and rectal, bladder, and other cancers. They found no
association between THMs and increased risk of cardio-
vascular disease.
Review suggests possible increases in risks of bladder
cancer with exposure to chlorinated drinking water. The
authors felt evidence for increased risk of colon and rec-
tal cancers is inconclusive, though evidence is stronger
for rectal cancer.

  Overall, bladder cancer data provide
the strongest basis for quantifying
cancer risks from DBFs. EPA has chosen
this endpoint to estimate the primary
benefits of the Stage 2 DBPR (see
Section VI).
  ii. Toxicology. Cancer toxicology
studies provide additional support that
chlorinated water is associated with
cancer. In general, EPA uses long term
toxicology studies that show a dose
response to derive MCLGs and cancer
potency factors. Short term studies are
used for hazard identification and to
design long term studies. Much of the
available cancer toxicology information
was available for the Stage 1 DBPR, but
there have also been a number of new
                         cancer toxicology and mode of action
                         studies completed since the Stage 1
                         DBPR was finalized in December 1998.
                           In support of this rule, EPA has
                         developed health criteria documents
                         which summarize the available
                         toxicology data for brominated THMs
                         (USEPA 2005b), brominated HAAs
                         (USEPA 2005c), MX (USEPA 2000b),
                         MCAA (USEPA 2005d), and TCAA
                         (USEPA 2005e). The 2003 IRIS
                         assessment of DCAA (USEPA 2003b)
                         and an addendum (USEPA 2005k) also
                         provides analysis released after Stage 1.
                         It summarizes information on exposure
                         from drinking water and develops a
                         slope factor for DCAA. IRIS also has
                         toxicological reviews for chloroform
(USEPA 2001a), chlorine dioxide and
chlorite (USEPA 2000c), and bromate
(USEPA 2001b), and is currently
reassessing TCAA.
  Slope factors and risk concentrations
for BDCM, bromoform, DBCM and
DCAA have been developed and are
listed in Table II.D-2. For BDCM,
bromoform, and DBCM, table values are
derived from the brominated THM
criteria document (USEPA 2005b),
which uses IRIS numbers that have been
updated using the 1999 EPA Proposed
Guidelines for Carcinogenic Risk
Assessment (USEPA 1999a). For DCAA,
the values are derived directly from
IRIS.
                                 TABLE II.D-2.—QUANTIFICATION OF CANCER RISK
Disinfection byproduct
Bromodichlorometha
Bromoform 	
Dibromochlorometha
Dichloroacetic Acid
ne ....

ne 	


LED,,,-'
Slope
factor
(mg/kg/day) - '
0.034
0.0045
0.04
0.048
10 6 Risk
concentration
(mg/L)
0.001
0.008
0.0009
0.0007
ED,,,-'
Slope
factor
(mg/kg/day) - '
0.022
0.0034
0.017
0.015"1
10 6 Risk
concentration
(mg/L)
0.002
0.01
0.002
0.0023"
  aLED,o is the lower 95% confidence bound on the (effective dose) EDlo value ED,,, is the estimated dose producing effects in 10% of ani-
mals.
  bThe ED,,, risk factors for DCAA have been changed from those given in the comparable table in the proposed Stage 2 DBPR to correct for
transcriptional errors.
  More research on DBFs is underway
at EPA and other research institutions.
Summaries of on-going studies may be
found on EPA's DRINK Web site (http://
                         www. epa.go v/safe water/drink/
                         intro.html). Two-year bioassays by the
                         National Toxicology Program (NTP)
                         released in abstract form have recently
been completed on BDCM and chlorate.
The draft abstract on BDCM reported no
evidence of carcinogenicity when
BDCM was administered via drinking

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             Federal  Register/Vol.  71, No. 2/Wednesday, January 4, 2006/Rules and Regulations
                                                                        399
water (NTP 2005a). Another recent
study, a modified two-year bioassay on
BDCM in the drinking water, reported
little evidence of carcinogenicity
(George et al. 2002). In a previous NTP
study, tumors were observed, including
an increased incidence of kidney, liver,
and colon tumors, when BDCM was
administered at higher doses by  gavage
in corn oil (NTP 1987). EPA will
examine new information on BDCM as
it becomes available. In the chlorate
draft abstract, NTP found  some evidence
that it may be a carcinogen (NTP 2004).
Chlorate is a byproduct of hypochlorite
and chlorine dioxide systems. A long-
term, two-year bioassay NTP study on
DBA is also complete but  has not yet
undergone peer review (NTP 2005b).
  b. Reproductive and developmental
health effects. Both human
epidemiology studies and animal
toxicology studies have examined
associations between chlorinated
drinking water or DBFs and
reproductive and developmental health
effects. Based on an evaluation of the
available science, EPA believes the data
suggest that exposure to DBFs is a
potential reproductive and
developmental health hazard.
  The following section briefly
discusses the reproductive and
developmental epidemiology and
toxicology information available to EPA.
Further discussion of these studies and
EPA's conclusions can be found in the
proposed Stage 2 DBPR (USEPA 2003a)
and the Economic Analysis (USEPA
2005a).
  i. Epidemiology. As discussed
previously, epidemiology studies have
the strength  of relating human exposure
to DBF mixtures through multiple
intake routes. Although the critical
exposure window for reproductive and
developmental effects is much smaller
than that for cancer (generally weeks
versus years), exposure assessment is
also a main limitation of reproductive
and developmental epidemiology
studies. Exposure assessment
uncertainties arise from limited  data on
DBF concentrations and maternal water
usage and source over the course of the
pregnancy. However, classification
errors typically push the true risk
estimate towards the null value  (Vineis
2004). According to Bove et al. (2002),
"Difficulties in assessing exposure may
result in exposure misclassification
biases that would most likely produce
substantial underestimates of risk  as
well as distorted or attenuated
exposure-response trends." Studies of
rare outcomes (e.g., individual birth
defects) often have limited statistical
power because of the small number of
cases being examined. This limits  the
ability to detect statistically significant
associations for small to moderate
relative risk estimates. Small sample
sizes also result in imprecision around
risk estimates reflected by wide
confidence intervals. In addition to the
limitations of individual studies,
evaluating reproductive and
developmental epidemiology studies
collectively is difficult because of the
methodological differences between
studies and the wide variety of
endpoints examined. These factors may
contribute to inconsistencies in the
scientific body of literature as noted
below.
  More recent studies tend to be of
higher quality because of improved
exposure assessments and other
methodological advancements. For
example, studies that use THM levels to
estimate exposure tend to be higher
quality than studies that define
exposure by source or treatment. These
factors were taken into account by EPA
when comparing and making
conclusions on the reproductive and
developmental epidemiology literature.
What follows is a summary of available
epidemiology literature on reproductive
and developmental endpoints such as
spontaneous abortion, stillbirth, neural
tube and other birth defects, low birth
weight, and intrauterine growth
retardation. Information is grouped,
where appropriate, into three categories
on fetal growth, viability, and
malformations, and reviews are
described separately afterward. Table
II.D—3 provides a more detailed
description of each study or review.
  Fetal growth. Many studies looked for
an association between fetal growth
(mainly small for gestational age,  low
birth weight, and pre-term delivery) and
chlorinated water or DBFs. The results
from the collection of studies as a whole
are inconsistent. A number of studies
support the possibility that exposure to
chlorinated water or DBFs are
associated with adverse fetal growth
effects (Infante-Rivard 2004; Wright et
al. 2004; Wright et al. 2003; Kallen and
Robert 2000; Gallagher et al. 1998;
Kanitz et al. 1996; Bove et al. 1995;
Kramer et al. 1992). Other studies
showed mixed results  (Porter et al.
2005; Savitz et al. 2005; Yang 2004) or
did not provide evidence of an
association (Toledano et al.  2005;
Jaakkola et al. 2001; Dodds et al. 1999;
Savitz et al. 1995) between DBF
exposure and fetal growth. EPA notes
that recent, higher quality studies
provide some evidence of an increased
risk of small for gestational age and low
birth weight.
  Fetal viability. While the database of
epidemiology studies for fetal loss
endpoints (spontaneous abortion or
stillbirth) remains inconsistent as a
whole, there is suggestive evidence of
an association between fetal loss and
chlorinated water or DBF exposure.
Various studies support the possibility
that exposure to chlorinated water or
DBFs is associated with decreased fetal
viability (Toledano et al. 2005; Dodds et
al. 2004; King et al. 2000b; Dodds et al.
1999; Waller et al. 1998; Aschengrau et
al. 1993; Aschengrau et al.  1989). Other
studies did not support an association
(Bove et al. 1995) or reported
inconclusive results (Savitz et al. 2005;
Swan et al. 1998; Savitz et  al. 1995)
between fetal viability and exposure to
THMs or tapwater. A recent study by
King et al. (2005) found little evidence
of an association between stillbirths and
haloacetic acids after controlling for
trihalomethane  exposures, though non-
statistically significant increases in
stillbirths were seen across various
exposure levels.
  Fetal malformations. A number of
epidemiology studies have examined
the relationship between fetal
malformations (such as neural tube, oral
cleft, cardiac, or urinary defects, and
chromosomal abnormalities) and
chlorinated water or DBFs. It is difficult
to assess fetal malformations in
aggregate due to inconsistent findings
and disparate endpoints being examined
in the available studies. Some studies
support the possibility that exposure to
chlorinated water or DBFs is associated
with various fetal malformations
(Cedergren et al. 2002; Hwang et al.
2002; Dodds and King 2001; Klotz and
Pyrch 1999; Bove et al. 1995;
Aschengrau et al. 1993). Other studies
found little evidence (Shaw et al. 2003;
Kallen and Robert 2000; Dodds et al.
1999; Shaw et al. 1991) or inconclusive
results (Magnus et al. 1999) between
chlorinated water or DBF exposure and
fetal malformations. Birth defects most
consistently identified as being
associated with DBFs include neural
tube defects and urinary tract
malformations.
  Other endpoints have also been
examined in recent epidemiology
studies. One study suggests an
association between DBFs and
decreased menstrual cycle length
(Windham et al. 2003), which, if
corroborated, could be linked  to the
biological basis of other reproductive
endpoints observed. No association
between THM exposure and semen
quality was found (Fenster et al. 2003).
More work is needed in both areas to
support these results.
  Reviews. An early review supported
an association between measures of fetal
viability and tap water (Swan et al.

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400
 Federal Register/Vol. 71, No. 2/Wednesday, January 4, 2006/Rules and Regulations
1992). Three other reviews found data
inadequate to support an association
between reproductive and
developmental health effects and THM
exposure (Reif et al. 1996; Craun 1998;
WHO 2000). Mills et al. (1998)
examined data on and found support for
an association between fetal viability
and malformations and THMs. Another
review presented to the Stage 2 MDBP
FACA found some evidence for an
association with fetal viability and some
fetal malformations and exposure to
DBFs but reported that the evidence was
inconsistent for these endpoints as well
as for fetal growth (Reif et al. 2000). Reif
                             et al. (2000) concluded that the weight
                             of evidence from epidemiology studies
                             suggests that "DBFs are likely to be
                             reproductive toxicants in humans under
                             appropriate exposure conditions," but
                             from a risk assessment perspective, data
                             are primarily at the hazard
                             identification stage. Nieuwenhuijsen et
                             al. (2000) found  some evidence for an
                             association between fetal growth and
                             THM exposure and concluded evidence
                             for associations with other fetal
                             endpoints is weak but gaining weight. A
                             qualitative review by Villanueva et al.
                             (2001) found evidence generally
                             supports a possible association between
                                               reproductive effects and drinking
                                               chlorinated water. Graves et al. (2001)
                                               supports a possible association for fetal
                                               growth but not fetal viability or
                                               malformations. More recently, Bove et
                                               al. (2002) examined and supported an
                                               association between small for
                                               gestational age, neural tube defects and
                                               spontaneous abortion endpoints and
                                               DBFs. Following a meta-analysis on five
                                               malformation studies, Hwang and
                                               Jaakkola (2003) concluded that there
                                               was evidence which supported
                                               associations between DBFs and risk of
                                               birth defects, especially neural tube
                                               defects and urinary tract defects.
                 TABLE  II.D-3.—SUMMARY OF REPRODUCTIVE/DEVELOPMENTAL EPIDEMIOLOGY STUDIES
  Author(s)
      Study type
  Exposure(s) studied
 Outcome(s) measured
                  Findings
Porter et al.
  2005.
Cross-sectional study in
  Maryland, 1998-2002.
Savitz et al.
  2005.
Population-based pro-
  spective cohort study
  in three communities
  around the U.S.,
  2000-2004.
Toledano et
  al. 2005.
Large cross-sectional
  study in England,
  1992-1998.
Dodds et al
  2004 (and
  King et al.
  2005).
Population-based case-
  control study in Nova
  Scotia and Eastern
  Ontario, 1999-2001.
Estimated THM and
  HAA exposure during
  pregnancy.
Estimated TTHM, HAA9,
  and TOC exposures
  during pregnancy. In-
  dices examined in-
  cluded concentration,
  ingested amount, ex-
  posure from show-
  ering and bathing,
  and an integration of
  all exposures com-
  bined.
Intrauterine growth re-
  tardation.
Early and late preg-
  nancy loss, preterm
  birth, small for gesta-
  tional age, and term
  birth weight.
Linked mother's resi-
  dence at time of deliv-
  ery to modeled esti-
  mates of TTHM levels
  in water zones.
Estimated THM and
  HAA exposure at resi-
  dence during preg-
  nancy. Linked water
  consumption and
  showering/bathing to
  THM exposure.
Stillbirth, low birth
  weight
Stillbirth
No consistent association or dose-response rela-
  tionship was found between exposure to either
  TTHM or HAAS and  intrautenne growth retar-
  dation. Results suggest  an increased risk of
  intrautenne growth retardation associated with
  TTHM  and HAAS exposure  in  the  third tri-
  mester, although only HAAS results were sta-
  tistically significant.
No association with  pregnancy loss was seen
  when looking at high exposure of TTHM com-
  pared to low exposure of TTHM. When exam-
  ining individual  THMs, a  statistically significant
  association     was     found      between
  bromodichloromethane   (BDCM)  and  preg-
  nancy loss. A  similar, non-statistically signifi-
  cant   association   was    seen    between
  dibromochloromethane   (DBCM)  and  preg-
  nancy loss. Some increased risk was  seen for
  losses at greater than 12 weeks' gestation for
  TTHM, BDCM,  and TOX  (total organic halide),
  but most results generally did not provide sup-
  port for an association Preterm birth showed
  a small  inverse relationship  with DBP  expo-
  sure  (i e. higher  exposures  showed  less
  preterm births), but this association was weak.
  TTHM exposure of 80  ug/L was  associated
  with twice the risk for small for gestational age
  during the third trimester and  was  statistically
  significant.
A significant association between TTHM and risk
  of stillbirth, low  birth weight, and very  low birth
  weight was observed  in  one of  the three re-
  gions. When all three regions were combined,
  small, but non-significant,  excess  risks were
  found between  all three  outcomes and TTHM
  and  chloroform No  associations  were ob-
  served between reproductive  risks and BDCM
  or total brominated THMs.
A  statistically significant association  was ob-
  served  between stillbirths  and  exposure  to
  total THM, BDCM, and  chloroform Associa-
  tions were also detected  for metrics, which in-
  corporated water consumption, showering and
  bathing habits. Elevated relative risks were ob-
  served  for intermediate  exposures for total
  HAA  and  DCAA  measures;  TCAA  and
  brominated HAA exposures showed no asso-
  ciation  No statistically significant associations
  or  dose-response relationships between any
  HAAs and stillbirth were detected after control-
  ling for THM exposure.

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  Federal Register/Vol.  71, No. 2/Wednesday, January 4, 2006/Rules and Regulations
401
TABLE II.D-3.—SUMMARY OF REPRODUCTIVE/DEVELOPMENTAL EPIDEMIOLOGY STUDIES—Continued
Author(s)
Infante-
Rivard
2004.






Wright et al.
2004.










Yang etal.
2004 (and
Yang et
al. 2000)

Fenster et
al. 2003.





Shaw et al.
2003.



Wmdham et
al. 2003.






Wright et al.
2003.







fpriprnrpn
et al. 2002.




Hwang et al.
2002.







Study type
Case-control study of
newborns in Montreal,
1998-2000.






Large cross-sectional
study. Massachusetts,
1995-1998.









Large cross-sectional
studies in Taiwan,
1994-1996.


Small prospective study
in California, 1990-
1991.




2 case-control maternal
interview studies: CA,
1987-1991.


Prospective study: CA,
1990-1991.






Cross-sectional study:
Massachusetts, 1990.







Retrospective case-con-
trol study: Sweden,
1982-1997.



Large cross-sectional
study in Norway,
1993-1998.






Exposure(s) studied
Estimated THM levels
and water consump-
tion during pregnancy.
Exposure from show-
ering and presence of
two genetic
polymorphisms.


Estimated maternal
third-trimester expo-
sures to TTHMs, chlo-
roform, BDCM, total
HAAs, DCA, TCA, MX
and mutagenicity in
drinking water.





Compared maternal
consumption of
chlorinated drinking
water (yes/no).

Examined TTHM levels
within the 90 days
preceding semen col-
lection.



Estimated THM levels
for mothers' resi-
dences from before
conception through
early pregnancy.
Estimated exposure to
THMs through show-
ering and ingestion
over average of 5.6
menstrual cycles per
woman.


Estimated TTHM expo-
sure in women during
pregnancy (average
for pregnancy and
during each trimester).




Examined maternal
periconceptional DBP
levels and used GIS
to assign water sup-
plies.

Compared exposure to
chlonnation (yes/no)
and water color levels
for mother's residence
during pregnancy.




Outcome(s) measured
Intrauterine growth re-
tardation.







Birth weight, small for
gestational age,
preterm delivery, ges-
tational age.








Low birth weight,
preterm delivery.



Sperm motihty, sperm
morphology.





Neural tube defects, oral
clefts, selected heart
defects.


Menstrual cycle, fol-
licular phase length
(in days)





Birth weight, small for
gestational age,
preterm delivery, ges-
tational age.





Cardiac defects





Birth defects (neural
tube defects, cardiac,
respiratory system,
oral cleft, urinary
tract).




Findings
No associations were found between exposure
to THMs and intrauterine growth retardation.
However, a significant effect was observed be-
tween THM exposure and intrauterine growth
retardation for newborns with the CYP2E1
gene variant. Findings suggest that exposure
to THMs at the highest levels can affect fetal
growth but only in genetically susceptible
newborns.
Statistically significant reductions in mean birth
weight were observed for BDCM, chloroform,
and mutagenic activity. An exposure-response
relationship was found between THM expo-
sure and reductions in mean birth weight and
risk of small for gestational age. There was no
association between preterm delivery and ele-
vated levels of HAAs, MX, or mutagenicity. A
reduced risk of preterm delivery was observed
with high THM exposures. Gestational age
was associated with exposure to THMs and
mutagenicity.
Residence in area supplied with chlorinated
drinking water showed a statistically significant
association with preterm delivery. No associa-
tion was seen between chlorinated drinking
water and low birth weight.
No association between TTHM level and sperm
mobility or morphology. BDCM was inversely
associated with linearity of sperm motion.
There was some suggestion that water con-
sumption and other ingestion metrics may be
associated with different indicators of semen
quality.
No associations or exposure-response relation
were observed between malformations and
TTHMs in either study.


Findings suggest that THM exposure may affect
ovarian function. All brominated THM com-
pounds were associated with significantly
shorter menstrual cycles with the strongest
finding for chlorodibromomethane. There was
little association between TTHM exposure and
luteal phase length, menses length, or cycle
variability.
Statistically significant associations between 2nd
trimester and pregnancy average TTHM expo-
sure and small for gestational age and fetal
birth weight were detected. Small, statistically
significant increases in gestational duration/
age were observed at increased TTHM levels,
but there was little evidence of an association
between TTHM and preterm delivery or low
birth weight.
Exposure to chlorine dioxide in drinking water
showed statistical significance for cardiac de-
fects. THM concentrations of 10 ug/L and
higher were significantly associated with car-
diac defects. No excess risk for cardiac defect
and nitrate were seen.
Risk of any birth defect, cardiac, respiratory sys-
tem, and urinary tract defects were signifi-
cantly associated with water chlorination. Ex-
posure to chlorinated drinking water was sta-
tistically significantly associated with risk of
ventricular septal defects, and an exposure-re-
sponse pattern was seen. No other specific
defects were associated with the exposures
that were examined.

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402
Federal Register/Vol. 71, No. 2/Wednesday, January 4, 2006/Rules and Regulations
         TABLE II.D-3.—SUMMARY OF REPRODUCTIVE/DEVELOPMENTAL EPIDEMIOLOGY STUDIES—Continued
Author(s)
Dodds and
King 2001 .





Jaakkola et
al. 2001.




Kallen and
Robert
2000.









Dodds et al
1999 (and
King et al.
2000b).








Klotz and
Pyrch
1999 (and
Klotz and
Pyrch
1998).
Magnus et
al. 1999.








Gallagher et
al. 1998.




Swan et al.
1998.


Study type
Population-based retro-
spective cohort in
Nova Scotia, 1 988-
1995.



Large cross-sectional
study in Norway,
1993-1995.



Large cross-sectional
cohort study in Swe-
den, 1985-1994.









Population-based retro-
spective cohort study
in Nova Scotia, 1 988-
1995.








Population -based case-
control study in New
Jersey, 1993-1994.



Large cross-sectional
study in Norway,
1993-1995.







Retrospective cohort
study of newborns in
Colorado, 1990-1993.



Prospective study in
California, 1990-1991.


Exposure(s) studied
Estimated THM, chloro-
form, and
bromodichloromethan-
e (BDCM) exposure.



Compared chlorination
(yes/no) and water
color (high/low) for
mother during preg-
nancy.

Linked prenatal expo-
sure to drinking water
disinfected with var-
ious methods (no
chlorine, chlorine di-
oxide only, sodium
hypochlonte only).





Estimated TTHM level
for women during
pregnancy.









Estimated exposure of
pregnant mothers to
TTHMs and HAAs,
and compared source
of water.

Compared chlorination
(yes/no) and water
color (high/low) at
mothers' residences
at time of birth.





Estimated THM levels in
drinking water during
third trimester of preg-
nancy.


Compared consumption
of cold tap water to
bottled water during
early pregnancy.
Outcome(s) measured
Neural tube defects,
cardiovascular de-
fects, cleft defects,
chromosomal abnor-
malities.


Low birth weight, small
for gestational age,
preterm delivery.



Gestational duration,
birth weight, intra-
uterme growth, mor-
tality, congenital mal-
formations, and other
birth outcomes.






Low birth weight,
preterm birth, small
for gestational age,
stillbirth, chromosomal
abnormalities, neural
tube defects, cleft de-
fects, major cardiac
defects.




Neural tube defects .. ..





Birth defects (neural
tube defects, major
cardiac, respiratory,
urinary, oral cleft).






Low birth weight, term
low birthweight, and
preterm delivery.



Spontaneous abortion ...



Findings
Exposure to BDCM was associated with in-
creased risk of neural tube defects, cardio-
vascular anomalies Chloroform was not asso-
ciated with neural tube defects, but was asso-
ciated with chromosomal abnormalities. No as-
sociation between THM and cleft defects were
detected.
No evidence found for association between pre-
natal exposure to chlorinated drinking water
and low birth weight or small for gestational
age. A reduced risk of preterm delivery was
noted for exposure to chlorinated water with
high color content.
A statistically significant difference was found for
short gestational duration and low birth weight
among infants whose mother resided in areas
using sodium hypochlonte, but not for chlorine
dioxide. Sodium hypochlorite was also associ-
ated with other indices of fetal development
but not with congenital defects. No other ef-
fects were observed for intrauterine growth,
childhood cancer, infant mortality, low Apgar
score, neonatal jaundice, or neonatal
hypothyroidism in relation to either disinfection
method.
A statistically significant increased risk for still-
births and high total THMs and specific THMs
during pregnancy was detected, with higher
risks observed among asphyxia-related still-
births Bromodichloromethane had the strong-
est association and exhibited an exposure-re-
sponse pattern. There was limited evidence of
an association between THM level and other
reproductive outcomes. No congenital anoma-
lies were associated with THM exposure, ex-
cept for a non-statistically significant associa-
tion with chromosomal abnormalities.
A significant association was seen between ex-
posure to THMs and neural tube defects No
associations were observed for neural tube
defects and haloacetic acids or
haloacetonitriles.

Statistically significant associations were seen
between urinary tract defects and chlorination
and high water color (high content of organic
compounds). No associations were detected
for other outcomes or all birth defects com-
bined. A non-statistically significant, overall ex-
cess risk of birth defects was seen within mu-
nicipalities with chlorination and high water
color compared to municipalities with no
chlorination and low color
Weak, non-statistically significant association
with low birth weight and TTHM exposure dur-
ing the third trimester. Large statistically sig-
nificant increase for term low birthweight at
highest THM exposure levels. No association
between preterm delivery and THM exposure.
Pregnant women who drank cold tap water com-
pared to those who consumed no cold tap
water showed a significant finding for sponta-
neous abortion at one of three sites.

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  Federal Register/Vol. 71, No. 2/Wednesday, January 4, 2006/Rules and Regulations
403
TABLE ll.D-3.—SUMMARY OF REPRODUCTIVE/DEVELOPMENTAL EPIDEMIOLOGY STUDIES—Continued
Author(s)
Waller et al.
1998 (and
Waller et
al. 2001).






Kanitz et al.
1996.






Bove et al.
1995 (and
Bove et
al. 1992a
& 1992b).



Savitz et al.
1995.











Aschengrau
etal. 1993.








Kramer et
al. 1992.








Shaw et al.
1991 (and
Shaw et
al. 1990).



Aschengrau
etal. 1989.

Study type
Prospective cohort in
California, 1989-1991.








Cross-sectional study in
Italy, 1988-1989.






Large cohort cross-sec-
tional study in New
Jersey, 1985-1988





Population-based case-
control study: North
Carolina, 1988-1991.










Case-control study in
Massachusetts, 1977-
1980.







Population-based case-
control study in Iowa,
1989-1990.







Small case-control
study: Santa Clara
County, CA, 1981-
1983.



Case-control study in
Massachusetts, 1976-
1978.
Exposure(s) studied
Estimated TTHM levels
during first trimester
of pregnancy via m-
gestion and show-
ering.





Compared 3 types of
water treatment (chlo-
rine dioxide, sodium
hypochlonte, and
chlorine dioxide/so-
dium hypochlorite).


Examined maternal ex-
posure to TTHM and
various other contami-
nants.




Examined TTHM con-
centration at resi-
dences and water
consumption (during
first and third tri-
mesters).







Source of water and 2
types of water treat-
ment (chlorination,
chloramination).






Examined chloroform,
DCBM, DBCM, and
bromoform levels and
compared type of
water source (surface,
shallow well, deep
well).



Estimated chlorinated
tap water consump-
tion, mean maternal
TTHM level, show-
ering/bathing expo-
sure at residence dur-
ing first trimester.
Source of water and ex-
posure to metals and
other contaminants.
Outcome(s) measured
Spontaneous abortion ...









Low birth weight, body
length, cranial circum-
ference, preterm de-
livery, and other ef-
fects.



Low birth weight, fetal
deaths, small for ges-
tational age, birth de-
fects (neural tube de-
fects, oral cleft, cen-
tral nervous system,
major cardiac)

Spontaneous abortion,
preterm delivery, low
birth weight.










Neonatal death, still-
birth, congenital
anomalies.







Low birth weight, pre-
maturity, intrauterine
growth retardation.







Congenital cardiac
anomalies.





Spontaneous abortion ...


Findings
Statistically significant increased risk between
high intake of TTHMs and spontaneous abor-
tion compared to low intake. BDCM statis-
tically associated with increased spontaneous
abortion; other THMs not. Reanalysis of expo-
sure yielded less exposure misclassification
and relative risks similar in magnitude to ear-
lier study. An exposure-response relationship
was seen between spontaneous abortion and
ingestion exposure to TTHMs.
Smaller body length and small cranial circum-
ference showed statistical significant associa-
tion with maternal exposure to chlorinated
drinking water. Neonatal jaundice linked statis-
tically to prenatal exposure to drinking water
treated with chlorine dioxide. Length of preg-
nancy, type of delivery, and birthweight
showed no association.
Weak, statistically significant increased rtsk
found for higher TTHM levels with small for
gestational age, neural tube defects, central
nervous system defects, oral cleft defects, and
major cardiac defects. Some association with
higher TTHM exposure and low birth weight.
No effect seen for preterm birth, very low birth
weight, or fetal deaths.
There was a statistically significant increased
miscarriage risk with high THM concentration,
but THM intake (based on concentration times
consumption level) was not related to preg-
nancy outcome. No associations were seen for
preterm delivery or low birth weight. Water
source was not related to pregnancy outcome
either, with the exception of a non-significant,
increased risk of spontaneous abortion for bot-
tled water users. There was a non-statistically
significant pattern of reduced risk with in-
creased consumption of water for all three out-
comes.
There was a non-significant, increased associa-
tion between frequency of stillbirths and mater-
nal exposure to chlorinated versus
chlorammated surface water. An increased risk
of urinary track and respiratory track defects
and chlorinated water was detected. Neonatal
death and other major malformations showed
no association. No increased risk seen for any
adverse pregnancy outcomes for surface
water versus ground and mixed water use.
Statistically significant increased risk for intra-
uterine growth retardation effects from chloro-
form exposure were observed. Non-significant
increased risks were observed for low birth
weight and chloroform and for intrauterine
growth retardation and DCBM. No intrauterine
growth retardation or low birth weight effects
were seen for the other THMs, and no effects
on prematurity were observed for any of the
THMs.
Following reanalysis, no association between
cardiac anomalies and TTHM level were ob-
served.




A statistically significantly association was de-
tected between surface water source and fre-
quency of spontaneous abortion.

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404
Federal Register/Vol. 71, No. 2/Wednesday,  January 4,  2006/Rules and Regulations
         TABLE II.D-3.—SUMMARY OF REPRODUCTIVE/DEVELOPMENTAL EPIDEMIOLOGY STUDIES—Continued
Author(s)
Reviews/
Meta-
analyses
Hwang and
Jakkola
2003.




Bove et al.
2002.






Graves et al.
2001.









Villanueva et
al. 2001.







Nieuwenhuij-
sen et al
2000.




Reif et al.
2000.








WHO 2000





Craun, ed
1998.






Study type



Review and meta-anal-
ysis of 5 studies.





Qualitative review of 1 4
studies.






Review of lexicological
and epidemiological
studies using a weight
of evidence approach.







Qualitative review of 14
reproductive and de-
velopmental health ef-
fect studies.





Qualitative review of nu-
merous toxicological
and epidemiological
studies.



Qualitative reviews of
numerous epidemio-
logical studies







Qualitative reviews of
various studies in Fin-
land, U S., and Can-
ada.


Qualitative review of 1 0
studies, focus on Cali-
fornia cohort study.





Exposure(s) studied



Compared DBP levels,
source of water, chlo-
rine residual, color
(high/low), and 2
types of disinfection.
chlorination and
chloramination.
Examined THM levels.
Compared drinking
water source and type
of water treatment.




Examined water con-
sumption, duration of
exposure, THM levels,
HAA levels, and other
contaminants. Com-
pared source of
water, water treat-
ment, water color
(high/low), etc.


Compared exposure to
TTHM levels, muta-
genic drinking water,
water consumption,
source water, types of
disinfection
(chlorination and
chloramination), and
residence times.
Examined levels of var-
ious DBPs, water con-
sumption, and dura-
tion of exposure.
Compared water
color, water treatment,
source of water, etc.
Compared source of
water supply and
methods of disinfec-
tion Estimated TTHM
levels.





Various exposures to
THMs.




Examined THM levels
and water consump-
tion, and compared
source of water and
water treatment (chlo-
rine, chloramines,
chlorine dioxide).

Outcome(s) measured



Birth defects (respiratory
system, urinary sys-
tem, neural tube de-
fects, cardiac, oral
cleft).


Birth defects, small for
gestational age, low
birth weight, preterm
delivery, spontaneous
abortion, fetal death.



Low birth weight,
preterm delivery,
small for gestational
age, intrauterine
growth retardation,
specific birth defects,
neonatal death, de-
creased fertility, fetal
resorption, and other
effects

Spontaneous abortion,
low birth weight, small
for gestational age,
neural tube defects,
other reproductive
and developmental
outcomes.


Low birth weight,
preterm delivery,
spontaneous abor-
tions, stillbirth, birth
defects, etc.


Birth weight, low birth
weight, intrauterine
growth retardation,
small for gestational
age, preterm deliver,
somatic parameters,
neonatal jaundice,
spontaneous abortion,
stillbirth, develop-
mental anomalies.
Various reproductive
and developmental ef-
fects.



Stillbirth, neonatal
death, spontaneous
abortion, low birth
weight, preterm deliv-
ery, intrauterine
growth retardation,
neonatal jaundice,
birth defects.
Findings



The meta-analysts supports an association be-
tween exposure to chlorination by-products
and the risk of any birth defect, particularly the
risk of neural tube defects and urinary system
defects.


Review found the studies of THMs and adverse
birth outcomes provide moderate evidence for
associations with small for gestational age,
neural tube defects, and spontaneous abor-
tions Authors felt risks may have been under-
estimated and exposure-response relation-
ships distorted due to exposure
misclassification
Weight of evidence suggested positive associa-
tion with DBP exposure for growth retardation
such as small for gestational age or intra-
uterine growth retardation and urinary tract de-
fects. Review found no support for DBP expo-
sure and low birth weight, preterm delivery,
some specific birth defects, and neonatal
death, and inconsistent findings for all birth de-
fects, all central nervous system defects, neu-
ral tube defects, spontaneous abortion, and
stillbirth.
Review found positive associations between in-
creased spontaneous abortion, low birth
weight, small for gestational age, and neural
tube defects and drinking chlorinated water in
most studies, although not always with statis-
tical significance.



The review supports some evidence of associa-
tion between THMs and low birth weight, but
inconclusive. Review found no evidence of as-
sociation between THMs and preterm delivery,
and that associations for other outcomes
(spontaneous abortions, stillbirth, and birth de-
fects) were weak but gaining weight.
Weight of evidence suggested DBPs are repro-
ductive toxicants in humans under appropriate
exposure conditions. The review reports find-
ings between TTHMs and effects on fetal
growth, fetal viability, and congenital anoma-
lies as inconsistent Reviewers felt data are at
the stage of hazard identification and did not
suggest a dose-response pattern of increasing
risk with increasing TTHM concentration.

Review found some support for an association
between increased risks of neural tube defects
and miscarriage and THM exposure. Other as-
sociations have been observed, but the au-
thors believed insufficient data exist to assess
any of these associations.
Associations between DBPs and various repro-
ductive effects were seen in some epidemio-
logical studies, but the authors felt these re-
sults do not provide convincing evidence for a
causal relationship between DBPs and repro-
ductive effects.



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                                                                      405
          TABLE II.D-3.—SUMMARY OF REPRODUCTIVE/DEVELOPMENTAL EPIDEMIOLOGY STUDIES—Continued
Author(s)
Mills et al.
1998.





Reif et al
1996.










Swan et al.
1992.








Study type
Qualitative review of 22
studies





Review of 3 case-con-
trol studies and 1
cross-sectional study.









Qualitative review of 5
studies in Santa Clara
County, CA (Deane et
al. 1992, Wrensch et
al. 1992, Hertz-
Picciotto et al. 1992,
Windham et al. 1992,
Fenster et al. 1992).


Exposure(s) studied
Examined TTHM levels
and water consump-
tion. Compared
source of water and 2
types of water treat-
ment (chlorination and
chloramination).
Examined THM levels at
residences, dose con-
sumption, chloroform.
Compared source of
waters and 2 types of
water treatment
(chlorination and
chloramination).




Compared maternal
consumption of resi-
dence tap water to
bottled water.






Outcome(s) measured
Various reproductive
and developmental ef-
fects.




Birth defects (central
nervous system, neu-
ral tube defects, car-
diac, oral cleft, res-
piratory, urinary tract),
spontaneous abortion,
low birth weight,
growth retardation,
preterm delivery,
intrauterine growth re-
tardation, stillbirth,
neonatal death.
Spontaneous abortion ...









Findings
Review found studies suggest possible increases
in adverse reproductive and developmental ef-
fects, such as increased spontaneous abortion
rates, small for gestational age, and fetal
anomalies, but that insufficient evidence exists
to establish a causal relationship.

Studies reviewed suggest that exposure to DBPs
may increase intrauterine growth retardation,
neural tube defects, major heart defects, and
oral cleft defects. Review found epidemiologic
evidence supporting associations between ex-
posure to DBPs and adverse pregnancy out-
comes to be sparse and to provide an inad-
equate basis to identify DBPs as a reproduc-
tive or developmental hazard.



Four of the studies reviewed suggest that
women drinking bottled water during the first
trimester of pregnancy may have reduced risk
of spontaneous abortion relative to drinking
tap water. No association seen in the fifth
study. Review concluded that if findings are
causal and not due to chance or bias, data
suggest a 10-50% increase in spontaneous
abortion risk for pregnant women drinking tap
water over bottled water
  ii. Toxicology. To date, the majority of
reproductive and developmental
toxicology studies have been short term
and higher dose. Many of these studies
are summarized in a review by Tyl
(2000). A summary of this review and of
additional studies is provided in the
proposed Stage 2 DBPR (USEPA 2003a).
Individual DBF supporting documents
evaluate and assess additional  studies as
well (USEPA 2000b; USEPA 2000c;
USEPA 2001a; USEPA 2001b; USEPA
2003b; USEPA 2005b; USEPA 2005c;
USEPA 2005d; USEPA 2005e; USEPA
2005k). A number of recent studies have
been published that include in vivo and
in vitro assays to  address mechanism of
action. Overall, reproductive and
developmental toxicology studies
indicate a possible reproductive/
developmental health hazard although
they are preliminary in nature  for the
majority of DBFs, and the dose-response
characteristics of most DBPs have not
been quantified. Some of the
reproductive effects of DCAA were
quantified as part of the RfD
development process, and impacts of
DCAA on testicular structure are one of
the critical effects in the study that is
the basis of the RfD (USEPA 2003b).
  A few long term, lower dose studies
have been completed. Christian et al.
(2002a and 2002b) looked for an
association between BDCM and DBAA
and reproductive and developmental
endpoints. The authors identified a
NOAEL and LOAEL of 50 ppm and 150
ppm, respectively, based on delayed
sexual maturation for BDCM and a
NOAEL and LOAEL of 50 ppm and 250
ppm based on abnormal
spermatogenesis for DBAA. The authors
concluded that similar effects in
humans would only be seen at levels
many orders of magnitude higher than
that of current drinking water levels. As
discussed in more detail in the
proposal, EPA believes that because of
key methodological differences
indicated as being important in other
studies (Bielmeier et al. 2001; Bielmeier
et al. 2004; Kaydos  et al. 2004;
Klinefelter et al. 2001; Klinefelter et al.
2004), definitive conclusions regarding
BDCM and DBAA cannot be drawn.
Other multi-generation research
underway includes a  study on BCAA,
but this research is  not yet published.
  Biological plausibility for the effects
observed in reproductive and
developmental epidemiological studies
has been demonstrated through various
toxicological studies on some individual
DBPs  (e.g., Bielmeier  et al. 2001;
Bielmeier et al. 2004; Narotsky et al.
1992; Chen et al. 2003; Chen et al.
2004). Some of these studies were
conducted at high doses, but similarity
of effects observed between toxicology
studies and epidemiology studies
strengthens the weight of evidence  for a
possible association between adverse
reproductive and developmental health
effects and exposure to chlorinated
surface water.
  c. Conclusions. EPA's weight of
evidence evaluation of the best available
science on carcinogenicity and
reproductive and developmental effects,
in conjunction with the widespread
exposure to DBPs, supports the
incremental regulatory changes in
today's rule that target lowering DBPs
and providing equitable public health
protection.
  EPA believes that the cancer
epidemiology and toxicology literature
provide important information that
contributes to the weight of evidence for
potential health risks from exposure to
chlorinated drinking water. At this time,
the cancer epidemiology studies support
a potential association between
exposure to chlorinated drinking water
and cancer, but evidence is insufficient
to establish a causal relationship. The
epidemiological evidence for an
association between DBF exposure and
colon and rectal cancers is not as
consistent as it is for bladder cancer,
although similarity of effects reported in
animal toxicity and human
epidemiology studies strengthens the
evidence for an association with colon
and rectal cancers. EPA believes that the
overall cancer epidemiology and
toxicology data support the decision to

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Federal  Register/Vol. 71, No.  2/Wednesday, January 4,  2006/Rules  and Regulations
 pursue additional DBF control measures
 as reflected in the Stage 2 DBPR.
   Based on the weight of evidence
 evaluation of the reproductive and
 developmental epidemiology data, EPA
 concludes that a causal link between
 adverse reproductive or developmental
 health effects and exposure to
 chlorinated drinking water or DBFs has
 not been established, but that there is a
 potential association. Despite
 inconsistent findings across studies,
 some recent studies continue to  suggest
 associations between DBF  exposure and
 various adverse reproductive and
 developmental effects. In addition, data
 from a number of toxicology  studies,
 although the majority  of them were
 conducted using high  doses,
 demonstrate biological plausibility for
 some of the effects observed in
 epidemiology studies. EPA concludes
 that no dose-response relationship or
 causal link has been established
 between exposure to chlorinated
 drinking water or disinfection
 byproducts and adverse developmental
 or reproductive health effects. EPA's
 evaluation of the best available studies,
 particularly epidemiology  studies is that
 they do not support a conclusion at this
 time as to whether exposure to
 chlorinated drinking water or
 disinfection byproducts causes adverse
 developmental and reproductive health
 effects, but do provide an indication of
 a potential health concern  that warrants
 incremental regulatory action beyond
 the Stage 1 DBPR.

 D. DBF Occurrence and DBF Control
   New information on the  occurrence of
 DBFs in distribution systems raises
 issues about the protection provided by
 the Stage 1 DBPR. This section presents
 new occurrence and treatment
 information used to identify key issues
 and to support the development  of the
 Stage 2 DBPR.  For a more detailed
 discussion see the proposed Stage 2
 DBPR (USEPA 2003a). For  additional
 information on occurrence of regulated
 and nonregulated DBFs, see the
 Occurrence Assessment for the Final
 Stage 2 Disinfectants and Disinfection
Byproducts Rule (USEPA 2005f).

 1.  Occurrence
  EPA, along with the  M-DBP Advisory
Committee, collected, developed, and
evaluated new information that became
available after the Stage 1 DBPR  was
published. The Information Collection
Rule (ICR) (USEPA 1996) provided new
field data on DBF exposure for large
water systems and new study data on
the effectiveness of several DBF control
technologies. The unprecedented
amount of information collected  under
                          the ICR was supplemented by a survey
                          conducted by the National Rural Water
                          Association, data provided by various
                          States, the Water Utility Database
                          (which contains data collected by the
                          American Water Works Association),
                          and ICR Supplemental Surveys for small
                          and medium water systems.
                            After analyzing the DBF occurrence
                          data, EPA and the Advisory Committee
                          reached three significant conclusions
                          that in part led the Advisory Committee
                          to recommend further control of DBFs
                          in public water systems. First, the data
                          from the Information Collection Rule
                          showed that the RAA compliance
                          calculation under the Stage 1 DBPR
                          allows elevated TTHM or HAAS levels
                          to regularly occur at some locations in
                          the distribution system while the overall
                          average of TTHM or HAAS levels at all
                          DBF monitoring locations is below the
                          MCLs of the Stage 1 DBPR. Customers
                          served at those sampling locations with
                          DBF levels that are regularly above
                          0.080 mg/L TTHM and 0.060 mg/L
                          HAAS experience higher exposure
                          compared to customers served at
                          locations where these levels are
                          consistently met.
                            Second, the new data demonstrated
                          that DBF levels in single samples can be
                          substantially above 0.080  mg/L TTHM
                          and 0.060 mg/L HAAS. Some customers
                          receive drinking water with
                          concentrations of TTHM and HAAS up
                          to 75% above 0.080 mg/L  and 0.060 mg/
                          L, respectively, even when their water
                          system is in compliance with the Stage
                          1 DBPR. Some studies support an
                          association between acute exposure to
                          DBFs and potential adverse
                          reproductive and developmental health
                          effects (see Section III.C for more detail).
                           Third, the data from the Information
                          Collection Rule revealed that the highest
                          TTHM and HAAS levels can occur at
                          any monitoring site in the distribution
                          system. In fact, the highest
                          concentrations did not occur at the
                          maximum residence time  locations in
                          more than 50% of all ICR  samples. The
                          fact that the locations with the highest
                          DBF levels vary in different public
                          water systems indicates that the Stage 1
                          DBPR monitoring may not accurately
                          represent the high DBF concentrations
                          that actually exist in distribution
                          systems, and that additional monitoring
                          is needed to identify distribution system
                          locations with elevated DBF levels.
                           These data showed that  efforts beyond
                         the Stage 1 DBPR are needed to provide
                          more equitable protection from DBF
                          exposure across the entire distribution
                          system. The incremental regulatory
                         changes made under the Stage 2 DBPR
                         meet this need by reevaluating the
                          locations of DBF monitoring sites and
 addressing high DBF concentrations that
 occur at particular locations or in single
 samples within systems in compliance.

 2. Treatment
   The analysis of the new treatment
 study data confirmed that certain
 technologies are effective at reducing
 DBF concentrations. Bench- and pilot-
 scale studies for granular activated
 carbon (GAC) and membrane
 technologies required by the
 Information Collection  Rule provided
 information on the effectiveness of the
 two technologies. Other studies found
 UV light to be highly effective for
 inactivating Cryptosporidium and
 Giardia at low doses without promoting
 the formation of DBFs (Malley et al.
 1996; Zheng et al. 1999). This new
 treatment information adds to the
 treatment options available to utilities
 for controlling DBFs beyond the
 requirements of the Stage 1 DBPR.

 E. Conclusions for Regulatory Action
   After extensive analysis of available
 data and rule options considered by the
 Advisory Committee and review of
 public comments on the proposed Stage
 2 DBPR (USEPA, 2003a), EPA is
 finalizing a Stage 2 DBPR control
 strategy consistent with the key
 elements of the Agreement in Principle
 signed in September 2000 by the
 participants in the Stage 2 M-DBP
 Advisory Committee. EPA believes that
 exposure to chlorinated drinking water
 may be associated with cancer,
 reproductive, and developmental health
 risks. EPA determined that the risk-
 targeting measures recommended in the
 Agreement in Principle will require
 only those systems with the greatest risk
 to make treatment and operational
 changes and will maintain simultaneous
 protection from potential  health
 concerns from DBFs and microbial
 contaminants. EPA has  carefully
 evaluated and expanded upon the
 recommendations of the Advisory
 Committee and public comments to
 develop today's rule. EPA also made
 simplifications where possible to
 minimize complications for public
 water systems as they transition to
 compliance with the Stage 2 DBPR
 while expanding public health
 protection. The requirements of the
 Stage 2 DBPR are described in detail in
 Section IV of this preamble.

IV. Explanation of Today's Action

A. MCLGs
  MCLGs are set at concentration levels
at which no known or anticipated
adverse health effects occur, allowing
for an adequate margin of safety.

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                                                                      407
Establishment of an MCLG for each
specific contaminant is based on the
available evidence of carcinogenicity or
noncancer adverse health effects from
drinking water exposure using EPA's
guidelines for risk assessment. MCLGs
are developed to ensure they are
protective of the entire population.
  Today's rule provides MCLGs for
chloroform and two haloacetic acids,
monochloroacetic acid (MCAA) and
trichloroacetic acid (TCAA).
1. Chloroform MCLG
  a. Today's rule. The final MCLG for
chloroform is 0.07 mg/L. The MCLG was
calculated using toxicological evidence
that the carcinogenic effects of
chloroform are due to sustained tissue
toxicity. EPA is not changing the other
THM MCLGs finalized in the Stage 1
DBPR.
  b. Background and analysis. The
MCLG for chloroform is unchanged
from the proposal. The MCLG is
calculated using a reference dose (RfD)
of 0.01 mg/kg/day and an adult tap
water consumption of 2 L per day for a
70 kg adult. A relative source
contribution (RSC) of 20% was used in
accordance with Office of Water's
current approach for deriving RSC
through consideration of data that
indicate that other routes and sources of
exposure may potentially contribute
substantially to the overall exposure to
chloroform. See the proposed Stage 2
DBPR (USEPA 2003a) for a detailed
discussion of the chloroform MCLG.
                      MCLG for Chloroform = (°'01 mg/kg/day)(70kg)(0.2) = „ Q7 mg/L (rounded)
                                                      2 L/day
  Based on an analysis of the available
scientific data on chloroform, EPA
believes that the chloroform dose-
response is nonlinear and that
chloroform is likely to be carcinogenic
only under high exposure conditions
(USEPA 2001a). This assessment is
supported by the principles of the 1999
EPA Proposed Guidelines for
Carcinogen Risk Assessment (USEPA
1999a) and reconfirmed by the 2005
final Cancer Guidelines (USEPA 20051).
The science in support of a nonlinear
approach for estimating the
carcinogenicity of chloroform was
affirmed by the Chloroform Risk
Assessment Review Subcommittee of
the EPA SAB Executive Committee
(USEPA 2000d). Since the nonzero
MCLG is based on a mode of action
consideration specific to chloroform, it
does not affect the MCLGs of other
trihalomethanes.
  c. Summary of major comments. EPA
received many comments in support of
the proposed MCLG calculation for
chloroform, although some commenters
disagreed with a non-zero MCLG.
  At this time, based on an analysis of
all the available scientific data on
chloroform, EPA concludes that
chloroform is likely to be carcinogenic
to humans only under high exposure
conditions that lead  to cytotoxicity and
regenerative hyperplasia and that
chloroform is not likely to be
carcinogenic to humans under
conditions that do not cause
cytotoxicity and cell regeneration
(USEPA 2001a). Therefore, the dose-
response is nonlinear, and the MCLG is
set at 0.07 mg/L. This conclusion has
been reviewed by the SAB (USEPA
2000d), who agree that nonlinear
approach is most appropriate for the
risk assessment of chloroform; it also
remains consistent with the principles
of the 1999 EPA Proposed Guidelines
for Carcinogenic Risk Assessment
(USEPA 1999a) and the final Cancer
Guidelines ( USEPA 2005i), which
allow for nonlinear extrapolation.
  EPA also received some comments
requesting a combined MCLG for THMs
or HAAs. This is not appropriate
because these different chemicals have
different health effects.

2. HAA MCLGs: TCAA and MCAA
  a. Today's rule. Today's rule finalizes
the proposed Stage 2 MCLG for TCAA
of 0.02 mg/L (USEPA 2003a) and sets an
MCLG for MCAA of 0.07 mg/L. EPA is
not changing the other HAA MCLGs
finalized in the Stage 1 DBPR (USEPA
1998a).
  b. Background and analysis. The Stage
1 DBPR included an MCLG for TCAA of
0.03  mg/L and did not include an MCLG
for MCAA (USEPA 1998a). Based on
toxicological data published after the
Stage 1 DBPR, EPA proposed new
MCLGs for TCAA and MCAA of 0.02
mg/L and 0.03 mg/L, respectively, in the
Stage 2 proposal (USEPA 2003a). The
proposed TCAA MCLG and its
supporting analysis is being finalized
unchanged in today's final rule. The
MCLG calculation for MCAA is revised
in this final rule, based on a new
reference dose, as discussed later. See
the proposed Stage 2 DBPR (USEPA
2003a) for a detailed discussion of the
calculation of the MCLGs.
  TCAA. The MCLG for TCAA was
calculated based on the RfD of 0.03 mg/
kg/day using a 70 kg adult body weight,
a 2 L/day drinking water intake, and a
relative source contribution of 20%. An
additional tenfold risk  management
factor has been applied to account for
the possible carcinogenicity of TCAA.
This approach is consistent with EPA
policy. TCAA induces  liver tumors in
mice (Ferreira-Gonzalez et al. 1995;
Pereira 1996; Pereira and Phelps 1996;
Tao et al. 1996; Latendresse and Pereira
1997; Pereira et  al. 1997) but not in rats
(DeAngelo et al. 1997). Much of the
recent data on the carcinogenicity of
TCAA have focused on examining the
carcinogenic mode(s) of action.
However, at this time, neither the
bioassay nor the mechanistic data are
sufficient to support the development of
a slope factor from which to quantify
the cancer risk.
                        MCLG for TCAA= (0-03 mg/kg/day)(70 kg)(0.2) =
                                                 (2L/day)(10)

  The chronic bioassay for TCAA by
DeAngelo et al. (1997) was selected as
the critical study for the development of
the RfD. In this chronic drinking water
study, a dose-response was noted for
several endpoints and both a LOAEL
and NOAEL were determined. The data
are consistent with the findings in both
the Pereira (1996) chronic drinking
water study and the Mather et al. (1990)
subchronic drinking water study. The
RfD of 0.03 mg/kg/day is based on the
NOAEL of 32.5 mg/kg/day for liver
histopathological changes in rats
(DeAngelo et al. 1997). A composite
uncertainty factor of 1000 was applied
in the RfD determination. A default
uncertainty factor of 10 was applied to

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Federal  Register/Vol. 71, No. 2/Wednesday,  January 4, 2006/Rules and Regulations
 the RfD to account for extrapolation
 from an animal study because data to
 quantify rat-to-human differences in
 toxicokinetics or toxicodynamics are not
 available. The default uncertainty factor
 of 10 was used to account for human
 variability in the absence of data on
 differences in human susceptibility.
 Although subchronic and chronic
 studies of TCAA have been reported for
 multiple species, many studies have
 focused on liver lesions and a full
 evaluation of a wide range of potential
 target organs has not been conducted in
 two different species. In addition, there
 has been no multi-generation study of
 reproductive toxicity and the data from
 teratology studies in rats provide
 LOAEL values but no NOAEL for
 developmental toxicity. Thus, an
 additional uncertainty factor of 10 was
 used to account for database
 insufficiencies.
  The MCLG calculation also includes a
 relative source contribution (RSC) of
 20%. The RSC was derived consistent
 with Office of Water's current approach
 for deriving RSC. In addition to
 disinfected water, foods are expected to
 contribute to daily exposure to TCAA
 (Raymer et al. 2001, 2004; Reimann et
 al. 1996). Some of the TCAA in foods
 comes from  cleaning and cooking foods
 in chlorinated water. Additional TCAA
 is found in some foods because of the
 widespread  use of chlorine as a
 sanitizing agent in the food industry
 (USFDA 1994). EPA was not able to
 identify any dietary surveys or duplicate
 diet studies  of TCAA in the diet. TCAA
 also has been identified in rain water,
                          suggesting some presence in the
                          atmosphere (Reimann et al. 1996);
                          however, due to the low volatility (0.5—
                          0.7 mm Hg at 25 °C) of TCAA, exposure
                          from ambient air is expected to be
                          minimal. Dermal exposure to
                          disinfected water is also unlikely to be
                          significant. A study by Xu et al. (2002)
                          reports that dermal exposure from
                          bathing and showering is only 0.01% of
                          that from oral exposure. In addition, the
                          solvents trichloroethylene,
                          tetrachlorethylene, 1,1,1-trichloroethane
                          (often found  in ambient air and drinking
                          water), and the disinfection byproduct
                          chloral hydrate all contribute to the
                          body's TCAA load since each of these
                          compounds is metabolized to TCAA
                          (ATSDR 2004; ATSDR 1997a; ATSDR
                          1997b; USEPA 2000e). Due to the
                          limitations primarily in  the dietary data
                          and a clear indication of exposure from
                          other sources, EPA applied a relative
                          source contribution of 20%.
                            MCAA. The MCLG for MCAA uses
                          the following calculations: An RfD of
                          0.01 mg/kg/day, a 70 kg adult
                          consuming 2 L/day of tap water, and a
                          relative source contribution of 20%.
                            The RfD included in the proposal was
                          based on a chronic drinking water study
                          in rats conducted by DeAngelo et al.
                          (1997). In the assessment presented for
                          the proposed rule, the LOAEL from this
                          study was identified as 3.5 mg/kg/day
                          based on increased absolute and relative
                          spleen weight in the absence of
                          histopathologic changes. After
                          reviewing comments and further
                          analysis of the data, EPA concludes that
                          it is more appropriate to identify this
 change as a NOAEL. Increased spleen
 weights in the absence of
 histopathological effects are not
 necessarily adverse. In addition, spleen
 weights were decreased, rather than
 increased in the mid- and high-dose
 groups in the DeAngelo et al. (1997)
 study and were accompanied by a
 significant decrease in body weight,
 decreased relative and absolute liver
 weights, decreased absolute kidney
 weight, and an increase in relative testes
 weight. Accordingly, the mid-dose in
 this same study (26.1 mg/kg/day) has
 been categorized as the LOAEL with the
 lower 3.5 mg/kg/day dose as a NOAEL.
  Based on a NOAEL of 3.5 mg/kg/day
 (DeAngelo et al. 1997), the revised RfD
 was calculated as shown below, with a
 composite uncertainty factor of 300.
 EPA used a default uncertainty factor of
 10 to account for extrapolation from an
 animal study, since no data on rat-to-
 human differences in toxicokinetics or
 toxicodynamics were identified. A
 default uncertainty factor of 10 was
 used to account for human variability in
 the absence of data on the variability in
 the toxicokinetics of MCAA in humans
 or in human susceptibility to MCAA.
 An additional uncertainty factor of three
 was used to account for database
 insufficiencies. Although there is no
 multi-generation reproduction study,
 the available studies of reproductive
 and developmental processes suggest
 that developmental toxicity is unlikely
 to be the most  sensitive endpoint. This
 led to the following calculation of the
 Reference Dose (RfD) and MCLG for
 MCAA:
                              = (3-5 mg/kg/day) =         /kg/day rounded to 0.01  g/kg/day
                                    (300)                      '                B   B   y
Where:

3.5 mg/kg/day = NOAEL for decreased
    body weight plus decreased liver,
    kidney and spleen weights in rats
                             exposed to MCA for 104 weeks in
                             drinking water (DeAngelo et al.
                             1997).
                         300 = composite uncertainty factor
                             chosen to account for inter species
    extrapolation, inter-individual
    variability in humans, and
    deficiencies in the database.
                             MCLG for MCAA =
                                  (°-01
                                                                  kg)(0.2)
                                                         2 L/day
                                                                          =
  The RSC for MCAA was selected
using comparable data to that discussed
for TCAA. MCAA, like TCAA, has been
found in foods and is taken up by foods
during cooking (15% in chicken to 62%
in pinto beans) and cleaning (2.5% for
lettuce) with water containing 500 ppb
MCAA (Reimann et al.1996; Raymer et
al. 2001, 2004). Rinsing of cooked foods
                         did not increase the MCAA content of
                         foods to the same extent as was
                         observed for TCAA (Raymer et al. 2004).
                         MCAA was found to be completely
                         stable in water boiled for 60 minutes
                         and is likely to be found in the diet due
                         to the use of chlorinated water in food
                         preparation and the use of chlorine as
                         a sanitizing agent by the food industry
(USFDA 1994). As with TCAA,
inhalation and dermal exposures are
unlikely to be significant. Dermal
exposure from bathing and showering
was estimated to contribute only 0.03%
of that from oral exposure (Xu et al.
2002). As with TCAA, due to the
limitations in dietary data and a clear
indication of exposure from other

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             Federal Register/Vol.  71, No. 2/Wednesday, January 4, 2006/Rules and  Regulations
                                                                      409
sources, EPA applied a relative source
contribution of 20%.
  c. Summary of major comments. EPA
received few comments on MCAA and
TCAA. The majority of comments about
the MCLGs for TCAA and MCAA were
genera] MCLG questions, including RSC
derivation. Some commenters
questioned why MCAA, TCAA, and
chloroform were calculated using an
RSC of 20%. In particular, some
commenters compared these
calculations to that for DBCM in the
Stage 1 DBPR, which uses 80%. Each of
the MCLGs set for chloroform, TCAA,
and MCAA under this rule is calculated
using the best available science and EPA
Office of Water's current approach for
deriving the RSC. EPA chose  an RSC of
20%, not 80%, because of clear
indications of exposure from  other
sources; data limitations preclude the
derivation of a specific RSC.
  The RSC for DBCM was 80% in the
Stage 1 DBPR. The DBCM MCLG is not
part of today's rulemaking. Any possible
future revision to the DBCM MCLG as
a result of an RSC change would not
affect the MCL for TTHM finalized in
today's rule.
  In response to comments received on
the RfD for MCAA, EPA has reviewed
the critical study regarding the
appropriateness of an increase in spleen
weight in the absence of histopathology
as a LOAEL. EPA has determined that
the dose associated with this  endpoint
is more appropriately categorized as a
NOAEL rather than a LOAEL and has
revised the RfD and MCLG for MCAA.

B. Consecutive Systems

  Today's rule includes provisions for
consecutive systems, which are public
water systems that receive some or all
of their finished water from another
water system (a wholesale system).
Consecutive systems face particular
challenges in providing water that meets
regulatory standards for DBFs and other
contaminants whose concentration can
increase in the distribution system.
Moreover, previous regulation of DBF
levels in consecutive systems varies
widely among States. In consideration
of these factors, EPA is finalizing
monitoring, compliance schedule, and
other requirements specifically for
consecutive systems. These
requirements are intended to facilitate
compliance by consecutive systems
with MCLs for TTHM and HAAS under
the Stage 2 DBPR and help to ensure
that consumers in consecutive systems
receive equivalent public health
protection.
1. Today's Rule
  As public water systems, consecutive
systems must provide water that meets
the MCLs for TTHM and HAA5 under
the Stage 2 DBPR, use specified
analytical methods, and carry out
associated monitoring, reporting,
recordkeeping, public notification, and
other requirements. The following
discusses a series of definitions needed
for addressing consecutive system
requirements  in today's rule. Later
sections of this preamble provide
further details on how rule requirements
(e.g., schedule and monitoring) apply to
consecutive systems.
  A consecutive system is a public
water system that receives some or all
of its finished water from one or more
wholesale  systems.
  Finished water is water that has been
introduced into the distribution system
of a public water system and is intended
for distribution and consumption
without further treatment, except as
necessary to maintain water quality in
the distribution system (e.g., booster
disinfection, addition of corrosion
control chemicals).
  A wholesale system is a public water
system that treats source water as
necessary to produce finished  water and
then delivers finished water to another
public water system. Delivery  may be
through a direct connection or through
the distribution system of one  or more
consecutive systems.
  The combined distribution system is
defined as the interconnected
distribution system consisting of the
distribution systems of wholesale
systems and of the consecutive systems
that receive finished water from those
wholesale system(s).
  EPA is allowing States some
flexibility in defining what systems are
a part of a  combined distribution
system.  This provision determines
effective dates for requirements in
today's rule; see Section IV.E
(Compliance Schedules) for further
discussion. EPA has consulted with
States and deferred to their expertise
regarding the nature of the connection
in making combined distribution system
determinations. In the absence of input
from the State, EPA will determine that
combined distribution systems include
all interconnected systems for the
purpose of determining compliance
schedules for implementation of this
rule.

2. Background and Analysis
  The practice of public water systems
buying and selling water to each other
has been commonplace for many years.
Reasons include saving money on
pumping, treatment, equipment, and
personnel; assuring an adequate supply
during peak demand periods; acquiring
emergency supplies; selling surplus
supplies; and delivering a better product
to consumers. EPA estimates that there
are more than 10,000 consecutive
systems nationally.
  Consecutive systems face particular
challenges in providing water that meets
regulatory standards for contaminants
that can increase in the distribution
system. Examples of such contaminants
include coliforms, which can grow if
favorable conditions exist, and some
DBFs, including THMs and HAAs,
which can increase when a disinfectant
and DBF precursors continue to react in
the distribution system.
  EPA included requirements
specifically for consecutive systems
because States have taken widely
varying approaches to regulating DBFs
in consecutive systems in previous
rules. For example, some States have
not regulated DBF levels in consecutive
systems that deliver disinfected water
but do not add a disinfectant. Other
States have determined compliance
with DBF standards based on the
combined distribution system that
includes both the wholesaler and
consecutive systems. In this case, sites
in consecutive systems are treated as
monitoring sites within the combined
distribution system. Neither of these
approaches provide the same level of
public health protection as non-
consecutive systems receive under the
Stage I DBPR. Once fully implemented,
today's rule will ensure similar
protection for consumers in consecutive
systems.
  In developing its recommendations,
the Stage 2 M-DBP Advisory Committee
recognized two principles related to
consecutive systems: (1) consumers in
consecutive systems should be just as
well protected as customers of all
systems, and (2) monitoring provisions
should be tailored to meet the first
principle. Accordingly, the Advisory
Committee recommended that all
wholesale and consecutive systems
comply with provisions of the Stage 2
DBPR on the same schedule required of
the wholesale or consecutive system
serving the largest population in the
combined distribution system. In
addition, the Advisory Committee
recommended that EPA solicit
comments on issues related to
consecutive systems that the Advisory
Committee had not fully explored
(USEPA 2000a). EPA agreed with these
recommendations and they are reflected
in today's rule.

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3. Summary of Major Comments
   Commenters generally supported the
proposed definitions. However,
commenters did express some concerns,
especially with including a time period
of water delivery that defined whether
a system was a consecutive system
(proposed to trigger plant-based
monitoring requirements) or wholesale
system (proposed to allow
determination that a combined
distribution system existed). EPA has
dropped this requirement from the final
rule; population-based monitoring
requirements in the final rule do not
need to define how long a plant must
operate in order to be considered a
plant, and EPA has provided some
flexibility for States to determine which
systems comprise a combined
distribution system (without presenting
a time criterion).
   Other commenters expressed concern
that the proposed definition of
consecutive system was inconsistent
with use of the term prior to the
rulemaking. EPA acknowledges that the
Agency has not previously formally
defined the term, but believes that the
definition in today's rule best considers
all commenters' concerns, while  also
providing for accountability and  public
health protection in as simple a manner
as is possible given the many
consecutive system scenarios that
currently exist.
   Several States requested flexibility to
determine which systems comprised a
combined distribution system under
this rule; EPA has included that
flexibility for situations in which
                          systems have only a marginal
                          association (such as an infrequently
                          used emergency connection) with other
                          systems in the combined distribution
                          system. To prepare for the IDSE and
                          subsequent Stage 2 implementation,
                          EPA has worked with States in
                          identifying all systems that are part of
                          each combined distribution system.
                           Finally, several commenters requested
                          that the wholesale system definition
                          replace "public water system" with
                          "water system" so that wholesale
                          systems serving fewer than 25 people
                          would not be considered public water
                          systems. EPA did not change the
                          definition in today's rule; EPA considers
                          any water system to be a public water
                          system (PWS) if it serves 25 or more
                          people either directly (retail) or
                          indirectly (by providing finished water
                          to a consecutive system) or through a
                          combination of retail and consecutive
                          system customers. If a PWS receives
                          water from an unregulated entity, that
                          PWS must meet all compliance
                          requirements (including monitoring and
                          treatment techniques) that any other
                          public water system that uses source
                          water of unknown quality must meet.

                          C. LRAA MCLs for TTHM and HAAS

                          1. Today's Rule
                           This rule requires the use of
                          locational running annual averages
                          (LRAAs) to determine compliance with
                          the Stage 2 MCLs of 0.080 mg/L TTHM
                          and 0.060 mg/L HAAS. All systems,
                          including consecutive systems, must
                          comply with the MCLs for TTHM and
                          HAA5 using sampling sites identified
under the Initial Distribution System
Evaluation (IDSE) or using existing
Stage 1 DBPR compliance monitoring
locations (as discussed in Section IV.F).
EPA has dropped the proposed phased
approach for LRAA implementation
(Stage 2A and Stage 2B) by removing
Stage 2A and redesignating Stage 2B as
Stage 2.
  Details of monitoring requirements
and compliance schedules are discussed
in preamble Sections IV.G and IV.E,
respectively, and may be found in
subpart V of today's rule.

2. Background and Analysis

  The MCLs for TTHM and HAAS are
the same as those proposed, 0.080 mg/
L TTHM and 0.060 mg/L HAAS as an
LRAA. See the proposed rule (68 FR
49584, August 18, 2003) (USEPA 2003a)
for a more detailed discussion of the
analysis supporting the  MCLs. The
primary objective of the LRAA is to
reduce exposure to high DBF levels. For
an LRAA, an annual average must be
computed at each monitoring location.
The RAA compliance basis of the 1979
TTHM rule and  the Stage 1 DBPR allows
a system-wide annual average under
which high DBF concentrations in one
or more locations are  averaged with, and
dampened by, lower concentrations
elsewhere in the distribution system.
Figure IV.C-1 illustrates the difference
in calculating compliance with the
MCLs for TTHM between a Stage 1
DBPR RAA, and the Stage 2 DBPR
LRAA.
BILLING CODE 6560-50-P

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                                                                           411
          Figure IV.C-1.  Comparison of RAA and LRAA compliance calculations'.
            Stage 1 DBPR

                   First Quarter
                                                       Distribution System
                                                      Sampling Location
    Second Quarter
    Third Quarter
       Fourth Quarter
               Average of All Samples
 Average of All Samples
Average of All Samples
    Average of All Samples
                                        Running Annual Average of Quarterly Averages
                                                 MUST BE BELOW MCL
            Stage 2 DBPR
                                                                 Third Quarter
                                                   Fourth Quarter
                   First Quarter   <
                   Second Quarter
                   Third Quarter
                   Fourth Quarter
       LRAA 1
MUST BE BELOW MCL
 First Quarter
 Second Quarter
 Third Quarter
 Fourth Quarter
       LRAA 3
MUST BE BELOW MCL
                   First Quarter   A
                   Second Quarter A
                   Third Quarter  A
                   Fourth Quarter A
       LRAA 2
MUST BE BELOW MCL
 First Quarter
 Second Quarter
 Third Quarter
 Fourth Quarter
       LRAA 4
MUST BE BELOW MCL
         'Stage 2 DBPR sampling locations will be selected based on the results of an IDSE and may occur at locations
         different from Stage 1 DBPR sampling sites.
BILLING CODE 6560-50-C
  EPA and the Stage 2 M-DBP Advisory
Committee considered an array of
alternative MCL strategies. The
Advisory Committee discussions
primarily focused on the relative
magnitude of exposure reduction versus
  the expected impact on the water
  industry and its customers. Strategies
  considered included across the board
  requirements, such as significantly
  decreasing the MCLs (e.g., 40/30) or
  single hit MCLs (e.g., all samples must
  be below 80/60); and risk targeting
                 requirements. In the process of
                 evaluating alternatives, EPA and the
                 Advisory Committee reviewed vast
                 quantities of data and many analyses
                 that addressed health effects, DBF
                 occurrence, predicted reductions in DBF
                 levels, predicted technology changes,

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Federal  Register/Vol. 71, No.  2/Wednesday, January 4, 2006/Rules and  Regulations
 and capital, annual, and household
 costs. The Advisory Committee
 recommended and EPA proposed the
 risk targeting approach of 80/60 as an
 LRAA preceded by an IDSE. Today's
 rule finalizes these requirements.
   EPA has chosen compliance based on
 an LRAA due to concerns about levels
 of DBFs above the MCL in some
 portions of the distribution system. The
 LRAA standard will eliminate system-
 wide averaging of monitoring results
 from different monitoring locations. The
 individuals served in areas of the
 distribution system with above average
 DBP occurrence levels masked by
 averaging under an RAA are not
 receiving the same level of health
 protection. Although an LRAA standard
 still allows averaging at a single location
 over an annual period, EPA concluded
 that changing the  basis of compliance
 from an RAA to an LRAA will result  in
 decreased exposure to higher DBP levels
 (see Section VI for predictions of DBP
 reductions under  the LRAA MCLs). This
 conclusion is based on three
 considerations:
   (l) There is considerable evidence
 that under the current RAA MCL
 compliance monitoring requirements, a
 small but significant proportion of
 monitoring locations experience high
 DBP levels at least some of the time. Of
 systems that collected data under the
 Information Collection Rule that met the
 Stage 1 DBPR RAA MCLs, 14 percent
 had TTHM single  sample concentrations
 greater than the Stage 1 MCL, and 21
 percent had HAAS single sample
 concentrations above the MCL.
 Although most TTHM and HAAS
 samples were below 100 Hg/L, some
 ranged up to 140 ng/L and 130 ng/L,
 respectively.
   (2) In some situations, the populations
 served by certain portions of the
 distribution system consistently receive
 water that exceeds 0.080 mg/L for
 TTHM or 0.060 mg/L for HAAS (both as
 LRAAs) even though the system is in
 compliance with Stage 1 MCLs). Of
 Information Collection Rule systems
 meeting the Stage  I DBPR MCLs as
 RAAs, five percent had monitoring
 locations that exceeded 0.080 mg/L
 TTHM and three percent exceeded
 0.060 mg/L HAAS as an annual average
 (i.e., as LRAAs) by up to 25%
 (calculated as indicated in Figure IV.C-
 1). Customers served at these locations
 consistently received water with TTHM
and/or HAAS concentrations higher
than the system-wide average and
higher than the MCL.
  (3) Compliance based on an LRAA
will remove the opportunity for systems
to average out samples from high and
low quality water sources. Some
                         systems are able to comply with an RAA
                         MCL even if they have a plant with a
                         poor quality water source (that thus
                         produces high concentrations of DBFs)
                         because they have another plant that has
                         a better quality water source (and thus
                         lower concentrations of DBFs).
                         Individuals served by the plant with the
                         poor quality source will usually have
                         higher DBP exposure than individuals
                         served by the other plant.
                           In part, both the TTHM and HAAS
                         classes are regulated because they occur
                         at high levels and represent chlorination
                         byproducts that are produced from
                         source waters with a wide range of
                         water quality. The combination of
                         TTHM and HAAS represent a wide
                         variety of compounds resulting from
                         bromine substitution  and  chlorine
                         substitution reactions (e.g., bromoform
                         has three bromines, TCAA has three
                         chlorines, BDCM has  one  bromine and
                         two chlorines). EPA believes that the
                         TTHM and HAAS classes  serve as an
                         indicator for unidentified and
                         unregulated DBFs. EPA believes that
                         controlling the occurrence levels of
                         TTHM and HAAS will help control the
                         overall levels of chlorination DBFs.

                         3. Summary of Major  Comments
                           Commenters supported  the proposed,
                         risk-targeted MCL strategy over the
                         alternative MCL strategies that were
                         considered by the Advisory Committee
                         as the preferred regulatory strategy.
                         Commenters concurred with EPA's
                         analysis that such an approach will
                         reduce peak and average DBP levels.
                         Commenters supported the Stage 2 long-
                         term MCLs of 0.080 mg/L TTHM and
                         0.060 mg/L HAAS as LRAAs.
                           EPA received many comments on
                         today's MCLs specific to consecutive
                         systems. While commenters supported
                         consecutive system compliance with the
                         Stage 2 DBPR in order to provide
                         comparable levels of public health
                         protection, they noted that it would be
                         difficult for many consecutive systems
                         to meet Stage 2 requirements because
                         they have not had to meet the full scope
                         of DBF requirements under previous
                         rules. EPA has developed  a training and
                         outreach program to assist these systems
                         and encourages States, wholesale
                         systems, and professional  associations
                         to also provide assistance.
                           Some commenters expressed concern
                         about holding consecutive systems
                         responsible for water quality over which
                         they have no control. Several
                         commenters were concerned about the
                         establishment of contracts between
                         wholesale and consecutive systems,
                         including concern about a strain on
                         their relationship, wholesale system
                         reluctance to commit to keep DBFs at a
 level suggested by the consecutive
 systems, and the time and money it
 could take to work out differences.
 Although setting up a contract is a
 prudent business action, commenters
 noted that small consecutive water
 systems have few resources to sue for
 damages should the wholesaler provide
 water exceeding the MCL.
  The purpose of DBPRs is to protect
 public health from exposure to high
 DBP levels. Not requiring violations
 when distributed water exceeds MCLs
 undermines the intent of the rule. While
 EPA recognizes consecutive systems do
 not have full control over the water they
 receive, agreements between wholesale
 and consecutive systems may specify
 water quality and actions required of the
 wholesaler if those water  quality
 standards are not met.
  Finally, commenters recommended
 that the Stage 2A  provisions in the
 proposed rule  be removed. These
 provisions (compliance with locational
 running annual average MCLs of 0.120
 mg/L for TTHM and 0.100 mg/L for
 HAAS) required systems to comply with
 the Stage 1 MCLs (as running annual
 averages) and the Stage 2A MCLs (as
 LRAAs) concurrently until systems were
 required to comply with Stage 2B MCLs.
 Commenters noted that having two
 separate MCLs for an individual system
 to comply with at the same time was
 confusing to the system and its
 customers. In addition, State resources
 needed  for compliance determinations
 and data management for  this short-term
 requirement would be resource-
 intensive. Finally, resources spent to
 comply with Stage 2A would be better
 spent in complying with Stage 2B,
 especially given that some of the
 changes for Stage  2A compliance might
 not provide any benefit for Stage 2B.
 Since EPA agrees  with commenters'
 concerns, the Stage 2A requirements
 have been removed from the final rule.

 D. BAT for TTHM and HAAS

 1. Today's Rule

  Today, EPA is identifying the best
 available technology (BAT) for the
 TTHM and HAAS LRAA MCLs (0.080
 mg/L and 0.060 mg/L respectively) for
 systems that treat their own source
 water as one of the three following
 technologies:
  (1) GAC10 (granular activated carbon
filter beds with an empty-bed contact
time of 10 minutes based on average
daily flow and  a carbon reactivation
frequency of every 120 days)
  (2) GAC20 (granular activated carbon
filter beds with an empty-bed contact
time of 20 minutes based on average

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             Federal Register/Vol.  71, No. 2/Wednesday, January  4,  2006/Rules and  Regulations        413
daily flow and a carbon reactivation
frequency of every 240 days)
  (3) Nanofiltration (NF) using a
membrane with a molecular weight
cutoff of 1000 Daltons or less.
  EPA is specifying a different BAT for
consecutive systems than for systems
that treat their own source water to meet
the TTHM and HAAS LRAA MCLs. The
consecutive system BAT is
chloramination with management of
hydraulic  flow and storage to minimize
residence time in the distribution
system for systems that serve at least
10,000 people and management of
hydraulic  flow and storage to minimize
residence time in the distribution
system for systems that serve fewer than
10,000 people.

2. Background and Analysis
  The BATs are the same as was
proposed, except that consecutive
systems serving fewer than 10,000
people do not have chloramination as
part of the consecutive system BAT. See
the proposal (68 FR 49588, August 18,
2003) (USEPA 2003a) for more detail on
the analysis supporting these
requirements. The Safe Drinking Water
Act directs EPA to specify BAT for use
in achieving compliance with the MCL.
Systems unable to meet the MCL after
application of BAT can get a variance
(see Section IV.K for a discussion of
variances). Systems are not required to
use BAT in order to comply with the
MCL. PWSs may use any State-approved
technologies as long  as they meet all
drinking water standards.
  EPA examined BAT options first by
analyzing  data from the Information
Collection Rule treatment studies
designed to evaluate the ability of GAG
and NF to remove DBF precursors.
Based on the treatment study results,
GAC is effective for controlling DBF
formation for waters with influent TOG
concentrations below approximately 6
mg/L (based on the Information
Collection Rule and NRWA data,  over
90 percent of plants have average
influent TOC levels below 6 mg/L
(USEPA 2003c)). Of the plants that
conducted an Information Collection
Rule GAC treatment study,
approximately 70 percent of the surface
water plants studied could meet the
0.080 mg/L TTHM and 0.060 mg/L
HAAS MCLs, with a 20 percent safety
factor (i.e., 0.064 mg/L and 0.048 mg/L,
respectively) using GAC with 10
minutes of empty bed contact time and
a 120 day reactivation frequency, and 78
percent of the plants could meet the
MCLs with  a 20 percent safety factor
using GAC with 20 minutes of empty
bed contact time and a 240 day
reactivation frequency. Because the
treatment studies were conducted at
plants with much poorer water quality
than the national average, EPA believes
that much higher percentages of plants
nationwide could meet the MCLs with
the proposed GAC BATs.
  Among plants using GAC, larger
systems would likely realize an
economic benefit from on-site
reactivation, which could allow them to
use smaller, 10-minute empty bed
contact time contactors with more
frequent reactivation (i.e., 120 days or
less). Most small systems would not
find  it economically advantageous to
install on-site carbon reactivation
facilities, and thus would opt for larger,
20-minute empty bed contact time
contactors, with less frequent carbon
replacement (i.e., 240 days or less).
  The Information Collection Rule
treatment study results also
demonstrated that nanofiltration was
the better DBF control technology for
ground water sources with high TOC
concentrations (i.e., above
approximately 6 mg/L). The results of
the membrane treatment studies showed
that all ground water plants could meet
the 0.080 mg/L TTHM and 0.060 mg/L
HAAS MCLs, with a 20% safety factor
(i.e., 0.064 mg/L and 0.048 mg/L,
respectively) at the system average
distribution system residence time using
nanofiltration. Nanofiltration would be
less expensive than GAC for high TOC
ground waters, which generally require
minimal pretreatment prior to the
membrane process. Also, nanofiltration
is an accepted technology for treatment
of high TOC ground waters in Florida
and parts of the Southwest, areas of the
country with elevated TOC levels in
ground waters.
  The second method that EPA used to
examine alternatives for BAT was the
Surface Water Analytical Tool model
that was developed to compare
alternative regulatory strategies as part
of the Stage 1 and Stage 2 M-DBP
Advisory Committee deliberations. EPA
modeled a number of BAT options. In
the model, GAC10 was defined as
granular activated carbon with an empty
bed contact time of 10 minutes and a
reactivation or replacement interval of
90 days or longer. GAC20 was defined
as granular activated carbon with an
empty bed contact time of 20 minutes
and a reactivation or replacement
interval of 90 days or longer.
  The compliance percentages
forecasted by the SWAT model are
indicated in Table IV.D-1. EPA
estimates that more than 97 percent of
large systems will be able to achieve the
Stage 2 MCLs with the GAC BAT,
regardless of post-disinfection choice
(Seidel Memo, 2001). Because the
source water quality (e.g., DBF
precursor levels) in medium and  small
systems is expected to be comparable to
or better than that for the large system
(USEPA 2005f), EPA believes it is
conservative to assume that at least 90
percent of medium and small systems
will be able to achieve the Stage 2 MCLs
if they were to apply one of the
proposed GAC BATs. EPA assumes that
small systems may adopt GAC20  in a
replacement mode (with replacement
every 240 days) over GAC10 because it
may not be economically feasible for
some small systems to install and
operate an on-site GAC reactivation
facility. Moreover, some small systems
may find nanofiltration cheaper than the
GAC20 in a replacement mode if their
specific geographic locations cause a
relatively high cost for routine GAC
shipment.
 TABLE IV.D-1.—SWAT MODEL PREDICTIONS OF PERCENT OF LARGE PLANTS IN COMPLIANCE WITH TTHM AND HAAS
                    STAGE 2 MCLs AFTER APPLICATION OF SPECIFIED TREATMENT TECHNOLOGIES
Technology
Enhanced Coagulation (EC) 	
EC (no pre-disinfection) 	
EC & GAC10 	
Compliance with 0.080 mg/L TTHM and 0.060
mg/L HAAS LRAAs
Residual disinfectant
Chlorine (per-
cent)
73.5
73.4
100
Chloramine
(percent)
76.9
88.0
97.1
All systems
(percent)
74.8
78.4
99.1
Compliance with 0.064 mg/L TTHM and 0.048
mg/L HAAS LRAAs (MCLs with 20% Safety fac-
tor)
Residual
disinfectant
Chlorine (per-
cent)
57.2
44.1
100
Chloramine
(percent)
65.4
62.7
95.7
All systems
(percent)
60.4
50.5
98.6

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Federal  Register/Vol. 71, No.  2/Wednesday, January 4, 2006/Rules and Regulations
  TABLE IV.D-1 .—SWAT MODEL PREDICTIONS OF PERCENT OF LARGE PLANTS IN COMPLIANCE WITH TTHM AND HAAS
              STAGE 2 MCLs AFTER APPLICATION OF SPECIFIED TREATMENT TECHNOLOGIES—Continued
Technology
EC & GAC20 	
EC & All Chloramines 	
Compliance with 0.080 mg/L TTHM and 0 060
mg/L HAAS LRAAs
Residual disinfectant
Chlorine (per-
cent)
100
NA
Chloramine
(percent)
100
839
All systems
(percent)
100
NA
Compliance with 0.064 mg/L TTHM and 0.048
mg/L HAAS LRAAs (MCLs with 20% Safety fac-
tor)
Residual
disinfectant
Chlorine (per-
cent)
100
NA
Chloramine
(percent)
100
73.6
All systems
(percent)
100
NA
  Note: Enhanced coagulation/softening is required under the Stage 1 DBPR for conventional plants.
  Source: Seidel (2001).
  The BAT requirements for large
consecutive systems are the same as
proposed, but the requirements have
changed for small consecutive systems.
EPA believes that the best compliance
strategy for consecutive systems is to
collaborate with wholesalers on the
water quality they need. For consecutive
systems that are having difficulty
meeting the MCLs, EPA is specifying a
BAT of chloramination with
management of hydraulic flow and
storage to  minimize residence time in
the distribution system for systems
serving at  least 10,000 and management
of hydraulic flow and storage to
minimize  residence time in the
distribution system for systems serving
fewer than 10,000. EPA believes that
small consecutive systems can use this
BAT to comply with the Stage 2 DBPR,
but if they cannot, then they can apply
to the State for a variance.
  Chloramination has been used for
residual disinfection for many years to
minimize  the formation of chlorination
DBFs, including TTHM and HAAS
(USEPA 2003d). EPA estimates  that over
50 percent of large subpart H systems
serving at  least 10,000  use
chloramination  for Stage 1. The BAT
provision  to manage hydraulic flow and
minimize  residence time in the
distribution system is to facilitate the
maintenance of the chloramine  residual
and minimize the likelihood for
nitrification. EPA has not included
chloramination for consecutive  systems
as part of the BAT for systems serving
fewer than 10,000 due  to concerns about
their ability to properly control  the
process, given that many have no
treatment capability or expertise and the
Agency's concern about such systems
having operational difficulties such as
distribution system nitrification.
                           EPA believes that the BATs for
                         nonconsecutive systems are not
                         appropriate for consecutive systems
                         because their efficacy in controlling
                         DBFs is based on precursor removal.
                         Consecutive systems face the unique
                         challenge of receiving waters in which
                         DBFs are already present if the
                         wholesale system has used a residual
                         disinfectant, which the BATs for non-
                         consecutive systems do not effectively
                         remove. GAC is not cost-effective for
                         removing DBFs. Nanofiltration is only
                         moderately effective at removing THMs
                         or HAAs if membranes with a very low
                         molecular weight cutoff (and very high
                         cost of operation are employed).
                         Therefore, GAC and nanofiltration are
                         not appropriate BATs for consecutive
                         systems.

                         3. Summary of Major Comments
                           Commenters concurred with EPA's
                         identification of BATs for non-
                         consecutive systems but expressed
                         concern about the BAT for consecutive
                         systems. Many corrtmenters agreed that
                         Stage 2 compliance for consecutive
                         systems would usually best be achieved
                         by improved treatment by the wholesale
                         system. However, they noted that the
                         proposed BAT  may not be practical for
                         compliance if water delivered to the
                         consecutive system is at or  near DBF
                         MCLs. In addition, chloramination
                         requires operator supervision and
                         adjustment and many consecutive
                         systems that buy water may be reluctant
                         to operate chemical feed systems.
                         Therefore, EPA included chloramines as
                         part of the BAT in today's rule only for
                         systems serving at least 10,000 because
                         of the operator  attention it requires and
                         concerns with safety and nitrification.
                         While some commenters believed that
                         having a BAT for consecutive systems
contradicts the premise of the Stage 1
DBPR that DBFs are best controlled
through TOG removal and optimizing
disinfection processes, the SDWA
requires EPA to identify a BAT for all
systems required to meet an MCL. No
commenter recommended an alternative
BAT. EPA still believes that precursor
removal remains a highly effective
strategy to reduce DBFs. Thus, EPA
encourages States to work with
wholesale systems and consecutive
systems to identify strategies to ensure
compliance, especially those systems
with DBF levels close to the MCL.

E. Compliance Schedules

I. Today's Rule

  This section specifies compliance
dates for the IDSE and MCL compliance
requirements in today's rule. As
described elsewhere in Section IV of
this preamble, today's rule requires
PWSs to carry out the following
activities:
  • Conduct initial distribution system
evaluations (IDSEs) on a required
schedule. Systems may comply by using
any of four approaches for which they
qualify (standard monitoring, system
specific study, 40/30 certification, or
very small system waiver).
  • Determine Stage 2 monitoring
locations based on the IDSE.
  • Comply with Stage 2 MCLs on a
required schedule.
  Compliance dates for these activities
vary by PWS size. Table IV.E-1 and
Figure IV.E-1 specify IDSE and Stage 2
compliance dates. Consecutive systems
of any size must comply with the
requirements of the Stage 2 DBPR on the
same schedule as required for the largest
system in the combined distribution
system.

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             Federal Register/Vol.  71, No.  2/Wednesday,  January 4, 2006/Rules and Regulations
415
                               TABLE IV.E-1.—IDSE AND STAGE 2 COMPLIANCE DATES
Requirement
Submit IDSE monitoring plan OR
Submit IDSE system specific
study plan OR.
Submit 40/30 certification OR 	
Receive very small system waiv-
er from State.
Complete standard monitoring or
system specific study.
Submit IDSE Report
Begin subpart V (Stage 2) com-
pliance monitoring2.
Compliance dates by PWS size (retail population served) 1
CWSs and
NTNCWSs serving
at least 100,000
October 1, 2006 	
September 30, 2008
January 1, 2009 	
April 1, 2012 	

CWSs and
NTNCWSs serving
50,000-99,999
April 1, 2007 	
March 31, 2009 	
July 1 2009
October 1,201 2 	
CWSs and
NTNCWSs serving
10,000-49,999
October 1, 2007 	
September 30, 2009
January 1, 2010 	
October 1, 2013 	
CWSs serving
<10,000
April 1, 2008 ... .
March 31, 2010 ..
July 1 2010 ...
October 1, 2013
(October 1 ,
2014 if Crypto-
sporidium mon-
itoring is re-
quired under
Subpart W)..
NTNCWSs serving
<10,000
Not applicable.
Not applicable.
Not applicable.
  1 Wholesale and consecutive systems that are part of a combined distribution system must comply based on the schedule required of the larg-
est system in the combined distribution system.
  2 States may grant up to an additional 2 years for systems making capital improvements.
BILLING CODE 6560-50-P

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 416
Federal Register/Vol.  71, No.  2/Wednesday, January 4,  2006/Rules and Regulations






















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             Federal  Register/Vol. 71, No.  2/Wednesday, January 4,  2006/Rules and Regulations
                                                                       417
2. Background and Analysis
  The compliance schedule in today's
final rule stems from the risk-targeted
approach of the rule, wherein PWSs
conduct initial monitoring to determine
locations and concentrations of high
DBFs. A primary objective of this
schedule is to ensure that PWSs identify
locations with high DBF concentrations
and provide appropriate additional
treatment in a timely manner for high
risk areas, while not requiring low risk
systems to add additional treatment.
The compliance schedule balances the
objective of early risk-targeted
monitoring with adequate time for
PWSs and the State or primacy agency
to assure full  implementation and
compliance. EPA is establishing
concurrent compliance schedules under
the Stage 2 DBPR for all systems (both
wholesale systems and consecutive
systems) in a  particular combined
distribution system because this will
assure comparable risk-based targeting
information being available at the same
time for all PWSs that  are part of a
combined distribution system and
thereby allow for more cost-effective
compliance with TTHM  and HAA5
MCLs.
  SDWA section 1412(b)(10) states that
a drinking water regulation shall take
effect 3 years  from the promulgation
date unless the Administrator
determines that an earlier date is
practicable. Today's rule requires PWSs
to begin monitoring prior to 3 years
from the promulgation date. Based on
EPA's assessment and  recommendations
of the Advisory Committee,  as described
in this section, EPA has determined that
these monitoring start  dates are
practicable and appropriate.
  Systems must submit their IDSE plans
(monitoring plans for standard
monitoring, study plans  for system
specific studies) to the primacy agency
for review and approval. The State or
primacy agency will then have 12
months to review, and, as necessary,
consult with the system. A number of
PWSs will then conduct one year of
distribution system monitoring for
TTHM and HAAS at locations other
than those currently used for Stage 1
DBPR compliance monitoring. At the
conclusion of this monitoring, these
PWSs have three months to  evaluate
analysis and monitoring results and
submit Stage  2 compliance monitoring
locations and schedules to the State or
primacy agency. Where required, PWSs
must provide the necessary level of
treatment to comply with the Stage 2
MCLs within three years of the
completion of State or primacy agency
review of the IDSE report, though States
may allow an additional two years for
PWSs making capital improvements.
  EPA has modified the proposed
compliance schedule to stagger
monitoring start dates for PWSs serving
10,000 to 99,999 people and to allow
more time for development and review
of IDSE monitoring plans prior to the
start of monitoring. The following
discussion addresses these changes from
the proposal.
  The proposed rule required all PWSs
serving at least  10,000 people (plus
smaller systems that are part of a
combined distribution system with a
PWS that serves at least 10,000 people)
to complete IDSE monitoring and
submit IDSE reports (including
recommended Stage 2 compliance
monitoring locations) two years after
rule promulgation, followed by one year
for review of IDSE  reports, after which
systems had three years to come into
compliance with Stage 2B MCLs.
  Under today's final rule, PWSs
serving at least  100,000 people (plus
smaller systems that are part of the
combined distribution system) will meet
the same Stage  2 compliance deadlines
as proposed. However, the timing of the
IDSE has been changed to allow for a
more even workload and a greater
opportunity for primacy agency
involvement (e.g., through monitoring
plan review and approval). The IDSE
plan submission dates for PWSs serving
50,000 to 99,999 people (plus smaller
systems that are part of the combined
distribution system) will be 12 months
after the effective date; for PWSs serving
10,000 to 49,999 (plus smaller systems
that are part of the combined
distribution system), the IDSE plan
submission dates will be 18 months
after the effective date. The Stage 2
compliance schedule for systems
serving fewer than 10,000 people
remains the same as proposed. Stage 2
MCL compliance dates are modified
accordingly.
  This staggering of IDSE start dates for
PWSs serving 10,000 to 99,999 people is
advantageous in several respects:
  • Provides PWSs greater assurance
that IDSEs are properly conducted by

FIGURE IV.E-2.—SCHEDULE EXAMPLES.
requiring IDSE plan review prior to
conducting the IDSE.
  • Provides additional time to develop
budgets and establish contracts with
laboratories.
  • Spreads out the workload for
technical assistance and guidance. The
staggered schedule will allow States and
EPA to provide more support to
individual PWSs as needed.
  • Provides time for DBP analytical
laboratories to build capacity as needed
to accommodate the sample analysis
needs of PWSs and extends and
smooths the demand for laboratory
services.
  • Maintains simultaneous rule
compliance with the LT2ESWTR as
recommended by the Stage 2 M-DBP
Advisory Committee and as mandated
by the 1996 SDWA Amendments, which
require that EPA "minimize the overall
risk of adverse health effects by
balancing the risk from the contaminant
and the risk from other contaminants
the concentrations of which may be
affected by  the use of a treatment
technique or process that would be
employed to attain the maximum
contaminant level" (Sec.
  The Advisory Committee
recommended the Initial Distribution
System Evaluation, as discussed in
Section IV.F, and EPA is finalizing an
IDSE schedule generally consistent with
the Advisory Committee timeframe
recommendation, but modified to
stagger the schedule for systems serving
more than 10,000 but less than 100,000,
and to address public comments on the
IDSE requirements.
  For all systems, the IDSE schedule has
been revised to allow systems to submit
and States or primacy agencies to
review (and revise, if necessary)
systems' recommendations for IDSE and
Stage 2 monitoring locations, while still
allowing systems three years after
completion of the State  or primacy
agency review of Stage 2 compliance
monitoring locations to  make necessary
treatment and operational changes to
comply with Stage 2 MCLs.
  Figure IV.E-2 illustrates compliance
schedules for examples  of three
combined distribution systems, with the
schedule dictated by the retail
population served by the largest system.
—Wholesale system (pop. 64,000) with three consecutive systems (pops. 21,000; 15,000; 5,000):
    —IDSE monitoring plan due for all systems April 1, 2007 since wholesale system serves 50,000-99,999
    —Stage 2 compliance beginning October 1, 2012 for all systems
—Wholesale system (pop. 4,000) with three consecutive systems (pops. 21,000; 5,000; 5,000):

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 418
Federal  Register/Vol. 71, No. 2/Wednesday,  January 4, 2006/Rules and  Regulations
                                 FIGURE IV.E-2.—SCHEDULE EXAMPLES.—Continued
    —IDSE monitoring plan due for all systems October 1, 2007 since the largest system in combined distribution system serves 10,000-
      49,999
    —Stage 2 compliance beginning October 1, 2013 for all systems
 —Wholesale system (pop. 4,000) with three consecutive systems (pops. 8,000; 5,000; 5,000).
    —IDSE monitoring plan due for all systems April 1, 2008 since no individual system in combined distribution system exceeds 10,000 (even
      though total population exceeds 10,000)
    —Stage 2 compliance beginning October 1, 2013 if no Cryptosporidium monitoring under the LT2ESWTR is required or beginning October
      1, 2014 if Cryptosporidium monitoring under the LT2ESWTR is required
   This schedule requires wholesale
 systems and consecutive systems that
 are part of a combined distribution
 system with at least one system with an
 earlier compliance deadline to conduct
 their IDSE simultaneously so that the
 wholesale system will be aware of
 compliance challenges facing the
 consecutive systems and will be able to
 implement treatment plant, capital, and
 operational improvements as necessary
 to ensure compliance of both the
 wholesale and consecutive systems. The
 Advisory Committee and EPA both
 recognized that DBFs, once formed, are
 difficult to remove and are generally
 best addressed by treatment plant
 improvements, typically through
 precursor removal or use of alternative
 disinfectants. For a wholesale system to
 make the best  decisions  concerning the
 treatment steps necessary to meet
 TTHM and HAAS LRAAs under the
 Stage 2 DBPR, both in its own
 distribution system and  in the
 distribution systems of consecutive
 systems it serves, the wholesale system
 must know the DBF levels throughout
 the combined distribution system.
 Without this information, the wholesale
 system may design treatment changes
 that allow the wholesale system to
 achieve compliance, but leave the
 consecutive system out of compliance.
  In summary, the compliance schedule
 for today's rule maintains the earliest
 compliance dates recommended by the
 Advisory Committee for  PWSs serving
 at least 100,000 people (plus smaller
 systems that are part of the combined
 distribution system). These PWSs serve
 the majority of people. The schedule
 also maintains the latest  compliance
 dates the Advisory Committee
 recommended, which apply to PWSs
 serving fewer than 10,000 people. EPA
 has staggered compliance schedules for
 PWSs between these two size categories
 in order to facilitate implementation of
 the rule. This staggered schedule is
 consistent with the schedule required
 under the LT2ESWTR  promulgated
 elsewhere in today's Federal Register.
 3. Summary of Major Comments
  EPA received significant public
comment on the compliance schedule in
                          the August 18, 2003 proposal. Major
                          issues raised by commenters include
                          providing more time for PWSs to
                          prepare for monitoring, giving States or
                          primacy agencies more time to oversee
                          monitoring, and establishing consistent
                          schedules for consecutive PWSs. A
                          summary of these comments and EPA's
                          responses follows.
                            Standard monitoring plan and system
                          specific study plan preparation. Many
                          commenters were concerned about the
                          proposed requirement to develop and
                          execute an IDSE monitoring plan
                          without any primacy agency review.
                          PWSs specifically expressed concern
                          about the financial commitment without
                          prior State approval and noted that
                          some PWSs would need  more than the
                          time allowed under the proposed rule to
                          develop and implement an IDSE
                          monitoring plan, especially without an
                          opportunity for State or primacy agency
                          review and approval. Smaller PWSs
                          may require substantial time and
                          planning to budget for IDSE expenses,
                          especially for systems that have  not
                          previously complied with DBF MCLs.
                           EPA recognizes these concerns and
                          today's final rule provides time for
                          PWSs to submit IDSE plans (monitoring
                          plans, study plans, or 40/30
                          certifications) for State or primacy
                          agency review and more  time before
                          having to begin monitoring.
                          Specifically, PWSs serving 50,000  to
                          99,999 people and those  serving 10,000
                          to 49,999 people must submit IDSE
                          plans about 12 months and 18 months
                          after the effective date, respectively, and
                          complete standard monitoring or a
                          system specific study within two years
                          after submitting their IDSE plan. This is
                          significantly more time than was
                          specified under the proposal, where
                         these systems would  have had to
                         conduct their IDSE and submit their
                         IDSE report 24 months after the effective
                         date. PWSs serving at least 100,000
                         people must submit IDSE plans about
                         six months after the effective date and
                         complete standard monitoring or a
                         system specific study about 30 months
                         after the effective date, which also
                         provides more time than  was specified
                         under the proposal. PWSs serving fewer
                         than 10,000 people, not associated with
 a larger system in their combined
 distribution system, do not begin
 monitoring until more than 36 months
 after the effective date.
  EPA believes that the final
 compliance schedule allows PWSs
 sufficient time to develop IDSE plans
 with these compliance dates. The
 schedule also allows 12 months for
 State or primacy agency review of IDSE
 plans, which allows additional time for
 review and for coordination with
 systems and provides more time to
 address deficiencies in IDSE plans. This
 is especially important for smaller
 PWSs, which are likely to need the most
 assistance from States. By staggering
 monitoring start dates, today's rule also
 eases implementation by  reducing the
 number of PWSs that will submit plans
 at any one time, when the most
 assistance from regulatory agencies will
 be required.
  In summary, today's schedule has
 been modified so that systems are
 required to submit IDSE plans for
 primacy agency review and approval
 prior to conducting their IDSE. Systems
 can consider that their plan has been
 approved if they have not heard back
 from the State by the end of the State
 review period. Systems are also required
 to conduct the approved monitoring and
 submit their IDSE report (including the
 system's recommended Stage 2
 compliance monitoring) for State or
 primacy agency review on a schedule
 that  allows for systems to still have a
 minimum of full three years to comply
 with Stage 2 following State or primacy
 agency review of the system's Stage 2
 recommended monitoring. As with the
 review of plans, systems can consider
 that  their IDSE report has been
 approved if they have not heard back
 from the State by the end  of the State
 review period.
  State/primacy agency oversight. EPA
 is preparing to support implementation
 of IDSE requirements that must be
 completed prior to States  achieving
 primacy. Several States have expressed
 concern about EPA providing guidance
and reviewing reports from systems that
the State has permitted, inspected, and
worked with for a long time. These
States believe that their familiarity with

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             Federal Register/Vol. 71, No.  2/Wednesday, January 4,  2006/Rules and Regulations
                                                                       419
the systems enables them to make the
best decisions to implement the rule
and protect public health and that the
rule requirement should be delayed
until States receive primacy.
Commenters were concerned that some
States will not participate in early
implementation activities and indicated
that States would prefer monitoring to
begin 24 months after rule
promulgation. Commenters also noted
that States need sufficient time  to
become familiar with the rule, train
their staff, prepare primacy packages,
and train PWSs.
  EPA agrees that State familiarity is an
important component of the review and
approval process, looks forward to
working closely with the State drinking
water program representatives during
IDSE implementation, and welcomes
proactive State involvement. However,
the Agency believes that delaying
implementation of risk-based IDSE
targeting activities until States receive
primacy is an unacceptable delay in
public health protection and also
inconsistent with the Advisory
Committee's recommendations. EPA
remains committed to working  with
States to the greatest extent feasible to
implement today's rule, consistent with
the schedule promulgated today. For
States unable to actively participate in
IDSE implementation, however, EPA
believes it has an obligation to provide
support and guidance to PWSs  who are
covered and independently responsible
for complying with the  IDSE
requirements of today's rule and is
prepared to oversee implementation.
Moreover, EPA believes that the
staggered compliance schedule in
today's final rule will enhance  States'
ability to help implement the rule.
  Consecutive systems. Most
commenters supported  consecutive
systems being on the same IDSE
schedule as wholesale systems,
recognizing the benefits of treatment
plant capital and operational
improvements by the wholesale system
as the preferred method of DBF
compliance, with the timely collection
of DBF data throughout the combined
distribution system a key component.
Several commenters preferred that
consecutive systems have a  later Stage
2 compliance date to allow for
evaluation of whether wholesale system
treatment changes are adequate to
ensure compliance and to consider
changes to water delivery specifications.
  EPA disagrees with those  commenters
recommending a different Stage 2
compliance date and thus has
maintained the approach in the
proposal, which keeps all systems  that
are part of a combined distribution
system (the interconnected distribution
system consisting of the distribution
systems of wholesale systems and of the
consecutive systems that receive
finished water) on the same Stage 2
compliance schedule. Extending the
Stage 2 compliance dates would
unnecessarily delay the public health
protection afforded by this rule.
Consecutive systems must be able to
evaluate whether wholesale system
changes are sufficient to ensure
compliance and, if they are not, to make
cost-effective changes to ensure
compliance where wholesale system
efforts address some, but not all, of the
concerns with compliance. Public
health protection through compliance
with Stage 2 MCLs will occur on the
schedule of the largest system for all
systems in the combined distribution
system (regardless of size). If a
consecutive system must make capital
improvements to comply with this rule,
the State may use its existing authority
to grant up to an additional 24 months
to that system. In addition,
implementation and data tracking will
be simplified because all systems in a
combined distribution system will be on
the same IDSE and Stage 2 compliance
schedule. EPA believes that this is a
better approach from both a public
health standpoint and an
implementation standpoint.
  EPA agrees with many commenters
that a high level of coordination among
wholesaler, consecutive system, and
States will be necessary to ensure
compliance. The schedule in today's
rule provides more time for planning,
reviewing, and conducting the IDSE
than the schedule in the proposed rule,
which will allow more time for
necessary coordination, including small
consecutive systems that need help in
negotiations with their wholesale
system. EPA will work with ASDWA
and States to develop guidance to
facilitate wholesale/consecutive system
cooperation. This additional time and
the staggered schedule discussed in this
section also lessens the laboratory
burden associated with IDSE
monitoring.
  The staggered schedule also helps
address commenter concerns about
evaluating combined distribution
systems. Other commenters' concerns
about time needed for developing
contracts between systems and for
planning, funding, and implementing
treatment changes are addressed by not
requiring Stage 2 compliance until at
least six years following rule
promulgation.
F. Initial Distribution System Evaluation
(IDSE)
1. Today's Rule
  Today's rule establishes requirements
for systems to perform an Initial
Distribution System Evaluation (IDSE).
The IDSE is intended to identify sample
locations for Stage 2 compliance
monitoring that represent distribution
system sites with high DBP
concentrations. Systems will develop an
IDSE plan, collect data on DBP levels
throughout their distribution system,
evaluate these data to determine which
sampling locations  are most
representative of high DBP levels, and
compile this information into a report
for submission to the State or primacy
agency. Systems must complete one
IDSE to meet the requirements of
today's rule.
  a. Applicability. This requirement
applies to all community water systems,
and to large nontransient
noncommunity water systems (those
serving at least 10,000 people) that use
a primary or residual disinfectant other
than ultraviolet light, or that deliver
water that has been treated with a
primary or residual disinfectant other
than ultraviolet light. Systems serving
fewer than 500 people are covered by
the very small system waiver provisions
of today's rule and are not required to
complete an IDSE if they have TTHM
and HAAS data collected under Subpart
L. Consecutive systems are subject to
the IDSE requirements of today's rule.
Consecutive systems must comply with
IDSE requirements  on the same
schedule as the system serving the
largest population in the combined
distribution system, as described in
section IV.E.
  b. Data collection. For those systems
not receiving a very small system
waiver, there are three possible
approaches by which a system can meet
the IDSE requirement.
  i. Standard monitoring. Standard
monitoring requires one year of DBP
monitoring throughout the distribution
system on a specified schedule. Prior to
commencing standard monitoring,
systems must prepare a monitoring plan
and submit it to the primacy agency for
review. The frequency and number of
samples required under standard
monitoring is determined by source
water type and system size.  The number
of samples does not depend on  the
number of plants per system. Section
IV.G provides a detailed discussion of
the specific population-based
monitoring requirements for IDSE
standard monitoring. Although standard
monitoring results are not to be used for
determining compliance with MCLs,

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systems are required to include
individual sample results for the IDSE
results when determining the range of
TTHM and HAAS levels to be reported
in their Consumer Confidence Report
(see section IV.J).
  ii. System specific study. Under this
approach, systems may choose to
perform a system specific study based
on earlier monitoring studies or
distribution system hydraulic models in
lieu of standard monitoring. Prior to
commencing a system specific study,
systems must prepare a study plan and
submit it  to the primacy agency for
approval. The two options for system
specific studies are:  (1) TTHM and
HAA5 monitoring data that encompass
                           a wide range of sample sites
                           representative of the entire distribution
                           system, including those judged to
                           represent high TTHM and HAAS
                           concentrations, and (2) extended period
                           simulation hydraulic models that
                           simulate water age in the distribution
                           system, in conjunction with one round
                           of TTHM and HAAS sampling.
                             iii. 40/30 certification. Under this
                           approach, systems must certify to their
                           State or primacy  agency that every
                           individual compliance sample taken
                           under subpart L during the period
                           specified in Table IV.F-2 were less than
                           or equal to 0.040  mg/L for TTHM and
                           less than or equal to 0.030 mg/L for
                           HAAS, and that there were no TTHM or
HAAS monitoring violations during the
same period. The State or primacy
agency may require systems to submit
compliance monitoring results,
distribution system schematics, or
recommend subpart V compliance
monitoring locations as part of the
certification. This certification must be
kept on file and submitted to the State
or primacy agency for review. Systems
that qualify for reduced monitoring for
the Stage 1 DBPR during the two years
prior to the start of the IDSE may use
results of reduced Stage 1 DBPR
monitoring to prepare the 40/30
certification. The requirements for the
40/30 certification are listed in Table
IV.F-1.
                                 TABLE IV.F-1.—40/30 CERTIFICATION REQUIREMENTS
40/30 Certification Requirements ...
                    A certification that every individual compliance sample taken under subpart L during the period specified
                    in Table IV F-2 were less than or equal to 0.040 mg/L for TTHM and less than or equal to 0.030 mg/L
                    for HAAS, and that there were no TTHM or HAAS monitoring violations during the same period.
                    Compliance monitoring results, distribution system schematics, and/or recommended subpart V compli-
                    ance monitoring locations as required by the State or primacy agency.
                                        TABLE IV.F-2.—40/30 ELIGIBILITY DATES
If your 40/30 Certification Is Due
(1) October 1 2006
(2) April 1 2007
(3) October 1 2007 	
(4} April 1 . 2008 	
Then your eligibility
calendar quarters o
January 2004
January 2004
January 2005
January 2005.
for 40/30 certification is based on
; subpart L compliance monitoring
no earlier than1




eight consecutive
results beginning




  1 Unless you are on reduced monitoring under subpart L and were not required to monitor during the specified period. If you did not monitor
during the specified period, you must base your eligibility on compliance samples taken during the 12 months preceding the specified period.
  c. Implementation. All systems
subject to the IDSE requirement under
this final rule (except those covered by
the very small system waiver) must
prepare and submit an IDSE plan
(monitoring plan for standard
                           monitoring, study plan for system
                           specific study) or 40/30 certification to
                           the State or primacy agency. IDSE plans
                           and 40/30 certifications must be
                           submitted according to the schedule
                           described in section IV.E and IV.M. The
requirements for the IDSE plan depend
on the IDSE approach that the system
selects and are listed  in Tables IV.F-1
and IV.F-3.
                               TABLE IV.F-3.—IDSE MONITORING PLAN REQUIREMENTS
  IDSE data collection alternative
                                                    IDSE plan requirements
Standard Monitoring
System Specific Study:
Hydraulic Model 	
                  •  Schematic of the distribution system (including distribution system entry points and their sources, and
                    storage facilities), with notes indicating locations and dates of all projected standard monitoring, and all
                    projected subpart L compliance monitoring.
                  •  Justification for all standard monitoring locations selected and a summary of data relied on to select
                    those locations.
                  •  Population served and system type (subpart H or ground water).

                  Hydraulic models must meet the following criteria:
                  •  Extended period simulation hydraulic model.
                  •  Simulate 24  hour variation in demand  and show a consistently repeating 24  hour pattern of residence
                    time.
                  •  Represent 75% of pipe volume; 50% of pipe length; all pressure zones; all 12-inch diameter and larger
                    pipes; all 8-inch  and larger pipes that connect pressure zones, influence zones from different sources,
                    storage facilities, major demand areas, pumps, and control valves, or are known or expected to be sig-
                    nificant conveyors of water; all pipes 6 inches and larger that connect remote areas of a distribution sys-
                    tem to the main  portion of the system; all storage facilities with standard operations represented in the
                    model; all active  pump stations with controls represented in the model; and all  active control valves.

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                                                                                           421
                           TABLE IV.F-3— IDSE MONITORING PLAN REQUIREMENTS—Continued
  IDSE data collection alternative
                                     IDSE plan requirements
System Specific Study:
Existing Monitoring Results
• The model must be calibrated, or have calibration plans, for the current configuration of the distribution
  system during the period of high  TTHM formation potential. All storage facilities must be evaluated as
  part of the calibration process.
• All required calibration must be completed no later than 12 months after plan submission.
Submission must include:
• Tabular or spreadsheet data demonstrating percent of total pipe volume and pipe length represented in
  the model, broken out by pipe diameter, and all required model elements.
• A description of all calibration activities undertaken, and if calibration is complete, a graph of predicted
  tank levels versus measured tank levels for the storage facility with the highest residence time in each
  pressure zone, and a time series graph of the residence time at the longest residence time storage facil-
  ity in the distribution system showing the predictions for the entire simulation  period (i.e., from time zero
  until the time it takes for the model to reach a consistently repeating pattern of residence time).
• Model output showing preliminary 24 hour average residence time predictions throughout the distribution
  system.
• Timing and number of samples planned for at least one  round of TTHM and HAAS monitoring at a num-
  ber of locations no less than  would be required for the system under standard monitoring  in § 141.601
  during the historical month of high TTHM. These samples must be taken at locations other than existing
  subpart L compliance monitoring locations.
• Description of how all requirements will be completed no later than 12 months  after submission of the
  system specific study plan.
• Schematic of the distribution  system (including distribution system entry points  and their sources, and
  storage facilities),  with notes  indicating the locations and dates of all completed system specific study
  monitoring (if calibration is complete) and all subpart L compliance monitoring
• Population served and system type (subpart H or ground water).
• If the  model submitted does not fully meet the requirements, the system must correct the deficiencies
  and respond to State inquiries on a schedule the State approves, or conduct standard monitoring

Existing monitoring results must meet the following criteria-
• TTHM and  HAAS  results  must be based  on  samples collected  and analyzed  in accordance with
  § 141.131. Samples must be collected within five years of the study plan submission date.
• The sampling locations and frequency must meet the requirements identified in Table IV.F-4. Each loca-
  tion must be sampled once during  the peak historical  month for TTHM  levels or HAAS  levels or the
  month of warmest water temperature for every 12 months of data submitted for that location. Monitoring
  results must include all subpart  L compliance monitoring results plus additional monitoring results as
  necessary to meet minimum sample requirements.
Submission must include:
• Previously collected monitoring results
• Certification that the reported  monitoring results include all compliance and non-compliance results gen-
  erated during the  time period beginning with the first reported result and ending with the  most recent
  subpart L results.
• Certification that the samples were representative of the entire distribution system  and that treatment
  and distribution system have not changed significantly since the samples were collected.
• Schematic of the distribution  system (including distribution system entry points  and their  sources, and
  storage facilities), with notes indicating the locations and dates of all completed or planned  system spe-
  cific study monitoring.
• Population served and system type (subpart H or ground water).
• If a system submits previously collected data that fully meet the number of samples required  for IDSE
  monitoring in Table IV.F-4 and some of the data are rejected due to not meeting the additional require-
  ments, the system must either conduct additional monitoring to replace rejected data on a schedule the
  State approves, or conduct standard monitoring.
                        TABLE IV.F-4.—SSS EXISTING MONITORING DATA SAMPLE REQUIREMENTS.
System type
Subpart H:






Population size category

<500
500-3,300
3,301-9,999
10,000-49,999
50,000-249,999
250,000-999,999
Number of
monitoring lo-
cations

3
3
6
12
24
36
Number of samples
TTHM

3
9
36
72
144
216
HAAS

3
9
36
72
144
216

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Federal Register/Vol. 71, No. 2/Wednesday, January 4,  2006/Rules and  Regulations
                TABLE IV.F-4.—SSS EXISTING MONITORING DATA SAMPLE REQUIREMENTS.—Continued
System type


Ground Water.




Population size category
1,000,000-4,999,999
> 5,000,000
<500
500-9,999
10,000-99,999
100,000-499,999
> 500,000
Number of
monitoring lo-
cations
48
60
3
3
12
18
24
Number of samples
TTHM
288
360
3
9
48
72
96
HAAS
288
360
3
9
48
72
96
   The State or primacy agency will
approve the IDSE plan or 40/30
certification, or request modifications. If
the State or primacy agency has not
taken action by the date specified in
section IV.E or has not notified the
system that review is not yet complete,
systems may consider their submissions
to be approved. Systems must
implement the IDSE option described in
                          the IDSE plan approved by the State or
                          primacy agency according to the
                          schedule described in section IV.E.
                            All systems completing standard
                          monitoring or a system specific study
                          must submit a report to the State or
                          primacy agency according to the
                          schedule described in section IV.E.
                          Systems that have completed their
                          system specific study at the time of
monitoring plan submission may submit
a combined monitoring plan and report
on the required schedule for IDSE plan
submissions. The requirements for the
IDSE report are listed in Table IV.F-5.
Some of these reporting requirements
have changed from the proposal to
reduce reporting and paperwork burden
on systems.
                                    TABLE IV.F-5.—IDSE REPORT REQUIREMENTS
  IDSE data collection alternative
                                                  IDSE report requirements
Standard Monitoring .
System Specific Study
                   All subpart L compliance monitoring and standard monitoring TTHM and HAAS analytical results in a
                   tabular format acceptable to the State.
                   If changed from the monitoring plan, a schematic of the distribution system, population served, and sys-
                   tem type.
                   An explanation of any deviations from the approved monitoring plan.
                   Recommendations and justifications for subpart V compliance monitoring locations and timing.
                   All subpart L compliance monitoring and all system specific study monitoring TTHM and HAAS analytical
                   results conducted during the period of the system specific study in a tabular or spreadsheet form accept-
                   able to the State.
                   If changed from the study plan, a schematic of the distribution system, population served, and system
                   type.
                   If using the modeling provision, include  final information for required plan submissions and a 24-hour
                   time series graph of residence time for each subpart V compliance monitoring location selected
                   An explanation of any deviations from the original study plan.
                   All analytical and modeling results used to select subpart V compliance monitoring locations that show
                   that the system specific study  characterized TTHM and HAAS levels throughout the entire distribution
                   system
                   Recommendations and justifications for subpart V compliance monitoring locations and timing.
  All systems must prepare Stage 2
compliance monitoring
recommendations. All IDSE reports
must include recommendations for
Stage 2 compliance monitoring
locations and sampling schedule.
Systems submitting a 40/30 certification
must include their Stage 2 compliance
monitoring recommendations in their
Stage 2 (Subpart V) monitoring plan
unless the State requests Subpart V site
recommendations as part of the 40/30
certification. The number of sampling
locations and the criteria for their
selection are described in § 141.605 of
                          today's final rule, and in section IV.G.
                          Generally, a system must recommend
                          locations with the highest LRAAs unless
                          it provides a rationale (such as ensuring
                          geographical coverage of the
                          distribution system instead of clustering
                          all sites in a particular section of the
                          distribution system) for selecting other
                          locations. In evaluating possible Stage 2
                          compliance monitoring locations,
                          systems must consider both Stage 1
                          DBPR compliance data and IDSE data.
                            The State or primacy agency will
                          approve the IDSE report or request
                          modifications. If the State or primacy
agency has not taken action by the date
specified in section IV.E or has not
notified the system that review is not
yet complete, systems may consider
their submission to be approved and
prepare to begin Stage 2 compliance
monitoring.
  EPA has developed the Initial
Distribution System Evaluation
Guidance Manual for the Final Stage 2
Disinfectants and Disinfection
Byproducts Rule (USEPA 2006) to assist
systems with implementing each of
these requirements. This guidance may
be requested from EPA's Safe Drinking

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                                                                      423
Water Hotline, which may be contacted
as described under FOR FURTHER
INFORMATION CONTACT in the beginning
of this notice. This guidance manual is
also available on the EPA Web site at
http://www.epa.gov/safewater/stage2/
index,html.

2. Background and Analysis
  In the Stage 2 DBPR proposal
(USEPA, 2003a), EPA proposed
requirements for systems to complete an
IDSE. The Agency based its proposal
upon the Stage 2 M-DBP Advisory
Committee recommendations in the
Agreement in Principle. The Advisory
Committee believed and EPA concurs
that maintaining Stage 1 DBPR
monitoring sites for the Stage 2  DBPR
would not accomplish the risk-targeting
objective of minimizing high DBF levels
and providing consistent and equitable
protection across the distribution
system. Most of these requirements have
not changed from the proposed rule.
  The data collection requirements of
the IDSE are designed to find both high
TTHM and high HAAS sites (see section
IV.G for IDSE monitoring requirements).
High TTHM and HAA5 concentrations
often occur at different locations in the
distribution  system. The Stage 1 DBPR
monitoring sites identified as the
maximum location are selected
according to residence time. HAAs can
degrade in the distribution system in the
absence of sufficient disinfectant
residual (Baribeau et al. 2000).
Consequently, residence time is not an
ideal criterion for identifying high
HAAS sites.  In addition, maximum
residence time locations that are
associated with high TTHM levels may
not be constant due to daily or seasonal
changes in demand. The analysis of
maximum residence time completed for
the selection of Stage 1 monitoring sites
may not have been capable of detecting
these variations. The Information
Collection Rule data show that  over 60
percent  of the highest HAA5 LRAAs and
50 percent of the highest TTHM LRAAs
were found at sampling locations in the
distribution  system other than the
maximum residence time compliance
monitoring location (USEPA 2003a).
Therefore, the method and assumptions
used to select the Information Collection
Rule monitoring sites and the Stage 1
DBPR compliance monitoring sites may
not reliably capture high DBF levels for
Stage 2 DBPR compliance monitoring
sites.
  a. Standard monitoring. The Advisory
Committee recommended that systems
sample throughout the distribution
system at twice the number of locations
as required under Stage 1 and, using
these results in addition to Stage 1
compliance data, identify high DBF
locations. Monitoring at additional sites
increases the chance of finding sites
with high DBF levels and targets both
DBFs that degrade and DBFs that form
as residence time increases in the
distribution system. EPA believes that
the required number of standard
monitoring locations plus Stage 1
monitoring results will provide an
adequate characterization of DBF levels
throughout the distribution system at a
reasonable cost. By revising Stage 2
compliance monitoring plans to target
locations with high DBFs, systems will
be required to take steps to  address high
DBF levels at locations that might
otherwise have gone undetected.
  The Advisory Committee
recommended that an IDSE be
performed by  all community water
systems, unless the system had
sufficiently low DBF levels or is a very
small system with a simple distribution
system. EPA believes that large
nontransient noncommunity water
systems (NTNCWS) (those serving at
least 10,000 people) also have
distribution systems that require further
evaluation to determine the locations
most representative of high DBF levels
and proposed that they be required to
conduct an IDSE. Therefore, large
NTNCWS and all community water
systems are required to comply with
IDSE requirements under today's final
rule, unless they submit a 40/30
certification or they are covered by the
very small system waiver provisions.
  b. Very small system waivers. Systems
serving fewer  than 500 people that have
taken samples under the Stage 1 DBPR
will receive a  very small system waiver.
EPA proposed and the Advisory
Committee recommended a very small
system waiver following a State
determination that the existing Stage 1
compliance monitoring location
adequately characterizes both high
TTHM and high HAAS for the
distribution system because many very
small systems have small or simple
distribution systems. The final rule
grants the very small system waiver to
all systems serving  fewer than 500 that
have Stage 1 DBPR data. This provision
was changed from the proposal to reflect
that most very small systems that
sample under the Stage 1 DBPR have
sampling locations that are
representative of both high  TTHM and
high HAAS because most very small
systems have small and simple
distribution systems. In addition, many
very small systems are ground water
systems that typically have stable DBF
levels that tend to be lower than surface
water DBF levels. NRWA survey data
show that free chlorine residual in very
small systems (serving <500) at both
average residence time and maximum
residence time locations are lower than
levels at both of those locations in larger
systems, and the change in residual
concentration between those two
locations is smaller in very small
systems compared to larger sized
systems. The magnitude of the
reduction in residual concentration
gives an indication of how much
disinfectant has reacted to form DBFs,
including TTHM and HAAS. The
smaller reduction in disinfectant
concentration between average
residence time and maximum residence
time in very small systems compared to
larger systems indicates that DBF
formation potential is probably lower in
very small systems compared to larger
systems, and the likelihood for
significant DBP variation within the
distribution system of very small
systems is low if the distribution system
is small and not complex. However,
there may be some small systems  with
extended or complex distribution
systems that should be studied further
to determine new sampling locations.
For this reason, States or primacy
agencies can require any particular very
small system to conduct an IDSE.  Very
small systems subject to the Stage 2
DBPR that do not have a Stage  1
compliance monitoring location may
monitor in accordance with the Stage 1
DBPR provisions to be  eligible for this
waiver.
  c. 40/30 certifications. Systems  that
certify to their State or primacy agency
that all compliance samples taken
during eight consecutive calendar
quarters prior to the start of the IDSE
were <0.040 mg/L TTHM and <0.030
mg/L HAAS are not required to collect
additional DBP monitoring data under
the IDSE requirements as long as the
system has no TTHM or HAAS
monitoring violations.  These criteria
were developed because both EPA and
the AdvisoryCommittee determined that
these systems most likely would not
have DBP levels that exceed the MCLs.
Systems must have qualifying TTHM
and HAAS data for eight consecutive
calendar quarters according to the
schedule in Table IV.F-2 to be eligible
for this option. Systems on reduced
monitoring that did not monitor during
the specified time period may use data
from the prior year to meet the 40/30
certification criteria. Systems that have
not previously conducted Stage 1  DBPR
compliance monitoring may begin such
monitoring to collect the data necessary
to qualify for 40/30 certification. The
certification and data supporting it must
be available to the public upon request.

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   The qualifying time period for the 40/
 30 certification has changed from the
 proposed rule.
   Under the proposed rule, the rule
 language identified a specific two year
 window with  start and end dates. In
 today's final rule, the qualifying time
 period has been changed to "eight
 consecutive calendar quarters of subpart
 L compliance  monitoring results
 beginning no earlier than * * *" (see
 Table IV.F-2). This change was made so
 that systems that have made a treatment
 change within the two years prior to
 rule promulgation and have collected
 initial data that meet the 40/30 criteria
 might have the opportunity to collect
 eight consecutive quarters of qualifying
 data and apply for a 40/30 certification.
 This schedule change also allows
 systems that have not previously
 monitored under Stage 1 an opportunity
 to qualify for a 40/30 certification.
   Under the proposed Stage 2 DBPR,
 systems that missed the deadline for
 submitting a 40/30 certification would
 be required to conduct either standard
 monitoring or a system specific study
 even if the system otherwise qualified
 for the 40/30 certification. Under
 today's final rule, systems that do not
 make any submission by the IDSE plan
 submission deadline will still receive a
 violation, but may submit a late 40/30
 certification if their data meet the
 requirements.  This change was made so
 that systems and primacy agencies do
 not spend time preparing and reviewing
 standard monitoring plans and IDSE
 reports for systems with a low
 likelihood of finding high TTHM and
 HAAS levels.
   The reporting requirements for this
 provision have been reduced from the
 requirements in the proposed
 rulemaking. In the proposal, systems
 qualifying for the 40/30 certification
 were required to submit all qualifying
 data and provide recommendations for
 Stage 2 compliance monitoring
 locations. The  final rule requires
 systems to submit a certification that
 their data meet all the requirements of
 the 40/30 certification and to include
 their Stage 2 compliance monitoring
 recommendations in their Stage 2
 monitoring plan. These changes were
 made to reduce the reporting burden on
 systems that qualify for the 40/30
 certification and to maintain
 consistency with monitoring plan
 requirements under the Stage 1 DBPR.
 This approach also gives systems more
time to select appropriate monitoring
sites for Stage 2 compliance monitoring.
The State or primacy agency may
request systems to submit the data, a
distribution system schematic, and/or
recommendations for Stage 2
                          compliance monitoring as part of the
                          40/30 certification. This provision was
                          included to facilitate primacy agency
                          review of 40/30 certifications; the
                          additional information is only required
                          if requested by the primacy agency.
                            d. System specific studies. Advisory
                          Committee members recognized that
                          some systems have detailed knowledge
                          of their distribution systems by way of
                          ongoing hydraulic modeling and/or
                          existing  widespread monitoring plans
                          (beyond that required for compliance
                          monitoring) that would provide
                          equivalent or superior monitoring site
                          selection information compared to
                          standard monitoring. Therefore, the
                          Advisory Committee recommended that
                          such systems be allowed to determine
                          new monitoring sites using system-
                          specific data such as hydraulic model
                          results or existing monitoring data; this
                          provision remains in the final rule. In
                          the proposed rule, the only specification
                          for SSSs was to identify  monitoring sites
                          that would be equivalent or superior to
                          those identified under Standard
                          Monitoring. The final rule includes
                          more specific requirements on how
                          these studies should be completed. The
                          requirements in the final rule were
                          developed  to be consistent with the
                          proposal, yet more specific to help
                          systems better understand expectations
                          under this  provision and lessen the
                          chances of a study plan not being
                          approved.
                           The new modeling requirements were
                          developed  to reflect that hydraulic
                          models can identify representative high
                          TTHM monitoring locations by
                          predicting hydraulic residence time in
                          the distribution system. Water age has
                          been found to correlate with TTHM
                          formation in the distribution system.
                          Consequently, for this system specific
                          study approach, hydraulic residence
                          time predicted by the model is used as
                          a surrogate for TTHM formation to
                          locate appropriate Stage  2 compliance
                          monitoring locations. To predict
                          hydraulic residence time in the
                          distribution system, the model must
                          represent most of the distribution
                          system and must have been calibrated
                          recently and appropriately to reflect
                          water age in the distribution system.
                          Requirements to reflect this are in
                          today's rule. All storage facilities must
                          be evaluated for the calibration, and
                          systems using this option must submit
                          a graph of predicted tank levels versus
                          measured tank levels for the storage
                          facility with the highest residence time
                          in each pressure zone.  These calibration
                          requirements are focused on storage
                          facilities because they are the largest
                          controlling factor for water age in the
                          distribution system. The  calibration
 requirements reflect the fact that the
 purpose of the model is to predict water
 age. ICR data show that HAA5 data do
 not necessarily correlate well with water
 age (USEPA 2003a). Because the
 purpose of the IDSE is to locate
 representative high locations for both
 TTHM and HAAS, one round of
 monitoring must be completed at
 potential Stage 2 compliance monitoring
 locations to determine appropriate
 HAA5 monitoring locations during the
 historical high month of TTHM
 concentrations. The number of locations
 must be no less than would be required
 under standard monitoring.
   Preliminary average residence time
 data are required as a part  of the study
 plan for systems to demonstrate that
 their distribution system hydraulic
 model is able to produce results for
 water age throughout the distribution
 system, even though calibration may not
 be complete. Systems also need  to
 describe their plans to complete the
 modeling requirements within 12
 months of submitting the study plan.
 These last two requirements were
 developed so that States can be assured
 that systems have the technical capacity
 to complete their modeling
 requirements by the IDSE report
 deadline. If systems cannot demonstrate
 that they are in a position to complete
 the modeling requirements according to
 the required schedule, they will be
 required to complete standard
 monitoring.
   All new modeling requirements were
 added to help systems demonstrate how
 their model will fulfill the purpose  and
 requirements of the IDSE and to assist
 primacy agencies with approval
 determinations. The associated
 reporting requirements were developed
 to balance the needs of systems to
 demonstrate that they have fulfilled the
 requirements and the needs of primacy
 agency reviewers to be able to
 understand the work completed  by the
 system.
  EPA has specified new requirements
 for systems complete an SSS using
 existing monitoring data to help systems
 understand the extent of historical data
 that would meet the requirements of the
 IDSE. The number of required sample
 locations and samples are consistent
 with sampling requirements under
 standard monitoring and the
recommendations made by the Advisory
 Committee. The Advisory Committee
recommended that systems complete an
IDSE sample at twice the number of
sites required by the Stage  1 DBPR in
addition to Stage 1 DBPR sampling.
Because the number of required Stage 1
DBPR monitoring locations varies
within each population category under

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                                                                       425
the Stage 1 plant-based monitoring
approach (since systems have different
numbers of plants), EPA used the
number of required Standard
Monitoring locations plus the number of
Stage 2 compliance monitoring
locations to develop minimum
requirements for the use of existing
monitoring data for the SSS. The
number of required locations and
samples are shown in Table IV.F-4.
Systems will use their Stage 1
monitoring results plus additional non-
compliance or operational samples to
fulfill these requirements. Small
systems with many plants may have
been collecting a disproportionate
number of samples under the Stage 1
DBPR compared to the population based
monitoring requirements presented in
today's rule and may have sufficient
historical data to characterize the entire
distribution system. These requirements
allow those systems to submit an SSS
based on existing Stage 1 monitoring
results, and they also accommodate
systems that have been completing
additional monitoring throughout the
distribution system.
  The requirement to sample during the
historical month of high TTHM, high
HAAS, or warmest water temperature
during each year for which data were
collected was added to maintain
consistency with the standard
monitoring requirements where each
location must be sampled one time
during the peak historical month.
Samples that qualify for this SSS must
have been collected  within five years of
the study plan submission date and
must reflect the current configuration  of
treatment and the  distribution system.
Five years was selected as a cut off for
eligible data so that all data submitted
would be reasonably representative of
current source water conditions and
DBF formation within the distribution
system. Data that are older may not
reflect current DBF formation potential
in the distribution system. Five years
prior to the submission of the study
plan also correlates with the signing of
the Agreement in Principle where the
Advisory Committee made the
recommendation for this provision.
Systems interested in using this
provision would have started eligible
monitoring after the agreement was
signed.
  Systems that submit existing
monitoring data must submit all Stage 1
sample results from the beginning of the
SSS to the time when the SSS plan is
submitted. The purpose of this
requirement is to demonstrate that there
have been no significant changes in
source water quality since the first
samples were collected, especially if all
existing monitoring results were taken
during the earliest eligible dates. Again,
these clarifications were made so that
systems could better understand the
extent of data necessary for a monitoring
plan to be deemed acceptable and be
confident that efforts to complete an
SSS would be found acceptable to the
State or primacy agency.
  e. Distribution System Schematics.
EPA has considered security concerns
that may result from the requirement for
systems to submit a distribution system
schematic as part of their IDSE plan.
EPA believes that the final rule strikes
an appropriate balance between security
concerns and the need for States and
primacy agencies to be able to review
IDSE plans. EPA has developed
guidance for systems on how to submit
a distribution system schematic that
does not include sensitive information.

3. Summary of Major Comments
  The Agency received significant
comments on the following issues
related to the proposed IDSE
requirements: Waiver limitations, and
State or primacy agency review of IDSE
plans.
  In the proposed rule, EPA requested
comment on what the appropriate
criteria should be for States or primacy
agencies to grant very small system
waivers. Commenters responded with a
wide range of suggestions including
support for the proposal as written,
different population cut-offs, State or
primacy agency discretion on what
system size should qualify for the
waiver, and alternative waiver criteria
such as pipe length or number of
booster stations. There was no
consensus among the commenters on
what changes should be made to the
proposal for the very small system
waiver requirements. EPA did not
change the population cutoff for the
very small system waiver because
analysis of NRW A survey data also
showed that systems serving fewer than
500 had different residence times and
lower free chlorine residual
concentrations compared to other
population categories,  indicating that
larger systems have different DBF
formation characteristics compared to
very small systems. Some of the
suggested changes for very  small system
waiver criteria may require data that are
not readily available to systems (such as
pipe length in service) and  for which
there were no specific criteria proposed
or recommended by the commenters.
Implementation of subjective very small
system waiver criteria would result in
reduced public health  protection from
the rule by allowing higher DBF levels
to go undetected.
  In addition to addressing the very
small system waivers, commenters
suggested that different criteria should
be used for the 40/30 certification, such
as higher minimum DBF levels, cut-offs
of 40/30 as LRAAs or RAAs rather than
single sample maximums, or State or
primacy agency discretion on which
systems should qualify for 40/30
certification. There was no consensus
among the commenters  on what changes
should be made to the proposal for the
40/30 certification requirements. EPA
did not change the requirements for the
40/30 certification eligibility because
the recommended alternatives were  not
technically superior to the requirements
of the proposed rule. Implementation of
40/30 criteria using an LRAA or RAA
would  result in reduced public health
protection from the rule by allowing
higher  DBF levels to go  undetected.  EPA
did change the eligibility dates and
reporting requirements for the 40/30
certification  to reduce the burden on the
system. Under today's final rule, States
or primacy agencies  can request TTHM
and HAA5 data as desired for a more in-
depth review of a system's
qualifications.
  Many commenters expressed concern
over the implementation schedule for
the IDSE. Commenters were especially
concerned that IDSE plans would be
developed and implemented prior to
State primacy, and once States receive
primacy, they might not support the
IDSE plan and would reject the results
of the completed IDSE. To address this
issue, commenters requested the
opportunity  for States to review the
IDSE plans prior to systems completing
their IDSEs. In today's rule EPA has
modified the compliance schedule for
the Stage 2 DBPR so that systems have
the opportunity to complete their IDSE
plan and have it reviewed by the
primacy agency prior to completing the
IDSE to address the concern that States
or primacy agencies  may reject the
results of the completed IDSE. The
changes to the compliance schedule are
discussed further in  section IV.E.

G. Monitoring Requirements and
Compliance  Determination for TTHM
and HAAS MCLs
  EPA is finalizing monitoring
requirements under  a population-based
approach described in this section. EPA
believes the population-based approach
will provide more representative high
DBF concentrations throughout
distribution  systems than would plant-
based monitoring, is equitable, and will
simplify implementation for both States
and systems. For these reasons, EPA
believes this approach is more
appropriate than the proposed plant-

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Federal Register/Vol. 71, No. 2/Wednesday, January 4,  2006/Rules  and Regulations
 based monitoring. Detailed discussion
 of the two approaches is presented in
 the preamble of the proposed rule
 (USEPA 2003a) and EA for today's rule
 (USEPA 2005a).
 1. Today's Rule
  Today's rule establishes TTHM and
 HAAS monitoring requirements for all
 systems based on a population-based
 monitoring approach instead of a plant-
 based approach. Under the population-
                          based approach, monitoring
                          requirements are based solely on the
                          retail population served and the type of
                          source water used and not influenced by
                          the number of treatment plants or entry
                          points in the distribution system as in
                          previous rules (i.e., TTHM Rule (USEPA
                          1979) and Stage 1 DBPR (USEPA
                          1998a)).
                            a. IDSE Monitoring. All systems
                          conducting IDSE standard monitoring
 must collect samples during the peak
 historical month for DBF levels or water
 temperature; this will determine their
 monitoring schedule. Table IV.G— 1
 contains the IDSE monitoring
 frequencies and locations for all source
 water and size category systems. Section
 IV.F identifies other approaches by
 which systems can meet IDSE
 requirements.
                          TABLE IV.G-1.—IDSE MONITORING FREQUENCIES AND LOCATIONS
Source water
type
Subpart H


Ground
Water

Population size category
<500 consecutive sys-
tems.
<500 non-consecutive
systems.
500-3,300 non-consecu-
tive systems.
500-3,300 consecutive
systems.
3301-9,999
1 0 000-49 999
50 000-249 999
250 000-999 999
1 000,000-4 999,999 	
>5 000 000

<500 consecutive sys-
tems.
<500 non-consecutive
systems.
500-9,999 	
1 0 000-99 999
1 00 000-499 999
>500.000 	
Monitoring periods and
frequency of sampling
one (during peak histor-
ical month)2.

four (every 90 days)


six (every 60 days)





one (during peak histor-
ical month)2.

four (every 90 days) 	


Distribution system monitoring locations 1
Total per
monitoring
period
2
2
2
2
4
8
16
24
32
40
2
2
2
6
8
12
Near entry
points
1

1


1
3
4
6
8
1


1
1
2
Average
residence
time






1
2
4
6
8
10




1
1
2
High TTHM
locations
1
1
1
1
2
3
5
8
10
12
1
1
1
2
3
4
High HAAS
locations
1

1
1
2
4
6
8
10


1
1
2
3
4
  1 A dual sample set (i.e., a TTHM and an HAA5 sample) must be taken at each monitoring location during each monitoring period.
  2The peak historical month is the month with the highest TTHM or HAA5 levels or the warmest water temperature.
  b. Routine Stage 2 Compliance
Monitoring. For all systems conducting
either standard monitoring or a system
specific study, initial Stage 2
compliance monitoring locations are
based on the system's IDSE results,
together with an analysis of a system's
Stage 1 DBPR compliance monitoring
results. Systems receiving 40/30
certification or a very small system
waiver, and nontransient
noncommunity water systems serving
<10,000 not required to conduct an
IDSE, base Stage 2 initial compliance
monitoring locations on the system's
Stage 1 DBPR compliance monitoring
results. Some of these systems may also
need an evaluation of distribution
system characteristics to identify
                         additional monitoring locations, if
                         required by the transition from plant-
                         based monitoring to population-based
                         monitoring.
                           Systems recommend Stage 2
                         monitoring locations generally by
                         arraying results of IDSE standard
                         monitoring (or system specific study
                         results) and Stage 1 compliance
                         monitoring by monitoring location (from
                         highest to lowest LRAA for both TTHM
                         and HAAS). Using the protocol in
                         §141.605(c) of today's rule, systems
                         then select the required number of
                         locations. Larger systems include
                         existing Stage 1 monitoring locations in
                         order to be able to have historical
                         continuity for evaluating how changes
                         in operations or treatment affect DBF
levels. Systems may also recommend
locations with lower levels of DBFs that
would not be picked up by the protocol
if they provide a rationale for the
recommendation. Examples of
rationales include ensuring better
distribution system or population
coverage (not having all locations in the
same area) or maintaining existing
locations with DBP levels that are nearly
as high as those that would otherwise be
selected. The State or primacy agency
will review these recommendations as
part of the review of the IDSE report
submitted by  systems that conducted
standard monitoring or a system specific
study.
  Table IV.G-2 contains the routine
Stage 2 TTHM and HAAS compliance

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             Federal Register/Vol.  71, No. 2/Wednesday, January 4, 2006/Rules and Regulations
                                                                       427
monitoring requirements for all systems
(both non-consecutive and consecutive
systems), as well as the protocol for
Stage 2 compliance monitoring location
selection in the IDSE report. Systems
that do not have to submit an IDSE
report (those receiving a 40/30
certification or very small system waiver
and nontransient noncommunity water
systems serving <10,000) must conduct
Stage 2 compliance monitoring as
indicated in the "Total per monitoring
period" column at current Stage 1
compliance monitoring locations, unless
the State or primacy agency specifically
directs otherwise. All systems are then
required to maintain and follow a Stage
2 compliance monitoring plan.
                   TABLE IV.G-2. ROUTINE COMPLIANCE MONITORING FREQUENCIES AND LOCATIONS
Source water type
Subpart H:
Ground water:
Population size category
<500 	
500-3300 	
3,301-9999 	
1 0 000-49 999
50 000-249 999
250 000-999 999 	
1 ,000 000-4 999 999
> 5 000 000 	
<500 	
500-9 999
1 0 000-99 999
100000-499999 	
> 500.000 	
Monitoring frequency1
oer vear ....
per quarter 	
per quarter 	
per quarter
per quarter
per quarter 	
per quarter . .
per quarter 	
per year 	 	
oer vear
per quarter
per quarter .. ..
oer Quarter 	
Distribution system monitoring location
Total per
monitoring
period2
2
2
2
4
8
12
16
20
2
2
4
6
8
Highest
TTHM loca-
tions
1
1
1
2
3
5
6
• 8
1
1
2
3
3
Highest
HAAS loca-
tions
1
1
1
1
3
4
6
7
1
1
1
2
3
Existing
Subpart L
compliance
locations



1
2
3
4
5

1
1
2
  1 All systems must monitor during month of highest DBF concentrations.
  2 Systems on quarterly monitoring must take dual sample sets every 90 days at each monitoring location, except for subpart H systems serving
500-3,300. Systems on annual monitoring and subpart H systems serving 500-3,300 are required to take individual TTHM and HAAS samples
(instead of a dual sample set) at the locations with the highest TTHM and HAAS concentrations, respectively. Only one location with a dual sam-
ple set per monitoring period is needed if highest TTHM and HAAS concentrations occur at the same location, and month, if monitored annually).
  Today's rule provides States the
flexibility to specify alternative Stage 2
compliance monitoring requirements
(but not alternative IDSE monitoring
requirements) for multiple consecutive
systems in a combined distribution
system. As a minimum under such an
approach, each consecutive system must
collect at least one sample among the
total number of samples required for the
combined distribution system and will
base compliance on samples collected
within its distribution system. The
consecutive system is responsible for
ensuring that required monitoring is
completed and the system is in
compliance. It also must document its
monitoring strategy as part of its subpart
V monitoring plan.
  Consecutive systems not already
conducting disinfectant residual
monitoring under the Stage 1 DBPR
must comply with the monitoring
requirements and MRDLs for chlorine
and chloramines. States may use the
provisions of § 141.134(c) to modify
reporting requirements. For example,
the State may require that only the
consecutive system distribution system
point-of-entry disinfectant
concentration be reported to
demonstrate MRDL compliance,
although monitoring requirements may
not be reduced.
  i. Reduced monitoring. Systems can
qualify for reduced monitoring, as
specified in Table IV.G-3, if the LRAA
at each location is <0.040 mg/L for
TTHM and <0.030 mg/L for HAA5 based
on at least one year of monitoring at
routine compliance monitoring
locations. Systems may remain on
reduced monitoring as long as the
TTHM LRAA is <0.040 mg/L and the
HAAS LRAA is <0.030 mg/L at each
monitoring location for systems with
quarterly reduced monitoring. If the
LRAA at any location exceeds either
0.040 mg/L for TTHM or 0.030 mg/L for
HAAS or if the source water annual
average TOC level, before any treatment,
exceeds 4.0 mg/L at any of the system's
treatment plants treating surface water
or ground water under the direct
influence of surface water, the system
must resume routine monitoring. For
systems with annual or less frequent
reduced monitoring, systems may
remain on reduced monitoring as long
as each TTHM sample is <0.060 mg/L
and each HAA5 sample is <0.045 mg/L.
If the annual (or less frequent) sample
at any location exceeds either 0.060 mg/
L for TTHM or 0.045 mg/L for HAAS,
or if the source water annual average
TOC level, before any treatment,
exceeds 4.0 mg/L at any treatment plant
treating surface water or ground water
under the direct influence of surface
water, the system must resume routine
monitoring.
                                TABLE IV.G-3.—REDUCED MONITORING FREQUENCY
Source water type
Subpart H:
Population size cat-
egory
<500 	
Monitoring fre-
quency '

Distribution system monitoring location per monitoring
Monitonna mav not be reduced.
period


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Federal  Register/Vol. 71, No. 2/Wednesday,  January 4, 2006/Rules and  Regulations
                           TABLE IV.G-3.—REDUCED MONITORING FREQUENCY—Continued
Source water type







Ground Water:





Population size cat-
egory
500-3 300
3301-9 999
10,000-49999 	
50,000-249 999 ....
250 000-999 999
1 ,000 000-
4,999,999.
>5,000 000
<500
500-9 999
1 0 000-99 999
1 00 000-499 999
>500,000 	

Monitoring fre-
quency '
per vear
psr year
per quarter 	
per Quarter 	
psr quarter
per quarter 	
per quarter 	
every third year ..
per year
per year
per quarter
per quarter 	

Distribution system monitoring location per monitoring period
1 TTHM and 1 HAAS sample' one at the location and during the quarter with
the highest TTHM single measurement, one at the location and during the
quarter with the highest HAA5 single measurement; 1 dual sample set per
year if the highest TTHM and HAA5 measurements occurred at the same
location and quarter.
2 dual sample sets1 one at the location and during the quarter with the highest
TTHM single measurement, one at the location and during the quarter with
the highest HAA5 single measurement.
2 dual sample sets at the locations with the highest TTHM and highest HAA5
LRAAs
4 dual sample sets — at the locations with the two highest TTHM and two high-
est HAA5 LRAAs.
6 dual sample sets — at the locations with the three highest TTHM and three
highest HAAS LRAAs
8 dual sample sets — at the locations with the four highest TTHM and four
highest HAAS LRAAs.
10 dual sample sets — at the locations with the five highest TTHM and five
highest HAA5 LRAAs.
1 TTHM and 1 HAAS sample' one at the location and during the quarter with
the highest TTHM single measurement, one at the location and during the
quarter with the highest HAA5 single measurement; 1 dual sample set per
year if the highest TTHM and HAA5 measurements occurred at the same
location and quarter.
1 TTHM and 1 HAAS sample' one at the location and during the quarter with
the highest TTHM single measurement, one at the location and during the
quarter with the highest HAAS single measurement; 1 dual sample set per
year if the highest TTHM and HAA5 measurements occurred at the same
location and quarter.
2 dual sample sets1 one at the location and during the quarter with the highest
TTHM single measurement, one at the location and during the quarter with
the highest HAAS single measurement.
2 dual sample sets' at the locations with the highest TTHM and highest HAAS
LRAAs
4 dual sample sets at the locations with the two highest TTHM and two high-
est HAAS LRAAs
  1 Systems on quarterly monitoring must take dual sample sets every 90 days.
  ii. Compliance determination. A PWS
is in compliance when the annual
sample or LRAA of quarterly samples is
less than or equal to the MCLs. If an
annual sample exceeds the MCL, the
system must conduct increased
(quarterly) monitoring but is not
immediately in violation of the MCL.
The system is out of compliance if the
LRAA of the quarterly samples for the
past four quarters exceeds the MCL.
  Monitoring and MCL violations are
assigned to the PWS where the violation
occurred. Several examples are as
follows:
  • If monitoring results in a
consecutive system indicate an MCL
violation, the consecutive system is in
violation because it has the  legal
responsibility for complying with the
MCL under State/EPA regulations. The
consecutive system may set up a
contract with its wholesale system that
details water quality delivery
specifications.
  • If a consecutive system has hired its
wholesale system under contract to
monitor in the consecutive system and
                          the wholesale system fails to monitor,
                          the consecutive system is in violation
                          because it has the legal responsibility
                          for monitoring under State/EPA
                          regulations.
                            • If a wholesale system has a
                          violation and provides that water to a
                          consecutive system, the wholesale
                          system is in violation. Whether the
                          consecutive system is in violation will
                          depend on the situation. The
                          consecutive system will also be in
                          violation unless it conducted
                          monitoring that showed that the
                          violation was not present in the
                          consecutive system.

                          2. Background and Analysis
                            EPA proposed the plant-based
                          approach for all systems that produce
                          some or all of their finished water and
                          the population-based monitoring
                          approach for systems purchasing all of
                          their finished water year-round. As part
                          of the proposal, EPA presented a
                          monitoring cost analysis for applying
                          this approach to all systems in the
                          Economic Analysis to better understand
the impacts of using the population-
based approach.
  The plant-based approach was
adopted from the 1979 TTHM rule and
the Stage 1 DBPR and was derived from
the generally valid assumption that, as
systems increase in size, they tend to
have more plants and increased
complexity. During the development of
the Stage 2 proposal, EPA identified a
number of issues associated with the
use of the plant-based monitoring
approach. These included: (1) Plant-
based monitoring is not as effective as
population-based monitoring in
targeting locations with the highest risk;
(2) a plant-based approach can result in
disproportionate monitoring
requirements for systems serving the
same number of people (due to widely
varying numbers of plants per system);
(3) it cannot be adequately applied to
plants or consecutive system entry
points that are operated seasonally or
intermittently if an LRAA is used for
compliance due to complex
implementation and a need for repeated
transactions between the State and

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             Federal Register/Vol. 71, No.  2/Wednesday, January 4,  2006/Rules and Regulations
                                                                       429
system to determine whether and how
compliance monitoring requirements
may need to be changed; (4) State
determinations of monitoring
requirements for consecutive systems
would be complicated, especially in
large combined distribution systems
with many connections between
systems; and (5) systems with multiple
disinfecting  wells would have to
conduct evaluation of common aquifers
in order to avoid taking unnecessary
samples for compliance (if they did not
conduct such evaluations under Stage
1). EPA requested comment on two
approaches to address these issues: (1)
keep the plant-based monitoring
approach and add new provisions to
address specific concerns; and (2) base
monitoring requirements on source
water type and population served, in
lieu of plant-based monitoring.
  The final rule's requirements of
population-based monitoring for all
systems are based on improved public
health protection, flexibility, and
simplified implementation. For
determining monitoring requirements,
EPA's objective was to maintain
monitoring loads consistent with Stage
1 and similar to monitoring loads
proposed for Stage 2 under a plant-
based approach, using a population-
based approach to facilitate
implementation, better target high DBP
levels, and protect human health. This
leads to a more cost-effective
characterization of where high levels
occur. For the proposed rule, EPA used
1995 CWSS  data to derive the number
of plants per system for calculating the
number of proposed monitoring sites
per system. During the comment period,
2000 CWSS  data became available.
Compared to the 1995 CWSS, the 2000
CWSS contained questions more
relevant for determining the number of
plants in each system. Based on 2000
CWSS data, EPA has modified the
number of monitoring sites per system
for several categories  (particularly for
the larger subpart H systems) to align
the median population-based
monitoring requirements with the
median monitoring requirements under
plant-based monitoring, as was
proposed.
  EPA also believes that more  samples
are necessary to characterize larger
systems (as defined by population) than
for smaller systems. This progressive
approach is included in Table  IV.G—4.
As system size increases, the number of
samples increases to better reflect the
hydraulic complexity of these  systems.
While the national monitoring burden
under the population-based approach  is
slightly less than under a plant-based
approach, some larger systems with few
plants relative to system population will
take more samples per system than they
had under plant-based monitoring.
However, EPA believes that many of
these  large systems with few plants have
traditionally been undermonitored (as
noted in the proposal). Systems with
more plants will see a reduction in
monitoring (e.g., small ground water
systems with multiple wells).
  While population-based monitoring
requirements for ground water systems
in today's rule remain the same as those
in the proposed rule, the final rule
consolidates ten population categories
for subpart H systems into eight
categories for ease of implementation.
As indicated in  Table IV.G-4, EPA has
gone from  four to three population size
categories for smaller subpart H systems
(serving fewer than 10,000 people) and
the ranges have been modified to be
consistent with those for other existing
rules (such as the Lead and Copper
Rule). This change will reduce
implementation transactional costs. For
medium and large subpart H systems
(serving at least 10,000 people), EPA has
gone from seven categories in the
proposal to five categories in final rule.
The population groups are sized so that
the ratio of maximum population to
minimum population for each of the
categories is consistent. EPA believes
that this will allow most systems to
remain in one population size category
and maintain the same monitoring
requirements within a reasonable range
of population variation over time. In
addition, it assures that systems within
a size category will not have disparate
monitoring burdens as could occur if
there were too few categories. Overall,
EPA believes that the population-based
monitoring approach allows systems to
have more flexibility to designate their
monitoring sites within the distribution
system to better target  high DBP levels
and is more equitable.
  To derive the number of monitoring
sites for IDSE standard monitoring, EPA
doubled the number of routine
compliance monitoring sites per system
for each size category.  This is consistent
with the advice and recommendations
of the M-DBP Advisory Committee for
the IDSE. EPA has developed the Initial
Distribution System Evaluation
Guidance Manual for the Final Stage 2
Disinfectants and Disinfection
Byproducts Rule (USEPA 2006) to assist
systems in choosing IDSE monitoring
locations, including criteria for selecting
monitoring.
      TABLE IV.G-4.—COMPARISON OF MONITORING LOCATIONS PER SYSTEM FOR STAGE 2 ROUTINE COMPLIANCE
                       MONITORING WITH PLANT-BASED AND POPULATION-BASED APPROACHES
Population category
<500 	
500 3 300
3 301-9 999 	
10000-49999 	
50 000-249 999
250 000— <1 million
1 million— <5 million
>5 million 	
Ratio of
maximum
population
to minimum
population
66
3
5
5
4
5
Number of
sampling
periods per
year
A
1
4
4
4
4
4
4
4
Plant-based
approach"
# Sites per
plant
B
"1
"1
2
4
4
4
4
4
Number of plants per sys-
tem (Based on 2000
CWSS data)
Median
C
1
1
1
1
1
2
4
4
Mean
D
1.21
1.22
1 56
1.37
1 83
253
3.62
433
Calculated number of sites
per system for plant-based
approach
Based on
median #
plants per
system
E=B*C
1
1
2
4
4
8
16
16
Based on
mean #
plants per
system
F=B*D
1 2
1 2
3.1
55
73
101
145
173
Number of
monitoring
sites per
system for
pop-based
approach
G
"1
"1
2
4
8
12
16
20
  *As in the proposal.
  " System is required to take individual TTHM and HAAS samples at the locations with the highest TTHM and HAAS concentrations, respectively, if highest TTHM
and HAA5 concentrations do not occur at the same location.

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  Note. To determine the number of routine compliance monitoring sites per population category, EPA took these steps- (1) Maintaining about the same sampling
 loads in the nation as required under the plant-based approach, but basing on population rather than number of plants to better target high DBP levels in distribution
 systems and facilitate implementation; (2) The number of monitoring sites per plant under the plant-based approach (Column B) were multiplied by the number of
 plants per system (Columns C and D) to calculate the number of monitoring sites per system under the plant-based approach (Columns E and F in terms of median
 and mean, respectively), and (3) The number of monitoring sites per system under the population-based approach were derived with adjustments to keep categories
 consistent and to maintain an even incremental trend as the population size category increases (Column G)
 3. Summary of Major Comments
   EPA received significant support for
 applying the population-based approach
 to all systems. EPA also received
 comments concerning the specific
 requirements in a population-based
 approach.
   Excessive Sampling Requirements.
 Several commenters believed that the
 proposed sampling requirements were
 excessive (especially in the larger
 population categories for subpart H
 systems) and that some individual
 systems would be required to sample
 more under the population-based
 approach than the plant-based
 approach. EPA recognizes that a small
 fraction of systems in some categories
 will have to take more samples under
 the population-based approach than the
 plant-based approach because their
 number of plants is substantially less
 than the national median or mean.
 However, the number of samples
 required under the Stage 1 DBPR for
 these systems may not have been
 sufficient to determine the
 concentrations of DBFs throughout the
 distribution system of these systems.  On
 the other hand, systems with many
 plants may have taken excessive
 samples under the Stage 1 DBPR that
 were not necessary to appropriately
 determine DBP levels throughout the
 distribution system. Consequently, the
 total number of samples taken
 nationally will be comparable to the
 Stage 1 DBPR, but will better target DBP
 risks in individual distribution systems.
  Consecutive systems. Some
 commenters noted that a consecutive
 system may need to take more samples
 than its associated wholesale system.
 Under today's rule, all systems,
 including consecutive systems, must
 monitor based on retail population
 served. Thus, large consecutive systems
 will take more samples than a smaller
 wholesale system. The population-based
 monitoring approach will allow the
 samples to  better represent the DBP
 concentrations consumed by the
 population associated with the sampling
 locations and to understand the DBP
 concentrations reaching consumers.
 There is also a provision that allows
 States to specify alternative monitoring
 requirements for a consecutive system
in a combined distribution system (40
CFR I42.16(m)(3)). This special primacy
condition allows the State to establish
monitoring requirements that account
                          for complicated distribution system
                          relationships, such as where
                          neighboring systems buy from and sell
                          to each other regularly throughout the
                          year. In this case, water may pass
                          through multiple consecutive systems
                          before it reaches a user. Another
                          example would be a large group of
                          interconnected systems that have a
                          complicated combined distribution
                          system. This approach also allows the
                          combined distribution system to
                          concentrate IDSE and Stage 2
                          monitoring sites in the system with the
                          highest known DBP concentrations,
                          while assigning fewer sample sites to
                          systems with low DBP concentrations.
                            Population Size Categories. Some
                          commenters recommended fewer
                          population categories for subpart H
                          systems (those using surface water or
                          ground water under the direct influence
                          of surface water as a source) than
                          proposed while others recommended
                          more. Today's rule has fewer categories
                          than proposed. However, EPA believes
                          that furtber reduction of the number  of
                          population size categories will not
                          reflect the fact that the number of plants
                          and complexity of distribution systems
                          (and DBP exposure) tend to increase  as
                          the population served increases. As a
                          result, the population served by a large
                          system in one particular category  would
                          receive much less protection from the
                          DBP risks than a smaller system in the
                          same size category. On the other hand,
                          too many categories with smaller
                          population ranges would result in
                          frequent category and requirement shifts
                          as population fluctuates. Much greater
                          implementation effort would be needed
                          for those systems without much benefit
                          in DBP exposure knowledge.
                            Population Definition. Some
                          commenters supported use of the
                          population of a combined distribution
                          system (i.e., the wholesale and
                          consecutive systems should be
                          considered a single system for
                          monitoring purposes) while others
                          preferred use of the retail population for
                          each individual  system (i.e., wholesale
                          systems and consecutive systems are
                          considered separately). Today's final
                          rule uses the retail population for each
                          individual system. EPA chose this
                          approach for today's rule because of the
                          complexity involved in making
                          implementation decisions for
                          consecutive systems. Using the retail
                          population to determine requirements
 eases the complexity by specifying
 minimum system-level requirements;
 simplicity is essential for meeting the
 implementation schedule in today's
 rule. If monitoring requirements were
 determined by the combined
 distribution system population, many
 implementation problems would occur.
 Some of these problems would have the
 potential to impact public health
 protection. For example, States or
 primacy agencies would have to decide
 how to allocate IDSE distribution
 system samples (where and how much
 to monitor in individual PWSs) in a
 complicated combined distribution
 system with many systems, multiple
 sources, multiple treatment plants, and
 varying water demand and with limited
 understanding of DBP levels throughout
 the combined distribution system. This
 would have to happen shortly after rule
 promulgation in order to meet the
 schedule. For example, some
 consecutive systems buy water
 seasonally (in times of high water
 demand) or buy from more than one
 wholesale system (with the volume
 purchased based on many factors). The
 State or primacy agency would find it
 difficult to properly assign a limited
 number of IDSE monitoring locations
 (especially since there are States where
 many consecutive systems have no DBP
 data) to adequately reflect DBP levels in
 such a system, as well as throughout the
 combined distribution system.
  EPA believes that assigning
 compliance monitoring requirements
 appropriately throughout the combined
 distribution system requires a case-by-
 case determination based on factors
 such as amount and percentage of
 finished  water provided; whether
 finished  water is provided seasonally,
 intermittently, or full-time; and
 improved DBP occurrence information.
 Since the IDSE will provide improved
 DBP occurrence information throughout
 the combined distribution system,
 States may consider modifications to
 Stage 2 compliance monitoring
requirements for consecutive systems on
 a case-by-case basis as allowed by
 § 141.29  or under the special primacy
 condition at § 142.16(m)(3) by taking all
these factors into consideration. In
making these case-by-case
determinations, the State will be able to
use its system-specific knowledge, along
with the  IDSE results, to develop an
appropriate monitoring plan for each

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                                                                       431
system within the combined
distribution system.
  Changes to monitoring plans.
Commenters requested more specific
language regarding how IDSE and Stage
2 monitoring plans should be updated
as a result of treatment or population
changes in the distribution system.
Changes to IDSE plans should not be
necessary since the State or primacy
agency will have reviewed those plans
shortly before the system must conduct
the IDSE and the reviewed plan should
identify such issues. EPA provided a
process in the Stage 2 DBPR proposal
for updating monitoring plans for
systems that have significant changes to
treatment or in the distribution system
after they complete their IDSE. This
process remains in today's rule, with an
added requirement that systems must
consult with the State or primacy
agency to determine whether the
changes are necessary and appropriate
prior to implementing changes to their
Stage 2 monitoring plan.
  In addition, the State or primacy
agency may require a system to revise
its IDSE plan, IDSE report, or Stage 2
monitoring plan at any time. This
change was made so that systems could
receive system-specific guidance from
the  State or primacy agency on the
appropriate revisions to the Stage 2
monitoring plan. Regulatory language
regarding changes that might occur is
not appropriate because any
modifications would be system-specific
and a national requirement is not
capable of addressing these  system-
specific issues.
H. Operational Evaluation
Requirements Initiated by TTHM and
HAAS Levels
  A system that is in full compliance
with the Stage 2 DBPR LRAA MCL may
still have individual DBP measurements
that exceed the  Stage 2 DBPR MCLs,
since compliance is based on individual
DBP measurements at a location
averaged over a four-quarter period.
EPA and the Advisory Committee were
concerned about these higher levels of
DBFs. This concern was clearly
reflected in the  Agreement in Principle,
which states, "... significant
excursions of DBP levels will sometimes
occur, even when systems are in full
compliance with the enforceable
MCL.-.  .".
  Today's final  rule addresses this
concern by requiring systems to conduct
operational evaluations that are initiated
by operational evaluation levels
identified in Stage 2 DBPR compliance
monitoring and to submit an operational
evaluation report to the State.
1. Today's Rule
  Today's rule defines the Stage 2 DBP
operational evaluation levels that
require systems to conduct operational
evaluations. The Stage 2 DBP
operational evaluation levels are
identified using the system's Stage 2
DBPR compliance monitoring results.
The operational evaluation levels for
each monitoring location are
determined by the sum of the two
previous quarters' TTHM results plus
twice the current quarter's TTHM result,
at that location, divided by 4 to
determine an average and the sum of the
two previous quarters' HAA5 results
plus twice the current quarter's HAAS
result, at that location, divided by 4 to
determine an average. If the average
TTHM exceeds 0.080 mg/L at any
monitoring location or the average
HAA5 exceeds 0.060  mg/L at any
monitoring location, the system must
conduct an operational evaluation and
submit a written report of the
operational evaluation to the State.
  Operational evaluation levels
(calculated at each monitoring location)
  IF (Qi + Cb + 2Q,)/4> MCL, then the
system must conduct an operational
evaluation
where:
  Q3 = current quarter measurement
  Q2 = previoius quarter measurement
  Qi = quarter before previous quarter
    measurement
  MCL = Stage 2 MCL for TTHM (0.080
mg/1) or Stage 2 MCL for HAAS (0.060
mg/L)
  The operational evaluation includes
an examination of system treatment and
distribution operational practices,
including changes in  sources or source
water quality, storage tank operations,
and excess storage capacity, that may
contribute to high TTHM and HAAS
formation. Systems must also identify
what steps could be considered to
minimize future operational evaluation
level exceedences. In cases where the
system can identify the cause of DBP
levels that resulted in the  operational
evaluation, based on factors such as
water quality data, plant performance
data, and distribution system
configuration the system may request
and the State may allow limiting the
evaluation to the identified cause. The
State must issue a written determination
approving limiting the scope of the
operational evaluation. The system must
submit their operational evaluation
report to the State for review within 90
days after being notified of the
analytical result that initiates the
operational evaluation. Requesting
approval to limit the scope of the
operational evaluation does not extend
the schedule (90 days after notification
of the analytical result) for submitting
the operational evaluation report.
2. Background and Analysis
  The Stage 2 DBPR proposal outlined
three components of the requirements
for significant excursions (definition,
system evaluation and excursion
report). In response to public comments,
the term "significant excursion" has
been replaced by the term "operational
evaluation level" in today's rule. The
evaluation and report components
remain the same as those  outlined in the
proposed rule for significant excursions.
However, the scope of the evaluation
and report components of the
operational evaluation has also been
modified from the proposed significant
excursion evaluation components based
on public  comments.
  In the Stage 2 DBPR proposal, States
were to define criteria to identify
significant excursions rather than using
criteria defined by EPA. Concurrent
with the Stage 2 DBPR proposal, EPA
issued draft guidance (USEPA 2003e)
for systems and States that described
how to determine whether a significant
excursion has occurred, using several
different options. The rule proposal
specifically requested public comment
on the definition of a significant
excursion, whether it should be defined
by the State or nationally, and the scope
of the evaluation.
  After reviewing comments on the
Stage 2 DBPR proposal, EPA determined
that DBP levels initiating  an operational
evaluation should be defined in the
regulation to ensure national
consistency. Systems were concerned
with the evaluation requirements being
initiated based on criteria that might not
be consistent nationally. Also, many
States believed the requirement for
States to define criteria to initiate an
evaluation would be difficult for States
to implement.
  Under today's rule, EPA is defining
operational evaluation levels with an
algorithm  based on Stage  2 DBPR
compliance monitoring results. These
operational evaluation levels will act as
an early warning for a possible MCL
violation in the following quarter. This
early warning is accomplished because
the operational evaluation requirement
is initiated when the system assumes
that the current quarter's result is
repeated and this will result in an MCL
violation.  This early identification
allows the system to act to prevent the
violation.
  Today's rule also modifies the scope
of an operational evaluation. EPA has
concluded that the source of DBP levels

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 that would initiate an operational
 evaluation can potentially be linked to
 a number of factors that extend beyond
 distribution system operations.
 Therefore, EPA believes that evaluations
 must include a consideration of
 treatment plant and other system
 operations rather than limiting the
 operational evaluation to only the
 distribution system, as proposed.
 Because the source of the problem could
 be associated with operations in  any of
 these system components (or more than
 one), an evaluation that provides
 systems with valuable information to
 evaluate possible modifications to
 current operational practices (e.g. water
 age management, source blending) or in
 planning system modifications or
 improvements (e.g. disinfection
 practices, tank modifications,
 distribution looping) will reduce DBF
 levels initiating an operational
 evaluation. EPA also believes that State
 review of operational evaluation  reports
 is valuable for both States and systems
 in their interactions, particularly when
 systems may be in discussions with or
 requesting approvals from the State for
 system improvements. Timely reviews
 of operational evaluation reports will be
 valuable for States in reviewing other
 compliance submittals and will be
 particularly valuable in reviewing and
 approving any proposed source,
 treatment or distribution system
 modifications for a water system. Under
 today's rule, systems must submit a
 written report of the operational
 evaluation to the State no later than 90
 days after being notified of the DBP
 analytical result initiating an
 operational evaluation. The written
 operational evaluation report must also
 be made available to the public upon
 request.

 3. Summary of Major Comments
  EPA received comments both in favor
 of and opposed to the proposed
 evaluation requirements. While some
 commenters felt that the evaluation
 requirements should not be a part of the
 Stage 2 DBPR until there was more
 information regarding potential health
 effects correlated to specific DBP levels,
 other commenters felt that the existing
 health effects data were sufficient to
 warrant strengthening the proposed
 requirements for an evaluation. Today's
 final rule requirements are consistent
 with the Agreement in Principle
 recommendations.
  Some commenters noted that health
 effects research on DBFs is insufficient
to identify a level at which health
effects occur and were concerned that
the proposed significant excursion
requirements placed an emphasis on
                          DBP levels that might not be warranted
                          rather than on system operational issues
                          and compliance with Stage 2 DBPR
                          MCLs.
                            Basis. The proposed requirements for
                          significant excursion evaluations were
                          not based upon health effects, but rather
                          were intended to be an indicator of
                          operational performance. To address
                          commenter's concerns and to emphasize
                          what EPA believes should initiate a
                          comprehensive evaluation of system
                          operations that may result in elevated
                          DBP levels and provide a proactive
                          procedure to address compliance with
                          Stage 2 DBP LRAA MCLs , EPA has
                          replaced the term "significant
                          excursion" used in the Stage 2 DBPR
                          proposal with the term "operational
                          evaluation level" in today's  rule.
                            Definition of the operational
                          evaluation levels. The majority of
                          commenters stated that EPA should
                          define the DBP levels initiating an
                          operational evaluation ("significant
                          excursion" in the proposal)  in the
                          regulation to ensure national
                          consistency rather than requiring States
                          to develop their own criteria (as  was
                          proposed). Commenters suggested
                          several definitions, including a single
                          numerical limit and calculations
                          comparing previous quarterly DBP
                          results to the current quarter's result.
                          Commenters that recommended  a single
                          numerical limit felt that such an
                          approach was justified by the available
                          health effects information, while other
                          commenters felt available heath  effects
                          information did not support a single
                          numerical limit. Commenters
                          recommended that any definition be
                          easy to understand and implement.
                           EPA agrees with commenter
                          preference for national criteria to
                          initiate an operational evaluation. The
                          DBP levels initiating an operational
                          evaluation in today's rule consider
                          routine operational variations in
                          distribution systems, are  simple  for
                          water systems to calculate, and
                          minimize the implementation burden
                          on States. They also provide an early
                          warning to help identify possible future
                          MCL violations and allow the system to
                          take proactive steps to remain in
                          compliance. EPA emphasizes, as it did
                          in the proposal and elsewhere in this
                          notice, that health effects research is
                          insufficient to identify a level at  which
                          health effects occur, and thus today's
                          methodology for initiating operational
                          evaluation is not based upon health
                          effects, but rather is intended as an
                          indicator of operational performance.
                           Scope of an evaluation. Some
                          commenters felt that the scope of an
                          evaluation initiated by locational DBP
                          levels should be limited to the
 distribution systems, as in the proposal.
 Others felt that the treatment processes
 should be included in the evaluation,
 noting that these can be significant in
 the formation of DBFs.
   The Agency agrees with commenters
 that treatment processes can be a
 significant factor in DBP levels initiating
 an operational evaluation and that a
 comprehensive operational evaluation
 should address treatment processes. In
 cases where the system can clearly
 identify the cause of the DBP levels
 initiating an operational evaluation
 (based on factors such as water quality
 data, plant performance data,
 distribution system configuration, and
 previous evaluations) the State may
 allow the system to limit the scope of
 the evaluation to the identified cause. In
 other cases, it is appropriate to evaluate
 the entire system, from source through
 treatment to distribution system
 configuration  and operational practices.
   Timing for completion and review of
 the evaluation report. While some
 commenters agreed that the evaluation
 report should  be reviewed as part of the
 sanitary survey process (as proposed),
 many commenters felt that the time
 between sanitary surveys (up to five
 years)  minimized the value of the
 evaluation report in identifying both the
 causes of DBP levels initiating an
 operational evaluation and in possible
 changes to prevent recurrence.
 Moreover, a number of commenters felt
 that the evaluation report was important
 enough to warrant a separate submittal
 and State review rather than have the
 evaluation report compete with other
 priorities during a sanitary survey.
  The  Agency agrees that completion
 and State review of evaluation reports
 on a three or five year sanitary survey
 cycle, when the focus of the evaluation
 is on what may happen in the next
 quarter, would allow for an
 unreasonable period of time to pass
 between the event initiating the
 operational evaluation and completion
 and State review of the report. This
 would diminish the value of the
 evaluation report for both systems and
 States, particularly when systems may
 be in discussions with or requesting
 approval for treatment changes from
 States, and as noted above, the focus of
 the report is on what may occur in the
 next quarter. EPA believes that timely
reviews of evaluation reports by States
 is important, would be essential for
 States in understanding system
operations and reviewing other
compliance submittals, and would be
extremely valuable in reviewing and
approving any proposed source,
treatment or distribution system
modifications for a water system.

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Having the evaluation information on an
ongoing basis rather than a delayed
basis would also allow States to
prioritize their resources in scheduling
and reviewing particular water system
operations and conditions as part of any
on-site system review or oversight.
Therefore, today's rule requires that
systems complete  the operational
evaluation and submit the evaluation
report to the State within 90 days of the
occurrence.

/. MCL, BAT, and Monitoring for
Bromate

1. Today's Rule
  Today EPA is confirming that the
MCL for bromate for systems using
ozone remains at 0.010 mg/L as an RAA
for samples taken at the entrance to the
distribution system as established by the
Stage 1 DBPR. Because the MCL remains
the same, EPA is not modifying the
existing bromate BAT. EPA is changing
the criterion for a system using ozone to
qualify for reduced bromate monitoring
from demonstrating low levels of
bromide to demonstrating low levels of
bromate.

2. Background and Analysis
  a. Bromate MCL. Bromate is a
principal byproduct from ozonation of
bromide-containing source waters. As
described in more detail in the Stage 2
DBPR proposal (USEPA 2003a), more
stringent bromate MCL has the potential
to decrease current levels of microbial
protection, impair the ability of systems
to control resistant pathogens like
Cryptosporidium, and increase levels of
DBFs from other disinfectants that may
be used instead of ozone. EPA
considered reducing the bromate MCL
from 0.010 mg/L to 0.005 mg/L as an
annual average but concluded that many
systems using ozone to inactivate
microbial pathogens would have
significant difficulty maintaining
bromate levels at or below 0.005  mg/L.
In addition, because of the high doses
required, the ability of systems to use
ozone to meet Cryptosporidium
treatment requirements under the
LT2ESWTR would be diminished if the
bromate MCL was decreased from 0.010
to 0.005 mg/L; higher doses will
generally lead to greater bromate
formation. After evaluation under the
risk-balancing provisions of section
1412(b)(5) of the SDWA, EPA concluded
that the existing MCL was justified. EPA
will review the bromate MCL as part of
the six-year review process and
determine whether the MCL should
remain at 0.010 mg/L or be reduced to
a lower level. As a part of that review,
EPA will consider the increased
utilization of alternative technologies,
such as UV, and whether the risk/risk
concerns reflected in today's rule, as
well as in the LT2ESWTR, remain valid.
  b. Criterion for reduced bromate
monitoring. Because more sensitive
bromate methods are now available,
EPA is requiring a new criterion for
reduced bromate monitoring. In the
Stage 1 DBPR, EPA required ozone
systems to demonstrate that source
water bromide levels, as a running
annual average, did not exceed 0.05 mg/
L. EPA elected to use bromide as a
surrogate for bromate in determining
eligibility for reduced monitoring
because the available analytical method
for bromate was not sensitive enough to
quantify levels well below the bromate
MCL of 0.010 mg/L.
  EPA approved several new analytical
methods for bromate that are far more
sensitive than the existing method as
part of today's rule. Since these methods
can measure bromate to levels of 0.001
mg/L or lower, EPA is replacing the
criterion for reduced bromate
monitoring (source water bromide
running annual average not to exceed
0.05 mg/L) with a bromate running
annual average not to exceed 0.0025 mg/
L.
  In the past, EPA has often set the
criterion for reduced monitoring
eligibility at 50% of the MCL, which
would be 0.005 mg/L. However, the
MCL for bromate will remain at 0.010
mg/L, representing a risk level of 2xlO/
b 2xlO~4, 10"4 and 1Q-(1 (higher than
EPA's usual excess cancer risk range of
10~4 to 10^6) because of risk tradeoff
considerations) (USEPA 2003a).
  EPA believes that the decision for
reduced monitoring is separate from
these risk tradeoff considerations. Risk
tradeoff considerations influence the
selection of the MCL, while reduced
monitoring requirements are designed to
ensure that the MCL, once established,
is reliably and consistently achieved.
Requiring a running annual average of
0.0025 mg/L for the reduced monitoring
criterion allows greater confidence that
the system is achieving the MCL and
thus ensuring public health protection.

3. Summary of Major Comments
  Commenters supported both the
retention of the existing bromate MCL
and the modified reduced monitoring
criterion.

/. Public Notice Requirements

1. Today's Rule
  Today's rule does not alter existing
public notification language for TTHM,
HAAS or TOG, which are listed under
40 CFR 141.201-141.210 (Subpart Q).
2. Background and Analysis
  EPA requested comment on including
language in the proposed rule
concerning potential reproductive and
developmental health effects. EPA
believes this is an important issue
because of the large population exposed
(58 million women of child-bearing age;
USEPA 2005a) and the number of
studies that, while not conclusive, point
towards a potential risk concern. While
EPA is not including information about
reproductive and developmental health
effects in public notices at this time, the
Agency plans to reconsider whether to
include this information in the future.
As part of this effort, EPA intends to
support research to assess
communication strategies on how to
best provide this information.
  The responsibilities for public
notification and consumer confidence
reports rest with the individual system.
Under the Public Notice Rule (Part 141
subpart Q) and Consumer Confidence
Report Rule (Part 141 subpart O), the
wholesale system is responsible for
notifying the consecutive system of
analytical results and violations related
to monitoring conducted by the
wholesale system. Consecutive systems
are required to conduct  appropriate
public notification after a violation
(whether in the wholesale system or the
consecutive system). In  their consumer
confidence report, consecutive systems
must include results of the testing
conducted by the wholesale system
unless the consecutive system
conducted equivalent testing (as
required in today's rule) that indicated
the consecutive system was in
compliance, in which case the
consecutive system reports its own
compliance monitoring  results.

3. Summary of Major Comments
  EPA requested and received many
comments on the topic of including
public notification language regarding
potential reproductive and
developmental effects. A number of
comments called for including
reproductive and developmental health
effects language to address the potential
health concerns that research has
shown. Numerous comments also
opposed such language  due to
uncertainties in the underlying science
and the implications such language
could have on public trust of utilities.
  EPA agrees on the importance  of
addressing possible reproductive and
developmental health risks. However,
given the uncertainties in the science
and our lack of knowledge of how to
best communicate undefined risks, a
general statement about reproductive

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and developmental health effects is
premature at this time. The Agency
needs to understand how best to
characterize and communicate these
risks and what to do to follow up any
such communication. The public
deserves accurate,  timely, relevant, and
understandable communication. The
Agency will continue to follow up on
this issue with additional research,
possibly including a project to work
with stakeholders to assess risk
communication strategies.
  Some comments also suggested
leaving the choice of language up to the
water server. EPA believes that this
strategy would cause undue confusion
to both the PWS and the public.
  Commenters generally agreed that
both wholesale and consecutive systems
that conduct monitoring be required to
report their own analytical results as
part of their CCRs.  One commenter
requested clarification of consecutive
system public  notification requirements
when there is a violation in the
wholesale system but the consecutive
system data indicate that it meets DBF
MCLs.
  Although EPA requires consecutive
systems to conduct appropriate public
notification of violations (whether in the
wholesale or consecutive system), there
may be cases where the violation  may
only affect an isolated portion of the
distribution system. Under the public
notification rule, the State may allow
systems to limit distribution of the
notice to the area that  is out of
compliance if the system can
demonstrate that the violation occurred
in a part of the distribution system that
is "physically  or hydraulically isolated
from other parts of the distribution
system." This  provision remains in
place. As for a consecutive system
whose wholesale system is in violation,
the consecutive system is not required
to conduct public notification if DBF
levels in the consecutive system are in
compliance.
K. Variances and Exemptions
1. Today's Rule
  States may grant variances in
accordance with sections 1415(a)  and
1415(e) of the SDWA and EPA's
regulations. States may grant
                          exemptions in accordance with section
                          1416(a) of the SDWA and EPA's
                          regulations.

                          2. Background and Analysis

                            a. Variances. The SDWA provides for
                          two types of variances—general
                          variances and small system variances.
                          Under section 1415(a)(l)(A) of the
                          SDWA, a State that has primary
                          enforcement responsibility (primacy), or
                          EPA as the primacy agency, may grant
                          general variances from MCLs to those
                          public water systems of any size that
                          cannot comply with the MCLs because
                          of characteristics of the raw water
                          sources. The primacy agency may grant
                          general variances to a system on
                          condition that the system install the best
                          technology, treatment techniques, or
                          other means that EPA finds available
                          and based upon an evaluation
                          satisfactory to the State that indicates
                          that alternative sources of water are not
                          reasonably available to the  system. At
                          the time this type of variance is granted,
                          the State must prescribe a compliance
                          schedule and may require the system to
                          implement additional control measures.
                          Furthermore, before EPA or the State
                          may grant a general variance, it must
                          find that the variance will not result in
                          an unreasonable risk to health  (URTH)
                          to the public served by the  public water
                          system. In today's final rule, EPA is
                          specifying BATs for general variances
                          under section  1415(a) (see section IV.D).
                            Section 1415(e) authorizes the
                          primacy agency to issue variances to
                          small public water systems (those
                          serving fewer than 10,000 people) where
                          the primacy agent determines (1) that
                          the system cannot afford to comply with
                          an MCL  or treatment technique and (2)
                          that the terms  of the variances will
                          ensure adequate protection of human
                          health (63 FR 43833, August 14, 1998)
                          (USEPA 1998c). These variances may
                          only be granted where EPA has
                          determined that there is no affordable
                          compliance technology and has
                          identified a small system variance
                          technology under section 1412(b)(15) for
                          the contaminant, system size and source
                          water quality in question. As discussed
                          below, small system variances under
                          section 1415(e) are not available because
EPA has determined that affordable
compliance technologies are available.
  The 1996 Amendments to the SDWA
identify three categories of small public
water systems that need to be addressed:
(1) Those serving a population of 3301-
10,000;  (2)  those serving a population of
500-3300; and (3) those serving a
population of 25-499. The SDWA
requires EPA to make determinations of
available compliance technologies for
each size category. A compliance
technology is a technology that is
affordable and that achieves compliance
with the MCL and/or treatment
technique.  Compliance technologies can
include point-of-entry or point-of-use
treatment units. Variance technologies
are only specified for those system size/
source water quality combinations for
which there are no listed affordable
compliance technologies.
  Using its current National
Affordability Criteria, EPA has
determined that multiple affordable
compliance technologies are available
for each of the three system sizes
(USEPA 2005a), and therefore did not
identify any variance treatment
technologies. The analysis was
consistent with the current methodology
used in the document "National-Level
Affordability Criteria Under the 1996
Amendments to the Safe Drinking Water
Act" (USEPA 1998d) and the "Variance
Technology Findings for Contaminants
Regulated Before 1996" (USEPA 1998e).
However, EPA is currently reevaluating
its national-level affordability criteria
and has solicited recommendations
from both the NDWAC and the  SAB as
part of this  review. EPA intends to
apply the revised criteria to the Stage 2
DBPR once they have been finalized  for
the purpose of determining whether to
enable States to give variances.  Thus,
while the analysis of Stage 2 household
costs will not change, EPA's
determination regarding the availability
of affordable compliance technologies
for the different categories of small
systems may.
  b. Affordable Treatment Technologies
for Small Systems. The treatment trains
considered  and predicted to be  used  in
EPA's compliance forecast for systems
serving under 10,000 people, are listed
in Table IV.K-1.
   TABLE IV.K-1.—TECHNOLOGIES CONSIDERED AND PREDICTED To BE USED IN COMPLIANCE FORECAST FOR SMALL
                                                     SYSTEMS
                     SW Water Plants
                                                                  GW Water Plants
  Switching to chloramines as a residual disinfectant	
  Chlorine dioxide (not for systems serving fewer than 100 people)	
  UV 	
  Ozone (not for systems serving fewer than 100 people) 	
  Micro-filtration/Ultra-filtration 	
                                               Switching to chloramines as a residual disinfectant
                                               UV
                                               Ozone (not for systems serving fewer than 100 people)
                                               GAC20
                                               Nanofiltration

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             Federal Register/Vol. 71, No. 2/Wednesday, January 4, 2006/Rules and  Regulations
                                                                       435
   TABLE IV.K-1.—TECHNOLOGIES CONSIDERED AND PREDICTED To BE USED IN COMPLIANCE FORECAST FOR SMALL
                                              SYSTEMS—Continued
SW Water Plants
• GAC20.
• GAC20 + Advanced disinfectants.
• Integrated Membranes.
GW Water Plants

  Note: Italicized technologies are those predicted to be used in the compliance forecast.
  Source: Exhibits 5.11b and 5.14b, USEPA 2005a.
  The household costs for these
technologies were compared against the
EPA's current national-level
affordability criteria to determine the
affordable treatment technologies. The
Agency's national level affordability
criteria were published in the August 6,
1998 Federal Register (USEPA 1998d).
A complete description of how this
analysis was applied to Stage 2 DBPR is
given in Section 8.3 of the Economic
Analysis (USEPA 2005a).
  Of the technologies listed in Table
IV.K-1, integrated membranes with
chloramines, GAC20 with advanced
oxidants, and ozone are above the
affordability threshold in the 0 to 500
category. No treatment technologies are
above the affordability threshold in the
500 to 3,300 category or the 3,300 to
10,000 category. As shown in the
Economic Analysis for systems serving
fewer than 500 people, 14 systems are
predicted to use GAC20 with advanced
disinfectants, one  system is predicted to
use integrated membranes, and no
systems are predicted to use ozone to
comply with the Stage 2 DBPR (USEPA
2005a). However, several alternate
technologies are affordable and likely
available to these systems. In some
cases, the compliance data for these
systems under the Stage 2 DBPR will be
the same as under the Stage 1 DBPR
(because many systems serving fewer
than 500 people will have the same
single sampling site under both rules);
these systems will have already
installed the necessary compliance
technology to comply with the Stage 1
DBPR. It is also possible that less costly
technologies such as those for which
percentage use caps were set in the
decision tree may actually be used to
achieve compliance (e.g., chloramines,
UV). Thus, EPA believes that
compliance by these systems will be
affordable.
  As shown in Table IV.K-2, the cost
model predicts that some households
served by very small systems will
experience household cost increases
greater than the available expenditure
margins as a result of adding advanced
technology for the Stage 2 DBPR
(USEPA 2005a). This prediction may be
overestimated because small systems
may have other compliance alternatives
available to them besides adding
treatment, which were not considered in
the model. For example, some of these
systems currently may be operated on a
part-time basis; therefore,  they may be
able to modify the current operational
schedule or use excessive capacity to
avoid installing a costly technology to
comply with the Stage 2 DBPR. The
system also may identify another water
source  that has lower TTHM and HAA5
precursor levels. Systems that can
identify such an alternate water source
may not have to treat that new source
water as intensely as their current
source, resulting in lower treatment
costs. Systems may elect to connect to
a neighboring water system. While
connecting to another system may not
be feasible for some remote systems,
EPA estimates that more than 22 percent
of all small water systems are located
within  metropolitan regions (USEPA
2000f) where distances between
neighboring systems will not present a
prohibitive barrier. Low-cost
alternatives to reduce total
trihalomethanes (TTHM) and haloacetic
acid (HAAS) levels also include
distribution system modifications such
as flushing distribution mains more
frequently, looping to prevent dead
ends, and optimizing storage to
minimize retention time. More
discussion of household cost increases
is presented in Section VI.E and the
Economic Analysis (USEPA 2005a).
       TABLE IV.K-2.—DISTRIBUTION OF HOUSEHOLD UNIT TREATMENT COSTS FOR PLANTS ADDING TREATMENT
Systems size
(population
seved)


0-500 	
501-3,300 . .
3,301-10,000 ..
Number of
households
served by
plants add-
ing treat-
ment (Per-
cent of all
households
subject to
the Stage 2
DBPR)
A
43045(3
205842 4
342525 (5
Mean an-
nual house-
hold cost in-
crease

B
$201.55
$5841
$3705
Median an-
nual house-
hold cost in-
crease

C
$299.01
$2996
$1459
90th Per-
centile an-
nual house-
hold cost in-
crease

D
$299.01
$75.09
$5525
95th Per-
centile an-
nual house-
hold cost in-
crease

E
$414.74
$366 53
$200 05
Available
expenditure
margin ($/
hh/yr)

F
$733
$724
$750
Number of
households
with annual
cost in-
creases
greater than
the avail-
able ex-
penditure
margin
G
964
0
0
Number of
surface
water plants
with annual
cost in-
creases
greater than
the avail-
penditure
margin
H
15
9
0
Number of
groundwater
plants with
annual cost
increases
greater than
the avail-
able ex-
penditure
margin
I
0
0
0
Total num-
ber of plants
with annual
cost in-
creases
greater than
the avail-
able ex-
penditure
margin
J = H + I
15
0
0
  Notes. Household unit costs represent treatment costs only All values in year 2003 dollars.
  Source. Exhibit 8 4c, USEPA 2005a
  c. Exemptions. Under section 1416(a),
EPA or a State that has primary
enforcement responsibility (primacy)
may exempt a public water system from
any requirements related to an MCL or
treatment technique of an NPDWR, if it
finds that (1) due to compelling factors
(which may include economic factors
such as qualification of the PWS as
serving a disadvantaged community),
the PWS is unable to comply with the
requirement or implement measures to
develop an alternative source of water
supply; (2) the exemption will not result
in an unreasonable risk to health; and;
(3) the PWS was in operation on the
effective date of the NPDWR, or for a
system that was not in operation by that
date, only if no reasonable alternative
source of drinking water is available to
the new system; and (4) management or
restructuring changes (or both) cannot
reasonably result in compliance with
the Act or improve the quality of

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 436
Federal  Register/Vol.  71, No. 2/Wednesday,  January 4, 2006/Rules and Regulations
 drinking water. If EPA or the State
 grants an exemption to a public water
 system, it must at the same time
 prescribe a schedule for compliance
 (including increments of progress or
 measures to develop an alternative
 source of water supply) and
 implementation of appropriate control
 measures that the State requires the
 system to meet while the exemption is
 in effect. Under section 1416(b)(2)(A),
 the schedule prescribed shall require
 compliance as expeditiously as
 practicable (to be determined by the
 State), but no later than 3 years after the
 effective date for the regulations
 established pursuant to section
 1412(b)(lO). For public water systems
 which do not serve more than a
 population of 3,300 and which need
 financial assistance for the necessary
 improvements, EPA or the State may
 renew an exemption for one or more
 additional two-year periods, but not to
 exceed a total of 6 years, if the system
 establishes that it is taking all
 practicable steps to meet the
 requirements above. A public water
 system shall not be granted an
 exemption unless it can establish that
 either: (l) the system cannot meet the
 standard without capital improvements
 that cannot be completed prior to the
 date established pursuant to section
 1412(b)(10); (2) in the case of a system
 that needs financial assistance for the
 necessary implementation, the system
 has entered into an agreement to obtain
 financial assistance pursuant to section
 1452 or any  other Federal or state
 program; or  (3) the system has entered
 into an enforceable agreement to
 become part of a regional public water
 system.

 3. Summary of Major Comments
  Several commenters agreed with the
 proposal not to list variances
 technologies for the Stage 2 DBPR. One
 commenter requested that EPA modify
 the methodology used to assess
 affordability. As mentioned earlier, EPA
 is currently reevaluating its national-
 level affordability criteria and has
 solicited recommendations from both
 the NDWAC and the SAB as part of this
 review. EPA intends to apply the
 revised criteria to the Stage 2 DBPR for
the purpose  of determining whether to
 enable States to give variances.

 L. Requirements for Systems to Use
 Qualified Operators
  EPA believes that systems that must
 make treatment changes to comply with
 requirements to reduce microbiological
risks and risks from disinfectants and
 disinfection byproducts should be
 operated by personnel who are qualified
                          to recognize and respond to problems.
                          Subpart H systems were required to be
                          operated by qualified operators under
                          the SWTR (§ 141.70). The Stage 1 DBPR
                          added requirements for all disinfected
                          systems to be operated by qualified
                          personnel who meet the requirements
                          specified  by the State, which may differ
                          based on system size and type. The rule
                          also requires that States maintain a
                          register of qualified operators (40 CFR
                          141.130(c)). While the Stage 2 DBPR
                          requirements do not supercede or
                          modify the requirement that disinfected
                          systems be operated by qualified
                          operators, such personnel play an
                          important role in delivering drinking
                          water that meets Stage 2 MCLs to the
                          public. States should also review and
                          modify, as required, their qualification
                          standards to take into account new
                          technologies (e.g., ultraviolet (UV)
                          disinfection) and new compliance
                          requirements (including simultaneous
                          compliance and consecutive system
                          requirements). EPA received only one
                          comment on this topic; the commenter
                          supported the need for a qualified
                          operator.

                          M. System Reporting and Recordkeeping
                          Requirements

                          1. Today's Rule
                           Today's Stage 2 DBPR, consistent
                          with the existing system reporting and
                          recordkeeping regulations under 40 CFR
                          141.134 (Stage 1 DBPR), requires public
                          water systems (including consecutive
                          systems) to report monitoring data to
                          States within ten days after the end of
                          the compliance period. In addition,
                          systems are required to submit the data
                          required in § 141.134. These data are
                          required to be submitted quarterly for
                          any monitoring conducted quarterly or
                          more frequently, and within ten days of
                          the end of the monitoring period for less
                          frequent monitoring. As with other
                          chemical analysis data, the system must
                          keep the results for 10 years.
                           In addition to the existing Stage 1
                          reporting requirements, today's rule
                          requires systems to perform specific
                          IDSE-related reporting to the primacy
                          agency, except for systems serving fewer
                          than 500 for which the State or primacy
                          agency has waived this requirement.
                          Required reporting includes submission
                          of IDSE monitoring plans, 40/30
                          certification, and IDSE reports. This
                          reporting must be accomplished on the
                          schedule specified in the rule (see
                          § 141.600(c)) and discussed in section
                          IV.E of today's preamble. System
                          submissions must include the elements
                          identified in subpart U and discussed
                          further in  section IV.F of today's
                          preamble. These elements include
 recommended Stage 2 compliance
 monitoring sites as part of the IDSE
 report.
   Systems must report compliance with
 Stage 2 TTHM and HAAS MCLs (0.080
 mg/LTTHM and 0.060 mg/L HAA5, as
 LRAAs) according to the schedules
 specified in §§ 141.620 and 141.629 and
 discussed in section IV.E of today's
 preamble. Reporting for DBF
 monitoring, as described previously,
 will remain generally consistent with
 current public water system reporting
 requirements {§ 141.31 and § 141.134);
 systems will be required to  calculate
 and report each LRAA (instead of the
 system's RAA) and each individual
 monitoring result (as required under the
 Stage 1 DBPR). Systems will also be
 required to provide  a report to the State
 about each operational evaluation
 within 90 days, as discussed in section
 IV.H. Reports and evaluations must be
 kept for 10 years and may prove
 valuable in identifying trends and
 recurring issues.

 2. Summary of Major Comments
  EPA requested comment on all system
 reporting and recordkeeping
 requirements. Commenters  generally
 supported EPA's proposed
 requirements, but expressed concern
 about two specific issues. The first issue
 was the data management and tracking
 difficulties that States would face if EPA
 finalized a monitoring approach which
 had both plant-based and population-
 based requirements, as was  proposed.
 Since today's rule contains  only
 population-based monitoring
 requirements, this concern is no longer
 an issue. See section IV.G in today's
 preamble for further discussion.
  The second concern related to
 reporting associated with the IDSE.
 Commenters who supported an
 approach other than the IDSE for
 determining Stage 2 compliance
 monitoring locations did not support
 IDSE-related reporting.  The IDSE
 remains a key component of the final*
 rule; thus, EPA has retained IDSE-
 related reporting. However,  the Agency
 has modified both the content and the
 timing of the reporting to reduce the
burden. See  sections IV.F and IV.E,
respectively, of today's preamble for
further discussion.

N. Approval of Additional Analytical
Methods

1. Today's Rule
  EPA is taking final action  to:
  (1) allow the use of 13 methods
published by the Standard Methods
Committee in Standard Methods for the
Examination of Water and Wastewater,

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             Federal Register/Vol. 71, No.  2/Wednesday, January 4, 2006/Rules and Regulations
                                                                     437
20th edition, 1998 (APHA 1998) and 12
methods in Standard Methods Online.
  (2) approve three methods published
by American Society for Testing and
Materials International.
  (3) approve EPA Method 327.0
Revision 1.1 (USEPA 2005h) for daily
monitoring of chlorine dioxide and
chlorite, EPA Method 552.3 (USEPA
2003f) for haloacetic acids (five)
(HAAS), EPA Methods 317.0 Revision 2
(USEPA 2001c) and 326.0 (USEPA 2002)
for bromate, chlorite, and bromide, EPA
Method 321.8 (USEPA 2000g) for
bromate only, and EPA Method 415.3
Revision 1.1 (USEPA 20051) for total
organic carbon (TOG) and specific
ultraviolet absorbance (SUVA).
  (4) update the citation for EPA
Method 300.1 (USEPA 2000h) for
bromate, chlorite, and bromide.
  (5) standardize the HAAS sample
holding times and the bromate  sample
preservation procedure and holding
time.
  (6) add the requirement to remove
inorganic carbon prior to determining
TOC or DOC, remove the specification
of type of acid used for TOC/DOC
sample preservation; and require that
TOC samples be preserved at the time
of collection.
  (7) clarify which methods are
approved for magnesium hardness
determinations (40 CFR 141.131 and
141.135).

2. Background and Analysis
  The Stage  1 Disinfectants and
Disinfection  Byproducts Rule (Stage 1
DBPR) was promulgated on December
16, 1998 (USEPA 1998a) and it included
approved analytical methods for DBPs,
disinfectants, and DBF precursors.
Additional analytical methods became
available subsequent to the rule and
were proposed in the Stage 2
Disinfectants and Disinfection
Byproducts Rule (Stage 2 DBPR)
(USEPA 2003a). These methods are
applicable to monitoring that is required
under the Stage  1 DBPR. After the Stage
2 DBPR proposal, analytical methods for
additional drinking water contaminants
were proposed for approval in a
Methods Update Rule proposal (USEPA
2004). The Stage 2 DBPR and Methods
Update Rule proposals both included
changes in the same sections of the CFR.
EPA decided to make all the changes to
§141.131 as part of the Stage 2 DBPR
and the remainder of the methods that
were proposed with the Stage 2 DBPR
will be considered as part of the
Methods Update Rule, which will be
finalized at a later date. Two ASTM
methods, D 1253-86(96) and D 1253-03,
that were proposed in the Methods
Update Rule, are being approved for
measuring chlorine residual as part of
today's action.
  Minor corrections have been made in
two of the methods that were proposed
in the Stage 2 DBPR. In today's rule, the
Agency is approving EPA Method 327.0
(Revision 1.1, 2005) which corrects
three typographical errors in the
proposed method.
  EPA  is also approving EPA Method
415.3 (Revision 1.1, 2005), which does
not contain the requirement that
samples for the analysis of TOC must be
received within 48 hours of sample
collection.
  A summary of the methods that are
included in today's rule is presented in
Table IV.N-1.
                         TABLE IV.N-1. ANALYTICAL METHODS APPROVED IN TODAY'S RULE
Analyte
EPA method
Standard methods 20th
edition
Standard methods online
Other
                                          § 141.131 —Disinfection Byproducts
HAAS 	
Bromate 	


Chlorite (monthly or daily)

Chlorite (daily)

552.3 	
317.0, Revision 2.0 	
321 8
3260
317 0 Revision 2 0
3260
327 0 Revision 1 1

6251 B 	





4500-CIOo E

6251 B-94 	





4500-CIO^ E-00


ASTM D 6581-00


ASTM D 6581-00



                                              §141.131—Disinfectants
Chlorine (free combined
total)

Chlorine (total) . 	

Chlorine (free)
Chlorine Dioxide








327 0 Revision 1 1


4500-CI D
4500-CI F
4500-CI G 	 	
4500-CI E 	
4500-CI I
4500-CI H
4500-CIO^ D
4500-CIO. E 	

4500-CI D-00
4500-CI F-00
4500-CI G-00 	
4500-CI E-00 	
4500-CI I-OO
4500-CI H-00 ..
4500-CK> E-00 .


ASTM D 1253-86(96)
ASTM D 1253-03







                                            § 141.131—Other parameters
Bromide

TOC/DOC


UV^4
SUVA

317 Q Revision 2 0
326 0 .. .
415 3 Revision 1 1


415 3 Revision 1 1
415 3 Revision 1 1



5310 B
5310 C
5310 D
5910 B 	




531 0 B-00
5310 C-00
5310 D-00
5910 B-00 	


ASTM D 6581-00








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 438
Federal Register/Vol.  71,  No. 2/Wednesday, January  4,  2006/Rules  and Regulations
 O. Laboratory Certification and
 Approval
 1. PE Acceptance Criteria
   a. Today's rule. Today's rule
 maintains the requirements of
 laboratory certification for laboratories
 performing analyses to demonstrate
 compliance with MCLs and all other
                          analyses to be conducted by approved
                          parties. It revises the acceptance criteria
                          for performance evaluation (PE) studies
                          which laboratories must pass as part of
                          the certification program. The new
                          acceptance limits are effective 60 days
                          after promulgation. Laboratories that
                          were certified under the Stage 1 DBPR
              PE acceptance criteria will be subject to
              the new criteria when it is time for them
              to analyze their annual DBF PE
              sample(s). Today's rule also requires
              that TTHM and HAAS analyses that are
              performed for the IDSE or system-
              specific study be conducted by
              laboratories certified for those analyses.
                       TABLE IV.O-1.—PERFORMANCE EVALUATION (PE) ACCEPTANCE CRITERIA
                        DBP
                                        Acceptance
                                        limits (per-
                                        cent of true
                                          value)
                                                                                      Comments
TTHM
    Chloroform
    Bromodichloromethane
    Dibromochloromethane
    Bromoform	
 HAAS
    Monochloroacetic Acid .
    Dichloroacetic Acid . ...
    Trichloroacetic Acid ...
    Monobromoacetic Acid
    Dibromoacetic Acid 	
Chlorite  	
Bromate 	
                                              ±20

                                              ±20
                                              ±20
                                              ±20

                                              ±40
                                              ±40
                                              ±40
                                              ±40
                                              ±40
                                              ±30
                                              ±30
Laboratory must meet all 4 individual THM acceptance limits in
  order to successfully pass a PE sample for TTHM
Laboratory must meet the acceptance limits for 4 out of 5 of the
  HAAS compounds in order to successfully pass a PE sample
  for HAAS
  b. Background and analysis. The Stage
 1 DBPR (USEPA 1998a) specified that in
 order to be certified the laboratory must
 pass an annual performance evaluation
 (PE) sample approved by EPA or the
 State using each method for which the
 laboratory wishes to maintain
 certification. The acceptance criteria for
 the DBP PE samples were set as
 statistical limits based on the
 performance of the laboratories in each
 study. This was done because EPA did
 not have enough data to specify fixed
 acceptance limits.
  Subsequent to promulgation of the
 Stage 1 DBPR, EPA was able to evaluate
 data from PE studies conducted during
 the Information Collection Rule (USEPA
 1996) and during the last five general
 Water Supply PE studies. Based on the
 evaluation process as described in the
 proposed Stage 2 DBPR (USEPA 2003a),
EPA determined that fixed acceptance
limits could be established for the DBFs.
Today's action replaces the statistical PE
acceptance limits with fixed limits
effective one year after promulgation.
  c. Summary of major comments. Four
commenters supported the fixed
acceptance criteria as presented in the
proposed rule. One requested that a
minimum concentration be set for each
                          DBP in the PE studies, so that
                          laboratories would not be required to
                          meet tighter criteria in the PE study than
                          they are required to meet with the
                          minimum reporting level (MRL) check
                          standard. EPA has addressed this
                          concern by directing the PE sample
                          suppliers to use concentrations no less
                          than 10 ug/L for the individual THM
                          and HAAs, 100 ug/L for chlorite, and 7
                          ug/L for bromate in PE studies used for
                          certifying drinking water laboratories.
                            Two commenters requested that the
                          effective date for the new PE acceptance
                          criteria be extended from 60 days to 180
                          days, because they felt that 60  days was
                          not enough time for laboratories to meet
                          the new criteria. EPA realized from
                          those comments that the original intent
                          of the  proposal was not clearly
                          explained; the 60 days was to be the
                          deadline for when the PE providers
                          must change the acceptance criteria that
                          are used when the studies are
                          conducted. Laboratories would have to
                          meet the criteria when it is  time for
                          them to analyze their annual PE samples
                          in order to maintain certification.
                          Depending upon when the  last PE
                          sample was analyzed, laboratories could
                          have up to one year to meet the new
                          criteria. In order to eliminate this
              confusion, EPA has modified the rule
              language to allow laboratories one year
              from today's date to meet the new PE
              criteria.

              2. Minimum Reporting Limits

                a. Today's rule. EPA is establishing
              regulatory minimum reporting limits
              (MRLs) for compliance reporting of
              DBFs by Public Water Systems. These
              regulatory MRLs (Table IV.O-2) also
              define the minimum concentrations that
              must be reported as part of the
              Consumer Confidence Reports (40 CFR
              § 141.151(d)). EPA is incorporating
              MRLs into the laboratory certification
              program for DBFs by requiring
              laboratories to include a standard near
              the MRL concentration as part of the
              calibration curve for each DBP and to
              verify the accuracy of the calibration
              curve at the MRL concentration by
              analyzing an MRL check standard with
              a concentration less than or equal to
              110% of the MRL with each batch of
              samples. The measured DBP
              concentration for the MRL check
              standard must be ±50% of the expected
              value, if any field sample in the batch
              has a concentration less than 5 times the
              regulatory MRL.

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             Federal Register/Vol.  71,  No. 2/Wednesday, January 4, 2006/Rules and Regulations
                                                                         439
                              TABLE IV.O-2— REGULATORY MINIMUM REPORTING LEVELS
                  DBP
   Minimum reporting level
         (mg/L) 1
                      Comments
TTHM2
    Chloroform 	
    Bromodichloromethane
    Dibromochloromethane
    Bromoform 	
HAA52
    Monochloroacetic Acid .
    Dichloroacetic Acid 	
    Trichloroacetic Acid 	
    Monobromoacetic Acid .
    Dibromoacetic Acid 	
Chlorite 	
Bromate
                 0.0010
                 0.0010
                 0.0010
                 0.0010

                 0.0020
                 0.0010
                 00010
                 0.0010
                 0.0010
                  0.020

         0.0050 or 0.0010
Applicable to monitoring  as  prescribed in  §141.132(b)(2)(i)(B)
  and (b)(2)(n).
Laboratories that use EPA Methods 317.0 Revision 2.0, 326.0 or
  321.8 must meet a 0.0010 mg/L MRL for bromate.
  1 The calibration curve must encompass the regulatory minimum reporting level (MRL) concentration. Data may be reported for concentrations
lower than the regulatory MRL as long as the precision and accuracy criteria are met by analyzing an MRL check standard at the lowest report-
ing limit chosen by the laboratory. The laboratory must verify the accuracy of the calibration curve at the MRL concentration by analyzing an
MRL check standard with a concentration less than or equal to 110% of the MRL with each batch of samples. The measured concentration for
the MRL check standard must be ±50% of  the expected value, if any field  sample in the batch has a concentration less than 5 times the regu-
latory MRL. Method requirements to analyze higher concentration check standards and meet tighter acceptance criteria for them must be met in
addition to the MRL check standard requirement.
  2 When adding the individual trihalomethane or haloacetic acid  concentrations to calculate the TTHM or HAA5 concentrations, respectively, a
zero is used for any analytical result that is less than the MRL concentration for that DBP, unless otherwise specified by the State.
  b. Background and analysis. EPA
proposed to establish regulatory MRLs
for DBFs in order to define expectations
for reporting compliance monitoring
data to the Primacy Agencies and in the
Consumer Confidence Reports. The
proposed MRLs were generally based on
those used during the Information
Collection Rule (USEPA 1996), because
an analysis of the quality control data
set from the Information Collection Rule
(Fair et al. 2002) indicated that
laboratories are able to provide
quantitative data down to those
concentrations.
  EPA also proposed that laboratories
be required to demonstrate ability to
quantitate at the MRL concentrations by
analyzing an MRL check standard and
meeting accuracy criteria on each day
that compliance samples are analyzed.
Three public commenters noted that
meeting the accuracy requirement for
the MRL check standard did not
contribute to the quality of the data in
cases in which the concentration of a
DBP in the samples was much higher
than the MRL. For example, if
chloroform concentrations are always
greater than 0.040 mg/L in a water
system's samples, then verifying
accurate quantitation at 0.0010 mg/L is
unnecessary and may require the
laboratory to dilute samples or maintain
two calibration curves in order to
comply with the requirement. EPA has
taken this into consideration in today's
rule and has adjusted the requirement
accordingly. EPA is maintaining the
requirement for all laboratories to
analyze the MRL check standard, but
the laboratory is only required to meet
the accuracy criteria (±50%) if a field
sample has a concentration less than
five times the regulatory MRL
concentration.
  EPA proposed a regulatory MRL of
0.200 mg/L for chlorite, because data
from the Information Collection Rule
indicated  that most samples would
contain concentrations greater than
0.200 mg/L (USEPA 2003c). EPA also
took comment on a  lower MRL of 0.020
mg/L. Commenters were evenly divided
concerning which regulatory MRL
concentration should be adopted in the
final rule. EPA has decided to  set the
chlorite regulatory MRL at 0.020 mg/L
in today's rule. This decision was based
on two factors. First, the approved
analytical methods  for determining
compliance with the chlorite MCL can
easily support an  MRL of 0.020 mg/L.
More importantly, since the proposal,
EPA has learned that water systems that
have low chlorite concentrations in
their water have been obtaining data on
these low  concentrations from their
laboratories and have been using these
data in their Consumer Confidence
Reports. Setting the MRL at 0.020 mg/
L is reflective of current practices in
laboratories and current data
expectations by water systems.
  c. Summary of major comments.
There were no major comments.
P. Other Regulatory Changes
  As part  of today's action, EPA has
included several "housekeeping"
actions to remove sections of Part 141
               that are no longer effective. These
               sections have been superceded by new
               requirements elsewhere in Part 141.
                 Sections 141.12 (Maximum
               contaminant levels for total
               trihalomethanes) and 141.30 (Total
               trihalomethanes sampling, analytical
               and other requirements) were
               promulgated as part of the 1979 TTHM
               Rule. These sections have been
               superceded in their entirety by § 141.64
               (Maximum contaminant levels for
               disinfection byproducts) and subpart L
               (Disinfectant Residuals, Disinfection
               Byproducts, and Disinfection Byproduct
               Precursors), respectively, as of
               December 31, 2003. Also,  § 141.32
               (Public notification) has been
               superceded by subpart Q (Public
               Notification of Drinking Water
               Violations), which is now fully in effect.
                 Section 553 of the Administrative
               Procedure Act, 5 U.S.C. 553(b)(B),
               provides that, when an agency for good
               cause finds that notice and public
               procedure are impracticable,
               unnecessary, or contrary to the public
               interest, the agency may issue a rule
               without providing prior notice and an
               opportunity for public comment. In
               addition to updating methods, this rule
               also makes minor corrections to the
               National Primary Drinking Water
               Regulations, specifically the Public
               Notification tables (Subpart Q,
               Appendices A and B). Two final
               drinking water rules (66 FR 6976 and 65
               FR 76708) inadvertently added new
               endnotes to two existing tables using the
               same endnote numbers. This rule
               corrects this technical drafting error by

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Federal Register/Vol.  71,  No. 2/Wednesday, January  4,  2006/Rules and Regulations
 renumbering the endnote citations in
 these two tables. Thus, additional notice
 and public comment is not necessary.
 EPA finds that this constitutes "good
 cause" under 5 U.S.C. 553{b)(B). For the
 same reasons, EPA is making this rule
 change effective upon publication. 5
 U.S.C. 553(d)(3).

 V. State Implementation

 A. Today's Rule
  This section describes the regulations
 and other procedures and policies States
 must adopt to implement today's rule.
 States must continue to  meet all other
 conditions of primacy in 40 CFR Part
 142. To implement the Stage 2 DBPR,
 States must adopt revisions to the
 following:
  —§141.2—Definitions
  —§ 141.33—Record maintenance;
  —§ 141.64—Maximum contaminant
     levels for disinfection byproducts;
  —subpart L—Disinfectant Residuals,
     Disinfection Byproducts, and
     Disinfection Byproduct Precursors;
  —subpart O, Consumer Confidence
     Reports;
  —subpart Q, Public Notification of
     Drinking Water Violations;
  —new subpart U, Initial Distribution
     System Evaluation;  and
  —new subpart V, Stage 2 Disinfection
     Byproducts  Requirements.

 1. State Primacy Requirementslor
 Implementation  Flexibility
  In addition to  adopting basic primacy
 requirements specified in 40 CFR part
 142, States are required to address
 applicable special primacy  conditions.
 Special primacy conditions pertain to
 specific regulations where
 implementation  of the rule  involves
 activities beyond general primacy
 provisions. The purpose of these special
 primacy requirements in today's rule is
 to ensure State flexibility in
 implementing a regulation that (1)
 applies to specific system configurations
 within the particular State and (2) can
 be integrated with a State's  existing
 Public Water Supply Supervision
 Program. States must include these rule-
 distinct provisions in an application for
approval or revision of their program.
These primacy requirements for
implementation flexibility are discussed
in this section.
  To ensure that a State program
includes all the elements necessary for
an effective and enforceable program
under today's rule, a State primacy
application must include a description
of how the State will implement a
procedure for modifying consecutive
system and wholesale system
monitoring requirements on a case-by-
                          case basis, if a State will use the
                          authority to modify monitoring
                          requirements under this special primacy
                          condition.

                          2. State Recordkeeping Requirements
                            Today's rule requires States to keep
                          additional records of the following,
                          including all supporting information
                          and an explanation of the technical
                          basis for each decision:
                            —very small system waivers.
                            —IDSE monitoring plans.
                            —IDSE reports and 40/30
                              certifications, plus any
                              modifications required by the State.
                            —operational evaluations conducted
                              by the system.

                          3. State Reporting Requirements
                            Today's rule has no new State
                          reporting requirements.

                          4. Interim Primacy
                            States that have primacy for every
                          existing NPDWR already in effect may
                          obtain interim primacy for  this rule,
                          beginning on the date that the State
                          submits the application for this rule to
                          USEPA, or the effective date of its
                          revised regulations, whichever is later.
                          A State that wishes to obtain interim
                          primacy for future NPDWRs must obtain
                          primacy for today's rule. As described
                          in Section IV.F, EPA expects to work
                          with States to oversee the individual
                          distribution system evaluation process
                          that begins shortly after rule
                          promulgation.

                          5. IDSE Implementation
                           As discussed in section IV.E, many
                          systems will be performing certain IDSE
                          activities prior to their State receiving
                          primacy. During that period, EPA will
                          act as the primacy agency, but will
                          consult and coordinate with individual
                          States to the extent practicable and to
                          the extent that States are willing and
                          able to do so. In addition, prior to
                          primacy, States may be asked to assist
                          EPA in identifying and confirming
                          systems that are required to comply
                          with certain IDSE activities. Once the
                          State has received primacy, it will
                          become responsible for IDSE
                          implementation activities.

                          B. Background and Analysis
                           SDWA establishes requirements that a
                          State or eligible Indian  Tribe must meet
                          to assume and maintain primary
                          enforcement responsibility  (primacy] for
                          its PWSs. These requirements include
                          the following activities: (1)  Adopting
                          drinking water regulations that are no
                          less stringent than Federal drinking
                          water regulations; (2) adopting and
                          implementing adequate procedures for
 enforcement; (3) keeping records and
 making reports available on activities
 that EPA requires by regulation; (4)
 issuing variances and exemptions (if
 allowed by the State), under conditions
 no less stringent than allowed under
 SDWA; and (5) adopting and being
 capable of implementing an adequate
 plan for the provisions of safe drinking
 water under emergency situations.
   40 CFR part 142 sets out the specific
 program implementation requirements
 for States to obtain primacy for the
 public water supply supervision
 program as authorized under SDWA
 section 1413. In addition to adopting
 basic primacy requirements specified in
 40 CFR Part 142, States may be required
 to adopt special primacy provisions
 pertaining to specific regulations where
 implementation of the rule involves
 activities beyond general primacy
 provisions. States must include these
 regulation specific provisions in an
 application for approval of their
 program revision.
   The current regulations in 40 CFR
 142.14 require States with primacy to
 keep various records, including the
 following: analytical results to
 determine compliance with MCLs,
 MRDLs, and treatment technique
 requirements; PWS inventories; State
 approvals; enforcement actions; and the
 issuance of variances and exemptions.
 Today's final rule requires States to
 keep additional records, including all
 supporting information and an
 explanation of the technical basis for
 decisions made by the State regarding
 today's rule requirements. The State
 may use these records to identify trends
 and determine whether to limit the
 scope of operational evaluations. EPA
 currently requires in 40 CFR 142.15 that
 States report to EPA information such as
 violations, variance and exemption
 status, and enforcement actions; today's
 rule does not add additional reporting
 requirements or modify existing
 requirements.
  On April 28,  1998, EPA amended its
 State primacy regulations at 40 CFR
 142.12 to incorporate the new process
 identified in the 1996 SDWA
 Amendments for granting primary
 enforcement authority to States while
 their applications to modify their
 primacy programs are under review (63
 FR 23362, April 28, 1998) (USEPA
 1998f). The new process grants interim
 primary enforcement authority for a
 new or revised regulation during the
 period in which EPA is making a
determination with regard to primacy
for that new or revised regulation. This
interim enforcement authority begins on
the date of the primacy application
 submission or the effective date of the

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             Federal  Register/Vol. 71, No.  2/Wednesday, January 4, 2006/Rules  and Regulations
                                                                       441
new or revised State regulation,
whichever is later, and ends when EPA
makes a final determination. However,
this interim primacy authority is only
available to a State that has primacy
(including interim primacy) for every
existing NPDWR in effect when the new
regulation is promulgated. States that
have primacy for every existing NPDWR
already in effect may obtain interim
primacy for this rule and a State that
wishes to obtain interim primacy for
future NPDWRs must obtain primacy for
this rule.
  EPA is aware that due to the
complicated wholesale system-
consecutive  system relationships that
exist nationally, there will be cases
where the standard monitoring
framework will be difficult to
implement. Therefore, States may
develop, as a special primacy condition,
a program under which the State can
modify monitoring requirements for
consecutive  systems. These
modifications must not undermine
public health protection and all
systems, including consecutive systems,
must comply with the TTHM and HAAS
MCLs based on the LRAA at each
compliance monitoring location. Each
consecutive  system must have at least
one compliance monitoring location.
However, such a program allows the
State to establish monitoring
requirements that account for
complicated distribution system
relationships, such as where
neighboring systems buy from and sell
to each other regularly throughout the
year, water passes through multiple
consecutive  systems before it reaches a
user, or a large group of interconnected
systems have a complicated combined
distribution system. EPA has developed
a guidance manual to address these and
other consecutive system issues.
C. Summary of Major Comments
  Public comment generally supported
the special primacy requirements in the
August 11, 2003 proposal, and many
commenters expressed appreciation for
the flexibility the special primacy
requirements provided to States.
  Many commenters expressed concern
about EPA as the implementer instead
of the State, given the existing
relationship between the State and
system. EPA agrees that  States perform
an essential  role in rule implementation
and intends to work with States to the
greatest extent possible,  consistent with
the rule schedule promulgated today.
EPA believes that pre-promulgation
coordination with States, changes  in the
final rule strongly supported by States
(e.g., population-based monitoring
instead of plant-based monitoring), and
the staggered rule schedule will
facilitate State involvement in pre-
primacy implementation.
  Many commenters also requested that
the State have more flexibility to grant
sampling waivers and exemptions. EPA
believes that it has struck a reasonable
balance among competing objectives in
granting State flexibility. State
flexibility comes at a resource cost and
excessive system-by-system flexibility
could overwhelm State resources. Also,
EPA believes that much of the
monitoring and  water quality
information a State would need to
properly consider whether a waiver is
appropriate is generally not available
and, if available, difficult to evaluate.

VI. Economic Analysis

  This section summarizes the
Economic Analysis for the Final Stage 2
Disinfectants and Disinfection
Byproducts Rule (Economic Analysis
(EA)) (USEPA 2005a). The EA is an
evaluation of the benefits and costs of
today's final rule and other regulatory
alternatives the  Agency considered.
Specifically, this evaluation addresses
both quantified  and non-quantified
benefits to PWS consumers, including
the general population and sensitive
subpopulations. Costs are presented for
PWSs, States, and consumer
households. Also included is a
discussion  of potential risks from other
contaminants, uncertainties in benefit
and cost estimates, and a summary of
major comments on the EA for the
proposed Stage  2 DBPR.
  EPA relied on data from several
epidemiologic and toxicologic studies,
the Information Collection Rule (ICR),
and other sources, along with analytical
models and input from technical
experts, to understand DBP risk,
occurrence, and PWS treatment changes
that will result from today's rule.
Benefits and costs are presented as
annualized values using social discount
rates of three and seven percent. The
time frame  used for benefit and cost
comparisons is 25 years—approximately
five years account for rule
implementation and 20 years for the
average useful life of treatment
technologies.
  EPA has  prepared this EA to comply
with the requirements of SDWA,
including the Health Risk Reduction
and Cost Analysis required by SDWA
section 1412(b)(3)(C), and Executive
Order 12866, Regulatory Planning and
Review. The full EA is available in the
docket for today's rule, which is
available online as described in the
ADDRESSES section. The full document
provides detailed explanations of the
analyses summarized in this section and
additional analytical results.

A. Regulatory Alternatives Considered
  The Stage 2 DBPR is the second in a
set of rules that address public health
risks from DBFs. EPA promulgated the
Stage 1 DBPR to decrease average
exposure to DBFs and mitigate
associated health risks—compliance
with TTHM and HAAS MCLs is based
on averaging concentrations across the
distribution system. In developing the
Stage 2 DBPR, EPA sought to identify
and further reduce remaining risks from
exposure to chlorinated DBFs.
  The regulatory options EPA
considered for the Stage 2 DBPR are the
direct result of a consensus rulemaking
process (Federal Advisory Committee
Act (FACA) process) that involved
various drinking water stakeholders (see
Section III for a description of the FACA
process). The Advisory Committee
considered the following key questions
during the negotiation process for the
Stage 2 DBPR:
  • What are the remaining health risks
after implementation of the Stage 1
DBPR?
  • What are approaches to addressing
these risks?
  • What are the risk tradeoffs that need
to be considered in evaluating these
approaches?
  • How do the estimated costs of an
approach compare to reductions in peak
DBP occurrences and overall DBP
exposure for that approach?
  The Advisory Committee considered
DBP occurrence estimates to be
important in understanding the nature
of public health risks. Although the ICR
data were collected prior to
promulgation of the Stage 1 DBPR, they
were collected under a similar sampling
strategy. The data support the concept
that a system could be in compliance
with the RAA Stage 1 DBPR MCLs of
0.080 mg/L and 0.060 mg/L for TTHM
and HAA5, respectively, and yet have
points in the distribution system with
either periodically or consistently
higher DBP levels.
  Based on these findings, the Advisory
Committee discussed an array of
alternatives to address disproportionate
risk within distribution systems.
Alternative options included lowering
DBP MCLs, revising the method for
MCL compliance determination e.g.,
requiring individual sampling locations
to meet the MCL as an LRAA or
requiring that no samples exceed the
MCL), and combinations of both. The
Advisory Committee also considered the
associated technology changes and costs
for these alternatives. After narrowing
down options, the Advisory Committee

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Federal Register/Vol.  71, No.  2/Wednesday, January 4, 2006/Rules and Regulations
primarily focused on four types of
alternative MCL scenarios. These are the
alternatives EPA evaluated in the EA, as
follows:
Preferred Alternative
  —MCLs of 0.080 mg/L for TTHM and
    0.060 mg/L for HAAS as LRAAs
  —Bromate MCL remaining at 0.010
    mg/L
Alternative 1
  —MCLs of 0.080 mg/L for TTHM and
    0.060 mg/L for HAA5 as LRAAs
  —Bromate MCL of 0.005 mg/L
Alternative 2
                           —MCLs of 0.080 mg/L for TTHM and
                             0.060 mg/L for HAA5 as absolute
                             maximums for individual
                             measurements
                           —Bromate MCL remaining at 0.010
                             mg/L
                         Alternative 3
                           —MCLs of 0.040 mg/L for TTHM and
                             0.030 mg/L for HAAS as RAAs
                           —Bromate MCL remaining at 0.010
                             mg/L.
                           Figure VI.A—l shows how compliance
                         would be determined under each of the
TTHM/HAA5 alternatives described and
the Stage 1 DBPR for a hypothetical
large surface water system. This
hypothetical system has one treatment
plant and measures TTHM in the
distribution system in four locations per
quarter (the calculation methodology
shown would be the same for HAAS).
Ultimately, the Advisory Committee
recommended the Preferred Alternative
in combination with an IDSE
requirement (discussed in Section IV.F).

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           Federal Register/Vol. 71, No. 2/Wednesday, January 4, 2006/Rules and Regulations
443
           Figure VI. A-1.  Calculations of Compliance for the Regulatory Alternatives Considered


                       f      JBasis of Compliance

                       ||      llviolation of MCL
                       Stage 1 DBPR
                       TTHM MCL = 80 ug/L measured as an RAA
                       No exceedance of MCL

Q1
"~Q2
Q3
Q4
Loc. 1 Loc. 2
100 j 40
75 i 50
55 | 45
60 55
Loc. 3
50
40
55
40
Loc. 4
50
100
110
75
Qtrly Avg.
60
66
66
58
RAAL 63 j
                       Preferred Stage 2 DBPR Alternative and Alternative 11
                       TTHM MCL = 80 ug/L measured as an LRAA
                       LRAA at Location 4 exceeds MCL

Q1
Q2
Q3
Q4
Loc. 12
100
75
55
60
LRAA [__ 73 I
Loc 22
40
50
45
55
f 48
i Loc. 32 :
I 50 !
40 ;
i 55- ;
i 40 i
T 46 I
Loc. 42
50
100
110
75
84
                        The Preferred Alternative and Alternative 1 have the same TTHM MCL;
                        they differ only in regard to the bromate MCL.
                       2Based on the IDSE, new locations targeted for high DBFs.

                       Alternative 2
                       TTHM MCL = 80 pg/L measured as a single highest value
                       Three samples at Locations 1 and 4 exceed MCL

Q1
Q2
Q3
Q4
Loc. 1
100
75
£ 55"
r~ eo
i
I
i

_i
Loc. 2
40
50
45
55

1
i
T
i
'f •
J_
Loc. 3
50
40
55
40

1


L_
Loc. 4
50
100
110
75




J
                       Alternative 3
                       TTHM MCL = 40 ug/L measured as an RAA
                       RAA exceeds MCL

Q1
Q2
Q3
Q4
Loc. 1
100
75
55
60
Loc. 2
40
50
45
55
Loc. 3 i Loc. 4
50 | 50
40 . 100
55 | 110
40 75
RAA
Qtriy Avg.
60
66
66
58
63
BILLING CODE 6560-50-C

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Federal  Register/Vol. 71, No. 2/Wednesday,  January 4, 2006/Rules and  Regulations
 B. Analyses That Support Today's Final
 Rule
  EPA's goals in designing the Stage 2
 DBPR were to protect public health by
 reducing peak DBF levels in the
 distribution system while maintaining
 microbial protection. As described
 earlier, the Stage 1 DBPR reduces
 overall average DBP levels, but specific
 locations within distribution systems
 can still experience relatively high DBP
 concentrations. EPA believes that high
 DBP concentrations should be reduced
 due to the potential association of DBFs
 with cancer, as well as reproductive and
 developmental health effects.
  EPA analyzed the benefits and costs
 of the four regulatory alternatives
 presented in the previous section.
 Consistent with the recommendations of
 the Advisory Committee, EPA is
 establishing the preferred alternative to
 achieve the Agency's goals for the Stage
 2 DBPR. The following discussion
 summarizes EPA's analyses that support
 today's final rule. This discussion
 explains how EPA predicted water
 quality and treatment changes,
 estimated benefits and costs, and
 assessed the regulatory alternatives.

 1. Predicting Water Quality and
 Treatment Changes
  Water quality and treatment data from
 the ICR were used in  predicting
 treatment plant technology changes (i.e.
 compliance forecasts) and reductions in
 DBP exposure resulting from the Stage
 2 DBPR. Because ICR data were gathered
 prior to Stage 1 DBPR compliance
 deadlines, EPA first accounted for
 treatment changes resulting from the
 Stage 1  DBPR. Benefit and cost
 estimates for the Stage 2 DBPR reflect
 changes following compliance with the
 Stage 1  DBPR.
  The primary model used to predict
 changes in treatment and reductions in
 DBP levels was the Surface Water
 Analytical Tool (SWAT), which EPA
 developed using results from the ICR.
 SWAT results were applied directly for
 large and medium surface water systems
 and were adjusted for small surface
 water systems to account for differences
 in source water DBP precursor levels
 and operational constraints in small
 systems. EPA used ICR data and a
Delphi poll process (a group of drinking
water experts who provided best
professional judgment in a structured
format) to project technologies selected
by ground water systems.
  To address uncertainty in SWAT
predictions, EPA also predicted
treatment changes using a second
methodology, called the "ICR Matrix
Method." Rather than a SWAT-
                          predicted pre-Stage 1 baseline, the ICR
                          Matrix Method uses unadjusted ICR
                          TTHM and HAAS pre-Stage 1 data to
                          estimate the percent of plants changing
                          technology to comply with the Stage 2
                          DBPR. EPA gives equal weight to SWAT
                          and ICR Matrix Method predictions in
                          estimating Stage 2 compliance forecasts
                          and resultant reductions in DBP
                          exposure. The ICR Matrix Method is
                          also used to estimate reductions in the
                          occurrence of peak TTHM and HAAS
                          concentrations because SWAT-
                          predicted TTHM  and HAAS
                          concentrations are valid only when
                          considering national averages, not at the
                          plant level.
                            When evaluating compliance with a
                          DBP MCL, EPA assumed that systems
                          would maintain DBP levels at least 20
                          percent below the MCL. This safety
                          margin represents the level at which
                          systems typically take action to ensure
                          they meet a drinking water standard and
                          reflects industry practice. In addition,
                          the safety margin accounts for year-to-
                          year fluctuations  in DBP levels. To
                          address the impact of the IDSE, EPA
                          also analyzed compliance using a safety
                          margin of 25 percent based on an
                          analysis of spatial variability in TTHM
                          and HAAS occurrence. EPA assigned
                          equal probability  to the 20 and 25
                          percent safety margin for large and
                          medium surface water systems for the
                          final analysis because both alternatives
                          are considered equally plausible. EPA
                          assumes the 20 percent operational
                          safety margin accounts for variability in
                          small surface water systems and all
                          groundwater systems.
                          2. Estimating Benefits
                            Quantified benefits estimates for the
                          Stage 2 DBPR are  based on potential
                          reductions in fatal and non-fatal bladder
                          cancer cases. In the EA, EPA included
                          a sensitivity analysis for benefits from
                          avoiding colon and rectal cancers.  EPA
                          believes additional benefits from this
                          rule could come from reducing potential
                          reproductive and  developmental risks.
                          EPA has not included these potential
                          risks in the primary benefit analysis
                          because of the associated uncertainty.
                            The major steps in deriving and
                          characterizing potential cancer cases
                          avoided include the following: (1)
                          estimate the current and future annual
                          cases of illness from all causes; (2)
                          estimate how many cases can be
                          attributed to DBP  occurrence and
                          exposure; and  (3)  estimate the reduction
                          in future cases corresponding to
                          anticipated reductions in DBP
                          occurrence and exposure due to the
                          Stage 2 DBPR.
                            EPA used results from the National
                          Cancer Institute's  Surveillance,
 Epidemiology, and End Results program
 in conjunction with data from the 2000
 U.S. Census to estimate the number of
 new bladder cancer cases per year
 (USEPA 2005a). Three approaches were
 then used to gauge the percentage of
 cases attributable to DBP exposure (i.e.,
 population attributable risk (PAR)).
 Taken together, the three approaches
 provide a reasonable estimate of the
 range of potential risks. EPA notes that
 the existing epidemiological evidence
 has not conclusively established
 causality between DBP exposure and
 any health risk endpoints, so the lower
 bound of potential risks may be as low
 as zero.
  The first approach used the range of
 PAR values  derived from consideration
 of five individual epidemiology studies.
 This range was used at the basis for the
 Stage 1 and the proposed Stage 2
 economic analyses (i.e., 2 percent to 17
 percent) (USEPA 2003a).
  The second approach used results
 from the Villanueva et al. (2003) meta-
 analysis. This study develops a
 combined Odds Ratio (OR) of 1.2 that
 reflects the ever-exposed category for
 both sexes from all studies considered
 in the meta-analysis and yields a PAR
 value of approximately 16 percent.
  The third  approach used the
 Villanueva et al. (2004) pooled data
 analysis to develop a dose-response
 relationship for OR as a function of
 average TTHM exposure. Using the
 results from this approach, EPA
 estimates a PAR value of approximately
 17 percent.
  EPA used  the PAR values from all
 three approaches to estimate the number
 of bladder cancer  cases ultimately
 avoided annually  as a result of the Stage
 2 DBPR. To quantify the reduction in
 cases, EPA assumed a linear
 relationship between average DBP
 concentration and relative risk of
 bladder cancer. Because of this, EPA
 considers these estimates to be an upper
 bound on the annual reduction in
 bladder cancer cases due to the rule.
  A lag period (i.e., cessation lag) exists
between when reduction in exposure to
 a carcinogen occurs and when the full
 risk reduction benefit of that exposure
 reduction is  realized by exposed
 individuals.  No data are available that
 address the rate of achieving bladder
 cancer benefits resulting from DBP
reductions. Consequently, EPA used
data from epidemiological studies that
address exposure reduction to cigarette
smoke and arsenic to generate three
possible cessation lag functions for
bladder cancer and DBFs. The cessation
lag functions are used in conjunction

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             Federal  Register/Vol. 71, No.  2/Wednesday,  January 4, 2006/Rules  and  Regulations
                                                                       445
with the rule implementation schedule
to project the number of bladder cancer
cases avoided each year as a result of
the Stage 2 DBPR.
  Although EPA used three approaches
for estimating PAR, for simplicity's
sake, EPA used the Villanueva et al.
(2003) study to calculate the annual
benefits of the  Stage 2 DBPR. The
benefits estimates derived from
Villanueva et al.  (2003)  capture a
substantial portion of the overall range
of results, reflecting the uncertainty in
both the underlying OR and PAR values,
as well as the uncertainty in DBF
reductions for  Stage 2.
  To assign a monetary value to avoided
bladder cancer cases, EPA used the
value of a statistical life (VSL) for fatal
cases and  used two alternate estimates
of willingness-to-pay to avoid non-fatal
cases (one based on curable lymphoma
and the other based on chronic
bronchitis). EPA believes additional
benefits from this rule could come from
a reduction in  potential reproductive
and developmental risks. See Chapter 6
of the EA for more information on
estimating benefits (USEPA 2005a).

3. Estimating Costs
  Analyzing costs for systems to comply
with the Stage  2 DBPR included
identifying and costing  treatment
process improvements that systems will
make, as well as estimating the costs to
implement the rule, conduct IDSEs,
prepare monitoring plans, perform
additional routine monitoring, and
evaluate significant DBF excursion
events. The cost analysis for States/
Primacy Agencies included estimates  of
the labor burdens for training employees
on the requirements of the Stage 2
DBPR, responding to PWS reports, and
record keeping.
  All treatment costs are based on mean
unit cost estimates for advanced
technologies and chloramines.
Derivation of unit costs are described  in
detail in Technologies and Costs for the
Final Long Term 2 Enhanced Surface
Water Treatment Rule and Final Stage 2
Disinfectants and Disinfection
Byproducts Rule (USEPA 2005g). Unit
costs (capital and O&M) for each of nine
system size categories are calculated
using mean design and  average daily
flows values. The unit costs are then
combined with the predicted number  of
plants selecting each technology to
produce national treatment cost
estimates.
  Non-treatment costs for
implementation, the IDSE, monitoring
plans, additional routine monitoring,
and operational evaluations are based
on estimates of labor hours for
performing these activities and on
laboratory costs.
  While systems vary with respect to
many of the input parameters to the
Stage 2 DBPR cost analysis (e.g., plants
per system, population served, flow per
population, labor rates), EPA believes
that mean values for the various input
parameters are appropriate to generate
the best estimate of national costs for
the rule. Uncertainty in the national
average unit capital and O&M  costs for
the various technologies has been
incorporated into the cost analysis
(using Monte Carlo simulation
procedures). Costs of the Stage 2 DBPR
are estimated at both mean and 90
percent confidence bound values.
  EPA assumes that systems will, to the
extent possible, pass cost increases on to
their customers through increases in
water rates. Consequently, EPA has also
estimated annual household cost
increases for the Stage 2 DBPR. This
analysis includes costs for all
households served by systems subject to
the rule, costs just for those households
served by systems actually changing
treatment technologies to comply with
the rule, costs for households served by
small systems, and costs for systems
served by surface water and ground
water sources.
4. Comparing Regulatory Alternatives
  Through the analyses summarized in
this section, EPA assessed the  benefits
and costs of the four regulatory
alternatives described previously.
Succeeding sections of this preamble
present the results of these analyses. As
recommended by the Advisory
Committee, EPA is establishing the
preferred regulatory alternative for
today's Stage 2 DBPR. This regulation
will reduce peak DBF concentrations in
distribution systems through requiring
compliance determinations with
existing TTHM and HAAS MCLs using
the LRAA. Further, the IDSE will ensure
that systems identify compliance
monitoring sites that reflect high DBF
levels. EPA believes that these provision
are appropriate given the association of
DBFs with cancer, as well as potential
reproductive and developmental health
effects.
  Alternative 1 would have established
the same DBF regulations as the
preferred alternative, and would have
lowered the bromate MCL from 0.010 to
0.005 mg/L. The Advisory Committee
did not recommend and EPA did not
establish this alternative because it
could have an  adverse effect on
microbial protection. The lower bromate
MCL could cause many systems to
reduce or eliminate the use of ozone,
which is an effective disinfectant for a
broad spectrum of microbial pathogens,
including microorganisms like
Cryptosporidium that are resistant to
chlorine.
  Alternative 2 would have prohibited
any single sample from exceeding the
TTHM or HAAS MCL. This  is
significantly more stringent than the
preferred alternative and would likely
require a large fraction of surface water
systems to switch from their current
treatment practices to more  expensive
advanced technologies. Consistent with
the Advisory Committee, EPA does not
believe such a drastic shift is warranted
at this time.
  Similarly, Alternative 3, which would
decrease TTHM and HAAS MCLs to
0.040 mg/L and 0.030 mg/L,
respectively, and would require a
significant portion of surface water
systems to implement expensive
advanced technologies in place of their
existing treatment. Further,  compliance
with TTHM and HAAS MCLs under this
alternative would be based on the RAA,
which does not specifically address DBF
peaks in the distribution system as the
LRAA, in conjunction with  the IDSE,
are designed to do. Based on these
considerations, EPA and the Advisory
Committee did not favor this alternative.

C. Benefits of the Stage 2 DBPR
  The benefits analysis for the Stage 2
DBPR includes a description of non-
quantified benefits, calculations of
quantified benefits, and a discussion of
when benefits will occur after today's
final rule is implemented. An overview
of the methods used to determine
benefits is provided in Section VLB.
More detail can be found in the final
EA. A summary of benefits for the Stage
2 DBPR is given in this section.

1. Nonquantified Benefits
  Non-quantified benefits of the Stage 2
DBPR include potential benefits from
reduced reproductive and
developmental risks, reduced risks of
cancers other than bladder cancer, and
improved water quality. EPA believes
that additional benefits from this rule
could come from a reduction in
potential reproductive and
developmental risks. However, EPA
does not believe the available evidence
provides an adequate basis for
quantifying these potential risks in the
primary analysis.
  Both toxicology and epidemiology
studies indicate that other cancers may
be associated with DBF exposure but
currently there is not enough data to
include them in the primary analysis.
However, EPA believes that the
association between exposure to DBFs
and colon and rectal cancer is possibly

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446
Federal Register/Vol.  71,  No. 2/Wednesday, January  4,  2006/Rules and Regulations
significant, so an analysis of benefits is
presented as a sensitivity analysis.
  To the extent that the Stage 2 DBPR
changes perceptions of the health risks
associated with drinking water and
improves taste and odor, it may reduce
actions such as  buying bottled water or
installing filtration devices. Any
resulting cost savings would be a
regulatory benefit. Also, as PWSs move
away from conventional treatment to
more advanced  technologies, other non-
health  benefits are anticipated besides
better tasting and smelling water. For
example, GAC lowers nutrient
availability for bacterial growth,
produces a biologically more stable
finished water, and facilitates
management of  water quality in the
distribution system. Since GAC also
removes synthetic organic chemicals
(SOCs), it provides additional protection
                          from exposure to chemicals associated
                          with accidental spills or environmental
                          runoff.

                          2. Quantified Benefits
                            EPA has quantified the benefits
                          associated with the expected reductions
                          in the incidence of bladder cancer. As
                          discussed in Section VLB, EPA used the
                          PAR values from all three approaches to
                          estimate the number of bladder cancer
                          cases ultimately avoided annually as a
                          result of the Stage 2 DBPR, shown in
                          Figure VI.C-1.
                           Table VI.C-1 summarizes the
                          estimated number of bladder cancer
                          cases avoided as a result of the Stage 2
                          DBPR, accounting for cessation lag and
                          the rule implementation schedule, and
                          the monetized value of those cases. The
                          benefits in Table VI.C—1 were developed
                          using the PAR value from Villanueva et
al. (2003), as described in Section VLB.
Table VI.C-1 summarizes the benefits
for the Preferred Regulatory Alternative
for the Stage 2 DBPR. Benefits estimates
for the other regulatory alternatives
were derived using the same methods as
for the Preferred Regulatory Alternative
and are presented in the EA.
  The confidence bounds of the results
in Table VI.C-1 reflect uncertainty in
PAR, uncertainty in the compliance
forecast and resulting reduction in DBF
concentrations, and cessation lag.
Confidence bounds of the monetized
benefits also reflect uncertainty in
valuation parameters. An estimated 26
percent of bladder cancer cases avoided
are fatal, and 74 percent are non-fatal
(USEPA 1999b). The monetized benefits
therefore reflect the estimate of avoiding
both fatal and non-fatal cancers in those
proportions.

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             Federal Register/Vol.  71, No. 2/Wednesday, January 4,  2006/Rules and Regulations
                                                                     447
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BILLING CODE 6560-50-C

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 448
Federal Register/Vol. 71, No. 2/Wednesday, January 4, 2006/Rules and Regulations
           TABLE VI.C-1 .—SUMMARY OF QUANTIFIED BENEFITS FOR THE STAGE 2 DBPR (MILLIONS OF $2003)
Annual a
Mean
279



188



333



verage cases
5th
103



61



138



avoided
95th
541



399



610



Discount rate, WTP for non-
fatal cases
3% Lymphoma
7% Lymphoma ...
3% Bronchitis
7% Bronchitis 	 	
3%, Lymphoma 	
7% Lymphoma
3% Bronchitis
7% Bronchitis
3% Lymphoma
7% Lymphoma
3% Bronchitis
7% Bronchitis 	
Annuahzed
Mean
$1 531
1 246
763
621
1 032
845
514
420
1 852
1 545
922
769
benefits of cas
5th
$233
190
165
135
157
129
111
91
282
235
200
167
es avoided
95th
$3 536
2878
1 692
1 376
2384
1 950
1 141
932
4276
3566
2045
1.704


Smoking/Lung Cancer



Smoking/Bladder Cancer



Arsenic/Bladder Cancer



  Notes1 Values are discounted and annualized in 2003$. The 90 percent confidence interval for cases incorporates uncertainty in PAR, reduc-
tion in average TTHM and HAAS concentrations, and cessation lag. The 90 percent confidence bounds for monetized benefits reflect uncertainty
in monetization  inputs relative to mean cases. Based on TTHM as an indicator, benefits were calculated using the Villanueva et al (2003) PAR.
EPA recognizes that benefits may be as low as zero since causality has not yet been established between exposure to chlorinated water and
bladder cancer.  Assumes 26 percent of cases are fatal, 74 percent are non-fatal (USEPA 1999b).
  Source: Exhibit 6.1, USEPA 2005a
 3. Timing of Benefits Accrual

   EPA recognizes that it is unlikely that
 all cancer reduction benefits would be
 realized immediately upon exposure
 reduction. Rather, it is expected that
 there will likely be some transition
 period as individual risks reflective of
 higher past exposures at the time of rule
 implementation become, over time,
 more reflective of the new lower
                           exposures. EPA developed cessation lag
                           models for DBFs from literature to
                           describe the delayed benefits, in
                           keeping with the recommendations of
                           the SAB (USEPA 2001d). Figure VI.C-2
                           illustrates the effects of the cessation lag
                           models. The results from the cessation
                           lag models show that the majority of the
                           potential cases avoided occur within the
                           first fifteen years after initial reduced
                           exposure to DBFs. For example, fifteen
 years after the exposure reduction has
 occurred, the annual cases avoided will
 be 489 for the smoking/lung cancer
 cessation lag model, 329 for the
 smoking/bladder cancer cessation lag
 model, and 534 cases for the arsenic/
 bladder cancer cessation lag model.
 These represent approximately 84%,
 57%, and 92%, respectively, of the
 estimated 581 annual cases ultimately
 avoidable by the Stage 2 DBPR.
                                Figure VI C-2, Comparison of Alternative Cessation Lag Models Estimates of Annual Cases
                                Avoided by Year Following Exposure Reduction (Excluding Implementation Schedule).
                                                        BP Exposure Reduction Begins
  In addition to the delay in reaching a
steady-state level of risk reduction as a
result of cessation lag, there is a delay
in attaining maximum exposure
reduction across the entire affected
population that results from the Stage 2
DBPR implementation schedule. For
example, large surface water PWSs have
                          six years from rule promulgation to
                          meet the new Stage 2 MCLs, with up to
                          a two-year extension possible for capital
                          improvements. In general, EPA assumes
                          that  a fairly constant increment of
                          systems will  complete installation of
                          new treatment technologies each year,
                          with the last  systems installing
treatment by 2016. The delay in
exposure reduction resulting from the
rule implementation schedule is
incorporated into the benefits model by
adjusting the cases avoided for the given
year and is illustrated in Table VI.C-2.

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             Federal Register/Vol.  71, No.  2/Wednesday, January 4, 2006/Rules and Regulations
                                                                        449
 TABLE Vl.C-2.—BLADDER CANCER CASES AVOIDED (TTHM AS INDICATOR) EACH YEAR USING THREE CESSATION LAG
                                                      MODELS
Year
1
2
3
4 	 	
5 	 	
6
7
8 	 	 	
9 	 	
10 	
11 	
12 .. 	
13 	 	 	
14 ... 	
15 . 	
16 	 	
17 	 	
18 .. 	
19 	 	
20 	 	
21 	
22 	
23
24 	
25 	
Smoking/lung cancer
cessation lag model
Total
0
0
0
0
0
24
62
111
170
220
265
305
341
371
396
416
433
448
460
471
481
489
496
503
509
Percent
0
0
0
0
0
4
11
19
29
38
46
53
59
64
68
72
75
77
79
81
83
84
86
87
88
Smoking/bladder can-
cer cessation lag
model
Total
0
0
0
0
0
23
54
90
132
161
184
204
221
237
251
265
278
289
301
311
321
330
339
347
355
Percent
0
0
0
0
0
4
9
16
23
28
32
35
38
41
43
46
48
50
52
54
55
57
59
60
61
Arsenic/bladder can-
cer cessation lag
model
Total
0
0
0
0
0
45
110
187
275
334
379
412
438
458
475
488
499
509
516
523
528
533
537
541
544
Percent
0
0
0
0
0
8
19
32
48
58
65
71
76
79
82
84
86
88
89
90
91
92
93
93
94
  Notes: Percent of annual cases ultimately avoidable achieved during each of the first 25 years. The benefits model estimates 581 (90% CB =
229-1,079) annual cases ultimately avoidable using the Villanueva et al. (2003) PAR inputs and including uncertainty in these and DBP reduc-
tions. EPA recognizes that benefits may be as low as zero since causality has not yet been established between exposure to chlorinated water
and bladder cancer.
  Source: Summarized from detailed results presented in Exhibits E.38a, E.38e and E.38i, USEPA 2005a.
D. Costs of the Stage 2 DBPR
  National costs include those of
treatment changes to comply with the
rule as well as non-treatment costs such
as for Initial Distribution System
Evaluations  (IDSEs), additional routine
monitoring,  and operational
evaluations. The methodology used to
estimate costs is described in Section
VLB. More detail is provided in the EA
(USEPA 2005a). The remainder of this
section presents summarized results of
EPA's cost analysis for total annualized
present value costs, PWS costs, State/
Primacy agency costs, and non-
quantified costs.

1. Total Annualized Present Value Costs

  Tables VI.D-1 and VI.D-2 summarize
the average annualized costs for the
Stage 2 DBPR Preferred Regulatory
Alternative at 3 and 7  percent discount
rates, respectively. System costs range
from approximately $55 to $101 million
annually at a 3 percent discount rate,
with a  mean estimate of approximately
$77 million per year. The mean and
range of annualized costs are similar at
a 7 percent discount rate. State costs are
estimated to be between $1.70 and $1.71
million per year depending on the
discount rate. These estimates are
annualized starting with the year of
promulgation. Actual dollar costs
during years when most treatment
changes are expected to occur would be
somewhat higher (the same is true for
benefits that occur in the future).
BILLING CODE 6560-50-P

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Federal Register/Vol.  71, No.  2/Wednesday, January 4, 2006/Rules and Regulations
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452
Federal Register/Vol. 71, No. 2/Wednesday,  January 4, 2006/Rules and Regulations
2. PWS costs

  PWS costs for the Stage 2 DBPR
include non-treatment costs of rule
implementation, Initial Distribution
System Evaluations (IDSEs), Stage 2
DBPR monitoring plans, additional
routine monitoring, and operational
evaluations. Systems required to install
treatment to comply with the MCLs will
accrue the additional costs of treatment
                         installation as well as operation and
                         maintenance. Significant PWS costs for
                         IDSEs, treatment, and monitoring are
                         described in this section, along with a
                         sensitivity analysis.
                           a. IDSE costs. Costs and burden
                         associated with IDSE activities differ
                         depending on whether or not the system
                         performs the IDSE and, if so, which
                         option a system chooses. All systems
                         performing the IDSE are expected to
incur some costs. EPA's analysis
allocated systems into five categories to
determine the costs of the IDSE—those
conducting standard monitoring, SSS,
VSS, 40/30, and NTNCWS not required
to do an IDSE. EPA then developed cost
estimates for each option. Tables VI.D—
3, VI.D-4, and VI.D-5 illustrate PWS
costs for IDSE for systems conducting an
SMP, SSS, and 40/30, respectively.
                    Table VI.D-3.  IDSE Costs for Systems Using Standard Monitoring.
Size Category
Total Number
of Systems
That Monitor
A
Develop IDSE monitoring plan and report
Preparation
of IDSE
Monitoring
Plan
B
Preparation of
IDSE Report
C
Reporting Cost
per Labor Hour
D
Sampling
Number of
Dual Sample
Sets per
System
E
Hours
per
Sample
F
Sampling
Cost per
Labor Hour
G
Laboratory
Cost per
Sample
H
Total Cost
=A'((B+C)'D+E'
F'G+H))
Total
Burden
(Hours)
J=A'(B+C+
E'F)
Total
Burden
(FTEs)
K=J/2,080
Surface Water and Mixed CWSs
<500
500-3,299
3,300-9,999
10,000^19,999
50,000-249,999
250,000-999,999
1,000,000-4.999.999
25 M
National Totals
2,060
3,823
1,888
1,524
436
63
14
1
9,809
4
4
4
8
8
12
16
24
2
2
2
4
8
12
24
24
$ 2255
$ 2474
$ 3051
$ 31 08
$ 3264
$ 3525
S 3525
S 3525

2
8
16
48
96
144
192
240
1
1
1
1
1
1
1
1
$ 2255
$ 24 74
$ 2534
$ 26 05
$ 2800
$ 31 26
$ 31 26
$ 31 26
$ 240
$ 240
$ 240
$ 210
$ 210
$ 210
$ 210
$ 210

$ 1.360,071
$ 8,664,294
$ 8,361,031
$ 17,835.921
$ 10,189,487
S 2.242,006
$ 668,246
$ 59.594
$ 49,380,649
16,476
53,522
41,536
91,440
48,832
10.584
3,248
288
265,926
79
25 7
200
440
235
51
1 6
01
127.8
Disinfecting Ground Water Only CWSs
<500
500-9.999
10,000-99.999
100,000^99.999
> 500.000
National Totals
752
1,956
240
18
1
2,966
4
4
8
12
16
2
2
8
12
24
$ 2235
S 2486
S 31 08
$ 3525
$ 3525

2
a
24
32
48
1
1
1
1
1
$ 2235
S 2486
$ 2605
S 31 26
S 31 26
$ 240
$ 240
$ 210
$ 210
$ 210

$ 495,114
$ 4435.321
$ 1,477.430
$ 152,514
$ 11,576
S 6,571,956
6,012
27,378
9.590
997
78
44,056
29
132
46
05
00
21.2
Surface Water and Mixed NTNCWSs
9,999
50,000-249,999
250,000-999.959
1,000,000-4,999,999
25 M
National Totals
N/A
N/A
N/A
4
1
0
0
0
5
N/A
N/A
N/A
8
8
12
16
24
N/A
N/A
N/A
4
8
12
24
24
N/A
N/A
N/A
S 31 08
$ 3525
N/A
N/A
N/A

N/A
N/A
N/A
48
96
144
192
240
N/A
N/A
N/A
1
1
1
1
1
N/A
N/A
N/A
$ 2605
$ 31 26
N/A
N/A
N/A
N/A
N/A
N/A
$ 210
$ 210
$ 210
$ 210
$ 210

N/A
N/A
N/A
S 46.813
$ 23.725
$
$
$
$ 70,538
N/A
N/A
N/A
240
112


-
352
N/A
NfA
N/A
0 1
01


-
0.2
Disinfecting Ground Water Only NTNCWSs
<500
500-9.999
10,000-99,999
100,000-499,999
> 500,000
National Totals
Grand Totals
N/A
WA
1
0
0
1
12,780
N/A
N/A
8
12
16
N/A
N/A
8
12
24
N/A
N/A
$ 31 08
$ 3525
N/A

N/A
N/A
24
32
48
N/A
N/A
1
1
1
N/A
N/A
$ 26.05
$ 31 26
N/A
N/A
N/A
$ 210
$ 210
$ 210


N/A
N/A
$ 3,759
$ 2,484
$
$ 6,243
$ 56,029.386
N/A
N/A
24
16

41
310.375
N/A
N/A
00
00

0.0
149.2
    Notes:   Detail my not add due to independent rounding.
            Shaded areas represent systems that are not subject to IDSE requirements.
            1 FTE = 2,080 hours (40 hours/week, 52 weeks/year)
    Source:  Exhibit H.4, USEPA 2005a.

-------
      Federal Register/Vol. 71,  No.  2/Wednesday, January 4, 2006/Rules  and Regulations
453
             Table VI.D-5. IDSE Costs Systems Qualifying for the 40/30 Certification.





Size Category
Selecting Additional Sites
Systems Receiving
40/30 Certification
but Adding Stage 2
site(s)
A


Hours per
System
B
Preparing IDSE Certification

Number of
Systems Receiving
40/30 Certification
C

Reporting
Hours per
System
D



Cost per Labor
Hour
E




Total Cost
F = (A'B+C'D)"E
Surface Water and Mixed CWSs
<500
500-3,299
3,300-9,999
10,000-49.999
50,000-249,999
250,000-999,999
1,000.000-4,999,999
>5M
National Total


154
-
75
11
2
-
242
1
3
3
8
8
8
8
8

-
235
154
249
75
11
2
-
726
1
1
1
2
2
2
2
2
$ 2255
$ 2474
$ 3051
S 3108
$ 3264
$ 3525
$ 3525
$ 3525

$
$ 5,814
$ 18,795
$ 15,478
$ 24,481
$ 3,877
$ 705
$
$ 69,150



Total Burden
(Hours)
G = A*B+C'D


Total
Burden
(FTEs)
H = G/2.080

-
235
616
498
750
110
20
-
2,229
-
0.1
03
02
04
0.1
00

1.1
Disinfecting Ground Water Only CWSs
<500
500-9,999
10,000-99,999
100.000-499,999
> 500,000
National Total
-
9,094
1,118


10,212
1
3
8
8
8

- ]
9.094
1,118
40
5
10,257
1
1
2
2
2
$ 2235
$ 2486
$ 31 08
$ 3525
S 3525

$
$ 904,287
$ 347,474
$ 2,820
$ 352
$ 1,254,934
Surface Water and Mixed NTNCWSs
<500
500-3,299
3,300-9,999
10,000-49,999
50,000-249,999
250,000-999,999
1,000,000-4,999,999
>5M
National Total
N/A
N/A
N/A
-
-
-
-
-
-
NiA
'"/• N/A
N/A
8
8
8
8
8

, , ' N/A
• '- " - N/A
N/A
1

-


1
N/A
N/A
N/A
2
2
2
2
2
N/A
•N/A
N/A
$ 3108
$ 3525
N/A
N/A
N/A

N/A
N/A
N/A
$ 62
$
$
S
$
$ 62

36,376
11,180
80
10
47,646
-
175
54
00
00
22.9

N/A
;.. - - ' N/A
N/A
2
-
-
-
-
2
Disinfecting Ground Water Only NTNCWSs
<500
500-9,999
10,000-99,999
100,000-499,999
> 500,000
National Total
Grand Totals
N/A
N/A
3
-
-
3
10,457
N/A
: N/A
8
8
8


N/A
N/A
3

-
3
10,987
N/A
N/A
2
3
6
N/A
N/A
$ 31 08
$ 3525
N/A


N/A
N/A
$ 932
$
S
$ 932
$ 1,325,079
N/A
N/A
30
-
-
30
49,907
N/A
N/A
N/A
00
-
-
-
-
0.0

N/A
N/A
00
-
-
0.0
240
Notes:  Shaded areas represent systems that are not subject to IDSE requirements.
Source: Exhibit H.6, USEPA 2005a.

-------
454
Federal Register/Vol.  71, No. 2/Wednesday, January 4, 2006/Rules  and Regulations
                              Table Vl.D-4.  IDSE Costs for Systems Using SSSs.
Size Category

Number of
Systems Qualifying for
SSS
A
Preparation of
IDSE Study Plan
B
Conduct Study
C
Preparation of
IDSE Study
Report
D
Cost per Labor
Hour
E
Total Cost
F= '
A"(B+C+D)'E
Total Burden
(Hours)
G =
A'(B+C+D)
Total
Burden
(FTEs)
H = G/2,080
Surface Water and Mixed CWSs
<500
500-3,299
3,300-9,999
10,000-49,999
50.000-249.999
250,000-999,999
1,000,000-4,999,999
>5M
National Total
-
-
-
-
23
7
1
-
31

-
-
-
20
20
20



-

40
40
40



-
-
20
20
20

$
$
$
$
$ 32.64
$ 3525
$ 35.25
$

$
$
$
$
$ 60,060
$ 19,739
$ 2,820
$
$ 82,618




1,840
560
80

2,480
-

-

0.9
03
00

1.2
Disinfecting Ground Water Only CWSs
<500
500-9,999
10,000-99,999
100.000-499,999
> 500,000
National Total
-
-
-
2

2
-
-

20

-

-
40
-
-


20
-
$
S
$
$ 3525
$

$
$
S
$ 5,640
$
$ 5,640



160

160


-
01

0.1
Surface Water and Mixed NTNCWSs
<500
500-3,299
3.300-9,999
10,000-49,999
50,000-249,999
250,000-999,999
1,000,000-4,999,999
National Total
N/A
N/A
N/A
-
-
-
;
-
N/A
N/A
N/A
-
-
-

N/A
N/A
N/A
-
-
-

N/A
N/A
N/A
-



N/A
N/A
N;A
$
$
S
$
$

N/A
N/A
N/A
S
$
$
$
$
$
MA
N/A
N/A



;
-
N/A
N/A
N/A


-
-
-
Disinfecting Ground Water Only NTNCWSs
<500
500-9,999
10,000-99,999
100,000-499,999
> 500,000
National Total
Grand Totals
N/A
N/A
-

-
-
33
N/A
N/A
-


N/A
N/A
-

-
N/A
N/A
-
-

N/A
N/A
$
$
$


N/A
N/A
S
$
$
$
$ 88,258
N/A
N/A

-
-
-
2.640
N/A
N/A

-
-
-
1.3
      Notes:  Detail my not add due to independent rounding.
              Shaded areas represent systems that are not subject to IDSE requirements.
              SSS = System Specific Study.
      Source:  Exhibit H.5, USEPA 2005a.
  b. PWS treatment costs. The number
of plants changing treatment as a result
of the Stage 2 DBPR and which
technology various systems will install
are determined from the compliance
                         forecast. The percent of systems
                         predicted to make treatment technology
                         changes and the technologies predicted
                         to be in place after implementation of
                         the Stage 2 DBPR are shown in Table
VI.D-6. The cost model includes
estimates for the cost of each
technology; the results of the cost model
for PWS treatment costs are summarized
in Table VI.D-7.

-------
Federal Register/Vol.  71, No. 2/Wednesday, January 4, 2006/Rules  and Regulations
455

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-------
456
Federal Register/Vol.  71, No. 2/Wednesday, January 4, 2006/Rules and Regulations
            Table VI.D-7.  Total Initial Capital Costs and Steady-State O&M Costs ($Millions/Year).
Source
Surface
Water
Ground
Water

System
Classification
CWSs
NTNCWSs
System
Size
(population
served)
<100
100-499
500-999
1,000-3.299
3.300-9.999
10.000-49,999
50,000-99,999
100,000-999,999
1,000,000+
All Sizes
•=100
100-499
500-999
1,000-3.299
3,300-9,999
10,000-49.999
50.000-99,999
100,000-999,999
1,000.000+
All Sizes
Subtota
CWSs





NTNCWSs





<100
100-499
500-999
1,000-3.299
3,300-9.999
10,000-49,999
50,000-99,999
100,000-999.999
1.000.000+
All Sizes
<100
100-499
500-999
1,000-3,299
3,300-9.999
10.000-49.999
50.000-99.999
100.000-999.999
1,000,000+
All Sizes
Subtotal
Total
Capital Costs
Mean
Value
$ 1 09
$ 3.27
$ 386
$ 2439
$ 6223
$ 11320
$ 6740
$ 18398
S 8604
$ 545.44
$ 067
$ 132
$ 0.85
$ 1 89
$ 1 29
$ 055
$
$ 041
$
$ 699
$ 552.43
$ 834
$ 3319
$ 2018
$ 3943
$ 6591
$ 5909
$ 1496
$ 29.70
$ 338
$ 274.18
$ 3.17
$ 504
$ 247
$ 161
$ 046
$ 0 10
$ 002
$ 003
$
$ 12.90
$ 287.08
t 839.51
Median
Value
$ 107
$ 322
$ 378
$ 2427
$ 61 92
$ 113.98
$ 6808
$ 186 24
$ 8646
$ 549 03
$ 066
$ 1 31
$ 084
$ 188
$ 128
$ 055
$
$ 041
$
$ 695
$ 555.97
$ 834
$ 3318
$ 20.18
$ 3942
$ 6586
$ 59.08
$ 14.96
$ 29.71
$ 338
$ 27411
$ 317
$ 504
$ 247
$ 161
S 046
$ 010
$ 002
$ 003
$
$ 1290
$ 287.01
I 842.98
90 Percent
Confidence Bound
Lower
(5th %tile)
$ 058
$ 177
$ 208
$ 1337
$ 3442
$ 6272
$ 37.41
$ 9821
$ 4714
$ 297 70
$ 036
$ 072
$ 046
$ 1 04
$ 071
$ 0.30
$
$ 022
$
$ 382
$ 301.52
$ 7 19
$ 2804
$ 1700
$ 32.35
$ 53.53
$ 5339
$ 13.38
$ 2643
$ 297
$ 23429
$ 2.73
$ 425
$ 2.07
$ 1.32
$ 038
$ 009
$ 002
$ 003
$
$ 10.87
$ 245.16
S 546.68
Upper
(95th %tile)
$ 168
$ 494
$ 589
$ 3607
$ 91.81
$ 157"05
$ 9350
$ 257 75
$ 12041
$ 769 10
$ 103
$ 200
$ 1 30
$ 280
$ 190
$ 076
$
$ 0.57
$
$ 1036
$ 779.46
$ 9.53
$ 3838
$ 2334
$ 4654
$ 7834
$ 6479
$ 16.53
$ 3295
$ 379
$ 314 20
$ 362
$ 581
$ 2.87
$ 1 90
$ 055
$ 011
$ 002
$ 003
$
$ 1491
$ 329.11
S 1,108.57
O&M Costs

Mean
Value
$ 020
$ 082
$ 061
$ 336
$ 532
$ 604
$ 341
$ 817
$ 491
$ 3284
$ 012
$ 0.33
$ 013
$ 026
$ 011
$ 003
$
$ 002
$
$ 1.00
S 33.85
$ 0.98
$ 368
$ 1 96
$ 3.00
$ 255
$ 503
$ 1 28
$ 283
$ 043
$ 2173
$ 037
$ 0.55
$ 023
$ 0.10
$ 0.01
$ 001
$ 0.00
$ 0.00
$
$ 129
$ 23.02
$ 56.86
Median
Value
$ 0,20
$ 082
$ 061
$ 336
$ 534
$ 600
$ 3.36
$ 7.87
$ 465
$ 3221
$ 0.12
$ 0.33
$ 0.13
$ 026
$ 011
$ 003
$
$ 0.02
$
$ 1.00
$ 33.22
$ 098
$ 368
$ 196
S 300
$ 255
$ 503
$ 1 28
$ 283
$ 043
$ 21.73
$ 037
$ 0.55
$ 023
$ 0.10
$ 0.01
$ 0.01
$ 000
$ 000
$
$ 129
$ 23.02
$ 56.23
90 Percent
Confidence Bound
Lower
(5th %tile)
$ 011
$ 046
$ 034
$ 1 88
$ 2.97
$ 374
$ 213
$ 5.21
$ 311
$ 1995
$ 0.07
$ 0.19
$ 0.07
$ 015
$ 006
$ 002
$
$ 001
$
$ 056
$ 20.52
$ 091
$ 338
$ 1 80
$ 273
$ 233
$ 476
$ 1.20
$ 264
$ 040
$ 20.16
$ 035
$ 051
$ 021
$ 009
$ 001
$ 001
$ 000
$ 0.00
$
$ 1.18
$ 21.34
$ 41.86
Upper
(95th %tile)
$ 0.29
$ 1 19
$ 0.88
$ 4.86
$ 7.70
$ 8.66
$ 4.95
$ 12.52
$ 7.73
$ 48.78
$ 0.17
$ 0.48
$ 0.20
$ 0.38
$ 016
$ 004
$
$ 0.03
$
$ 1.46
$ 50.24
$ 1.05
$ 3.98
J 2.12
$ 3.26
$ 276
$ 530
$ 136
$ 302
$ 046
$ 23.31
$ 0.40
$ 0.60
$ 0.25
$ 0.11
$ 002
$ 001
S 0.00
$ 000
$
$ 1.39
$ 24.70
$ 74.94
        Notes:  Estimates are discounted to 2003 and given in 2003 dollars.
               Detail may not add to totals due to independent rounding.
        Source: Exhibit J.la, USEPA 2005a.
  c. Monitoring costs. Because systems
already sample for the Stage 1 DBPR,
                         costs for additional routine monitoring
                         are determined by the change in the
number of samples to be collected from
the Stage 1 to the Stage 2 DBPR. The

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             Federal Register/Vol.  71, No. 2/Wednesday, January  4, 2006/Rules and Regulations
                                                                      457
Stage 2 DBPR monitoring requirements
for systems are based only on
population served and source water
type, while the Stage 1 DBPR
requirements are also based on the
number of treatment plants. With this
modification in monitoring scheme, the
average system will have no change in
monitoring costs. The number of
samples required is estimated to
increase for some systems but actually
decrease from the Stage 1 to the Stage
2 DBPR for many systems. Table VI.D-
8 summarizes the estimated additional
routine monitoring costs for systems.
                     Table VI.D-8.  Total Additional Routine Monitoring Costs for Systems.





Size Category
Total
Additional
Compliance
Samples per
Year
A



Total Labor
Costs
B


Total
Sampling
Costs
C




Total Costs
D


Total
Burden
(Hours)
E


Total
Burden
(FTEs)
F= E/2080
Surface Water and Mixed CWSs
<500
500-3,299
3,300-9,999
10,000-49,999
50,000-249,999
250,000-999,999
1,000,000-4,999,999
>5M
National Totals
(692)
(3,571)
3,594
(10,496)
1,452
609
128
24
(8,953)
$ 7,844
$ (58,617)
$ 91,070
$ (273,425)
$ 40,671
$ 19,041
$ 3,996
$ 735
$ (168,684)
$ (166,169)
$ (857,050)
$ 862,541
$ (2,204,194)
$ 305,021
$ 127,915
$ 26,846
$ 4,939
$ (1,900,150)
$ (158,325)
$ (915,667)
$ 953,611
$ (2,477,619)
$ 345,692
$ 146,956
$ 30,843
$ 5,674
$ (2,068,834)
348
(2,369)
3,594
(10,496)
1,452
609
128
24
(6,711)
0.17
(1.14)
1.73
(5.05)
0.70
0.29
0.06
0.01
(3.23)
Disinfecting Ground Water Only CWSs
<500
500-9,999
10,000-99,999
100,000-499,999
> 500,000
National Totals
793
5,777
552
(277)
(209)
6,636
$ 26,209
$ 143,617
$ 14,385
$ (8,665)
$ (6,546)
$ 169,000
$ 190,302
$ 1,386,523
$ 115,964
$ (58,213)
$ (43,976)
$ 1,590,600
$ 216,511
$ 1,530,140
$ 130,349
$ (66,879)
$ (50,522)
$ 1,759,600
1,173
5,777
552
(277)
(209)
7,015
0.56
2.78
0.27
(0.13)
(0.10)
3.37
Surface Water and Mixed NTNCWSs
<500
500-3,299
3,300-9,999
10,000-49,999
50,000-249,999
250,000-999,999
1,000,000-4,999,999
>5M
National Totals
0
0
96
0
16
-
-
-
112
$ 0
$ 0
$ 2,433
$ 0
$ 500
$
$
$
$ 2,933
$ 0
$ 0
$ 23,040
$ 0
$ 3,360
$
$
$
$ 26,400
$ 0
$ 0
$ 25,473
$ 0
$ 3,860
$
$
$
$ 29,333
0
0
96
0
16
0
0
0
112
0.00
0.00
0.05
0.00
0.01
0.00
0.00
0.00
0.05
Disinfecting Ground Water Only NTNCWSs
<500
500-9,999
10,000-99,999
100,000-499,999
> 500,000
National Totals
Grand Totals
1,241
1,393
63
9
-
2,705
500
$ 27,552
$ 34,481
$ 1,633
$ 270
$
$ 63,936
$ 67,185
$ 297,860
$ 334,297
$ 13,163
$ 1,815
$
$ 647,135
$ 363,986
$ 325,412
$ 368,779
$ 14,796
$ 2,085
$
$ 711,072
$ 431,171
1,241
1,393
63
9
0
2,705
3,122
0.60
0.67
0.03
0.00
0.00
1.30
1.50
        Notes:  (A) Shows the difference in total compliance monitoring samples from Stage 1 to Stage 2 for disinfecting
               systems and systems predicted to install disinfection for the GWR.
        Source: Exhibits H.8a and H.8b, USEPA 2005a.
BILLING CODE 6560-50-c

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458         Federal Register/Vol. 71, No. 2/Wednesday, January 4, 2006/Rules  and Regulations
3. State/Primacy Agency Costs

   To estimate State/Primacy Agency
costs, the estimated number of full-time
equivalents (FTEs) required per activity
is multiplied by the number of labor
hours per FTE, the State/Primacy
Agency hourly wage, and the number of
States/Primacy Agencies. EPA estimated
the number of FTEs required per
activity based on experience
implementing previous rules, such as
the Stage 1 DBPR. State/Primacy Agency
costs are summarized in Table VI.D—9.
 Table VI.D-9.  State/Primacy Agency Cost Summary.

Total Hours
A
Average
Hours per
State
B = A/57
Cost/Labor
Hour
C
Total Cost
D
Cost per
State
E = D/57
Implementation Activities
Public Notification
Regulation Adoption and Program Development
Training State Staff
Training PWS Staff and Technical Assistants
Updating Data Management System
Subtotal
11,856
59,280
29,640
118,560
11,856
231,192
208
1,040
520
2,080
208
4,056
$ 33.60
$ 33.60
$ 33.60
$ 33.60
$ 33.60

$ 398,362
$ 1,991,808
$ 995,904
$ 3,983,616
$ 398,362
$ 7,768,051
$ 6,989
$ 34,944
$ 17,472
$ 69,888
$ 6,989
$ 136,282
Monitoring Plan Activities
Monitoring Plans
27,464
482
$ 33.60
$ 926,016
$ 16,246
IDSE Activities
IDSE Monitoring
66,312
1,163
$ 33.60
$ 2,228,095
$ 39,089
Additional Routine Monitoring Activities
Recordkeeping and Compliance Tracking
Operational Evaluation Costs
Subtotal
Grand Total
47,424
3,398
50,822
375,790
832
60
892
6,593
$ 33.60
$ 33.60


$ 1,593,446
$ 114,173
$ 1,707,619
$ 12,629,781
$ 27,955
$ 2,003
$ 29,958
$ 221,575
Notes:   All states/primacy agencies are assumed to incur some costs for each activity.
Source:  Exhibits H. 17 to H.20, USEPA 2005a.
4. Non-quantified Costs
  All significant costs that EPA has
identified have been quantified. In some
instances, EPA did not include a
potential cost element because its effects
are relatively minor and difficult to
estimate. For example, it may be less
costly for a small system to merge with
neighboring  systems than to add
advanced treatment. Such changes have
both costs (legal fees and connecting
infrastructure) and benefits (economies
of scale). Likewise, procuring a new
source of water would have costs for
new  infrastructure, but could result in
lower treatment costs. Operational costs
such as changing storage tank operation
were also not considered as alternatives
to treatment. These might be options for
systems with a single problem area with
a long residence time. In the absence of
detailed information needed to evaluate
situations such as these, EPA has
included a discussion of possible effects
where appropriate. In general, however,
the expected net effect of such
situations is lower costs to PWSs. Thus,
the EA tends to present conservatively
high estimates of costs in relation to
non-quantified costs.
E. Household Costs of the Stage 2 DBPR
  EPA estimates that, as a whole,
households subject to the Stage 2 DBPR
face minimal increases in their annual
costs. Approximately 86 percent of the
households potentially subject to the
rule are served by systems serving at
least 10,000 people; these systems
experience the lowest increases in costs
due to significant economies of scale.
Households served by small systems
that add treatment will face the greatest
increases in annual costs. Table VI.E—1
summarizes annual household cost
increases for all system sizes.

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             Federal Register/Vol. 71, No.  2/Wednesday,  January 4, 2006/Rules and Regulations         459
                               TABLE VI.E-1 .—ANNUAL HOUSEHOLD COST INCREASES.





Total number
of households
served



Mean an-
nual house-
hold cost in-
crease


Median an-
nual house-
hold cost in-
crease


90th per-
centile an-
nual house-
hold cost in-
crease


95th per-
centile an-
nual house-
hold cost in-
crease

Percentage
of annual
household
cost in-
crease <
$12 (per-
cent)
Percentage
of annual
household
cost in-
crease <
$120 (per-
cent)
                                            Households Served by All Plants
All Systems
All Small Systems
SW < 10000
SW>10000
GW < 10000
GW > 1 0 000

101 553 868
14261 241
3 251 893
62 1 37 350
1 1 009 348
25 155 277

$062
2 20
458
046
1 49
0 13

$0 03
0 10
0 79
002
002
000

$0 36
0 79
2 69
0 35
039
0 03

$098
257
724
1 81
0 99
0 08

99
97
95
99
98
100

100
100
99
100
100
100

                                      Households Served by Plants Adding Treatment
All Systems ... . 	
All Small Systems 	
SW < 1 0 000
SW > 1 0 000
GW < 10 000
GW > 10 000

10 161 304
591 ,623
285 91 1
9 060 1 1 9
305 712
509 562

$553
46.48
4305
2 83
4969
597

$080
18.47
13 79
0 80
16 65
1 37

$1004
16885
173 53
6 98
109 86
26 82

$2240
19762
17793
11 31
197 62
3384

92
38
47
96
31
79

99
89
85
100
92
100

  Notes: Detail may not add to total due to independent rounding Number of households served by systems adding treatment will be higher
than households served by plants adding treatment because an entire system will incur costs even if only some of the plants for that system add
treatment (this would result in lower household costs, however).
  Source: Exhibit 7.15, USEPA 2005a.
F. Incremental Costs and Benefits of the
Stage 2 DBPR
  Incremental costs and benefits are
those that are incurred or realized in
reducing DBF exposures from one
alternative to the next more stringent
alternative. Estimates of incremental
costs and benefits are useful in
considering the economic efficiency of
different regulatory options considered
by the Agency. Generally, the goal of an
incremental analysis is to identify the
regulatory option where net social
benefits are maximized.  However, the
usefulness of this analysis is
constrained when major benefits and/or
costs are not quantified or not
monetized. Also, as pointed out by the
Environmental Economics Advisory
Committee of the Science Advisory
Board, efficiency is not the only
appropriate criterion for social decision
making (USEPA 2000i).
  For the proposed Stage 2 DBPR,
presentation of incremental quantitative
benefit and cost comparisons may be
unrepresentative of the true net benefits
of the rule because a significant portion
of the rule's potential benefits are not
quantified, particularly potential
reproductive and developmental health
effects (see Section VI.C). Table VI.F-1
shows the incremental monetized costs
and benefits for each regulatory
alternative. Evaluation of this table
shows that incremental costs generally
fall within the range of incremental
benefits for each more stringent
alternative. Equally important, the
addition of any benefits attributable to
the non-quantified categories would add
to the benefits without any increase in
costs.
  Table VI.F-1 shows that the Preferred
Alternative is the least-cost alternative.
A comparison of Alternative 1 with the
Preferred Alternative shows that
Alternative 1 would have approximately
the same benefits as the Preferred
Alternative. The costs of Alternative 1
are greater due to the additional control
of bromate. However, the benefits of
Alternative 1 are less than the Preferred
Alternative because the Agency is not
able to estimate the additional benefits
of reducing the bromate MCL.
Alternative 1 was determined to be
unacceptable due to the potential for
increased risk of microbial exposure.
Both benefits and costs are greater for
Alternative 2 and Alternative 3 as
compared to the Preferred Alternative.
However, these regulatory alternatives
do not have the risk-targeted design of
the Preferred Alternative. Rather,
implementation of these stringent
standards would require a large number
of systems to change treatment
technology. The high costs of these
regulatory alternatives and the drastic
shift in the nation's drinking water
practices were considered unwarranted
at this time. (See Section VI. A of this
preamble for a description of regulatory
alternatives.)
                     TABLE VI.F-1.—INCREMENTAL COSTS AND BENEFITS OF THE STAGE 2 DBPR
WTP for non-fatal
bladder cancer cases
Rule alternative
Annual
costs
A
Annual ben-
efits
B
Incremental costs
C
Incremental benefits
D
Incremental net bene-
fits
E=D-C
                                                3 Percent Discount Rate
Lymphoma



Bronchitis 	
Preferred
Alternative 1 1
Alternative 2
Alternative 3
Preferred 	
$79
254
422
634
79
$1 531
1 377
5 167
7,130
763
$79 	
(1)
343 . .
212 	
79 	
$1,531 	
(1)
3,637 	
1,962 	
763 	
$1 ,452
(1)
3,294
1,750
684

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 460
Federal Register/Vol.  71, No.  2/Wednesday,  January 4, 2006/Rules and Regulations
                TABLE VI.F-1.—INCREMENTAL COSTS AND BENEFITS OF THE STAGE 2 DBPR—Continued








Rule alternative

Alternative 1 1
Alternative 2
Alternative 3

Annual

A
254
422
634

Annual ben-
fafitQ

B
686
2575
3552

Incremental costs

C
(1)
343
212

Incremental benefits

D
(i)
1 812
978

Incremental net bene-
fifc

E=D-C
(i)
1 469
765

                                                7 Percent Discount Rate
Lymphoma 	



Bronchitis




Preferred
Alternative 1 1 	
Alternative 2 	
Alternative 3
Preferred
Alternative 1 1
Alternative 2
Alternative 3

$77
242
406
613
77
242
406
613

$1,246
1,126
4,227
5832
621
561
2 105
2904

$77 	
(i) 	
330 	
207
77
(1)
330
207

$1 246
(1)
2,981 	
1 605
621
(')
1 484
799

$1 170
(i)
2 651
1 399
544
(')
1 154
593

  Notes1 Estimates are discounted to 2003 and given in 2003 dollars Based on TTHM as an indicator, Villanueva et al. (2003) for baseline risk,
 and smoking/lung cancer cessation lag model. Assumes 26 percent of cases are fatal, 74 percent are non-fatal (USEPA 1999b). EPA recognizes
 that benefits may be as low as zero since causality has not yet been established between exposure to chlorinated water and bladder cancer.
  1 Alternative 1 appears to have fewer benefits than the Preferred Alternative because it does not incorporate the IDSE, as explained in Chapter
 4. Furthermore, this EA does not quantify the benefits of reducing the MCL for bromate (and potentially associated cancer cases), a requirement
 that is included only in Alternative 1. This means that Alternative 1 is dominated by the Preferred Alternative in this analysis (having higher costs
 than the Preferred Alternative but lower benefits), and so  it is not included in the incremental comparison of alternatives (Columns C-E). OMB
 states this in terms of comparing cost effectiveness ratios,  but the same rule applies to an incremental cost, benefits, or net benefits comparison:
 "When constructing and comparing incremental cost-effectiveness ratios, [analysts] * * * should make sure that inferior alternatives identified by
 the principles of strong and weak dominance are eliminated from consideration." (OMB Circular A-4, p. 10)
  Source: Exhibit 9.13,  USEPA 2005a.
 G. Benefits From the Reduction of Co-
 occurring Contaminants
  Installing certain advanced
 technologies to control DBFs has the
 added benefit of controlling other
 drinking water contaminants in addition
 to those specifically targeted by the
 Stage 2 DBPR. For example, membrane
 technology installed  to reduce DBF
 precursors can also reduce or eliminate
 many other  drinking water
 contaminants (depending on pore size),
 including those that EPA may regulate
 in the future. Removal of any
 contaminants that may face regulation
 could result in future cost savings to a
 water system. Because of the difficulties
 in establishing which systems would be
 affected by other current or future rules,
 no estimate  was made of the potential
 cost savings from addressing more than
 one contaminant simultaneously.
 H. Potential Risks From Other
 Contaminants
  Along with the reduction in DBFs
 from chlorination such as TTHM and
 HAAS as a resultof the Stage 2 DBPR,
 there may be increases in other DBFs as
 systems switch from  chlorine to
 alternative disinfectants. For all
 disinfectants, many DBFs are not
regulated and many others have not yet
been identified. EPA will continue to
review new  studies on DBFs and their
 occurrence levels to determine if they
pose possible health risks. EPA
continues to support  regulation of
                          TTHM and HAA5 as indicators for
                          chlorination DBF occurrence and
                          believes that operational and treatment
                          changes made because of the Stage 2
                          DBPR will result in an overall decrease
                          in risk.
                          1. Emerging DBFs
                            lodo-DBPs and nitrogenous DBFs
                          including halonitromethanes are DBFs
                          that have recently been reported
                          (Richardson et al. 2002, Richardson
                          2003). One recent occurrence study
                          sampled quarterly at twelve surface
                          water plants using different
                          disinfectants across the U.S. for several
                          iodo-THMs and halonitromethane
                          species (Weinberg et al. 2002).  The
                          concentrations of iodo-THMs and
                          halonitromethane in  the majority of
                          samples in this study were less than the
                          analytical minimum reporting levels;
                          plant-average concentrations of iodo-
                          THM and halonitromethane species
                          were typically less than 0.002 mg/L,
                          which is an order of magnitude lower
                          than the corresponding average
                          concentrations of TTHM and HAAS at
                          those same plants. Chloropicrin, a
                          halonitromethane species, was also
                          measured in the ICR with a median
                          concentration of 0.00019 mg/L  across all
                          surface water samples. No occurrence
                          data exist for the iodoacids due to the
                          lack of a quantitative method and
                          standards. Further work on chemical
                          formation of iodo-DBPs and
                          halonitromethanes is needed.
  lodoacetic acid was found to be
cytotoxic and genotoxic in Salmonella
and mammalian cells (Plewa et al.
2004a) as were some of the
halonitromethanes (Kundu et al. 2004;
Plewa et al. 2004b). Although potent in
these in vitro screening studies, further
research is needed to determine if these
DBFs are active in living systems. No
conclusions on human health risk can
be drawn from such preliminary
studies.
2. N-Nitrosamines
  Another group of nitrogenous DBFs
are the N-nitrosamines. A number of N-
nitrosamines exist, and N-
nitrosodimethylamine  (NDMA), a
probable human carcinogen (USEPA
1993), has been identified as a potential
health risk in drinking  water. NDMA is
a contaminant from industrial sources
and a potential disinfection byproduct
from reactions of chlorine or chloramine
with nitrogen containing organic matter
and from some polymers used as
coagulant aids. Studies have produced
new information on the mechanism of
formation of NDMA, but there is not
enough information at this time to draw
conclusions regarding a potential
increase  in NDMA occurrence as
systems change treatment. Although
there are studies that examined the
occurrence of NDMA in some water
systems,  there are no systematic
evaluations of the occurrence of NDMA
and other nitrosamines in U.S. waters.

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             Federal Register/Vol. 71, No.  2/Wednesday, January 4,  2006/Rules and Regulations
                                                                       461
Recent studies have provided new
occurrence information that shows
NDMA forms in both chlorinated and
chloraminated systems. Barrett et al.
(2003) reported median concentrations
of less than 2ng/L for the seven chlorine
systems studied and less than 3 ng/L for
13 chloramine systems. Another study
demonstrated that factors other than
disinfectant type may play an important
role in the formation of NDMA
(Schreiber and Mitch 2005). More
research is underway to determine the
extent of NDMA occurrence in drinking
water systems. EPA has proposed
monitoring for NDMA under
Unregulated Contaminant Monitoring
Rule 2 (70 FR 49094, at 49103, August
22, 2005) (USEPA 2005m).
  Risk assessments have estimated that
the 10 ~6 lifetime cancer risk level is 7
ng/L based on induction of tumors at
multiple sites. NDMA is also present in
food, tobacco smoke, and industrial
emissions, and additional research is
underway to determine the relative
exposure of NDMA in drinking water to
these other sources.

3. Other DBFs

  Some systems, depending on bromide
and organic precursor levels in the
source water and technology selection,
may experience a shift to higher ratios,
or concentrations, of brominated DBFs
while the overall TTHM or HAAS
concentration may decrease. In some
instances where alternative
disinfectants are used, levels of chlorite
and bromate may increase as a result of
systems switching to chlorine dioxide or
ozone, respectively. However, EPA
anticipates that changes in chlorite and *
bromate concentration as a result of the
Stage 2 DBPR will be minimal (USEPA
2005a).  For most systems, overall levels
of DBFs, as well as brominated DBF
species, should decrease as a result of
this rule. EPA continues to believe that
precursor removal is a highly effective
strategy to reduce levels of DBFs.
  EPA also considered the impact this
rule  may have on microbial
contamination that may result from
altering disinfection practices. To
address this concern, the Agency
developed this rule jointly with the
Long Term 2 Enhanced Surface Water
Treatment Rule (LT2ESWTR). EPA
expects that the LT2ESWTR provisions
will  prevent increases in microbial risk
resulting from the Stage 2 DBPR.
I. Effects of the Contaminant on the
General Population and Groups Within
the General Population That Are
Identified As Likely To Be at Greater
Risk of Adverse Health Effects

  EPA's Office of Water has historically
considered risks to sensitive
subpopulations (including fetuses,
infants, and children) when establishing
drinking water assessments, advisories
and other guidance, and standards
(USEPA 1989) (56 FR 3526, January 30,
1991) (USEPA 1991). In the case of
Stage 2 DBPR, maximizing health
protection for sensitive subpopulations
requires balancing risks to achieve the
recognized benefits of controlling
waterborne pathogens while minimizing
risk of potential DBF toxicity.
Experience shows that waterborne
disease from pathogens in drinking
water is a major concern for children
and other subgroups (e.g., the elderly,
immunocompromised, and pregnant
women) because  of their greater
vulnerabilities (Gerba et al. 1996). EPA
believes DBFs may also potentially pose
risks to fetuses and pregnant women
(USEPA 1998a). In addition, because the
elderly population (age 65 and above) is
naturally at a higher risk of developing
bladder cancer, their health  risks may
further increase as a result of long-term
DBF exposure (National Cancer Institute
2002).
  In developing this rule, risks to
sensitive subpopulations, including
children, were taken into account in the
assessments  of disinfectants and DBFs.
More details on sensitive
subpopulations can be found in the
Economic Analysis (USEPA 2005a). For
each of the DBFs  included in the Stage
2 DBPR, the  maximum contaminant
level goals (MCLG) are derived using the
most sensitive endpoint among all
available data and an  intraspecies
uncertainty factor of 10 which accounts
for human variability including
sensitive subpopulations,  like children.
The Agency  has evaluated several
alternative regulatory options and
selected the one that balances cost with
significant benefits, including those for
sensitive subpopulations.  The Stage 2
DBPR will result  in a potential
reduction in cancer risk and a potential
reduction in reproductive and
developmental risk to fetuses and
pregnant women. It should be noted that
the LT2ESWTR, which accompanies
this rule, reduces pathogens in drinking
water and further protects sensitive
subpopulations. See Section VII.G for a
discussion of EPA's requirements under
Executive Order 13045.
/. Uncertainties in the Risk, Benefit, and
Cost Estimates for the Stage 2 DBPR
  For today's final rule, EPA has
estimated the current baseline risk from
exposure to DBFs in drinking water and
projected the risk reduction and cost for
various rule  alternatives. There is
uncertainty in the risk calculation, the
benefit estimates, the cost estimates, and
the interaction with other regulations.
The EA has an extensive discussion of
relevant uncertainties (USEPA 2005a).
This section briefly summarizes the
major uncertainties. Table VI.J-1
presents a summary of uncertainty in
the cost and benefit estimates, refers to
the section or appendix of the EA where
the information is introduced, and
estimates the potential effects that each
may have on national cost and benefit
estimates.
  EPA believes that uncertainty in the
compliance forecast has a potentially
large influence on cost and benefit
estimates for today's rule. Thus, the
Agency has attempted to quantify the
uncertainty by giving equal weight to
two different compliance forecast
approaches.  One compliance forecast
approach is based on the SWAT
predictions,  and the other is based on
the "ICR Matrix Method." The ICR
Matrix Method uses the same basic
approach as  SWAT, but uses TTHM and
HAAS data from the ICR directly to
estimate the percent of plants changing
technology to comply with the Stage 2
DBPR and the resulting DBF reduction.
To characterize the uncertainty of the
compliance forecast results, EPA
assumes a uniform  distribution between
SWAT and ICR Matrix Method results
(USEPA 2005a). That is, the cost and
benefit estimates presented in the
preamble represent the midpoint
between costs and benefits estimated
using the SWAT model, and those
estimated using the ICR Matrix Method.
Cost estimates using the SWAT model
are about 25% lower than the midpoint
estimates, while those using the ICR
Matrix Method are about 25% higher.
Benefits estimated using the SWAT
model are about 30% lower than the
midpoint estimates, while those using
the ICR Matrix Method are about 30%
higher.
  EPA believes the compliance forecast
may be overstated because the
technology decision tree does not
consider low-cost, non-treatment system
improvements that could be used to
comply with the Stage 2 DBPR. These
improvements, including things like
flushing more frequently and managing
storage facilities to  reduce water age,
could be used by systems to reduce
TTHM and HAAS levels for specific

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Federal Register/Vol. 71, No. 2/Wednesday, January 4, 2006/Rules  and Regulations
 locations in their distribution system to
 meet Stage 2 DBPR MCLs. Thus, the
 standard compliance forecast method as
 developed during the M/DBP FACA
 (with a 20 percent safety margin) is a
 reasonable estimation. However,  SWAT
 does not explicitly consider the IDSE.
 To address uncertainty in the impact of
 the IDSE on the compliance forecast,
 EPA revised the compliance forecast
 methodology, assigning equal
 probability to 20 and 25 percent
 operational safety margins. EPA believes
 the 25 percent safety margin is a
 reasonable high-end estimate of system
 response to account for the influences of
 the IDSE. EPA used a spatial  variability
 analysis to determine the appropriate
 safety margin to use to estimate the
 impact of the IDSE on the compliance
 forecast.
  These alternative approaches for the
 compliance forecast estimate are used to
 represent a range of possible results and
 are incorporated into the cost and
 benefit models using Monte Carlo
 probability functions. EPA believes this
 approach helps inform the reader of the
 likely magnitude of the impact of the
 uncertainties.
  In addition to quantifying some
 uncertainties in the compliance
 forecasts, EPA has explicitly accounted
 for uncertainty in estimated treatment
 technology costs. Treatment costs are
 modeled using a triangular distribution
 of ± 30 percent for Capital, and ± 15
 percent for O&M costs to recognize that
 the assumptions for cost analysis to
                           produce the national average are
                           uncertain.
                             For the cost estimates, uncertainty
                           also exists in baseline data inputs, such
                           as the total number of disinfecting
                           plants and their typical average and
                           design flow rates. Other cost model
                           inputs such as labor rates and laboratory
                           fees also contain uncertainties. In these
                           cases, EPA has evaluated available data
                           and estimated a cost input value to
                           represent the average of all water
                           systems nationally. EPA recognizes that
                           there is uncertainty in this average and
                           variability in the characteristics of
                           individual systems. The influence of
                           these uncertainties on national cost
                           estimates is expected to be fairly minor.
                             For the benefits estimates, uncertainty
                           exists in model inputs such as the
                           estimated PAR values and the cessation
                           lag models. EPA considered three
                           approaches to estimate attributable risk:
                           (1) a range of risk derived from
                           individual studies, (2) a risk estimate
                           from a meta-analysis, and (3) a risk
                           estimate from a pooled analysis. To
                           quantify uncertainty in cessation lag,
                           three independent cessation lag models
                           derived from three different
                           epidemiological studies are used. Also,
                           two functional forms are used for each
                           of these data sets and uncertainty in the
                           parameters of those functions is
                           included in the analysis. As noted
                           previously, causality has not been
                           established between DBP levels and
                           cancer endpoints, so the lower bound of
                           potential risk reductions may be as low
                           as zero.
                                           In a number of different contexts over
                                         the past few years, the Agency has
                                         considered the relative merits and
                                         assumptions encountered when
                                         employing meta-analyses. Cessation lag
                                         modeling is a relatively recent analysis
                                         that the Agency has incorporated into
                                         its risk analyses to more appropriately
                                         model the timing of health benefits. The
                                         specific papers upon which the Stage 2
                                         analysis is based have been peer
                                         reviewed. However, the Agency believes
                                         that it is time to consider these Agency-
                                         wide science issues in a broader sense
                                         with outside experts to better inform the
                                         Agency's future analyses.
                                           For monetization of benefits, EPA
                                         uses two alternatives for valuing non-
                                         fatal bladder cancer. Other
                                         uncertainties, such as the linear
                                         relationship between DBP reductions
                                         and reductions in bladder cancer cases
                                         avoided, are discussed qualitatively.
                                           In addition to the uncertainties
                                         quantified as part  of the benefits
                                         evaluation, other uncertainties that have
                                         not been quantified could result in
                                         either an over-or under-estimation of the
                                         benefits. Two of the greatest
                                         uncertainties affecting the benefits of
                                         the Stage 2 DBPR, benefits from
                                         potential reductions of cancers other
                                         than bladder and benefits from possible
                                         reductions in potential reproductive and
                                         developmental health effects, are
                                         unquantified. Both of these factors
                                         could result in an  underestimation  of
                                         quantified Stage 2 DBPR benefits.
                         TABLE VI.J-1.—EFFECTS OF UNCERTAINTIES ON NATIONAL ESTIMATES
Assumptions for which there
       is uncertainty
             Section with
            full discussion
            of uncertainty
                                            Potential effect on benefit estimate
 Under-esti-
   mate
                                                     Over-estimate
Unknown im-
   pact
                                                                       Potential effect on cost estimates
Under-esti-
  mate
                                                                                             Over-estimate
Unknown im-
   pact
Uncertainty in the industry
  baseline (SDWIS and
  1995 CWSS data).
Uncertainty in observed data
  and predictive tools used
  to characterize DBP oc-
  currence for the  pre-Stage
  1 baseline.
Uncertainty in predictive
  tools used to develop the
  compliance forecast for
  surface water systems
  (SWAT and ICR Matrix
  Method).
Uncertainty in ground water
  compliance forecast meth-
  odologies.
Operational safety  margin of
  20%.
Impacts of the IDSE on the
  compliance forecast for
  the Preferred Regulatory
  Alternative.
            3.4
            3.7
            Chapter 5,
             Appendix A
            Chapter 5, A
             and B.
Quantified in primary analysis (addresses po-
   tential underestimate or overestimate)
              Quantified in primary analysis (addresses po-
                 tential underestimate or overestimate)
            5.2

            5.3
Quantified in the primary analysis (addresses
         potential underestimate)
                                                                  Quantified in the primary analysis (addresses
                                                                           potential underestimate)

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             Federal  Register/Vol.  71,  No. 2/Wednesday, January  4, 2006/Rules and Regulations
                                                                        463
                  TABLE VI.J-1.—EFFECTS OF UNCERTAINTIES ON NATIONAL ESTIMATES—Continued
Assumptions for which there
is uncertainty
Uncertainty in the PAR
value.
Reduction in TTHM and
HAAS used as proxies for
all chlorination DBFs.
DBFs have a linear no-
threshold dose-response
relationship for bladder
cancer effects.
Uncertainty in benefits valu-
ation inputs.
Benefits of reduced cancers
other than bladder cancer
are not included in the
quantitative analysis.
Value of potential reproduc-
tive and developmental
health effects avoided is
not quantified in the pri-
mary analysis.
Treatment costs do not in-
clude costs for minor
operational changes pre-
dicted by SWAT.
Median operational and
water quality parameters
considered for technology
unit costs.
Economies of scale for com-
bination treatment tech-
nologies not considered.
Possible UV-chloramine
synergy not taken into ac-
count.
Potential low-cost alter-
natives to treatment not
considered.
Uncertainties in unit costs

Section with
full discussion
of uncertainty
6.1.1 Appen-
dix E
633
621
652
67
6 8
741
741
741
741
742
743

Potential effect on benefit estimate
Under-esti-
mate
Over-estimate
Quantified in the primary analj
range of potential effects, t
could lie outside range)

Quantified in t
potential un
Quantified in a
pot(
X.






X.
he primary analy
derestimate or o\
sensitivity analy
sntial underestim






Unknown im-
pact
reis (addresses
ut true values
X.
sis (addresses
/erestimate)
sis (addresses
ate)






Potential effect on cost estimates
Under-esti-
mate
X.



Quantified in p
tential ove
Over-estimate

X.
X.
X.
rimary analysis (
restimate or unds
Unknown im-
pact
X
addresses po-
jrestimate)
K. Benefit/Cost Determination for the
Stage 2 DBPR

  The Agency has determined that the
benefits of the Stage 2 DBPR justify the
costs. As discussed previously, the main
concern for the Agency and the
Advisory Committee involved in the
Stage 2 rulemaking process was to
provide more equitable protection from
DBFs across the entire distribution
system and reduce high DBF levels. The
final rule achieves this  objective using
the least cost alternative by targeting
sampling locations with high DBF levels
and modifying how  the annual average
DBF level is calculated. This will reduce
both average DBF levels associated with
bladder cancer (and possibly other
cancers) and peak DBF  levels which  are
potentially associated with reproductive
and developmental effects. In addition,
this rule may reduce uncertainty about
drinking water quality and may allow
some systems to avoid installing
additional technology to meet future
drinking water regulations.
  Table VI.K-1 presents net benefits for
the four regulatory alternatives
evaluated by EPA. This table shows that
net benefits are positive for all four
regulatory alternatives. Generally,
analysis of net benefits is used to
identify alternatives where benefits
exceed costs, as well as the alternative
that maximizes net benefits. However,
analyses of net benefits should consider
both quantified and non-quantified
(where possible) benefits and costs. As
discussed previously with incremental
net benefits, the usefulness of this
analysis in evaluating regulatory
alternatives for the Stage 2 DBPR is
somewhat limited because many
benefits from this rule are non-
quantified and non-monetized.
  Table VI.K— 1 shows that the Preferred
Alternative is the least cost alternative.
The Preferred Alternative has higher
mean net benefits than Alternative 1.
Alternatives 2 and 3 have higher
benefits than the Preferred Alternative
but also much greater costs. These
regulatory alternatives do not have the
risk-targeted design of the Preferred
Alternative. Rather, a large number of
systems would be required to make
treatment technology changes to meet
the stringent standards under these
regulatory alternatives. Also, because
causality has not been established
between DBF exposure and bladder
cancer, actual benefits may be as low as
zero. EPA is promulgating the preferred
regulatory alternative because the
Agency believes that such a drastic shift
in the nation's drinking water practices
is not warranted at this time.

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Federal Register/Vol.  71, No.  2/Wednesday, January 4, 2006/Rules and Regulations
                     TABLE VI.K-1.—MEAN NET BENEFITS BY REGULATORY ALTERNATIVE ($MILLION)
Rule alternative
WTP for non-fatal bladder cancer cases
Mean annual
costs
Mean annual
benefits
Mean net
benefits
                                              3 Percent Discount Rate, 25 Years
Preferred
A1
A2 	
A3 	
Preferred
A1 	
A2 	
A3 	 	

Lyrnphoma



Bronchitis 	




$788
254 1
421 7
6342
788
254 1
421 7
634.2

$1 530 8
1 ,376 6
5,1674
7,1296
7628
6859
2,574 6
3,552.2

$1 452
1 122
4746
6495
684
432
2,153
2,918

                                             7 Percent Discount Rate, 25 Years
Preferred
A1
A2
A3
Preferred
A1
A2
A3 	
Lyrnphoma



Bronchitis 	



$768
241 8
4064
613 1
768
241 8
4064
613.1
$1 246 5
1 1264
42272
5 832 4
6207
5608
2 1046
2,903.8
$1 170
885
3 821
5 219
544
319
1 698
2.291
  Notes: Estimates are discounted to 2003 and given in 2003 dollars. Based on TTHM as an indicator, Villanueva et al. (2003) for baseline risk,
and smoking/lung cancer cessation lag model.  Assumes 26 percent of cases are fatal, 74 percent are non-fatal (USEPA 1999b). EPA recognizes
that benefits may be as low as zero since causality has not yet been established exposure to chlorinated water and bladder cancer.
  Source: Exhibits 9.10 and 9.11, USEPA 2005a.
   The Agency also compared the costs
and benefits for each regulatory
alternative by calculating which option
is the most cost-effective. The cost-
effectiveness analysis compares the cost
of the rule per bladder cancer case
avoided. This cost-effectiveness
measure is another way of examining
                           the benefits and costs of the rule, but
                           should not be used to compare
                           alternatives because an alternative with
                           the lowest cost per illness/death
                           avoided may not result in the highest
                           net benefits. Table VI.K-2 shows the
                           cost of the rule per case avoided. This
                           table shows that cost per case avoided
for the preferred alternative seems
favorable when compared to the
willingness to pay estimates. Additional
information about this analysis and
other methods of comparing benefits
and costs can be found in the EA
(USEPA 2005a).
   TABLE VI.K-2.—ESTIMATED COST PER DISCOUNTED CASED AVOIDED 1 FOR THE REGULATORY ALTERNATIVES, USING
           TTHM AS DBP INDICATOR AND SMOKING/LUNG CANCER CESSATION LAG MODEL ($MILLIONS, 2003)


Preferred 	 	 	 	
Alternative 1 . .. 	
Alternative 2 	 	
Alternative 3 	 . 	 	

Cost per ca
3%
$ 033
1 18
052
0 57

se avoided
7%
$ 041
1 42
0 63
0 69

  1 The cost effectiveness ratios are a potentially a high estimate because regulatory costs in the numerator are not adjusted by subtracting the
avoided  medical costs associated with cases avoided to produce a net cost numerator. Subtraction of theses costs would  not be expected to
alter the ranking of alternatives. In the case where thresholds of maximum public expenditure per case avoided are prescribed, defining the nu-
merator more precisely by making such adjustments would be appropriate.
  Notes: In reference to conducting incremental CEA, OMB states that analyst should make sure that "When constructing and comparing incre-
mental cost-effectiveness ratios, [analysts] should make sure that inferior alternatives identified by the principles of strong and weak dominance
are  eliminated from consideration" (OMB Circular A-4,  p. 10)  Alternative 1 is dominated by the Preferred Alternative and  is therefore  not in-
cluded in the incremental analysis. The reason for this domination is mainly that the Preferred Alternative includes IDSE and Alternative  1 does
not; and to a lesser degree because the bromate control included in Alternative 1  increases the costs but the benefits of this control are not
quantified at this time. Alternative 2 is compared directly  to the Preferred Alternative (skipping Alternative 1) in this analysis. Cost per case avoid-
ed is in year 2003 dollars ($Millions), discounted for the 25 year analysis period to year 2005.
  Source: Exhibit 9.14, USEPA, 2005a.
L. Summary of Major Comments

  EPA received significant public
comment on the analysis of benefits and
costs of the proposed Stage 2 DBPR in
the following areas: interpretation of
health effects studies, derivation of
benefits, use of SWAT, illustrative
                           example, unanticipated risk issues, and
                           valuation of cancer cases avoided. The
                           following discussion summarizes public
                           comment in these areas and EPA's
                           responses.
1. Interpretation of Health Effects
Studies

  EPA requested comment on the
conclusions of the cancer health effects
section and the epidemiology and
toxicology studies discussed. A number
of comments questioned the overall

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             Federal  Register/Vol. 71, No.  2/Wednesday, January 4, 2006/Rules  and Regulations
                                                                       465
interpretation of the studies presented
by EPA. A few comments pointed out
missed studies. Commenters also asked
about concordance between cancer
epidemiology and toxicology. Some
commenters also felt EPA did not
discuss the broad range of risks from
DBFs other than the ones regulated.
  The Agency continues to believe that,
although there is not a causal link, the
cancer literature points to an association
between bladder cancer and potentially
rectal and colon cancer and exposure to
chlorinated surface water. EPA has
included in today's preamble the
literature that commenters pointed out
as missing and expands on its
discussion of non-regulated DBFs.
  EPA believes that a lack of bladder
cancer effect in toxicological studies
does not negate the findings in
epidemiological studies at this time.
Tumor site concordance between
human and test animal is not necessary
to determine carcinogenic potential.
While there is evidence from human
cancer epidemiology studies that
lifetime consumption of the DBF
mixture within chlorinated surface
water poses a bladder cancer risk, the
specific causative constituents have not
been identified. EPA will continue to
evaluate new mode-of-action data as it
becomes available.
  Several comments were received on
EPA's characterization of the literature
on reproductive and developmental
health risk. Some commenters wanted
EPA to characterize reproductive and
developmental health effects more
strongly, stating that current research
shows more evidence for these  effects
than described in the proposed
preamble. Others thought that EPA's
characterization in the proposal was too
strong, and that EPA had
overemphasized these health concerns.
Some commenters noted that certain
published studies were missing from
EPA's risk discussion.
  EPA believes that the characterization
of reproductive and developmental  risks
in the final Stage 2 DBPR preamble is
appropriate based on the weight of
evidence evaluation of the reproductive
and developmental epidemiology
database described in Section III.C. EPA
considered comments  and incorporated
additional and recent studies into its
characterization of health risks in
today's final preamble. While no causal
link has been established, EPA's
evaluation of the available studies
continues to indicate a potential health
hazard that warrants additional
regulatory action beyond the Stage 1
DBPR. The inconsistencies and
uncertainties remaining in the available
science support the incremental nature
of change in today's rule.
  EPA did not include all findings from
every study in the proposed DBPR
preamble because the intent was to
provide a summary overview and more
importantly, the Agency's conclusions
regarding the weight of evidence. The
epidemiology literature has
inconsistencies in its findings on the
relationship between various
reproductive and developmental health
effects and DBFs. In this final preamble,
EPA describes how recent studies since
the proposal further inform the
perspective of overall risk from
exposure to DBFs. EPA continues to
believe that studies indicate a potential
hazard.

2. Derivation of Benefits
  EPA received numerous comments on
the derivation of benefits from
occurrence estimates for the Stage 2
DBPR. The majority of the comments
provided addressed EPA's use of a
cessation lag model to estimate the
timing of benefits and a PAR analysis to
estimate reduced risks. Several
commenters opposed the cessation lag
model proposed by EPA, suggesting that
EPA use a longer cessation lag period or
conduct a sensitivity analysis on the
cessation lag exponent.
  In the effort to develop a cessation lag
model specific to DBFs, EPA reviewed
the available epidemiological literature
for information relating to the timing of
exposure and response, but could not
identify any studies that could, alone or
in combination, support a specific
cessation lag model for DBFs in
drinking water. Thus, in keeping with
the SAB recommendation to consider
other models in the absence of specific
cessation lag information (USEPA
2001d), EPA explored the use of
information  on other carcinogens that
could be used to characterize the
influence of cessation lag in calculating
benefits. The benefit analysis for today's
rule uses three cessation lag models,
which allows for a better
characterization of uncertainty  than did
the approach used in the proposal. More
details on this analysis are in the EA
(USEPA 2005a).
  Additional comments were received
on the use of PAR values derived from
epidemiology studies to determine the
number of bladder cancer cases
attributable to DBF exposure. Some
commenters remarked that there was
not sufficient evidence in the
epidemiology studies used to develop a
reliable PAR estimate. A key issue
expressed in the comments was that
studies that developed the PAR
estimates did not adequately control for
confounders. One commenter supported
EPA review of the Villanueva (2003)
meta-analysis, stating that this was the
best available data on the issue.
  EPA revised the methodology for
calculating PAR values for bladder
cancer associated with exposure to
chlorinated drinking water by
considering three different analytical
approaches as described in Section
V.B.2. EPA used the PAR values from all
three approaches to estimate the number
of bladder cancer cases ultimately
avoided annually as a result of the Stage
2 DBPR. Taken together, the three
approaches provide a reasonable
estimate of the range of potential risk.
For simplicity, EPA used the Villanueva
et al. (2003) study to calculate the
annual benefits of the rule. The benefit
estimates derived from Villanueva et al.
(2003) capture a substantial  portion of
the overall range of results, reflecting
the uncertainty in both the underlying
OR and PAR values, as well as the
uncertainty in DBF reductions for Stage
2. More details on the PAR analysis can
be found in the EA (USEPA  2005a).
3. Use of SWAT
  Comments received on the use of
SWAT for the compliance forecast
claimed that the model probably
underestimates DBF occurrence levels
and hence underestimates compliance
costs. Other commenters supported
EPA's occurrence estimation methods
and results. Some commenters added
that monitoring under the IDSE will
produce different results than
monitoring for the ICR and that SWAT
did not capture these changes.
  EPA describes  in detail the limitations
of SWAT as well as all assumptions and
uncertainties associated with the model
in the EA published with today's rule.
EPA believes that, for the reasons stated
below, the standard compliance forecast
method using SWAT, as developed
during the M-DBP FACA, provides a
reasonable prediction of national
treatment changes and resulting DBF
levels anticipated for the Stage 2 DBPR:
  1. SWAT predictive equations for
TTHM and HAAS were calibrated to
ICR-observed TTHM and HAA5 data.
  2. SWAT estimates are based on 12
months of influent water quality data,
treatment train information, and related
characteristics for the 273 ICR surface
water plants. EPA believes the ICR data
provide a robust basis for the
compliance forecast as it represents
significant variability with respect to
factors influencing DBF formation,
including temperature, residence time,
and geographical region.
  3. EPA uses a "delta" approach to
reduce the impact of uncertainty in

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Federal Register/Vol. 71, No.  2/Wednesday, January 4,  2006/Rules and Regulations
 SWAT's predictive equations for TTHM
 and HAAS. Under this approach, EPA 1)
 estimates the difference in technology
 and TTHM and HAA5 concentration
 predictions between pre-Stage 1 and
 post-Stage 1; 2) estimates the difference
 in technology and TTHM and HAA5
 concentration predictions between pre-
 Stage 1 and post-Stage 2; and 3)
 subtracts the result of the first estimate
 from the second estimate to predict the
 impacts between Stage 1 and Stage 2.
 Since each predictive estimate has bias
 in the same direction, EPA believes that
 this methodology minimized overall
 predictive error.
  In response to commenters concerns
 about potential uncertainties in the
 SWAT predictions, EPA also developed
 the "ICR Matrix Method." The ICR
 Matrix Method uses TTHM and HAAS
 data from the ICR to estimate the
 percent of plants changing technology to
 comply with the Stage 2 DBPR and the
 resulting DBF reduction. The EA
 includes a detailed description of the
 ICR Matrix Method (USEPA 2005a). In
 the analysis for today's rule,  EPA gives
 equal weight to SWAT and ICR Matrix
 Method predictions in estimating Stage
 2 compliance forecasts and resultant
 reductions in DBF exposure. The ICR
 Matrix Method is also used to estimate
 reductions in the occurrence of peak
 TTHM and HAAS concentrations
 because SWAT-predicted TTHM and
 HAAS concentrations are valid only
 when considering national averages, not
 at the plant level.
  EPA revised the  Stage 2 DBPR
 compliance forecast methodology to
 quantify the potential impacts of the
 IDSE for large and  medium surface
 water systems. For these systems, EPA
 predicted compliance implications
 using a  safety margin of both 20 and 25
 percent based on an analysis of spatial
 variability in TTHM and HAAS
 occurrence. EPA assigned equal
 probability to the 20 and 25 percent
 safety margins because both alternatives
 are considered equally plausible. These
 changes result in a wider uncertainty
 range for the compliance cost estimates
 than under the EA  of the proposed rule.
 EPA assumes the 20 percent operational
 safety margin accounts for variability in
 small surface water systems and all
 ground water systems. Small systems
 are  not expected  to find significantly
 higher levels that affect their
 compliance as a result of the IDSE
 because their distribution systems  are
 not as complex as large systems.
 Additionally, the IDSE is not expected
to significantly impact the compliance
 forecast for ground water systems
because they have more consistent
 source water quality and do not
                          experience significant year-to-year
                          variability in TTHM and HAAS
                          occurrence.
                            As some commenters noted, any
                          underestimation in costs as a result of
                          the compliance forecast is associated
                          with an underestimation in the benefits.
                          Accordingly, EPA adjusted both cost
                          and benefits estimates based on the ICR
                          Matrix Method and the impact of the
                          IDSE for the upper end of the
                          compliance forecast range.

                          4. Illustrative Example
                            Many comments were received on the
                          illustrative calculation of fetal loss
                          benefits included in the proposed EA.
                          Many commenters recommended that
                          EPA remove this calculation because of
                          uncertainties in the underlying data.
                          Other commenters, however, expressed
                          support for this calculation because of
                          the magnitude of potential benefits, and
                          suggested that EPA include  these
                          benefits in its primary analysis.
                            EPA believes that the reproductive
                          and developmental epidemiologic data,
                          although not conclusive, are suggestive
                          of potential health effects in humans
                          exposed to DBFs. EPA does  not believe
                          the available evidence provides an
                          adequate basis for quantifying potential
                          reproductive and developmental risks.
                          Nevertheless, given the widespread
                          nature of exposure to DBFs, the
                          importance our society places on
                          reproductive and developmental health,
                          and the large number of fetal losses
                          experienced each year in the U.S.
                          (nearly 1 million), the Agency believes
                          that it is appropriate to provide some
                          quantitative indication of the potential
                          risk suggested by some of the published
                          results on reproductive and
                          developmental endpoints, despite the
                          absence of certainty regarding a causal
                          link between disinfection byproducts
                          and these risks and the inconsistencies
                          between studies. However, the Agency
                          is unable at this time to either develop
                          a specific estimate of the value of
                          avoiding fetal loss or to use a benefit
                          transfer methodology to estimate the
                          value from studies that address other
                          endpoints.

                          5. Unanticipated Risk Issues
                            Comments were received that
                          expressed concern about unanticipated
                          risks that could result from the
                          proposed Stage 2 DBPR. Several
                          commenters remarked that regulation of
                          TTHM and HAAS would not control
                          levels of other DBFs that may be more
                          toxic than these indicator compounds,
                          such as NDMA. Some commenters
                          supported future research on the
                          potential health effects of other DBFs.
                          Other comments  suggested that EPA
 further consider these risks when
 developing the final Stage 2 DBPR.
   EPA has addressed the occurrence of
 other DBFs in Section VI.H of this
 document and in the EA (USEPA
 2005a). Levels of some DBFs may
 increase because of treatment changes
 anticipated as a result of today's rule.
 However, these DBFs generally occur at
 much lower levels than TTHM and
 HAAS, often more than an order of
 magnitude less (USEPA 2005f, Weinberg
 et al. 2002). For NDMA, studies have
 shown formation in both  chlorinated
 and chloraminated systems (Barrett et
 al. 2003). The uncertainties surrounding
 NDMA formation make determinations
 regarding the impact of the Stage 2
 DBPR difficult. In addition, other routes
 of exposure appear to be more
 significant than drinking  water. Dietary
 sources of NDMA include preserved
 meat and fish  products, beer and
 tobacco. EPA is looking at calculating
 the relative source contribution of these
 routes of exposure compared to drinking
 water.
  EPA continues to support the use of
 TTHM and HAAS as indicators for DBF
 regulation. The presence of TTHM and
 HAAS is representative of the
 occurrence of many other chlorination
 DBFs; thus, a reduction in the TTHM
 and HAAS  generally indicates an overall
 reduction of DBFs. EPA also supports
 additional research on unregulated and
 unknown DBFs to ensure continual
 public health protection.

 6. Valuation of Cancer Cases Avoided
  A number of commenters remarked
 on the valuation of cancer cases
 avoided. Some commenters supported
 the use of value of statistical life (VSL)
 analysis in  monetizing the benefits of
 fatal bladder cancer cases avoided.
 Comments  were also received in
 support of the addition of expected
 medical costs for treating  fatal bladder
 cancer cases to the VSL estimates. Other
 commenters recommended that EPA
 further review the use of willingness-to-
 pay estimates used to value the non-
 fatal cancer cases avoided. These
 comments stated concern over the
 similarity of bronchitis and lymphoma
 to bladder cancer and the resulting
 limitation of benefits transfer.
  EPA thanks commenters for
 expressing support of the  use of VSL
 and valuation of fatal bladder cancer
 cases. EPA acknowledges  that the
willingness to  pay (WTP)  to avoid
curable lymphoma or chronic bronchitis
 is not a perfect substitute  for the WTP
to avoid a case of non-fatal bladder
cancer. However, non-fatal internal
cancers, regardless of type, generally
present patients with very similar

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                                                                        467
treatment, health, and long-term quality
of life implications, including surgery,
radiation or chemotherapy treatments
(with attendant side effects), and
generally diminished vitality over the
duration of the illness. In the absence of
more specific WTP studies, EPA
believes the WTP values for avoiding a
case of curable lymphoma or a case of
chronic bronchitis provides a
reasonable, though not definitive,
substitute for the value of avoiding non-
fatal bladder cancer.

VII. Statutory and Executive Order
Reviews

A. Executive Order 12866: Regulatory
Planning and Review
  Under Executive Order 12866,  [58 FR
51735, (October 4, 1993)] the Agency
must determine whether the regulatory
action is "significant" and therefore
subject to OMB review and  the
requirements of the Executive Order.
The Order defines "significant
regulatory action" as one that is likely
to result in a rule that  may:
  (1) Have an annual effect  on the
economy of $100 million or more or
adversely affect in a material way the
economy,  a sector of the economy,
productivity, competition, jobs, the
environment, public health or safety, or
State, local, or Tribal governments or
communities;
  (2) Create a serious inconsistency or
otherwise interfere with an  action taken
or planned by another agency;
  (3) Materially alter the budgetary
impact of entitlements, grants, user fees,
or loan programs or the rights and
obligations of recipients thereof; or
  (4) Raise novel legal or policy issues
arising out of legal mandates, the
President's priorities, or the principles
set forth in the Executive Order.
  Pursuant to the terms of Executive
Order 12866, it has been determined
that this rule is a "significant regulatory
action." As such,  this  action was
submitted to OMB for review. Changes
made in response to OMB suggestions or
recommendations will be documented
in the public record.

B. Paperwork Reduction Act
  The Office of Management and Budget
(OMB) has approved the information
collection requirements contained in
this rule under the provisions of the
Paperwork Reduction  Act, 44 U.S.C.
3501 et seq. and has assigned OMB
control number 2040-0265  (USEPA
2005n).
  The information collected as a  result
of this rule will allow  the States and
EPA to determine appropriate
requirements for specific systems, and
to evaluate compliance with the rule.
For the first three years after Stage 2
DBPR promulgation, the major
information requirements involve
monitoring activities, which include
conducting the IDSE and submission of
the IDSE report, and tracking
compliance. The information collection
requirements are mandatory (Part 141),
and the information collected is not
confidential.
  The estimate of annual average
burden hours for the Stage 2 DBPR for
systems and States is 228,529 hours.
This estimate covers the  first three years
of the Stage 2 DBPR and  most of the
IDSE (small system reports are not due
until the fourth year). The annual
average aggregate cost estimate is $9.8
million for operation and maintenance
as a purchase of service for lab work and
$6.6 million is associated with labor.
The annual burden hour per response is
4.18 hours. The frequency of response
(average responses per respondent) is
7.59 annually. The estimated number of
likely respondents is 7,202 per year (the
product of burden hours per response,
frequency, and respondents does not
total the annual average burden hours
due to rounding). Because disinfecting
systems have already purchased basic
monitoring equipment to comply with
the Stage 1 DBPR, EPA assumes no
capital start-up costs are associated with
the Stage 2 DBPR ICR.
  Burden  means the total time, effort, or
financial resources expended by persons
to generate, maintain, retain, or disclose
or provide information to or for a
Federal agency. This includes the time
needed to review instructions; develop,
acquire, install, and utilize technology
and systems for the purposes of
collecting, validating, and verifying
information, processing and
maintaining information, and disclosing
and providing information; adjust the
existing ways to comply with any
previously applicable instructions and
requirements; train personnel to be able
to respond to a collection of
information; search data sources;
complete and review the collection of
information; and transmit or otherwise
disclose the information.
  An agency may not conduct or
sponsor, and a person is  not required to
respond to a collection of information
unless it displays a currently valid OMB
control number. The OMB  control
numbers for EPA's regulations in 40
CFR are listed in 40 CFR part 9. In
addition, EPA is  amending the table in
40 CFR part 9 of currently approved
OMB control numbers for various
regulations to list the regulatory
citations for the information
requirements contained in this final
rule.

C. Regulatory Flexibility Act
  The Regulatory Flexibility Act (RFA)
generally requires an agency to prepare
a regulatory flexibility analysis for any
rule subject to notice and comment
rulemaking requirements under the
Administrative Procedure Act or other
statute unless the agency certifies that
the rule will not have a significant
economic impact on a substantial
number of small entities. Small entities
include small businesses, small
organizations, and small governmental
jurisdictions.
  The RFA provides default definitions
for each type of small entity. Small
entities are defined as: (1) A small
business as defined by the Small
Business Administrations's (SBA)
regulations at 13  CFR 121.201; (2) a
small governmental jurisdiction that is a
government of a city, county, town,
school district or special district with a
population of less than 50,000; and (3)
a small organization that is any "not-for-
profit enterprise which is independently
owned and operated and is not
dominant in its field." However, the
RFA also authorizes an agency to use
alternative definitions for each category
of small entity, "which are appropriate
to the activities of the agency" after
proposing the alternative definition(s) in
the Federal Register and taking
comment. 5 U.S.C. 601(3)-(5). In
addition, to establish an alternative
small business definition, agencies must
consult with SBA's Chief Council for
Advocacy.
  For purposes of assessing the impacts
of today's rule on small entities, EPA
considered small entities to be public
water systems serving 10,000 or fewer
persons. As required by the  RFA, EPA
proposed using this alternative
definition in the Federal Register (63 FR
7620, February 13, 1998), requested
public comment, consulted with the
Small Business Administration (SBA),
and finalized the alternative definition
in the Consumer Confidence Reports
regulation (63 FR 44511, August 19,
1998). As stated in that Final Rule, the
alternative definition is applied to this
regulation as well.
  After considering the economic
impacts of today's final rule on small
entities, I certify that this action will not
have a significant economic impact on
a substantial number of small entities.
The small entities regulated by this final
rule are PWSs serving fewer than 10,000
people. We have determined that 92
small surface water and ground water
under the direct influence of surface
water (GWUDI) systems (or 2.16% of all

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Federal  Register/Vol. 71, No. 2/Wednesday,  January 4, 2006/Rules  and Regulations
 small surface water and GWUDI systems
 affected by the Stage 2 DBPR) will
 experience an impact of 1% or greater
 of average annual revenues. Of the 92,
 40 small surface water and GWUDI
 systems (or 0.94% of all small surface
 water and GWUDI systems affected by
 the Stage  2 DBPR) will experience an
 impact of 3% or greater of average
 annual revenues. Further, 354 small
 ground water systems (or 1.02% of all
 small ground water systems affected by
 the Stage  2 DBPR) will experience an
 impact of 1% or greater of average
 annual revenues. Of the 354, 45 small
 ground water systems (or 0.13% of all
 small ground water systems affected by
 the Stage 2 DBPR) will experience an
 impact of 3% or greater of average
 annual revenues.
   Although this final rule will not have
 a significant economic impact on a
 substantial number of small entities,
 EPA nonetheless has tried to reduce the
 impact of this rule on small entities. The
 Stage 2 DBPR contains a number of
 provisions to minimize the impact of
 the rule on systems generally, and on
 small systems in particular. For
 example, small systems have a longer
 time frame to comply with requirements
 than large systems (see § 141.600(c) and
 § 141.620(c)). The final rule determines
 monitoring frequency based on
 population rather than plant-based
 monitoring requirements (see § 141.605
 and § 141.621(a)) as proposed. Small
 systems will also have to take fewer
 samples than large systems due to the
 40/30 waiver (see § 141.603(a)), for
 which small, ground water systems are
 expected to be able to qualify, and the
 very small system waiver (see
 §141.604).
  Funding may be available from
 programs administered by EPA and
 other Federal agencies to assist small
 PWSs in complying with the Stage 2
 DBPR. The Drinking Water State
 Revolving Fund (DWSRF) assists PWSs
 with financing the costs of
 infrastructure needed to achieve or
 maintain compliance with SDWA
 requirements. Through the DWSRF,
 EPA awards capitalization grants to
 States, which in turn can provide low-
cost loans and other types of assistance
to eligible PWSs. Loans made under the
program can have interest rates between
0 percent and market rate and
repayment terms of up to 20 years.
 States prioritize funding based on
projects that address the most serious
risks to human health and assist PWSs
most in need. Congress provided the
DWSRF program $8 billion for fiscal
years 1997 through 2004.
  The DWSRF places an emphasis on
small and  disadvantaged communities.
                          States must provide a minimum of 15%
                          of the available funds for loans to small
                          communities. A State has the option of
                          providing up to 30% of the grant
                          awarded to the State to furnish
                          additional assistance to State-defined
                          disadvantaged communities. This
                          assistance can take the form of lower
                          interest rates, principal forgiveness, or
                          negative interest rate loans. The State
                          may also extend repayment terms of
                          loans for disadvantaged communities to
                          up to 30 years. A State can set aside up
                          to 2% of the grant to provide technical
                          assistance to PWSs serving communities
                          with populations fewer than 10,000.
                            In addition to the DWSRF, money is
                          available from the Department  of
                          Agriculture's Rural Utility Service
                          (RUS) and Housing and Urban
                          Development's Community
                          Development Block Grant (CDBG)
                          program. RUS provides loans,
                          guaranteed loans, and grants to improve,
                          repair, or construct water supply and
                          distribution systems in rural areas and
                          towns of up to 10,000 people. In fiscal
                          year 2003, RUS had over $1.5 billion of
                          available funds for water and
                          environmental programs. The CDBG
                          program includes direct grants  to States,
                          which in turn are awarded to smaller
                          communities, rural areas, and colonas in
                          Arizona, California, New Mexico, and
                          Texas and direct grants to U.S.
                          territories and trusts. The CDBG budget
                          for fiscal year 2003 totaled over $4.4
                          billion.
                            Although not required by the RFA to
                          convene a Small Business Advocacy
                          Review (SBAR) Panel because EPA
                          determined that the proposed rule
                          would not have a significant economic
                          impact on a substantial number of small
                          entities, EPA did convene a panel to
                          obtain advice and recommendations
                          from representatives of the small
                          entities potentially subject to this rule's
                          requirements. For a description of the
                          SBAR Panel and stakeholder
                          recommendations, please see the
                          proposed rule (USEPA 2003a).

                          D. Unfunded Mandates Reform Act
                            Title II of the Unfunded Mandates
                          Reform Act of 1995 (UMRA), Public
                          Law 104-4, establishes requirements for
                          Federal agencies to assess the effects of
                          their regulatory actions on State, local,
                          and Tribal governments and the private
                          sector. Under section 202 of the UMRA,
                          EPA generally must prepare a written
                          statement, including a cost-benefit
                          analysis, for proposed and final rules
                          with "Federal mandates" that may
                          result in expenditures to State, local and
                          Tribal governments, in the aggregate, or
                          to the private sector, of $100 million or
                          more in any one year. Before
 promulgating an EPA rule for which a
 written statement is needed, section 205
 of the UMRA generally requires EPA to
 identify and consider a reasonable
 number of regulatory alternatives and
 adopt the least costly, most cost-
 effective or least burdensome alternative
 that achieves the objectives of the rule.
 The provisions of section 205 do not
 apply when they are inconsistent with
 applicable law. Moreover, section 205
 allows EPA to adopt an alternative other
 than the least costly, most cost-effective
 or least burdensome alternative if the
 Administrator publishes with the final
 rule an  explanation why that alternative
 was not adopted. Before EPA establishes
 any regulatory requirements that may
 significantly or uniquely affect small
 governments, including Tribal
 governments, it must have developed
 under section 203 of the UMRA a small
 government agency plan. The plan must
 provide for notifying potentially
 affected small governments, enabling
 officials of affected small governments
 to have meaningful and timely  input in
 the development of EPA regulatory
 proposals with significant Federal
 intergovernmental mandates, and
 informing, educating, and advising
 small governments on compliance with
 the regulatory requirements.
  EPA has determined that this rule
 may contain a Federal mandate that
 results in expenditures of $100 million
 or more for the State, Local, and Tribal
 governments, in the aggregate in the
 private sector in  any one year. While the
 annualized costs fall below  the $100
 million threshold, the costs in some
 future years may be above the $100
 million mark  as public drinking water
 systems make capital investments and
 finance these through bonds, loans, and
 other means. EPA's year by  year cost
 tables do not reflect that investments
 through bonds, loans, and other means
 spread out these  costs over many years.
 The cost analysis in general does not
 consider that  some systems  may be
 eligible  for financial assistance  such as
 low-interest loans and grants through
 such programs as the Drinking Water
 State Revolving Fund.
  As noted earlier, today's final rule is
 promulgated pursuant to section 1412
 (b)(l)(A) of the Safe Drinking Water Act
 (SDWA), as amended in 1996, which
 directs EPA to promulgate a national
 primary drinking water regulation for a
 contaminant if EPA determines that the
contaminant may have an adverse effect
on the health  of persons, occurs in
PWSs with a frequency and  at levels of
public health  concern, and regulation
presents a meaningful opportunity for
health risk reduction.

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             Federal  Register/Vol. 71, No.  2/Wednesday,  January 4, 2006/Rules  and Regulations
                                                                       469
  Section VI of this preamble discusses
the cost and benefits associated with the
Stage 2 DBPR. Details are presented in
the Economic Analysis (USEPA 2005a).
 TABLE VII.D-1—PUBLIC AND PRIVATE COSTS FOR THE STAGE 2 DBPR (ANNUALIZED AT 3 AND 7 PERCENT, $MILLIONS)

Surface Water Systems Costs
Ground Water Systems Costs 	
State Costs 	 	
Tribal Costs 	 	
Total Public 	
Surface Water Systems Costs 	
Ground Water Systems Costs 	
Total Private 	
Grand total 	
3% discount rate
$41 4
20 3
1 7
04
63 8
64
85
150
78.8
7% discount rate
$41 2
19 2
1 7
0 4
62 5
63
80
143
76.8
Percent of 3%
grand total costs
(percent)
53
26
2
1
81
8
11
19
100
Percent of 7%
grand total costs
(percent)
54
25
2
0
81
8
10
19
100
  Note: Detail may not add due to independent rounding. Estimates are discounted to 2003 and given in 2003 dollars.
  Source: Exhibits 3.2 and 7.5, USEPA 2005a.
  To meet the UMRA requirement in
section 202, EPA analyzed future
compliance costs and possible
disproportionate budgetary effects. The
Agency believes that the cost estimates
and regulatory alternatives indicated
earlier and discussed in more detail in
section VI of this preamble, accurately
characterize future compliance costs of
today's rule.
  In analyzing disproportionate
impacts, EPA considered the impact on
(1) different regions of the United States,
(2) State, local, and Tribal governments,
(3) urban, rural and other types of
communities, and (4) any segment of the
private sector. This analysis is presented
in Chapter  7of the Economic Analysis
(USEPA 2005a). EPA analyzed four
regulatory alternatives and selected the
least costly of these in accordance with
UMRA Section 205.
  EPA has  determined that the Stage 2
DBPR contains no regulatory
requirements that might  significantly or
uniquely affect small governments. The
Stage 2 DBPR affects all size systems. As
described in section VII.C, EPA has
certified that today's rule will not have
a significant economic impact on a
substantial number of small entities.
Average annual expenditures for small
CWSs to comply with the Stage 2 DBPR
range from $27.7 to  $26.1 million at a
3 and 7 percent discount rate,
respectively.
  Consistent with the intergovernmental
consultation provisions of section 204 of
the UMRA and Executive Order 12875,
"Enhancing the Intergovernmental
Partnership," EPA has already initiated
consultations with the governmental
entities affected by this rule. The
consultations are described in the
proposed rule (68 FR 49654, August 18,
2003).
E. Executive Order 13132: Federalism

  Executive Order 13132, entitled
"Federalism"- (64 FR 43255, August 10,
1999), requires EPA to develop an
accountable process to ensure
"meaningful and timely input by State
and local officials  in the development of
regulatory policies that have federalism
implications." "Policies that have
federalism implications" is defined in
the Executive Order to include
regulations that have "substantial direct
effects on the States, on the relationship
between the national government and
the States, or on the distribution of
power and responsibilities among the
various levels of government."
  This final rule does not have
federalism implications. It will not have
substantial direct effects on the States,
on the relationship between national
government and the States, or on the
distribution of power and
responsibilities among various levels of
government, as specified in Executive
Order 13132. The  final rule has one-
time costs for implementation of
approximately $7.8 million. Thus,
Executive Order 13132 does not apply
to this rule.
  Although section 6 of Executive Order
13132 does not apply to this rule, in the
spirit of Executive Order 13132, and
consistent with EPA policy to promote
communications between EPA and State
and local governments, EPA nonetheless
specifically solicited comment on the
proposed rule from State and local
officials and did consult with State and
local officials in developing this rule. A
description of that consultation can be
found in the preamble to the proposed
rule, 68 FR 49548, (August 18, 2003).
F. Executive Order 13175: Consultation
and Coordination With Indian Tribal
Governments
  Executive Order 13175, entitled
"Consultation and Coordination with
Indian Tribal Governments" (65 FR
67249, November 9, 2000), requires EPA
to develop "an accountable process to
ensure meaningful and timely input by
tribal officials in the development of
regulatory policies that have tribal
implications." Under Executive Order
13175, EPA may not issue a regulation
that has Tribal implications, that
imposes substantial direct compliance
costs, and that is not required by statute,
unless the Federal government provides
the funds necessary to pay the direct
compliance costs incurred by Tribal
governments, or EPA consults with
Tribal officials early in the process of
developing the proposed regulation and
develops a Tribal summary impact
statement.
  EPA has concluded that this final rule
may have Tribal implications, because it
may impose substantial direct
compliance costs on Tribal
governments, and the Federal
government will not provide the funds
necessary to pay those costs.
  Accordingly, EPA provides the
following Tribal summary impact
statement as required by section 5(b).
EPA provides further detail on Tribal
impact in the Economic Analysis
(USEPA 2005a). Total Tribal costs are
estimated to be approximately $391,773
per year (at a 3 percent discount rate)
and this cost is distributed across 755
Tribal systems. The cost for individual
systems depend on system size and
source water type. Of the 755 Tribes that
may be affected in some form by the
Stage 2 DBPR, 654 use ground water as
a source and 101 systems use surface
water or GWUDI. Since the majority of
Tribal systems are ground water systems

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 serving fewer than 500 people,
 approximately 15.6 percent of all Tribal
 systems will have to conduct an IDSE.
 As a result, the Stage 2 DBPR is most
 likely to have an impact on Tribes using
 surface water or GWUDI serving more
 than 500 people.
   EPA consulted with Tribal officials
 early in the process of developing this
 regulation to permit them to have
 meaningful and timely input into its
 development. Moreover, in the spirit of
 Executive Order 13175, and consistent
 with EPA policy to promote
 communications between EPA and
 Tribal governments, EPA specifically
 solicited comment on the proposed rule
 from Tribal officials.
   As required by section 7(a), EPA's
 Tribal Consultation Official has certified
 that the requirements of the Executive
 Order has been met in a meaningful and
 timely manner. A copy of this
 certification has been included in the
 docket for this rule.

 G. Executive order 13045: Protection of
 Children From Environmental Health
 Risks and Safety Risks

   Executive Order 13045: "Protection of
 Children from Environmental Health
 Risks and Safety Risks" (62 FR 19885,
 April 23, 1997) applies to any rule that:
 (1) is determined to be "economically
 significant" as defined under 12866,
 and; (2) concerns an environmental
 health or safety risk that EPA has reason
 to believe may have a disproportionate
 effect on children. If the regulatory
 action meets both criteria, the Agency
 must evaluate the environmental health
 or safety effects of the planned rule on
 children, and explain why the planned
 regulation is  preferable to other
 potentially effective and reasonably
 feasible alternatives considered by the
 Agency.
   While this final rule is not subject to
 the Executive Order because it is not
 economically significant as defined in
 Executive Order 12866, EPA
 nonetheless has reason to believe that
 the environmental health or safety risk
 (i.e., the risk associated with DBFs)
 addressed by this action may have a
 disproportionate effect on children. EPA
believes that the Stage 2 DBPR will
 result in greater risk reduction for
 children than for the general
population. The results of the
 assessments are contained in Section
VI.I of this preamble and in the
Economic Analysis (USEPA 2005a). A
copy of all documents has been placed
in the public docket for this action.
                          H. Executive Order 13211: Actions
                          Concerning Regulations That
                          Significantly Affect Energy Supply,
                          Distribution, or Use
                            This rule is not a "significant energy
                          action" as defined in Executive Order
                          13211, "Actions Concerning Regulations
                          That Significantly Affect Energy Supply,
                          Distribution, or Use" (66 FR 28355, May
                          22, 2001) because it is not likely to have
                          a significant adverse effect on the
                          supply, distribution, or use  of energy.
                          This determination is based on the
                          following analysis.
                            The first consideration is  whether the
                          Stage 2 DBPR would adversely affect the
                          supply of energy. The Stage 2 DBPR
                          does not regulate power generation,
                          either directly or indirectly. The public
                          and private utilities that the Stage 2
                          DBPR regulates do not,  as a  rule,
                          generate power. Further, the cost
                          increases borne by customers of water
                          utilities as a result of the Stage 2 DBPR
                          are a low percentage of  the total cost of
                          water, except  for a very few small
                          systems that might install advanced
                          technologies that must spread that cost
                          over a narrow customer base. Therefore,
                          the customers that are power generation
                          utilities are unlikely to  face  any
                          significant effects as a result of the Stage
                          2 DBPR. In sum, the Stage 2 DBPR does
                          not regulate the supply  of energy, does
                          not generally regulate the utilities that
                          supply energy, and is unlikely
                          significantly to affect the customer base
                          of energy suppliers. Thus, the Stage 2
                          DBPR would not translate into adverse
                          effects on the supply of energy.
                            The second consideration is whether
                          the Stage 2 DBPR would adversely affect
                          the distribution of energy. The Stage 2
                          DBPR does not regulate  any  aspect of
                          energy distribution. The utilities that are
                          regulated by the Stage 2 DBPR already
                          have electrical service. As derived later
                          in this section, the final rule is projected
                          to increase peak electricity demand at
                          water utilities by only 0.009 percent.
                          Therefore, EPA estimates that the
                          existing connections are adequate and
                          that the Stage  2 DBPR has no
                          discernable adverse effect on energy
                          distribution.
                            The third consideration is whether
                          the Stage 2 DBPR would adversely affect
                          the use of energy. Because some
                          drinking water utilities  are expected to
                          add treatment technologies that use
                          electrical power, this potential impact is
                          evaluated in more detail. The analyses
                          that underlay the estimation of costs for
                          the Stage 2 DBPR are national in scope
                          and do not identify specific plants or
                          utilities that may install treatment in
                          response to the rule. As  a result, no
                          analysis of the effect on  specific energy
 suppliers is possible with the available
 data. The approach used to estimate the
 impact of energy use, therefore, focuses
 on national-level impacts. The analysis
 estimates the additional energy use due
 to the Stage 2 DBPR and compares that
 analysis to the national levels of power
 generation in terms of average and peak
 loads.
   The  first step in the analysis is to
 estimate the energy used by the
 technologies expected to be installed as
 a result of the Stage 2 DBPR. Energy use
 is not directly stated in Technologies
 and Costs for the Final Long Term 2
 Enhanced Surface Water Treatment Rule
 and Final Stage 2 Disinfectants and
 Disinfection Byproducts Rule (USEPA
 2005g), but the annual cost of energy for
 each technology addition or upgrade
 necessitated by the Stage 2  DBPR is
 provided. An estimate of plant-level
 energy use is derived by dividing the
 total energy cost per  plant for a range of
 flows by an average national cost of
 electricity of $0.076/ kilowatt hours  per
 year (kWh/yr) (USDOE 2004a). These
 calculations are shown in detail in the
 Economic Analysis (USEPA 2005a).  The
 energy use per plant  for each flow range
 and technology is then multiplied bv
 the number of plants predicted to install
 each technology in a given flow range.
 The energy requirements for each flow
 range are then added to produce a
 national total. No electricity use is
 subtracted to account for the
 technologies that may be replaced by
 new technologies, resulting in a
 conservative estimate of the increase in
 energy use. The incremental national
 annual energy usage  is 0.12 million
 megawatt-hours (MWh).
  According to the U.S. Department of
 Energy's Information Administration,
 electricity producers generated 3,848
 million MWh of electricity  in 2003
 (USDOE 2004b). Therefore, even using
 the highest assumed  energy use for the
 Stage 2 DBPR, the rule when fully
 implemented would  result in only a
 0.003 percent increase in annual average
 energy use.
  In addition to average energy use, the
 impact at times of peak power demand
 is important. To examine whether
 increased energy usage might
 significantly affect the capacity margins
 of energy suppliers, their peak season
 generating capacity reserve  was
compared to an estimate of  peak
 incremental power demand by water
utilities.
  Both energy use and water use peak
in the summer months, so the most
significant effects on  supply would be
seen then. In the summer of 2003, U.S.
generation capacity exceeded
consumption by 15 percent, or

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                                                                      471
approximately 160,000 MW (USDOE
2004b). Assuming around-the-clock
operation of water treatment plants, the
total energy requirement can be divided
by 8,760 hours per year to obtain an
average power demand of 13.28 MW. A
more detailed derivation of this value is
shown in the Economic Analysis
(USEPA 2005a). Assuming that power
demand is proportional to water flow
through the plant and that peak flow
can be as high as twice the average daily
flow during the summer months, about
26.55  MW could be needed for
treatment technologies installed to
comply with the Stage 2 DBPR. This is
only 0.017 percent of the capacity
margin available at peak use.
  Although EPA recognizes that not all
areas have a 15 percent capacity margin
and that this margin varies across
regions and through time, this analysis
reflects the effect of the rule on national
energy supply, distribution, and use.
While certain areas, notably California,
have experienced shortfalls in
generating capacity in the recent past, a
peak incremental power requirement of
26.55  MW nationwide is not likely to
significantly change the energy supply,
distribution, or use in any given area.
Considering this analysis, EPA has
concluded that Stage 2 DBPR will not
have any significant effect on the use of
energy, based on annual average use and
on conditions of peak power demand.

/. National Technology Transfer and
Advancement Act
  As noted in the proposed rule,
Section 12(d)  of the National
Technology Transfer and Advancement
Act of 1995 ("NTTAA"), Public Law
104-113, section 12(d] (15 U.S.C. 272
note) directs EPA to use voluntary
consensus standards in its regulatory
activities unless to do so would be
inconsistent with applicable law or
otherwise impractical. Voluntary
consensus standards are technical
standards (e.g., materials specifications,
test methods, sampling procedures, and
business practices) that are developed or
adopted by voluntary consensus
standard bodies. The NTTAA directs
EPA to provide Congress, through OMB,
explanations when the Agency decides
not to use available and applicable
voluntary consensus standards.
  This rulemaking involves technical
standards. EPA has decided to use two
voluntary consensus methods for HAA5
(Standard Method 6251 B, 1998 in the
20th Edition of Standard Methods for
the Examination of Water and
Wastewater and Standard Method 6251
B-94,1994 available at http://
www.standardmethods.org). In addition
to these two consensus methods, EPA is
also approving EPA Method 552.3 for
HAAS, which also can be used to
measure three unregulated HAAs that
are not included in the consensus
methods. The unregulated HAAs are
included in the EPA method because
some water systems monitor for them in
order to better understand their
treatment processes and provide greater
public health protection. EPA is
approving two voluntary consensus
standards for daily monitoring for
chlorite (Standard Method 4500-C1O2 E,
1998, in the 20th Edition of Standard
Methods for the Examination of Water
and Wastewater and Standard Method
4500-C1O2 E-00, 2000, available at
http://www.standardmethods.org). EPA
Method 327.0, Revision 1.1 is also being
approved for daily monitoring for both
chlorite and chlorine dioxide in order to
provide an alternative to the titration
procedure that is required in the
Standard Methods. EPA is approving a
method from American Society for
Testing and Materials International for
bromate,  chlorite and bromide analyses
(ASTM D 6581-00, 2000, ASTM
International. Annual Book of ASTM
Standards, Volume 11.01, American
Society for Testing and Materials
International, 2001 or any year
containing the cited version of the
method may be used). EPA is also
approving three EPA methods (EPA
Methods 317.0 Revision 2.0, 321.8, and
326.0) that provide greater sensitivity
and selectivity for bromate than the
ASTM consensus standard. These EPA
methods  are required in order to
provide better process control for water
systems using ozone in the treatment
process and to allow for a reduced
monitoring option. EPA Methods 317.0
Revision 2.0 and 326.0 can also be used
to determine chlorite and bromide.
Today's action approves eight voluntary
consensus standards for determining
free, combined, and total chlorine (SM
4500-C1 D, SM 4500-C1 F, and 4500-C1
G, 1998, in the 20th Edition of Standard
Methods for the Examination of Water
and Wastewater and SM 4500-C1 D-00,
SM 4500-Cl F-00, and 4500-C1 G-00,
2000 available at http://
www.standardmethods.org and ASTM D
1253-86(96), 1996, ASTM International,
Annual Book of ASTM Standards,
Volume 11.01, American Society for
Testing and Materials International,
1996 or any year containing the cited
version of the method may be used and
ASTM  D 1253-03, 2003, ASTM
International, Annual Book of ASTM
Standards, Volume 11.01, American
Society for Testing and Materials
International, 2004 or any year
containing the cited version of the
method may be used). EPA is approving
four standards for determining total
chlorine (SM 4500-Cl E and SM 4500-
Cl I, 1998, in the 20th Edition of
Standard Methods for the Examination
of Water and Wastewater and SM 4500-
Cl E-00 and SM 4500-Cl 1-00, 2000
available at http://
www.standardmethods.org). Two
standards for determining free chlorine
are approved in today's rule (SM 4500-
Cl H, 1998, in the 20th Edition of
Standard Methods for the Examination
of Water and Wastewater and SM 4500-
Cl H-00,  2000 available at http://
www.standardmethods.org). Today's
action approves three voluntary
consensus standards for measuring
chlorine dioxide (4500-C1O2 D and
4500-C1O2 E, 1998, in the 20th Edition
of Standard Methods  for the
Examination of Water and Wastewater
and 4500-C1O2 E-00, 2000 available at
http://www.standardmethods.org). EPA
is approving six standards for
determining TOC and DOC (SM 5310 B,
SM 5310  C, and SM 5310 D, 1998, in the
20th Edition of Standard Methods for
the Examination of Water and
Wastewater and SM 5310 B-00, SM
5310 C-00, and SM 5310 D-00, 2000
available at http://
www.standardmethods.org). Two
standards for determining UV254 are
approved in today's rule (SM 5910 B,
1998, in the 20th Edition of Standard
Methods  for the Examination of Water
and Wastewater and SM 5910 B-00,
2000 available at http://
www.standardmethods.org). EPA is also
approving EPA Method 415.3 Revision
1.1 for the determination of TOC and
SUVA (DOC and UV254). This EPA
method contains method performance
data that  are not available in the
consensus standards.
  Copies of the ASTM standards may be
obtained  from the American Society for
Testing and Materials International, 100
Barr Harbor Drive, West Conshohocken,
PA 19428-2959.  The  Standard Methods
may be obtained from the American
Public Health Association,  1015
Fifteenth Street, NW., Washington, DC
20005.

/. Executive Order 12898: Federal
Actions To Address Environmental
Justice in Minority Populations or Low-
Income Populations
  Executive Order 12898 establishes a
Federal policy for incorporating
environmental justice into Federal
agency missions by directing agencies to
identify and address disproportionately
high and  adverse human health or
environmental effects of its programs,
policies, and activities on minority and
low-income populations. EPA has

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Federal Register/Vol.  71, No.  2/Wednesday, January 4, 2006/Rules and Regulations
 considered environmental justice
 related issues concerning the potential
 impacts of this action and consulted
 with minority and low-income
 stakeholders. A description of this
 consultation can be found in the
 proposed rule (USEPA 2003a).

 K. Consultations With the Science
 Advisory Board, National Drinking
 Water Advisory Council, and the
 Secretary of Health and Human Services
  In accordance with Section 1412(d)
 and (e) of the SDWA, the Agency
 consulted with the Science Advisory
 Board, the National Drinking Water
 Advisory Council (NOWAC), and  the
 Secretary of Health and Human Services
 on today's rule,
  EPA met with the SAB to discuss the
 Stage 2 DBPR on June 13, 2001
 (Washington, DC), September 25-26,
 2001 (teleconference), and December
 10-12, 2001 (Los Angeles, CA). Written
 comments from the December 2001
 meeting of the SAB addressing the
 occurrence analysis and risk assessment
 were generally supportive. SAB
 comments are discussed in greater detail
 within the proposal.
  EPA met with the NDWAC on
 November 8, 2001, in Washington, DC
 to discuss the Stage 2 DBPR proposal.
 The Advisory Committee generally
 supported the need for the Stage 2 DBPR
 based on .health and occurrence data,
 but also stressed the importance of
 providing flexibility to the systems
 implementing the rule. The results of
 these discussions are included in the
 docket for the proposed rule.

 L. Plain Language
  Executive Order 12866 requires each
 agency to write its rules in plain
 language. Readable regulations help the
 public find requirements quickly and
 understand them easily. They increase
 compliance, strengthen enforcement,
 and decrease mistakes, frustration,
 phone calls, appeals, and distrust of
 government. EPA made every effort  to
 write this preamble to the final rule  in
 as clear, concise, and unambiguous
 manner as possible.

M. Analysis of the Likely Effect of
Compliance With the Stage 2 DBPR  on
the Technical, Managerial, and
Financial Capacity of Public Water
Systems
  Section 1420(d)(3) of SDWA, as
amended, requires that, in promulgating
a National Primary Drinking Water
Regulation (NPDWR), the Administrator
shall include an analysis of the likely
effect of compliance with the regulation
on the technical, managerial, and
financial (TMF) capacity of PWSs. This
                          analysis is described in more detail and
                          can be found in the Economic Analysis
                          (USEPA 2005a). Analyses reflect only
                          the impact of new or revised
                          requirements, as established by the
                          LT2ESWTR; the impacts of previously
                          established requirements on system
                          capacity are not considered.
                            EPA has defined overall water system
                          capacity as the ability to plan for,
                          achieve, and  maintain compliance with
                          applicable drinking water standards.
                          Capacity encompasses three
                          components: technical, managerial, and
                          financial.  Technical capacity is the
                          physical and operational ability of a
                          water system to meet SDWA
                          requirements. This refers to the physical
                          infrastructure of the water system,
                          including  the adequacy of source water
                          and the adequacy of treatment, storage,
                          and distribution infrastructure. It also
                          refers to the ability of system personnel
                          to adequately operate and maintain the
                          system and to otherwise implement
                          requisite technical knowledge.
                          Managerial capacity is the ability of a
                          water system to conduct its affairs to
                          achieve and maintain compliance with
                          SDWA requirements. Managerial
                          capacity refers to the system's
                          institutional and administrative
                          capabilities. Financial capacity is a
                          water system's ability to acquire and
                          manage sufficient financial resources to
                          allow the system to achieve and
                          maintain compliance with SDWA
                          requirements.
                            EPA estimated the impact of the Stage
                          2 DBPR on small and large system
                          capacity as a result of the measures that
                          systems are expected to adopt to  meet
                          the requirements of the rule (e.g.,
                          selecting monitoring sites for the IDSE,
                          installing/upgrading treatment, operator
                          training, communication with regulators
                          and the service community, etc.). The
                          Stage 2 DBPR may have a substantial
                          impact on the capacity of the 1,743
                          plants in small systems and 518 plants
                          in large systems that must make changes
                          to their treatment process to meet the
                          Stage 2 DBPR requirements. However,
                          while the impact to these  systems is
                          potentially significant, only 3.8 percent
                          of all plants regulated under the Stage
                          2 DBPR (2,261 of 60,220) will be
                          affected by this requirement. Since
                          individual systems may employ more
                          than one plant, it is likely that fewer
                          than 1,620 systems (3.4 percent of
                          48,293 systems) will be affected by this
                          requirement. The new IDSE and
                          monitoring requirements are expected to
                          have a small impact on the technical
                          and managerial capacity of small
                          systems, a  moderate impact on the
                          financial capacity of some small
                          systems, and a much smaller impact on
 large systems. The capacity of systems
 that must conduct an operational
 evaluation will only be impacted in a
 minor way, while those systems that
 must only familiarize themselves with
 the rule (the large majority of systems)
 will not face any capacity impact as a
 result of the Stage 2 DBPR.

 N. Congressional Review Act

  The Congressional Review Act, 5
 U.S.C. 801 et seq., as added by the Small
 Business Regulatory Enforcement
 Fairness Act of 1996, generally  provides
 that before a rule may take effect, the
 agency promulgating the rule must
 submit a rule report, which includes a
 copy of the  rule, to each House  of the
 Congress and to the Comptroller General
 of the United States. EPA will submit a
 report containing this rule and other
 required information  to the U.S. Senate,
 the U.S. House of Representatives, and
 the Comptroller General of the United
 States prior to publication of the rule in
 the Federal Register.  A Major rule
 cannot take effect until 60 days after it
 is published in the Federal Register.
 This action  is a "major rule" as defined
 by 5 U.S.C.  804(2). This rule will be
 effective March 6, 2006.

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                                Control of Microbial Pathogens and
                                Disinfection Byproducts. Prepared by the
                                Cadmus Group and Malcolm Pirnie.
                             USEPA. 2003e. Draft Significant Excursion
                                Guidance Manual. Washington, DC.
                                EP A-815-D-03-004.
                             USEPA. 2003f. Method 552.3. Determination
                                of Haloacetic Acids and Dalapon in
                                Drinking Water by Liquid-liquid
                                Extraction, Derivatization. and Gas
                                Chromatography with Electron Capture
                                Detection. Revision 1.0. EPA-815-B-03-
                                002.  (Available at http://www.epa.gov/
                                safewater/methods/sourcalt.html.)
                             USEPA. 2004. Guidelines Establishing Test
                                Procedures for the Analysis of Pollutants
                                Under the Clean Water Act; National
                                Primary Drinking Water Regulations; and
                                National Secondary Drinking Water
                                Regulations; Analysis and Sampling
                                Procedures; Proposed Rule. 66 FR 18166,
                                April 6, 2004.
                             USEPA. 2005a. Economic Analysis for the
                                Final Stage 2 Disinfectants and
                                Disinfection  Byproducts Rule.
                                Washington, DC. EPA 815-R-Q5-010.
                             USEPA. 2005b. Drinking Water Criteria
                                Document for Brominated
                                Trihalomethanes. Washington, DC. EPA
                                822-R-05-011.
                             USEPA. 2005c. Drinking Water Criteria
                                Document for Brominated Acetic Acids.
                                Washington, DC. EPA 822-R-05-007.
                             USEPA. 2005d. Drinking Water Addendum
                                to the Criteria Document for
                                Monochloroacetic Acid. Washington,
                                DC. EPA 822-R-05-008.
                             USEPA. 2005e. Drinking Water Addendum to
                                the Criteria Document for Trichloroacetic
                                Acid. Washington, DC. EPA 822-R-05-
                                010.
                            USEPA. 2005f. Occurrence Assessment for
                                the Final Stage 2 Disinfectants and
                                Disinfection  Byproducts Rule.
                                Washington, DC. EPA 815-R-05-011.
                            USEPA. 2005g. Technologies and Costs for
                                the Final Long Term 2 Enhanced Surface
                                Water Treatment Rule and Final Stage 2
                                Disinfectants and Disinfection
                                Byproducts Rule. Washington, DC. EPA
                                815-R-05-012.
                            USEPA. 2005h. Method 327.0. Determination
                                of Chlorine Dioxide and Chlorite Ion in
                                Drinking Water Using Lissamine Green B
                                and Horseradish Peroxidase with
                                Detection by  Visible Spectrophotometry.
                                Revision 1.1. EPA 815-R-05-008.
                                (Available at http://www.epa.gov/
                                safewater/methods/sourcalt.html.)
                            USEPA. 2005L Guidelines for carcinogen risk
                                assessment. Office of Research and
                                Development, Washington, DC. EPA/
    630/P-03/001F. Available online at
    http://cfpub.epa.gov/ncea/.
 USEPA. 2005J. Supplemental guidance for
    assessing susceptibility from early-life
    exposure to carcinogens. Office of
    Research and Development, Washington,
    DC. EPA/630/R-03/003F. Available
    online at http://cfpub.epa.gov/ncea/.
 USEPA. 2005k. Drinking Water Addendum to
    the IRIS Toxicological Review of
    Dichloroacetic Acid. Washington, DC.
    EPA 822-R-05-009.
 USEPA. 20051. Method 415.3. Determination
    of Total Organic Carbon and Specific UV
    Absorbance at 254 nm in Source Water
    and Drinking Water. Revision 1.1. EPA/
    600/R-05/055. (Available at http://
    www. epa.gov/n erlcwww/ordm eth.htm.)
 USEPA. 2005m. Unregulated Contaminant
    Monitoring Regulation (UCMR) for
    Public Water Systems Revions; Proposed
    Rule. 70  FR 49094, August 22, 2005.
 USEPA. 2005n. Information Collection
    Request for National Primary Drinking
    Water Regulations: Final Stage 2
    Disinfectants and Disinfection
    Byproducts Rule. Washington, DC. EPA
    815-Z-05-002.
 USEPA. 2006. Initial Distribution System
    Evaluation Guidance Manual for the
    Final Stage 2 Disinfectants and
    Disinfection Byproducts Rule.
    Washington, DC. EPA 815-B-06-002.
 USFDA (Food and Drug Administration).
    1994. Sanitizing Solutions. 21 Code of
    Federal Regulation, Part
    178.1010. &http://ecfr.gpoaccess.gov/cgi/
    t/text/text-idx?c=ecfrS-tpl= %2Findex. tpl
 Villanueva, C.M.. M. Kogevinas and J.O.
    Grimalt.  2001. Drinking water
    chlorination and adverse health effects: a
    review of epidemiological studies.
    Medicina Clinica 117(1): 27-35.
    (Spanish).
 Villanueva, C.M., Fernandez, F., Malats, N.,
    Grimalt, J.O., and Kogenvinas,  M. 2003.
    Meta-analvsis of Studies on Individual
    Consumption of Chlorinated Drinking
    Water and Bladder Cancer. Journal of
    Epidemiology Community Health 57:
    166-173.
 Villanueva, C.M.,  K.P. Cantor, S. Cordier,
    J.J.K. Jaakkola, W.D. King, C.F.  Lynch. S.
    Porru and M. Kogevinas. 2004.
    Disinfection byproducts and bladder
    cancer  a pooled analysis. Epidemiology.
    15(3):357-367.
 Vinceti, M., G. Fantuzzi, L. Monici, et al
    2004. A retrospective cohort study of
    trihalomethane exposure through
    drinking  water and cancer mortality in
    northern  Italy. Science of the Total
    Environment. 330(1-3):47-53.
Vinois, P. 2004. A self-fulfilling prophecy:
    are we underestimating the role of the
    environment in gene-environment
    interaction research? International
    Journal of Epidemiology. 33:945-946.
Waller, K., S.H. Swan, G. DeLorenze, B.
    Hopkins.  1998. Trihalomethanes in
    drinking water and spontaneous
    abortion.  Epidemiology. 9(2):134-140.
Waller, K., S.H. Swan, G.C." Windham and L.
    Fenster. 2001. Influence of exposure
    assessment methods on risk estimates in
    an epidemiologic study of total

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             Federal  Register/Vol. 71, No. 2/Wednesday,  January  4,  2006/Rules and Regulations
                                                                           477
    trihalomethane exposure and
    spontaneous abortion. Journal of
    Exposure Analysis and Environmental
    Epidemiology. 11(6): 522-531.
Weinberg, H.S., S.W. Krasner, S.D.
    Richardson and A.D. Thruston, Jr. 2002.
    The Occurrence of Disinfection By-
    products (DBFs) of Health Concern in
    Drinking Water: Results of a Nationwide
    DBF Occurrence Study, U.S.
    Environmental Protection Agency,
    National Exposure Research Laboratory,
    Athens, GA. EPA/600/R-02/068. http:'//
    www.epa.gov/athens/publications/
    EPA600R02068.pdf.
WHO. 2000, World Health Organization,
    International Programme on Chemical
    Safety (IPCS). Environmental Health
    Criteria 216: Disinfectants and
    Disinfectant By-products.
Windham, GC, Swan SH, Fenster L, Neutra
    RR. 1992. Tap or bottled water
    consumption and spontaneous abortion:
    a 1986 case-control study in California.
    Epidemiology. 3:113-9.
Windham GC, Waller K, Anderson M,
    Fenster L, Mendola P, and Swan S. 2003.
    Chlorination by-products in drinking
    water and menstrual cycle function.
    Environ Health Perspect: doi:10.1289/
    ehp.5922. http://ehpnetl.niehs.nih.gov/
    docs/2003/5922/abstract.html.
Wrensch, M., S.H. Swan, J. Lipscomb, D.M.
    Epstein, R.R. Neutra, and L. Fenster.
    1992. Spontaneous abortions and birth
    defects related to tap and bottled water
    use, San Jose, California, 1980-1985.
    Epidemiology. 3(2):98-lQ3.
Wright, J.M., J. Schwartz and D.W. Dockery.
    2003. Effect of trihalomethane exposure
    on fetal development. Occupational and
    Environmental Medicine. 60(3):173-180.
Wright, J.M., J. Schwartz and D.W. Dockery.
    2004. The effect of disinfection by-
    products and mutagenic activity on birth
    weight and gestational duration.
    Environmental Health Perspectives.
    112(8):920-925.
Xu, X., T.M. Marino, J.D.  Laskin and C.P.
    Weisel. 2002. Pericutaneous absorption
    of trihalomethanes, haloacetic acids, and
    haloketones. Toxicology and Applied
    Pharmacology. 184(l):19-26.
Yang, C.Y., Chiu, H.F, Cheng, M.F., and Tsai,
    S.S. 1998. Chlorination of Drinking
    Water and Cancer Mortality in Taiwan.
    Environ Res, 78:1-6.
Yang, V., B. Cheng, S. Tsai, T. Wu, M. Lin
    M. and K. Lin. 2000.  Association
    between Chlorination of drinking water
    and adverse pregnancy outcome in
    Taiwan. Environ. Health. Perspect.
    108:765-68.
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    chlorination and adverse birth outcomes
    in Taiwan.  Toxicology. 198(2004):249-
    254.
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    Impacts of medium-pressure UV on THM
    and HAA formation in pre-UV
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    Water Quality Technology Conference of
    the American Water Works Association,
    Denver, CO.
List of Subjects

40 CFR Part 9
  Reporting and recordkeeping
requirements.

40 CFR Part 141
  Environmental protection, Chemicals,
Indians-lands, Incorporation by
reference, Intergovernmental relations,
Radiation protection, Reporting and
recordkeeping requirements, Water
supply.

40 CFR Part 142
  Environmental protection,
Administrative practice and procedure,
Chemicals, Indians-lands, Radiation
protection, Reporting and recordkeeping
requirements, Water supply.
  Dated: December 15, 2005.
Stephen L. Johnson,
Administrator.
• For the reasons set forth in the
preamble, title 40 chapter I of the Code
of Federal Regulations is amended as
follows:

PART 9—OMB APPROVALS UNDER
THE PAPERWORK REDUCTION ACT

• 1. The authority citation for part 9
continues to read as follows:
  Authority: 7 U.S.C. 135 et seq., 136-136y;
15 U.S.C. 2001, 2003, 2005, 2006, 2601-2671;
21 U.S.C. 331J, 346a, 348; 31 U.S.C. 9701; 33
U.S.C. 1251 etseq., 1311, 1313d, 1314, 1318,
1321, 1326, 1330, 1342, 1344, 1345 (d) and
(e), 1361; Executive Order 11735, 38 FR
21243, 3 CFR, 1971-1975 Comp. p. 973; 42
U.S.C. 241, 242b, 243, 246, 300f. 300g, 300g-
1, 300g-2, 300g-3, 300g-4, 300g-5,300g-6,
300J-1, 300J-2, 300J-3, 300J-4, 300J-9, 1857
etseq., 6901-6992k, 7401-7671q, 7542,
9601-9657, 11023, 11048.

• 2. In § 9.1 the table is amended as
follows:
• a. Under the heading "National
Primary Drinking Water Regulations
Implementation" by adding entries in
numerical order for "§ 141.600-141.605,
141.620-141.626, 141.629".
• b. Under the heading "National
Primary Drinking Water Regulations
Implementation" by removing entries
"§ 142.14(a),142.14(a)-(d)(3)" and
adding entries in numerical order for
"142.14(a) (l)-(7), 142.14(a)(8),
142.14(bJ-(d) and 142.16(m)" as
follows:

§9.1   OMB approvals under the Paperwork
Reduction Act.
                   40 CFR citation
                           OMB control
                               No.
                  National Primary Drinking Water
                           Regulations
              141.600-141.605
              141.620-141.626
              141.629 	
                             2040-0265
                             2040-0265
                             2040-0265
                  National Primary Drinking Water
                    Regulations Implementation
                             2040-0265
                             2040-0265
                             2040-0090
             142.14(a)(8)
             142.14(b)-(d)
              142.16(m)
                             2040-0265
      40 CFR citation
OMB control
    No.
             PART 141—NATIONAL PRIMARY
             DRINKING WATER REGULATIONS

             • 3. The authority citation for part 141
             continues to read as follows:
               Authority: 42 U.S.C. 300f, 300g-l, 300g-2,
             300g-3, 300g-4, 300g-5, 300g-6, 300J-4,
             300J-9, andSOOj-ll.

             • 4. Section 141.2 is amended by
             adding, in alphabetical order,
             definitions  for "Combined distribution
             system", "Consecutive system", "Dual
             sample sets", "Finished water",
             "GAC20", "Locational  running annual
             average", and "Wholesale system" and
             revising the definition of "GAC10" to
             read as follows:

             §141.2  Definitions.
             *****

               Combined distribution  system is the
             interconnected distribution system
             consisting of the distribution systems of
             wholesale systems and of the
             consecutive systems that  receive
             finished water.
  Consecutive system is a public water
system that receives some or all of its
finished water from one or more
wholesale systems. Delivery may be
through a direct connection or through
the distribution system of one or more
consecutive systems.
*****

  Dual sample set is a set of two
samples collected at the same time and
same location, with one sample
analyzed for TTHM and the other

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478
Federal Register/Vol.  71,  No. 2/Wednesday, January 4, 2006/Rules and Regulations
sample analyzed for HAA5. Dual sample
sets are collected for the purposes of
conducting an IDSE under subpart U of
this part and determining compliance
with the TTHM and HAAS MCLs under
subpart V of this part.
*****
  Finished water is water that is
introduced into the distribution system
of a public water system and is intended
for distribution and consumption
without further treatment, except as
treatment necessary to maintain water
quality in the distribution system (e.g.,
booster disinfection, addition of
corrosion control chemicals).
*****
  GAClO means granular activated
carbon filter beds with an empty-bed
contact time of 10 minutes based on
average daily flow and a carbon
reactivation frequency of every 180
days, except that the reactivation
frequency for GAClO used as  a best
available technology for compliance
with subpart V MCLs under
§ 141.64(b)(2) shall be 120 days.
  GAC20 means granular activated
carbon filter beds with an empty-bed
contact time of 20 minutes based on
average daily flow and a carbon
reactivation frequency of every 240
days.
*****
  Locational running annual  average
(LRAA) is the average of sample
analytical results for samples  taken at a
particular monitoring  location during
the previous four calendar quarters.
*****
  Wholesale system is a public water
system that treats source water as
necessary to produce finished water and
then delivers some or  all of that finished
water to another public water system.
Delivery may be through a direct
connection or through the distribution
system of one or more consecutive
systems.

§141.12  [Removed]
• 5. Section 141.12 is removed and
reserved.

§141.30  [Removed]
• 6. Section 141.30 is removed.

§141.32  [Removed]
• 7. Section 141.32 is removed and
reserved.
• 8. Section 141.33 is amended by
revising the first sentence of paragraph
(a) introductory text and adding
paragraph (f) to read as follows:

§ 141.33  Record maintenance.
*****
  (a) Records of microbiological
analyses and turbidity analyses made
                          pursuant to this part shall be kept for
                          not less than 5 years. * * *
                          *****

                            (f) Copies of monitoring plans
                          developed pursuant to this part shall be
                          kept for the same period of time as the
                          records of analyses taken under the plan
                          are required to be kept under paragraph
                          (a) of this section, except as specified
                          elsewhere in this part.

                          • 9. Section 141.53 is amended by
                          revising the table to read as follows:

                          § 141.53  Maximum contaminant level goals
                          for disinfection byproducts.
                             Disinfection byproduct
                 MCLG (mg/L)
Bromodichloromethane 	
Bromoform 	
Bromate . 	
Chlorite
Chloroform . 	
Dibromochloromethane 	
Dichloroacetic acid
Monochloroacetic acid
Trichloroacetic acid

zero
zero
zero
08
007
0.06
zero
0 07
002

                          • 10. Section 141.64 is revised to read
                          as follows:

                          § 141.64  Maximum contaminant levels for
                          disinfection byproducts.

                            (a) Bromate and chlorite. The
                          maximum contaminant levels (MCLs)
                          for bromate and chlorite are as follows:
Disinfection byproduct
Bromate ... 	
Chlorite ... 	

MCL (mg/L)
0010
1 0

                            (1) Compliance dates for CWSs and
                          NTNCWSs. Subpart H systems serving
                          10,000 or more persons must comply
                          with this paragraph (a) beginning
                          January 1, 2002. Subpart H systems
                          serving fewer than  10,000 persons and
                          systems using only ground water not
                          under the direct influence of surface
                          water must comply with this paragraph
                          (a) beginning January 1, 2004.
                            (2) The Administrator, pursuant to
                          section 1412 of the Act, hereby
                          identifies the following as the best
                          technology, treatment techniques, or
                          other means available for achieving
                          compliance with the maximum
                          contaminant levels for bromate and
                          chlorite identified in this paragraph (a):
                          Disinfec-
                          tion by-
                          product
                          Bromate
    Best available technology
Control  of ozone treatment proc-
  ess to reduce production of bro-
  mate
                               Disinfec-
                               tion by-
                               product
                              Chlorite
              Best available technology
          Control of treatment processes to
           reduce disinfectant demand and
           control of disinfection treatment
           processes to reduce disinfectant
           levels
   (b) TTHM and HAAS. (1) Subpart L—
RAA compliance, (i) Compliance dates.
Subpart H systems serving 10,000 or
more persons must comply with this
paragraph (b)(l) beginning January 1,
2002. Subpart H systems serving fewer
than 10,000 persons and systems using
only ground water not under the direct
influence of surface water must comply
with this paragraph (b)(l) beginning
January 1, 2004. All systems must
comply with these MCLs until the date
specified for subpart V compliance in
§141.620(c).
Disinfection byproduct
Total trihalomethanes (TTHM)
Haloacetic acids (five) (HAAS)
MCL (mg/L)
0.080
0.060
                                (ii) The Administrator, pursuant to
                              section 1412 of the Act, hereby
                              identifies the following as the best
                              technology, treatment techniques, or
                              other means available for achieving
                              compliance with the maximum
                              contaminant levels for TTHM and
                              HAAS identified in this paragraph
                                                                 Disinfection byproduct
                              Total trihalomethanes
                                (TTHM) and
                                Haloacetic acids
                                (five) (HAAS).
                                                   Best available tech-
                                                        nology
                    Enhanced coagula-'
                      tion or enhanced
                      softening or
                      GAC10, with chlo-
                      rine as the primary
                      and residual dis-
                      infectant
                                (2) Subpart V—LRAA compliance, (i)
                              Compliance dates. The subpart V MCLs
                              for TTHM and HAAS must be complied
                              with as a locational running annual
                              average at each monitoring location
                              beginning the date specified for subpart
                              V compliance in § 141.620(c).
                                  Disinfection byproduct
                              Total trihalomethanes (TTHM)
                              Haloacetic acids (five) (HAAS)
                            MCL (mg/L)
                                 0.080
                                 0.060
  (ii) The Administrator, pursuant to
section 1412 of the Act, hereby
identifies the following as the best
technology, treatment techniques, or
other means available for achieving
compliance with the maximum
contaminant levels for TTHM and
HAAS identified in this paragraph (b)(2)

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             Federal Register/Vol. 71, No.  2/Wednesday, January 4,  2006/Rules and Regulations
                                                                                               479
for all systems that disinfect their source
water:
Disinfection by-
   product
Total
  trihalometha-
  nes (TTHM)
  and
  Haloacetic
  acids (five)
  (HAAS).
 Best available technology
Enhanced coagulation or en-
  hanced softening, plus
  GAC10; or nanofiltration
  with a molecular weight
  cutoff <1000 Daltons; or
  GAC20
  (iii) The Administrator, pursuant to
section 1412 of the Act, hereby
identifies the following as the best
technology, treatment techniques, or
other means available for achieving
compliance with the maximum
contaminant levels for TTHM and
HAAS identified in this paragraph (b)(2)
for consecutive systems and applies
only to the disinfected water that
consecutive systems buy or otherwise
receive:
Disinfection by-
   product
Total
  trihalometha-
  nes (TTHM)
  and
  Haloacetic
  acids (five)
  (HAAS).
 Best available technology
Systems serving >10,000:
  Improved distribution sys-
  tem and storage tank
  management to reduce
  residence time, plus the
  use of chloramines for dis-
  infectant residual mainte-
  nance
Systems serving <10,000:
  Improved distribution sys-
  tem and storage tank
  management to reduce
  residence time
• 11. Section 141.131 is amended as
follows:
• a. By revising paragraph (a),
• b. By revising paragraphs (b)(l) and
  c. By revising the table in paragraph
  d. By revising paragraphs (d)(2),
(d)(3), (d)(4)(i), and (d)(4)(ii),
• e. By adding paragraph (d)(6).

§141.131  Analytical requirements.
  (a) General. (1) Systems must use only
the analytical methods specified in this
section, or their equivalent as approved
by EPA, to demonstrate compliance
with the requirements of this subpart
and with the requirements of subparts U
and V of this part. These methods are
effective for compliance monitoring
February 16, 1999, unless a different
effective date is specified in this section
or by the State.
  (2) The following documents are
incorporated by reference. The Director
of the Federal Register approves this
incorporation by reference in
accordance with 5 U.S.C. 552(a) and 1
CFR part 51. Copies may be inspected
at EPA's Drinking Water Docket, 1301
Constitution Avenue, NW., EPA West,
Room B102, Washington, DC 20460, or
at the National Archives and Records
Administration (NARA). For
information on the availability of this
material at NARA, call 202-741-6030,
or go to: http://www.archives.gov/
federal_register/
code_of_federal_regulations/
ibr_locations.html. EPA Method 552.1 is
in Methods for the Determination of
Organic Compounds in Drinking Water-
Supplement II, USEPA, August 1992,
EPA/600/R-92/129 (available through
National Information Technical Service
(NTIS), PB92-207703). EPA Methods
502.2, 524.2, 551.1, and 552.2 are in
Methods for the Determination of
Organic Compounds in Drinking Water-
Supplement III, USEPA, August 1995,
EPA/600/R-95/131 (available through
NTIS, PB95-261616). EPA Method
300.0 is in Methods for the
Determination of Inorganic Substances
in Environmental Samples, USEPA,
August 1993, EPA/600/R-93/100
(available through NTIS, PB94-121811).
EPA Methods 300.1 and  321.8 are in
Methods for the Determination of
Organic and Inorganic Compounds in
Drinking Water, Volume 1, USEPA,
August 2000, EPA 815-R-00-014
(available through NTIS, PB2000-
106981). EPA Method 317.0, Revision
2.0, "Determination of Inorganic
Oxyhalide Disinfection By-Products in
Drinking Water Using Ion
Chromatography  with the Addition of a
Postcolumn Reagent for Trace Bromate
Analysis," USEPA, July 2001, EPA 815-
B-01-001, EPA Method 326.0, Revision
1.0, "Determination of Inorganic
Oxyhalide Disinfection By-Products in
Drinking Water Using Ion
Chromatography  Incorporating the
Addition of a Suppressor Acidified
Postcolumn Reagent for Trace Bromate
Analysis," USEPA, June 2002, EPA 815-
R-03-007, EPA Method 327.0, Revision
1.1, "Determination of Chlorine Dioxide
and Chlorite Ion in Drinking Water
Using Lissamine  Green B and
Horseradish Peroxidase with Detection
by Visible Spectrophotometry," USEPA,
May 2005, EPA 815-R-05-008 and EPA
Method 552.3, Revision 1.0,
"Determination of Haloacetic Acids and
Dalapon in Drinking Water by Liquid-
liquid Microextraction, Derivatization,
and Gas Chromatography with Electron
Capture Detection," USEPA, July 2003,
EPA-815-B-03-002 can be accessed
and downloaded  directly on-line at
http://www.epa.gov/safewater/methods/
sourcalt.html. EPA Method 415.3,
Revision 1.1, "Determination of Total
Organic Carbon and Specific UV
Absorbance at 254 nm in Source Water
and Drinking Water," USEPA, February
2005, EPA/600/R-05/055 can be
accessed and downloaded directly on-
line at www.epa.gov/nerlcwww/
ordmeth.htm. Standard Methods 4500-
Cl D, 4500-C1 E, 4500-C1 F, 4500-C1 G,
4500-C1 H, 4500-C11, 4500-C1O2 D,
4500-C1O2 E, 6251 B, and 5910 B shall
be followed in accordance with
Standard Methods for the Examination
of Water and Wastewater, 19th or 20th
Editions, American Public Health
Association, 1995 and 1998,
respectively. The cited methods
published  in either edition may be used.
Standard Methods 5310 B, 5310 C, and
5310 D shall be followed in accordance
with the Supplement to the 19th Edition
of Standard Methods for the
Examination of Water and Wastewater,
or the Standard Methods for the
Examination of Water and Wastewater,
20th Edition,  American Public Health
Association, 1996 and  1998,
respectively. The cited methods
published  in either edition may be used.
Copies may be obtained from the
American  Public Health Association,
1015 Fifteenth Street, NW., Washington,
DC 20005. Standard Methods 4500-C1
D-00, 4500-C1 E-00, 4500-C1 F-00,
4500-C1 G-00, 4500-C1 H-00, 4500-C1
1-00, 4500-C1O2 E-00, 6251 B-94, 5310
B-00, 5310 C-00,  5310 D-00 and 5910
B-00 are available at http://
www.standardmethods.org or at EPA's
Water Docket. The year in which each
method was approved by the Standard
Methods Committee is designated by the
last two digits in the method number.
The methods  listed are the only Online
versions that are IBR-approved. ASTM
Methods D 1253-86 and D 1253-86
(Reapproved 1996) shall be followed in
accordance with the Annual Book of
ASTM Standards, Volume 11.01,
American  Society for Testing and
Materials International, 1996 or any
ASTM edition containing the IBR-
approved version  of the method may be
used. ASTM Method D1253-03 shall be
followed in accordance with the Annual
Book of ASTM Standards, Volume
11.01, American Society for Testing and
Materials International, 2004 or any
ASTM edition containing the IBR-
approved version  of the method may be
used. ASTM Method D 6581-00 shall be
followed in accordance with the Annual
Book of ASTM Standards, Volume
11.01, American Society for Testing and
Materials International, 2001 or any
ASTM edition containing the IBR-
approved version  of the method may be
used; copies may be obtained from the
American  Society for Testing and

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480
Federal Register/Vol.  71, No.  2/Wednesday, January  4,  2006/Rules and Regulations
Materials International, 100 Barr Harbor
Drive, West Conshohocken, PA 19428-
2959.
                              (b) Disinfection byproducts. (1)
                           Systems must measure disinfection
                           byproducts by the methods (as modified
by the footnotes) listed in the following
table:
                     APPROVED  METHODS FOR DISINFECTION BYPRODUCT COMPLIANCE MONITORING
Contaminant and methodology 1
TTHM
P&T/GC/EICD & PID
P&T/GC/MS
LLE/GC/ECD
HAAS
LLE (diazomethane)/GC/ECD 	
SPE (acidic methanol)/GC/ECD 	
LLE (acidic methanol)/GC/ECD 	
Bromate
Ion chromatography
Ion chromatography & post column reac-
tion.
IC/ICP-MS
Chlorite
Amperometnc titration
Spectrophotometry
Ion chromatography

EPA method
502 2 4
5242
551 1

552 1 5 	
552.2, 552.3 	
300 1
317 0 Rev 2 O6 326 O6
321 867

327 0 Rev 1 1 8
300 0 300 1 317 0
Rev 2.0, 326.0.
Standard method2



6251 B5 	





4500-CIO^ E8



SM online9



6251 B-94 	





4500-CIO^ E-008



ASTM method3






D 6581-00




D 6581-00

  1 P&T = purge and trap; GC = gas chromatography, EICD = electrolytic conductivity detector, PID = photoiomzation detector; MS = mass spec-
trometer; LLE = liquid/liquid extraction; ECD = electron capture detector; SPE = solid phase extraction; 1C = ion chromatography; ICP-MS = in-
ductively coupled plasma/mass spectrometer.
  219th and 20th editions of Standard  Methods for the Examination of Water and Wastewater, 1995 and 1998, respectively, American Public
Health Association; either of these editions may  be used.
  3 Annual Book of ASTM Standards, 2001 or any year containing the cited version of the method, Vol 11.01
  4 If TTHMs are the only analytes being measured  in the sample, then a PID is not required.
  5The samples must be extracted within 14 days of sample collection.
  6 Ion chromatography & post column reaction  or IC/ICP-MS must be used for monitoring of bromate for purposes of demonstrating eligibility of
reduced monitoring, as prescribed in §141.132(b)(3)(h).
  7 Samples must be preserved at the time of sampling with 50  mg ethylenediamine (EDA)/L of sample and must be analyzed within 28 days.
  8Amperometric titration or spectrophotometry  may be used for routine daily monitoring of chlorite at the entrance to the distribution system, as
prescribed in § 141.132(b)(2)(i)(A). Ion chromatography must be used for routine monthly monitoring of chlorite and additional monitoring  of chlo-
rite in the  distribution system, as prescribed in §141.132(b)(2)(i)(B) and (b)(2)(ii).
  9 The Standard Methods Online version that is approved is indicated by the last two digits in the method number which is the year of approval
by the Standard Method Committee. Standard Methods Online are available at http.//www.standardmethods.org.
  (2) Analyses under this section for
disinfection byproducts must be
conducted by laboratories that have
received certification by EPA or the
State, except as specified under
paragraph (b)(3) of this section. To
receive certification to conduct analyses
for the DBP contaminants in §§ 141.64,
141.135, and subparts U and V of this
part, the laboratory must:
                             (i) Analyze Performance Evaluation
                           (PE) samples that are acceptable to EPA
                           or the State at least once during each
                           consecutive 12 month period by each
                           method for which the laboratory desires
                           certification.
                             (ii) Until March 31, 2007, in these
                           analyses of PE samples, the laboratory
                           must achieve quantitative results within
                           the acceptance limit on a minimum of
                           80% of the analytes included in each PE
sample. The acceptance limit is defined
as the 95% confidence interval
calculated around the mean of the PE
study between a maximum and
minimum acceptance limit of +/ - 50%
and +/ —15% of the study mean.
  (iii) Beginning April 1,  2007, the
laboratory must achieve quantitative
results on the PE sample analyses that
are within the following acceptance
limits:
DBP
TTHM
Chloroform 	 	
Bromodichloromethane
Dibromochloromethane 	 	
Bromoform 	
HAA5
Monochloroacetic Acid 	
Dichloroacetic Acid 	 	
Trichloroacetic Acid
Monobromoacetic Acid
Dibromoacetic Acid 	
Chlorite 	
Acceptance
limits (percent
of true value)
±20
+20
+20
+20
+40
+40
+40
+40
+40
+30
Comments
Laboratory must meet all 4 individual THM acceptance limits
in order to successfully pass a PE sample for TTHM


Laboratory must meet the acceptance limits for 4 out of 5 of
the HAA5 compounds in order to successfully pass a PE
sample for HAA5





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              Federal  Register/Vol.  71, No. 2/Wednesday, January 4,  2006/Rules  and  Regulations
                                                                              481

DBP
Bromate 	 .. .... 	


Acceptance
limits (percent
of true value)
+30


Comments


  (iv) Beginning April 1, 2007, report
quantitative data for concentrations at
least as low as the ones listed in the
following table for all DBP samples
analyzed for compliance with §§ 141.64,
               141.135, and subparts U and V of this
               part:
                          DBP
               Minimum re-
               porting level
                 (mg/L)1
                       Comments
TTHM2
    Chloroform 	
    Bromodichloromethane .
    Dibromochloromethane
    Bromoform 	
HAAS 2
    Monochloroacetic Acid  .
    Dichloroacetic Acid 	
    Trichloroacetic Acid 	
    Monobromoacetic Acid
    Dibromoacetic Acid	
Chlorite	
Bromate
                    00010
                    0.0010
                    0.0010
                    0.0010

                    0.0020
                    0.0010
                    0.0010
                    0.0010
                    0.0010
                     0.020

                 0.0050 or
                    0.0010
Applicable to monitoring as prescribed in §141.132(b)(2)(1)(B)
  and (b)(2)(h).
Laboratories that use EPA Methods 317.0 Revision 2.0, 326.0
  or 321.8 must meet a 0.0010 mg/L MRL for bromate.
  1 The calibration curve must encompass the regulatory minimum reporting level (MRL) concentration Data may be reported for concentrations
lower than the regulatory MRL as long as the precision and accuracy criteria are met by analyzing an MRL check standard at the lowest report-
ing limit chosen by the laboratory. The laboratory must verify the accuracy of the calibration curve  at the MRL concentration by analyzing an
MRL check standard with a concentration less than or equal to 110% of the MRL with each batch of samples. The measured concentration for
the MRL check standard must be ±50% of the expected value, if any field sample in the batch has a concentration less than 6 times the regu-
latory MRL. Method requirements to analyze higher concentration check standards and meet tighter acceptance criteria for them must be met in
addition to the MRL check standard requirement.
  2When adding the individual trihalomethane or haloacetic acid concentrations to calculate the TTHM or HAA5 concentrations, respectively, a
zero is used for any analytical result that is  less than the MRL concentration for that DBP, unless otherwise specified by the State.
  (c)*  * *
                                             (D*
Methodology
Amperometric Titration
Low Level Ampero-
metric Titration.
DPD Ferrous Titrimetnc
DPD Colonmetric 	
Syringaldazme (FACTS)
lodometric Electrode ....
DPD 	
Amperometric Method II
Lissamine Green
Spectrophotometric.
SM (19th or
20th ed)
4500-C D
4500-C E
4500-C F
4500-C G
4500-C H
4500-C I
4500-C O2 D
4500-C O2 E
SM
Online2
4500-C D-
00
4500-C E-
00
4500-C F-
00
4500-C G-
00
4500-C H-
00
4500-C I-OO
4500-C O2
E-00
ASTM
method
D 1253-86 (96),
03
EPA
method
327.0 Rev
1.1
Residual measured '
Free
CI2
X
X
X
X
Combined
CI2
X
X
X
Total
CI2
X
X
X
X
X
CIO2
X
X
X
  1X indicates method is approved for measuring specified disinfectant residual.  Free chlorine or total chlorine may be measured  for dem-
onstrating compliance with the chlorine MRDL and combined chlorine, or total chlorine may be measured for demonstrating compliance with the
chloramine MRDL.
  2 The Standard Methods Online version that is approved is indicated by the last two digits in the method number which is the year of approval
by the Standard Method Committee. Standard Methods Online are available at http://www.standardmethods.org.
  (d)*
  (2) Bromide. EPA Methods 300.0,
300.1, 317.0 Revision 2.0, 326.0, or
ASTM D 6581-00.
                 (3) Total Organic Carbon (TOC).
               Standard Method 5310Bor5310 B-00
               (High-Temperature Combustion

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 482
Federal  Register/Vol. 71, No. 2/Wednesday,  January 4, 2006/Rules and Regulations
 Method) or Standard Method 5310 C or
 5310 C-00 (Persulfate-Ultraviolet or
 Heated-Persulfate Oxidation Method) or
 Standard Method 5310 D or 5310 D-00
 (Wet-Oxidation Method) or EPA Method
 415.3 Revision 1.1. Inorganic carbon
 must be removed from the samples prior
 to analysis. TOC samples may not be
 filtered prior to analysis. TOC samples
 must be acidified at the time of sample
 collection to achieve pH less than or
 equal to 2 with minimal addition of the
 acid specified in the method or by the
 instrument manufacturer. Acidified
 TOC  samples must be analyzed within
 28 days.
  (4)  *  *  *
  (i) Dissolved Organic Carbon (DOC).
 Standard Method 5310Bor5310 B-00
 (High-Temperature Combustion
 Method) or Standard Method 5310 C or
 5310  C-00 (Persulfate-Ultraviolet or
 Heated-Persulfate Oxidation  Method) or
 Standard Method 5310 D or 5310 D-00
 (Wet-Oxidation Method) or EPA Method
 415.3 Revision 1.1. DOC samples must
 be filtered through the 0.45 um pore-
 diameter filter as soon as practical after
 sampling, not to exceed 48 hours. After
 filtration, DOC samples must be
 acidified to achieve pH less than or
 equal to 2 with minimal addition of the
 acid specified in the method or by the
 instrument manufacturer. Acidified
 DOC  samples must be analyzed within
 28 days of sample collection. Inorganic
 carbon must be removed from the
 samples prior to analysis. Water passed
 through the filter prior to filtration of
 the sample must serve as the filtered
 blank. This filtered blank must be
 analyzed using procedures identical to
 those used for analysis of the samples
 and must meet the following criteria:
 DOC  < 0.5 mg/L.
  (ii)  Ultraviolet Absorption at 254 nm
 (UV254). Standard Method 5910 B or
 5910  B-00  (Ultraviolet Absorption
 Method) or EPA Method 415.3 Revision
 1.1. UV absorption must be measured at
 253.7 nm (maybe rounded off to 254
 nm). Prior to analysis, UV^M  samples
 must  be filtered through a 0.45 \nm pore-
 diameter filter. The pH of UV254 samples
 may not be adjusted. Samples must be
 analyzed as soon as practical after
 sampling, not to exceed 48 hours.
 *****
  (6) Magnesium. All methods allowed
 in § 141.23(k)(l) for measuring
 magnesium.
• 12.  Section 141.132 is amended by:
• a. Redesignating paragraphs (b)(l)(iii)
through (b)(l)(v) as paragraphs (b)(l)(iv)
through (b)(l)(vi);
• b. Adding a new paragraph (b)(l)(iii);
• c. Revising newly redesignated
paragraph (b)(l)(iv); and
                          • d. Revising paragraph (b)(3)(ii).
                            The addition and revisions read as
                          follows:

                          §141.132  Monitoring requirements.
                          *****
                            (b) * *  *
                            (1)* *  *
                            (iii) Monitoring requirements for
                          source water TOC. In order to qualify for
                          reduced monitoring for TTHM and
                          HAAS under paragraph (b)(l)(ii) of this
                          section, subpart H systems not
                          monitoring under the provisions of
                          paragraph (d) of this section must take
                          monthly TOC samples every 30 days at
                          a location prior to any treatment,
                          beginning April 1, 2008 or earlier, if
                          specified by the State. In addition to
                          meeting other criteria for reduced
                          monitoring in paragraph (b)(l)(ii) of this
                          section, the source water TOC running
                          annual average must be <4.0 mg/L
                          (based on the most recent four quarters
                          of monitoring) on a continuing basis at
                          each treatment plant to reduce or
                          remain on reduced monitoring for
                          TTHM and HAAS. Once qualified for
                          reduced monitoring for TTHM and
                          HAAS under paragraph (b)(l)(ii) of this
                          section, a system may reduce source
                          water TOC monitoring to quarterly TOC
                          samples taken every 90 days at a
                          location prior to any treatment.
                            (iv) Systems on a reduced monitoring
                          schedule may remain on that reduced
                          schedule as long as the average of all
                          samples taken in the year (for systems
                          which must monitor quarterly) or the
                          result of the sample (for systems which
                          must monitor no more frequently than
                          annually) is no more than 0.060 mg/L
                          and 0.045 mg/L for TTHMs and HAAS,
                          respectively. Systems that do not meet
                          these levels must resume monitoring at
                          the frequency identified in paragraph
                          (b)(l)(i) of this section (minimum
                          monitoring frequency column) in the
                          quarter immediately following the
                          monitoring period in which the system
                          exceeds 0.060 mg/L or 0.045 mg/L for
                          TTHMs and HAAS, respectively. For
                          systems using only ground water not
                          under the direct influence of surface
                          water and serving fewer than 10,000
                          persons, if either the TTHM annual
                          average is >0.080 mg/L or the HAAS
                          annual average is >0.060 mg/L, the
                          system must go to the increased
                          monitoring identified in paragraph
                          (b)(l)(i) of this section  (sample location
                          column) in the quarter immediately
                          following the monitoring period in
                          which the system exceeds 0.080 mg/L or
                          0.060 mg/L for TTHMs or HAAS
                          respectively.
                           (3)***
                           rn ***
   (ii) Reduced monitoring.
   (A) Until March 31, 2009, systems
 required to analyze for bromate may
 reduce monitoring from monthly to
 quarterly, if the system's average source
 water bromide concentration is less than
 0.05 mg/L based on representative
 monthly bromide measurements for one
 year. The system may remain on
 reduced bromate monitoring until the
 running annual average  source water
 bromide concentration, computed
 quarterly, is equal to or greater than 0.05
 mg/L based on representative monthly
 measurements. If the running annual
 average source water bromide
 concentration is >0.05 mg/L, the system
 must resume routine monitoring
 required by paragraph (b)(3)(i) of this
 section in the following month.
   (B) Beginning April 1, 2009, systems
 may no longer use the provisions of
 paragraph (b)(3)(ii)(A) of this section to
 qualify for reduced monitoring. A
 system required to analyze for bromate
 may reduce monitoring from monthly to
 quarterly, if the system's running annual
 average bromate concentration is
 <0.0025 mg/L based on monthly
 bromate measurements under paragraph
 (b)(3)(i) of this section for the most
 recent four quarters, with samples
 analyzed using Method 317.0 Revision
 2.0, 326.0 or 321.8. If a system has
 qualified for reduced bromate
 monitoring under paragraph (b)(3)(ii)(A)
 of this section, that system may remain
 on reduced monitoring as long as the
 running annual average of quarterly
 bromate samples <0.0025 mg/L based on
 samples analyzed using Method 317.0
 Revision 2.0, 326.0, or 321.8. If the
 running annual average bromate
 concentration is >0.0025 mg/L, the
 system must resume routine monitoring
 required by paragraph (b)(3)(i) of this
 section.
§141.133  [Amended]
• 13. Section 141.133 is amended in the
last sentence of paragraph (d) by
revising the reference "§ 141.32" to read
"subpart Q of this part".
• 14. Section 141.135 is amended by
revising paragraph (a)(3)(ii) to read as
follows:

§ 141.135  Treatment technique for control
of disinfection byproduct (DBP) precursors.
  (a) *  *  *
  (3) *  *  *
  (ii) Softening that results in removing
at least 10 mg/L of magnesium hardness
(as CaCOj), measured monthly
according to § 141.131(d)(6) and
calculated quarterly as a running annual
average.

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             Federal  Register/Vol. 71, No.  2/Wednesday, January 4,  2006/Rules  and Regulations
                                                                       483
• 15. Section 141.151 is amended by
revising paragraph (d) to read as
follows:

§141.151  Purpose and applicability of this
subpart.
*****
  (d) For the purpose of this subpart,
detected means: at or above the levels
prescribed by §.141.23(a)(4) for
inorganic contaminants, at or above the
levels prescribed by § 141.24(f)(7) for
the contaminants listed in § 141.61{a), at
or above the levels prescribed by
§ 141.24(h)(18) for the contaminants
listed in § 141.61(c), at or above the
levels prescribed by § 141.131(b)(2)(iv)
for the contaminants or contaminant
groups listed in § 141.64, and at or
above the levels prescribed by
§ 141.25(c) for radioactive contaminants.
*****
• 16. Section 141.153 is amended by
revising paragraphs (d)(4)(iv)(B) and
(d)(4)(iv)(C) to read as follows:

§141.153  Content of the reports.
     * *  *
  (d)
  (4) * * *
  (iv) *  * *
  (B) When compliance with the MCL is
determined by calculating a running
annual average of all samples taken at
a monitoring location: the highest
average of any of the monitoring
locations and the range of all monitoring
locations expressed in the same units as
the MCL. For the MCLs for TTHM and
HAAS in § 141.64(b)(2), systems must
include the highest locational running
annual average for  TTHM and HAAS
and the range of individual sample
results for all monitoring locations
expressed in the same units as the MCL.
If more than one location exceeds the
TTHM or HAAS MCL, the system must
include the locational running annual
averages for all locations that exceed the
MCL.
  (C) When compliance with the MCL is
determined on a system-wide basis by
calculating a running annual average of
all samples at all monitoring locations:
the average and range of detection
expressed in the same units as the MCL.
The system is required to include
individual sample  results for the IDSE
conducted under subpart U of this part
when determining  the range of TTHM
and HAAS results to be reported in the
annual consumer confidence report for
the calendar year that the IDSE samples
were taken.
Appendix A to Subpart Q [Amended]

• 17. In Subpart Q, Appendix A is
amended as follows:
• a. In entry I.E.2. in the fifth column,
remove the endnote citation "9" and
add in its place "11";
• b. In entry I.B.ll. in the fourth
column, remove the endnote citation
"10" and add in its place "12";
• c. In entry I.E.12. in the fourth
column, remove the endnote citation
"10" and add in its place "12";
• d. In entry I.G. in the first column,
remove the endnote citation "n" and
add in its place "13";
• e. In entry I.G.I, in the third column,
remove the endnote citation "12" and
add in its place "14" and remove the
citation in the third column "141.12,
141.64(a)" and in its place add
"141.64(b)" (keeping the endnote
citation to endnote 14) and in the fifth
column remove the citation "141.30"
and add in numerical order the citations
"141.600-141.605, 141.620-141.629";
• f. In entry I.G.2. revise the entry
"141.64(a)" to read "141.64(b)" and in
the fifth column add in numerical order
the citations "141.600-141.605,
141.620-141.629".
• g. In entry I.G.7. in the fourth column,
remove the endnote citation "13" and
add in its place "15";
• h. In entry I.G.8. in the second
column, remove the endnote citation
"14" and add in its place "16";
• i. In entry II. in the first column,
remove the endnote citation "15" and
add in its place "17";
• j. In entry III. A. in the third column,
remove the endnote citation "16" and
add in its place "18";
• k. In entry III.B in the third column,
remove the endnote citation "17" and
add in its place "19";
• 1. In entry IV.E. in the first column,
remove the endnote citation "18" and
add in its place 20"; and
• m. In entry III.F in the second column,
remove the endnote citation "19" and
add in its place "21".
• 18. In Subpart Q, Appendix A, remove
endnote 14 and add in its place, to read
as follows: "14.§§ 141.64(b)(l)
141.132(a)-(b) apply until §§ 141.620-
141.630 take effect under the schedule
in§141.620(c).
• 19-20. In Subpart Q, Appendix B is
amended as follows:
• a. In entry G.77. in the third column,
remove the endnote citation "16" and
add in its place "17";
• b. In entry H. (the title) in the first
column, remove the endnote citation
"17" and add in its place "18";
• c. In entry H.80. in the third column,
remove the endnote citations "17, 18"
and add in its place "19, 20" and
remove the number "0.10/";
• d. In entry H.81. in the third column,
remove the endnote citation "20" and
add in its place "21"; and
• e. In entry H.84. in the second
column, remove the endnote citation
"21" and add in its place "22" and in
the third column remove the endnote
citation "22" and add in its place "23".
• f. Revise endnotes 18 and 19.
  The revisions read as follows:
Appendix B to Subpart Q
*****
• 18. Surface water systems and ground
water systems under the  direct
influence of surface water are regulated
under subpart H of 40 CFR 141. Subpart
H community and non-transient non-
community systems serving >10,000
must comply with subpart L DBF MCLs
and disinfectant maximum residual
disinfectant levels (MRDLs) beginning
January 1, 2002. All other community
and non-transient non-community
systems must comply with subpart L
DBF MCLs and disinfectant MRDLs
beginning January 1, 2004. Subpart H
transient non-community systems
serving >10,000 that use  chlorine
dioxide as a disinfectant or oxidant
must comply with the chlorine dioxide
MRDL beginning January 1, 2002. All
other  transient non-community systems
that use chlorine dioxide as a
disinfectant or oxidant must comply
with the chlorine dioxide MRDL
beginning January 1, 2004.
• 19. Community and non-transient
non-community systems must comply
with subpart V TTHM and HAAS MCLs
of 0.080 mg/L and 0.060  mg/L,
respectively (with compliance
calculated as a locational running
annual average) on the schedule in
§141.620.
*****
• 21. Part 141 is amended by adding
new subpart U to read as follows:

Subpart U—Initial Distribution System
Evaluations

141.600  Genera] requirements.
141.601  Standard monitoring.
141.602  System specific studies.
141.603  40/30 certification.
141.604  Very small system waivers.
141.605  Subpart V compliance monitoring
   location recommendations.

Subpart U—Initial Distribution System
Evaluations

§141.600  General requirements.
  (a) The requirements of subpart U of
this part constitute national primary
drinking water regulations. The
regulations in this subpart establish
monitoring and other requirements for
identifying subpart V compliance
monitoring locations for  determining
compliance with maximum
contaminant levels for total

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 484
Federal Register/Vol. 71, No. 2/Wednesday, January 4, 2006/Rules and Regulations
 trihalomethanes (TTHM) and haloacetic
 acids (five)(HAA5). You must use an
 Initial Distribution System Evaluation
 (IDSE) to determine locations with
 representative high TTHM and HAAS
 concentrations throughout your
 distribution system. IDSEs are used in
 conjunction with, but separate from,
 subpart L compliance monitoring, to
                           identify and select subpart V
                           compliance monitoring locations.
                             (b) Applicability. You are subject to
                           these requirements if your system is a
                           community water system that uses a
                           primary or residual disinfectant other
                           than ultraviolet light or delivers water
                           that has been treated with a primary or
                           residual disinfectant other than
                           ultraviolet light; or if your system is a
                           nontransient noncommunity water
                            system that serves at least 10,000 people
                            and uses a primary or residual
                            disinfectant other than ultraviolet light
                            or delivers water that has been treated
                            with a primary or residual disinfectant
                            other than ultraviolet light.
                              (c) Schedule. (1) You must comply
                            with the requirements of this subpart on
                            the schedule in the table in this
                            paragraph (c){l).
  If you serve this
    population
      You must submit your standard moni-
       toring plan or system specific study
       plan 1 or 40/30 certification2 to the
      State by or receive very small system
              waiver from State
  You must complete your standard
 monitoring or system specific study by
 You must submit your IDSE report to
           the State by3
     Systems that are not part of a combined distribution system and systems that serve the largest population in the combined
                                                   distribution system
(i) >1 00,000
(li) 50,000-99 999
(iii) 10,000-49999
(iv) <1 0,000 (CWS
Only).
October 1 2006
April 1 2007
October 1 2007
April 1 2008 	 	

September 30, 2008 	 	
March 31 2009 . ...
September 30, 2009 	
March 31, 2010 	

January 1 2009
July 1 2009
January 1 2010
July 1 2010.

                                Other systems that are part of a combined distribution system
 (v) Wholesale sys-
  tem or consecu-
  tive system.
     —at the same time as the system with
       the earliest compliance date in the
       combined distribution system
—at the same time as the system with
  the earliest compliance date in the
  combined distribution system.
—at the same time as the system with
  the earliest compliance date in the
  combined distribution system.
  11f, within 12 months after the date identified in this column, the State does not approve your plan or notify you that it has not yet completed its
review, you may consider the plan that you submitted as approved. You must implement that plan and you must complete standard monitoring or
a system specific study no later than the date identified in the third column.
  2 You must submit your 40/30 certification under §141.603 by the date indicated
  3 If, within three months after the date identified in this column (nine months after the date identified in this column if you must comply on the
schedule in paragraph (c)(1)(iii) of this section), the State does not approve your IDSE report or notify you that it has not yet completed its re-
view, you may consider the report that you submitted as approved and you must implement the recommended subpart V monitoring as required.
  (2) For the purpose of the schedule in
paragraph (c)(l) of this section, the State
may determine that the combined
distribution system does not include
certain consecutive systems based on
factors such as receiving water from a
wholesale system only on a'n emergency
basis or receiving only a  small
percentage and small volume of water
from a wholesale system. The  State may
also determine that the combined
distribution system does not include
certain wholesale systems based on
factors such as delivering water to a
consecutive system only on an
emergency basis or delivering  only a
small percentage and small volume of
water to a consecutive system.
  (d) You must conduct standard
monitoring that meets the requirements
in § 141.601, or a system specific study
that meets the requirements in
§ 141.602, or certify to the State that you
meet 40/30 certification criteria under
§ 141.603, or qualify for a very small
system waiver under § 141.604.
  (1) You must have taken the full
complement of routine TTHM and
HAA5  compliance samples required of
a system with your population and
source water under subpart L of this
                          part (or you must have taken the full
                          complement of reduced TTHM and
                          HAA5 compliance samples required of
                          a system with your population and
                          source water under subpart L if you
                          meet reduced monitoring criteria under
                          subpart L of this part) during the period
                          specified in § 141.603(a) to meet the 40/
                          30 certification criteria in § 141.603.
                          You must have taken TTHM and HAAS
                          samples under §§ 141.131 and 141.132
                          to be eligible for the very small system
                          waiver in § 141.604.
                            (2) If you have not taken the required
                          samples, you must conduct standard
                          monitoring that meets the requirements
                          in § 141.601, or a system specific study
                          that meets the requirements in
                          §141.602.
                            (e) You must use only the analytical
                          methods specified in § 141.131, or
                          otherwise approved by EPA for
                          monitoring under this subpart, to
                          demonstrate compliance with the
                          requirements of this subpart.
                            (f) IDSE results will not be used for
                          the purpose of determining compliance
                          withMCLs in §141.64.
                            §141.601  Standard monitoring.
                              (a) Standard monitoring plan. Your
                            standard monitoring plan must comply
                            with paragraphs (a)(l) through (a)(4) of
                            this section. You must prepare and
                            submit your standard monitoring plan
                            to the State according to the schedule in
                            §141.600(c).
                              (1) Your standard monitoring plan
                            must include a schematic of your
                            distribution system (including
                            distribution system entry points and
                            their sources, and storage facilities),
                            with notes indicating locations and
                            dates of all  projected standard
                            monitoring, and all projected subpart L
                            compliance monitoring.
                              (2) Your standard monitoring plan
                            must include justification of standard
                            monitoring location selection and a
                            summary of data you relied on to justify
                            standard monitoring location selection.
                              (3) Your standard monitoring plan
                            must specify the population served and
                            system type (subpart H or ground
                            water).
                              (4) You must retain a complete copy
                            of your standard monitoring plan
                            submitted under this paragraph (a),
                            including any State modification of your
                            standard monitoring plan, for as long as

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             Federal  Register/Vol.  71, No. 2/Wednesday,  January 4, 2006/Rules and Regulations
                                                                       485
you are required to retain your IDSE
report under paragraph (c)(4) of this
section.
  (b) Standard monitoring. (1) You must
monitor as indicated in the table in this
paragraph (b)(l). You must collect dual
sample sets at each monitoring location.
One sample in the dual sample set must
be analyzed for TTHM. The other
sample in the dual sample set must be
analyzed for HAA5. You must conduct
one monitoring period during the peak
historical month for TTHM levels or
HAAS levels or the month of warmest
water temperature. You must review
available compliance, study, or
operational data to determine the peak
historical month for TTHM or HAAS
levels or warmest water temperature.
Source water
type
Subpart H
Ground Water
Population size
category
<500 consecutive systems 	
<500 non-consecutive systems
500-3,300 consecutive sys-
tems.
500-3,300 non-consecutive
systems.
3 301-9,999 	
10 000-49,999 	
50,000-249,999 	
250 000-999 999
1 000 000-4 999 999
>5 000 000
<500 consecutive systems 	
<500 non-consecutive systems
500-9,999 	
10000-99 999 	
100000-499,999 	
>500.000 	
Monitoring periods and fre-
quency of
sampling
one (during peak historical
month) 2.
four (every 90 days)


six (every 60 days) ....




one (during peak historical
month)2.
four (every 90 days)



Distribution system monitoring locations 1
Total per
moni-
toring
period
2
2
2
2
4
8
16
24
32
40
2
2
2
6
8
12
Near
entry
points
1
1

1
3
4
6
8
1

1
1
2
Average
residence
time




1
2
4
6
8
10


1
1
2
High
TTHM
locations
1
1
1
1
2
3
5
8
10
12
1
1
1
2
3
4
High
HAAS
locations
1
1
1
2
4
6
8
10
1
1
2
3
4
  1A dual sample set (i.e., a TTHM and an HAA5 sample) must be taken at each monitoring location during each monitoring period.
  2The peak historical month is the month with the highest TTHM or HAAS levels or the warmest water temperature.
  (2) You must take samples at locations
other than the existing subpart L
monitoring locations. Monitoring
locations must be distributed
throughout the distribution system.
  (3) If the number of entry points to the
distribution system is fewer than the
specified number of entry point
monitoring locations, excess entry point
samples must be replaced equally at
high TTHM and HAAS locations. If
there is an odd extra location number,
you must take a sample at a high TTHM
location. If the number of entry points
to the distribution system is more than
the specified  number of entry  point
monitoring locations, you must take
samples at entry points to the
distribution system having the highest
annual water flows.
  (4) Your monitoring under this
paragraph (b) may not be reduced under
the provisions of § 141.29 and the State
may not reduce your monitoring using
the provisions of § 142.16(m).
  (c) IDSE report. Your IDSE report
must include the elements required in
paragraphs (c)(l) through (c)(4) of this
section. You must submit your IDSE
report to the State according to the
schedule in § 141.600(c).
  (1) Your IDSE report must include all
TTHM and HAAS analytical results
from subpart L compliance monitoring
and all standard monitoring conducted
during the period of the IDSE as
individual analytical results and LRAAs
presented in a tabular or spreadsheet
format acceptable to the State. If
changed from your standard monitoring
plan submitted under paragraph (a) of
this section, your report must also
include a schematic of your distribution
system, the population served, and
system type (subpart H or ground
water].
  (2) Your IDSE report must include an
explanation of any deviations from your
approved standard monitoring plan.
  (3) You must recommend and justify
subpart V compliance monitoring
locations and timing based on the
protocol in § 141.605.
  (4) You must retain a complete copy
of your IDSE report submitted under
this section for 10 years after the date
that you submitted your report. If the
State modifies the subpart V monitoring
requirements that you recommended in
your IDSE report or if the State approves
alternative monitoring locations, you
must keep a copy of the State's
notification on file for 10 years after the
date of the State's notification. You
must make the IDSE report and any
State notification available for review by
the State or the public.

§ 141.602 System specific studies.
  (a) System specific study plan. Your
system specific study plan must be
based on either existing monitoring
results as required under paragraph
(a)(l) of this section or modeling as
required under paragraph (a)(2) of this
section. You must prepare and submit
your system specific study plan to the
State according to the  schedule in
§141.600(c).
  (1) Existing monitoring results. You
may comply by submitting monitoring
results collected before you are required
to begin monitoring under § 141.600(c).
The monitoring results and analysis
must meet the criteria in paragraphs
(a)(l)(i) and (a)(l)(ii) of this section.
  (i) Minimum requirements. (A) TTHM
and HAAS results must be based on
samples collected and analyzed in
accordance with § 141.131. Samples
must be collected no earlier than five
years prior to the study plan submission
date.

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 486
Federal Register/Vol.  71, No. 2/Wednesday, January 4, 2006/Rules and Regulations
   (B) The monitoring locations and
 frequency must meet the conditions
 identified in this paragraph (a)(l)(i)(B).
 Each location must be sampled once
 during the peak historical month for
                          TTHM levels or HAAS levels or the
                          month of warmest water temperature for
                          every 12 months of data submitted for
                          that location. Monitoring results must
                          include all subpart L compliance
 monitoring results plus additional
 monitoring results as necessary to meet
 minimum sample requirements.
System Type
Subpart H:











Ground Water:






Population
size
category

<500
500-3,300
3,301-9,999
10,000-49,999
50,000-
249,999
250,000-
999,999
1 ,000,000-
4,999,999
> 5,000,000

<500
500-9,999
10,000-99,999
100,000-
499,999
> 500,000
Number of
monitoring
locations

3
3
6
12
24

36

48

60

3
3
12
18

24
Number of samples
TTHM

3
9
36
72
144

216

288

360

3
9
48
72

96
HAAS

3
9
36
72
144

216

288

360

3
9
48
72

96
   (ii) Reporting monitoring results. You
must report the information in this
paragraph (a)(l)(ii).
   (A) You must report previously
collected monitoring results and certify
that the reported monitoring results
include all compliance and non-
compliance results generated during the
time period beginning with the first
reported result and ending with the
most recent subpart L results.
   (B) You must certify that the samples
were representative of the entire
distribution system and that treatment,
and distribution system have not
changed significantly since the samples
were collected.
   (C) Your study monitoring plan must
include a schematic of your distribution
system (including distribution system
entry points and their sources, and
storage facilities), with notes indicating
the locations and dates of all completed
or planned system specific study
monitoring.
   (D) Your system specific study plan
must specify the population served and
system type (subpart H or ground
water).
  (E) You must retain a complete copy
of your system specific study plan
submitted under this paragraph (a)(l),
including any State modification of your
system specific study plan, for as long
as you are required to retain your IDSE
report under paragraph (b)(5) of this
section.
  (F) If you submit previously collected
data that fully meet the number of
samples required under paragraph
                          (a)(l)(i)(B) of this section and the State
                          rejects some of the data, you must either
                          conduct additional monitoring to
                          replace rejected data on a schedule the
                          State approves or conduct standard
                          monitoring under § 141.601.
                            (2) Modeling. You may comply
                          through analysis of an extended period
                          simulation hydraulic model. The
                          extended period simulation hydraulic
                          model and analysis must meet the
                          criteria in this paragraph (a) (2).
                            (i) Minimum requirements. (A) The
                          model must simulate 24 hour variation
                          in demand and show a consistently
                          repeating 24 hour pattern of residence
                          time.
                            (B) The model must represent the
                          criteria listed in paragraphs
                          (a)(2)(i)(B)(l) through (9) of this section.
                            (1) 75% of pipe volume;
                            (2) 50% of pipe length;
                            (3) All pressure zones;
                            (4) All 12-inch diameter and larger
                          pipes;
                            (5) All 8-inch and larger pipes that
                          connect pressure zones, influence zones
                          from different sources, storage facilities,
                          major demand areas, pumps, and
                          control valves, or are known or expected
                          to be significant conveyors of water;
                            (6) All 6-inch and larger pipes that
                          connect remote areas of a distribution
                          system to the main portion of the
                          system;
                            (7) All storage facilities with standard
                          operations represented in the model;
                          and
                            (8) All active pump stations with
                          controls represented in the model; and
  (9) All active control valves.
  (C) The model must be calibrated, or
have calibration plans, for the current
configuration of the distribution system
during the period of high TTHM
formation potential. All storage facilities
must be evaluated as part of the
calibration process. All required
calibration must be completed no later
than 12 months after plan submission.
  (ii) Reporting modeling. Your system
specific study plan must include the
information in this paragraph (a)(2)(ii).
  (A) Tabular or spreadsheet data
demonstrating that the model meets
requirements in paragraph (a)(2)(i)(B) of
this section.
  (B) A description of all calibration
activities undertaken, and if calibration
is complete, a graph of predicted tank
levels versus measured tank levels for
the storage facility with the highest
residence time in each pressure zone,
and a time series graph of the residence
time at the longest residence time
storage facility in the distribution
system showing the predictions for the
entire simulation period (i.e., from time
zero  until the time it takes to for the
model to reach a consistently repeating
pattern of residence time).
  (C) Model output showing
preliminary  24 hour average residence
time predictions throughout the
distribution  system.
  (D) Timing and number of samples
representative of the distribution system
planned for at least one monitoring
period of TTHM and HAAS dual  sample
monitoring at a number of locations no

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             Federal Register/Vol.  71,  No. 2/Wednesday, January 4, 2006/Rules and  Regulations
                                                                        487
less than would be required for the
system under standard monitoring in
§ 141.601 during the historical month of
high TTHM. These samples must be
taken at locations other than existing
subpart L compliance monitoring
locations.
  (E) Description of how all
requirements will be completed no later
than 12 months after you submit your
system specific study plan.
  (F) Schematic of your distribution
system (including distribution system
entry points and their sources, and
storage facilities), with notes indicating
the locations and dates of all completed
system specific study monitoring (if
calibration is complete) and all subpart
L compliance monitoring.
  (G) Population served and system
type (subpart H or ground water).
  (H) You must retain a complete copy
of your system specific study plan
submitted under this paragraph (a)(2),
including any State modification of your
system specific study plan, for as long
as you are required to retain your IDSE
report under paragraph (b)(7) of this
section.
  (iii) If you submit a model that does
not fully meet the requirements under
paragraph (a)(2) of this section, you
must correct the deficiencies and
respond to State inquiries concerning
the model. If you fail to correct
deficiencies or respond to inquiries to
the State's satisfaction, you must
conduct standard monitoring under
§141.601.
  (b) IDSE report. Your IDSE report
must include the elements required in
paragraphs (b)(l) through (b)(6) of this
section. You must submit your IDSE
report according to the schedule in
§141.600(c).
  (1) Your IDSE report must include all
TTHM and HAAS analytical results
from subpart L compliance monitoring
and all system specific study monitoring
conducted during the period of the
system specific study presented in a
tabular or spreadsheet format acceptable
to the State. If changed from your
system specific study plan submitted
under paragraph (a) of this section, your
IDSE report must also include a
schematic of your distribution system,
the population served, and system type
(subpart H or ground water).
  (2) If you used the modeling provision
under paragraph (a)(2) of this section,
you must include final information for
the elements described in paragraph
(a)(2)(ii) of this section, and a 24-hour
time series graph of residence time for
each subpart V compliance monitoring
location selected.
  (3) You must recommend and justify
subpart V compliance monitoring
locations and timing based on the
protocol in §141.605.
  (4) Your IDSE report must include an
explanation of any deviations from your
approved system specific study plan.
  (5) Your IDSE report must include the
basis (analytical and modeling results)
and justification you used to select the
recommended subpart V monitoring
locations.
  (6) You may submit your IDSE report
in lieu of your system specific study
plan on the schedule identified in
§ 141.600(c) for submission of the
system specific study plan if you believe
that you have the necessary information
by the time that the system specific
study plan is due. If you elect this
approach, your IDSE report must also
include all information required under
paragraph (a) of this section.
  (7) You must retain  a complete copy
of your IDSE report submitted under
this section for 10 years after the date
that you submitted your IDSE report. If
the State modifies the  subpart V
monitoring requirements that you
recommended in your IDSE report or if
the State approves alternative
monitoring locations, you must keep a
copy of the State's notification on file
for 10 years after the date of the State's
notification. You must make the IDSE
report and any State notification
available for review by the State or the
public.

§ 141.603  40/30 certification.
  (a) Eligibility. You are eligible for 40/
30 certification if you had no TTHM or
HAAS monitoring violations under
subpart L of this part and no individual
sample exceeded 0.040 mg/L for TTHM
or 0.030 mg/L for HAAS during an eight
consecutive calendar quarter period
beginning no earlier than the date
specified in this paragraph (a).
 If your 40/30
 certification is
     due
(1) October 1,
  2006.
(2) April 1,
  2007.
(3) October 1,
  2007.
(4) April 1,
  2008.
Then your eligibility for 40/30
  certification is based on
 eight consecutive calendar
quarters of subpart L compli-
 ance monitoring results be-
  ginning no earlier than1
January 2004.

January 2004.

January 2005.

January 2005.
  1 Unless  you  are  on reduced  monitoring
under subpart L of this part and were not re-
quired to monitor during the specified period. If
you did not monitor  during the specified pe-
riod,  you must base your eligibility on  compli-
ance samples taken during the 12 months pre-
ceding the specified period.
  (b) 40/30 certification. (1) You must
certify to your State that every
individual compliance sample taken
under subpart L of this part during the
periods specified in paragraph (a) of this
section were <0.040 mg/L for TTHM and
<0.030 mg/L for HAAS, and that you
have not had any TTHM or HAAS
monitoring violations during the period
specified in paragraph (a) of this
section.
  (2) The State may require you to
submit compliance monitoring results,
distribution system schematics,  and/or
recommended subpart V compliance
monitoring locations in addition to your
certification. If you fail to submit the
requested information, the State may
require standard monitoring under
§ 141.601 or a system specific study
under §141.602.
  (3) The State may still require
standard monitoring under § 141.601  or
a system specific study under § 141.602
even if you meet the criteria in
paragraph (a) of this section.
  (4) You must retain a complete copy
of your certification submitted under
this section for 10 years after the date
that you submitted your certification.
You must make the certification, all data
upon which the certification is based,
and any State notification available for
review by the State or the public.

§ 141.604  Very small system waivers.
  (a) If you serve fewer than 500 people
and you have taken TTHM and HAAS
samples under subpart L of this  part,
you are not required to comply with this
subpart unless the State notifies you
that you must conduct standard
monitoring under § 141.601 or a system
specific study under § 141.602.
  (b) If you have not taken TTHM and
HAAS samples under subpart L  of this
part or if the State notifies you that you
must comply with this subpart, you
must conduct standard monitoring
under § 141.601 or a system specific
study under §141.602.

§ 141.605  Subpart V compliance
monitoring location recommendations.
  (a) Your IDSE report must include
your recommendations and justification
for where and during what month(s)
TTHM and HAAS monitoring for
subpart V of this part should be
conducted. You must base your
recommendations on the criteria in
paragraphs (b) through (e) of this
section.
  (b) You must select the number of
monitoring locations specified in the
table in this paragraph (b). You will use
these recommended locations as subpart
V routine compliance monitoring
locations, unless State requires different

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Federal Register/Vol. 71, No.  2/Wednesday, January  4,  2006/Rules  and Regulations
 or additional locations. You should
 distribute locations throughout the
                          distribution system to the extent
                          possible.
Source water type
Subpart H.












Ground water-







Population
size category

<500
500-3,300
3 301 9 999
10,000-
49,999
50,000-
249,999
250,000-
999,999
1 ,000,000-
4,999,999
>5,000,000

<500
500-9,999
10,000-
99,999
100,000-
499,999
>500,000
Monitoring
frequency 1

oer vear
r«vji JT^*«'
per quarter
per quarter
per quarter

per quarter

per quarter

per quarter

per quarter

per year
per year
per quarter

per quarter

per quarter
Distribution system monitoring location
Total per
monitoring
period 2

2
2
2
4

8

12

16

20

2
2
4

6

8
Highest
TTHM loca-
tions

1
1
1
2

3

5

6

8

1
1
2

3

3
Highest
HAAS loca-
tions

1
1
1
1

3

4

6

7

1
1
1

2

3
Existing
subpart L
compliance
locations




1

2

3

4

5



1

1

2
  1 All systems must monitor during month of highest DBP concentrations
  2 Systems on quarterly monitoring must take dual sample sets every 90 days at each monitoring location, except for subpart H systems serving
500-3,300. Systems on annual monitoring and subpart H systems serving 500-3,300 are required to take individual TTHM and HAAS samples
(instead of a dual sample set) at the locations with the highest TTHM and  HAAS concentrations, respectively. Only one location with a dual sam-
ple set per monitoring period is needed if highest TTHM and HAAS concentrations occur at the same location, and month, if monitored annually).
   (c) You must recommend subpart V
compliance monitoring locations based
on standard monitoring results, system
specific study results, and subpart L
compliance monitoring results. You
must follow the protocol in paragraphs
(c)(l) through (c)(8) of this section. If
required to monitor at more than eight
locations, you must repeat the protocol
as necessary. If you do not have existing
subpart L compliance monitoring results
or if you do not have enough existing
subpart L compliance monitoring
results, you must repeat the protocol,
skipping the provisions of paragraphs
(c)(3) and (c)(7) of this section as
necessary, until you have identified the
required total number of monitoring
locations.
  (1) Location with the highest TTHM
LRAA not previously selected as a
subpart V monitoring  location.
  (2) Location with the highest HAAS
LRAA not previously selected as a
subpart V monitoring  location.
  (3) Existing subpart L average
residence time compliance monitoring
location (maximum residence time
compliance monitoring location for
ground water systems) with the highest
HAAS LRAA not previously selected as
a subpart V monitoring location.
                            (4) Location with the highest TTHM
                          LRAA not previously selected as a
                          subpart V monitoring location.
                            (5) Location with the highest TTHM
                          LRAA not previously selected as a
                          subpart V monitoring location.
                            (6) Location with the highest HAAS
                          LRAA not previously selected as a
                          subpart V monitoring location.
                            (7) Existing subpart L average
                          residence time compliance monitoring
                          location (maximum residence time
                          compliance monitoring location for
                          ground water systems) with the highest
                          TTHM LRAA not previously selected as
                          a subpart V monitoring location.
                            (8) Location with the highest HAAS
                          LRAA not previously selected as a
                          subpart V monitoring location.
                            (d) You may recommend locations
                          other than those specified in paragraph
                          (c) of this section if you include a
                          rationale for selecting other locations. If
                          the State approves  the alternate
                          locations, you must monitor at these
                          locations to determine compliance
                          under subpart V of this part.
                            (e) Your recommended schedule must
                          include subpart V monitoring during the
                          peak historical month for TTHM and
                          HAAS concentration, unless the State
                          approves another month. Once you have
                          identified the peak historical month,
                          and if you are required to conduct
routine monitoring at least quarterly,
you must schedule subpart V
compliance monitoring at a regular
frequency of every 90 days or fewer.
• 20. Part 141 is amended by adding
new subpart V to read as follows:

Subpart V—Stage 2 Disinfection
Byproducts Requirements

141.620  General requirements.
141.621  Routine monitoring.
141.622  Subpart V monitoring plan.
141.623  Reduced monitoring.
141.624  Additional requirements for
    consecutive systems.
141.625  Conditions requiring increased
    monitoring.
141.626  Operational evaluation levels.
141.627  Requirements for remaining on
    reduced TTHM and HAAS monitoring
    based on subpart L results.
141.628  Requirements for remaining on
    increased TTHM and HAAS monitoring
    based on subpart L results.
141.629  Reporting and recordkeeping
    requirements.

Subpart V—Stage 2 Disinfection
Byproducts Requirements

§141.620 General requirements.
  (a) General. The requirements of
subpart V of this part constitute national
primary drinking water regulations. The
regulations in this subpart establish
monitoring and other requirements for

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             Federal Register/Vol.  71, No. 2/Wednesday, January 4, 2006/Rules and Regulations
                                                                        489
achieving compliance with maximum
contaminant levels based on locational
running annual averages (LRAA) for
total trihalomethanes (TTHM) and
haloacetic acids (five)(HAA5), and for
achieving compliance with maximum
residual disinfectant residuals for
chlorine and chloramine for certain
consecutive systems.
  (b) Applicability. You are subject to
these requirements if your system is a
community water system or a
nontransient noncommunity water
system that uses a primary or residual
disinfectant other than ultraviolet light
or delivers water that has been treated
with a primary or residual disinfectant
other than ultraviolet light.
  (c) Schedule. You must comply with
the requirements in this subpart on the
schedule in the following table based on
your system type.
            If you are this type of system
                       You must comply with subpart V monitoring by.
     Systems that are not part of a combined distribution system and systems that serve the largest population in the combined
                                                  distribution system
(1) System serving > 100,000	
(2) System serving 50,000-99,999
(3) System serving 10,000-49,999
(4) System serving > 10,000 	
        April 1, 2012.
        October 1, 2012.
        October 1, 2013.
        October 1, 2013 if no Cryptosporidium monitoring is required under §141.701(a)(4)
          or
        October 1, 2014 if Cryptosporidium monitoring is required under § 141.701(a)(4) or
                               Other systems that are part of a combined distribution system
(5) Consecutive system or wholesale system
        —at the same time as the system with the earliest compliance date in the combined
          distribution system.
  1 The State may grant up to an additional 24 months for compliance with MCLs and operational evaluaton levels if you require capital improve-
ments to comply with an MCL.
  (6) Your monitoring frequency is
specified in § 141.621(a)(2).
  (i) If you are required to conduct
quarterly monitoring, you must begin
monitoring in the first full calendar
quarter that includes the compliance
date in the table in this paragraph  (c).
  (ii) If you are required to conduct
monitoring at a frequency that is less
than quarterly, you must begin
monitoring in the calendar month
recommended in the IDSE report
prepared under § 141.601 or § 141.602
or the calendar month identified in the
subpart V monitoring plan developed
under § 141.622 no later than  12 months
after the compliance date in this table.
  (7) If you are required  to conduct
quarterly monitoring, you must make
compliance calculations at the end of
the fourth calendar quarter that follows
the compliance date and at  the end of
each subsequent quarter (or earlier if the
LRAA calculated based on fewer than
four quarters of data would cause the
MCL to be exceeded regardless of the
monitoring results of subsequent
quarters). If you are required to conduct
monitoring at a frequency that is less
than quarterly, you must make
compliance calculations beginning with
the first compliance sample taken  after
the compliance date.
  (8) For the purpose of the schedule in
this paragraph (c), the State may
determine that the combined
distribution system does not include
certain consecutive systems based on
factors such as receiving water from a
wholesale system only on an emergency
basis or receiving only a small
percentage and small volume of water
from a wholesale system. The State may
also determine that the combined
distribution system does not include
certain wholesale systems based on
factors such as delivering water to a
consecutive system only on an
emergency basis or delivering only a
small percentage and small volume of
water to a consecutive system.
  (d) Monitoring and compliance. (1)
Systems required to monitor quarterly.
To comply with subpart V  MCLs in
§ 141.64(b)(2), you must calculate
LRAAs for TTHM and HAA5 using
monitoring results collected under this
subpart and determine that each LRAA
does not exceed the MCL. If you fail to
complete four consecutive quarters of
monitoring, you must calculate
compliance with the MCL based on the
average of the available data from the
most recent four quarters. If you take
more than one sample per quarter at a
monitoring location, you must average
all samples taken in the quarter at that
location to determine a quarterly
average to be  used in the LRAA
calculation.
  (2) Systems required to monitor yearly
or less frequently. To determine
compliance with subpart V MCLs in
§ 141.64(b)(2), you must determine that
each sample taken is less than the MCL.
If any sample exceeds the MCL, you
must comply with the requirements of
§ 141.625. If no sample exceeds the
MCL, the sample result for each
monitoring location is considered the
LRAA for that monitoring location.
  (e) Violation. You are in violation of
the monitoring requirements for each
quarter that a monitoring result would
be used in calculating an LRAA if you
fail to monitor.

§141.621   Routine monitoring.
  [a] Monitoring. (1) If you submitted an
IDSE report, you must begin monitoring
at the locations and months you have
recommended in your IDSE report
submitted under § 141.605 following the
schedule in § 141.620(c), unless the
State requires other locations or
additional locations after its review. If
you submitted a 40/30 certification
under § 141.603 or you qualified for a
very small system waiver under
§ 141.604 or you are a nontransient
noncommunity water system serving
<10,000,  you must monitor at the
location(s) and dates identified in your
monitoring plan in § 141.132(f), updated
as required by § 141.622.
  (2) You must monitor at no fewer than
the number of locations identified in
this paragraph (a)(2).

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Federal Register/Vol.  71, No.  2/Wednesday,  January 4, 2006/Rules and Regulations
Source water type
Subpart H:







Ground Water:




Population size category
<500 	
500-3 300
3301-9,999 ..
10000-49,999
50000-249,999 	
250 000-999,999
1000,000-4,999999 	
> 5000,000 	
<500
500-9 999 ....
10000-99,999
100000-499,999 	
> 500,000 	
Monitoring Frequency1
per year 	
per quarter
per quarter
per quarter . ..
per quarter 	
per quarter
per quarter
per quarter 	
per year
per year
per quarter
per quarter
oer Quarter 	
Distribution
system moni-
toring location
total per moni-
toring period2
2
2
2
4
8
12
16
20
2
2
4
6
8
  1 All systems must monitor during month of highest DBF concentrations.
  2 Systems on quarterly monitoring must take dual sample sets every 90 days at each monitoring location, except for subpart H systems serving
500-3,300. Systems on annual monitoring and subpart H systems serving 500-3,300 are required to take individual TTHM and HAA5 samples
(instead of a dual sample set) at the locations with the highest TTHM and HAAS concentrations, respectively. Only one location with a dual sam-
ple set per monitoring period is needed if highest TTHM and HAAS concentrations occur at the same location (and month, if monitored annually).
   (3) If you are an undisinfected system
that begins using a disinfectant other
than UV light after the dates in subpart
U of this part for complying with the
Initial Distribution System Evaluation
requirements, you must consult with the
State to identify compliance monitoring
locations for this subpart. You must
then develop a monitoring plan under
§ 141.622 that includes those
monitoring locations.
   (b) Analytical methods. You must use
an approved method listed in § 141.131
for TTHM and HAA5 analyses in this
subpart. Analyses must be conducted by
laboratories that have received
certification by EPA or the State as
specified in § 141.131.

§ 141.622  Subpart V monitoring plan.
   (a)(l) You must develop and
implement a monitoring plan to be kept
on file for State and public review. The
monitoring plan must contain  the
elements in paragraphs (a)(l)(i) through
(a)(l)(iv) of this section and be complete
no later than the date you conduct your
initial  monitoring under this subpart.
   (i) Monitoring locations;
  (ii) Monitoring dates;
  (iii) Compliance calculation
procedures; and
  (iv) Monitoring plans for any other
systems in the combined distribution
system if the State has reduced
monitoring requirements under the
State authority in § 142.16(m).
  (2) If you were not required to submit
an IDSE report under either § 141.601 or
                          § 141.602, and you do not have
                          sufficient subpart L monitoring
                          locations to identify the required
                          number of subpart V compliance
                          monitoring locations indicated in
                          § 141.605(b), you must identify
                          additional locations by alternating
                          selection of locations representing high
                          TTHM levels and high HAAS levels
                          until the required number of
                          compliance monitoring locations have
                          been identified. You must also provide
                          the rationale for identifying the
                          locations as having high levels of TTHM
                          or HAAS. If you have more subpart L
                          monitoring locations than required for
                          subpart V compliance  monitoring in
                          § 141.605(b), you must identify which
                          locations you will use for subpart V
                          compliance monitoring by alternating
                          selection of locations representing high
                          TTHM levels and high HAAS levels
                          until the required number of subpart V
                          compliance monitoring locations have
                          been identified.
                            (b) If you are a subpart H system
                          serving > 3,300 people, you must submit
                          a copy of your monitoring plan to the
                          State prior to the date you conduct your
                          initial monitoring under this subpart,
                          unless your IDSE report submitted
                          under subpart U of this part contains all
                          the information required by this section.
                            (c) You may revise your monitoring
                          plan to reflect changes in  treatment,
                          distribution system operations and
                          layout (including new service areas), or
                          other factors that may affect TTHM  or
HAAS formation, or for State-approved
reasons, after consultation with the
State regarding the need for changes and
the appropriateness of changes. If you
change monitoring locations, you must
replace existing compliance monitoring
locations with the lowest LRAA with
new locations that reflect the current
distribution system locations with
expected high TTHM or HAAS levels.
The State may also require
modifications in your monitoring plan.
If you are a subpart H system serving >
3,300 people, you must submit a copy
of your modified  monitoring plan to the
State prior to the  date you are required
to comply with the revised  monitoring
plan.

§141.623  Reduced monitoring.

  (a) You may reduce monitoring to the
level specified in the table in this
paragraph (a) any time the LRAA is
<0.040 mg/L for TTHM and <0.030
mg/L for HAAS at all monitoring
locations. You may only use data
collected under the provisions of this
subpart or subpart L of this  part to
qualify for reduced monitoring.  In
addition, the source water annual
average TOC level, before any treatment,
must be <4.0 mg/L at each treatment
plant treating surface water or ground
water under the direct influence of
surface water, based on monitoring
conducted under  either
§ 141.132(b)(l)(iii) or § 141.132(d).

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             Federal Register/Vol. 71, No.  2/Wednesday,  January 4, 2006/Rules and  Regulations
                                                                       491
Source water type
Subpart H'







Ground Water:





Population
size category
<500
500-3 300
3301-9999
1 0 000-49 999
50 000-
249,999
250,000-
999,999
1 000,000-
4,999,999
> 5,000,000
<500
500-9 999
1 0 000-99 999
100 000-
499,999
> 500,000

Monitoring
frequency 1

per year
per year 	
per quarter
per quarter
per quarter 	 	
per quarter 	 	
per quarter 	 	
every third year 	
per year 	 	
oer vear
per quarter
per quarter 	

Distribution system monitoring location per moni-
toring period
monitoring may not be reduced
1 TTHM and 1 HAAS sample' one at the location
and during the quarter with the highest TTHM sin-
gle measurement, one at the location and during
the quarter with the highest HAA5 single meas-
urement; 1 dual sample set per year if the highest
TTHM and HAA5 measurements occurred at the
same location and quarter.
2 dual sample sets' one at the location and during
the quarter with the highest TTHM single meas-
urement, one at the location and during the quar-
ter with the highest HAAS single measurement.
2 dual sample sets at the locations with the highest
TTHM and highest HAA5 LRAAs.
4 dual sample sets — at the locations with the two
highest TTHM and two highest HAAS LRAAs.
6 dual sample sets — at the locations with the three
highest TTHM and three highest HAA5 LRAAs.
8 dual sample sets — at the locations with the four
highest TTHM and four highest HAA5 LRAAs.
10 dual sample sets — at the locations with the five
highest TTHM and five highest HAAS LRAAs.
1 TTHM and 1 HAAS sample: one at the location
and during the quarter with the highest TTHM sin-
gle measurement, one at the location and during
the quarter with the highest HAA5 single meas-
urement; 1 dual sample set per year if the highest
TTHM and HAAS measurements occurred at the
same location and quarter.
1 TTHM and 1 HAAS sample' one at the location
and during the quarter with the highest TTHM sin-
gle measurement, one at the location and during
the quarter with the highest HAAS single meas-
urement; 1 dual sample set per year if the highest
TTHM and HAAS measurements occurred at the
same location and quarter.
2 dual sample sets' one at the location and during
the quarter with the highest TTHM single meas-
urement, one at the location and during the quar-
ter with the highest HAAS single measurement.
2 dual sample sets' at the locations with the highest
TTHM and highest HAA5 LRAAs.
4 dual sample sets at the locations with the two
highest TTHM and two highest HAAS LRAAs.
  1 Systems on quarterly monitoring must take dual sample sets every 90 days.
  (b) You may remain on reduced
monitoring as long as the TTHM LRAA
<0.040 mg/L and the HAAS LRAA
<0.030 mg/L at each monitoring location
(for systems with quarterly reduced
monitoring) or each TTHM sample
<0.060 mg/L and each HAA5 sample
<0.045 mg/L (for systems with annual or
less frequent monitoring). In addition,
the source water annual average TOG
level, before any treatment, must be <4.0
mg/L at each treatment plant treating
surface water or ground water under the
direct influence of surface water, based
on monitoring conducted under either
§ 141.132(b)(l)(iii) or § 141.132(d).
  (c) If the LRAA based on quarterly
monitoring at any monitoring location
exceeds either 0.040 mg/L for TTHM or
0.030 mg/L for HAAS or if the annual
(or less frequent) sample at any location
exceeds either 0.060 mg/L for TTHM or
0.045 mg/L for HAAS, or if the source
water annual average TOC level, before
any treatment, >4.0 mg/L at any
treatment plant treating surface water or
ground water under the direct influence
of surface water, you must resume
routine monitoring under § 141.621 or
begin increased monitoring if § 141.625
applies.
  (d) The State may return your system
to routine monitoring at the State's
discretion.

§ 141.624 Additional requirements for
consecutive systems.
  If you are a consecutive system that
does not add a disinfectant but delivers
water that has been treated with a
primary or residual disinfectant other
than ultraviolet light, you must comply
with analytical and monitoring
requirements for chlorine and
chloramines in § 141.131 (c) and
§ 141.132(c)(l) and the compliance
requirements in § 141.133(c)(l)
beginning April 1, 2009, unless required
earlier by the State, and report
monitoring results under § 141.134(c).

§ 141.625   Conditions requiring increased
monitoring.

  (a) If you are required to monitor at
a particular location annually or less
frequently than annually under
§ 141.621 or § 141.623, you must
increase monitoring to dual sample sets
once per quarter (taken every 90 days)
at all locations if a TTHM sample is
>0.080 mg/L or a HAAS sample is
>0.060 mg/L at any location.

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 492
Federal Register/Vol.  71, No. 2/Wednesday, January 4, 2006/Rules and Regulations
   (b) You are in violation of the MCL
 when the LRAA exceeds the subpart V
 MCLs in § 141.64(b)(2), calculated based
 on four consecutive quarters of
 monitoring (or the LRAA calculated
 based on fewer than four quarters of
 data if the MCL would be exceeded
 regardless of the monitoring results of
 subsequent quarters). You are in
 violation of the monitoring
 requirements for each quarter that a
 monitoring result would be used in
 calculating an LRAA if you fail to
 monitor.
   (c)  You may return to routine
 monitoring once you have conducted
 increased monitoring for at least four
 consecutive quarters and the LRAA for
 every monitoring location  is <0.060
 mg/L for TTHM and <0.045 mg/L for
 HAA5.

 § 141.626  Operational evaluation levels.
   (a)  You have exceeded the operational
 evaluation level at any monitoring
 location where the sum of the two
 previous quarters' TTHM results plus
 twice the current quarter's TTHM result,
 divided by 4 to determine an average,
 exceeds 0.080 mg/L, or where the sum
 of the two previous quarters' HAA5
 results plus twice the current quarter's
 HAA5 result, divided by 4 to determine
 an average, exceeds 0.060 mg/L.
   (b)(l) If you exceed the operational
 evaluation level, you must conduct an
 operational evaluation and submit a
 written report of the evaluation to the
 State  no later than 90 days after being
 notified of the analytical result that
 causes you to exceed the operational
 evaluation level. The written report
 must  be made available to the public
 upon request.
   (2)  Your operational evaluation must
 include an examination of system
 treatment and distribution operational
 practices, including storage tank
 operations, excess storage capacity,
 distribution system flushing, changes in
 sources or source water quality, and
 treatment changes or problems that may
 contribute to TTHM and HAAS
 formation and what steps could be
 considered to minimize future
 exceedences.
   (i) You may request and the State may
 allow you to limit the scope of your
 evaluation if you are able to identify the
 cause of the operational evaluation level
 exceedance.
   (ii)  Your request to limit the scope of
the evaluation does not extend the
schedule in paragraph (b)(l) of this
section for submitting the written
report. The State must approve this
limited scope of evaluation in writing
and you must keep that approval with
the completed report.
                          § 141.627  Requirements for remaining on
                          reduced TTHM and HAAS monitoring based
                          on subpart L results.
                            You may remain on reduced
                          monitoring after the dates identified in
                          § 141.620(c) for compliance with this
                          subpart only if you qualify for a 40/30
                          certification under § 141.603 or have
                          received a very small system waiver
                          under § 141.604, plus you meet the
                          reduced monitoring criteria in
                          § 141.623(a), and you do not change or
                          add monitoring locations from those
                          used for compliance monitoring under
                          subpart L of this part.  If your monitoring
                          locations under this subpart differ from
                          your monitoring locations under subpart
                          L of this part, you may not remain on
                          reduced monitoring after the dates
                          identified in § 141.620(c) for compliance
                          with this subpart.

                          § 141.628  Requirements for remaining on
                          increased TTHM and HAAS monitoring
                          based on subpart L results.
                           If you were on increased monitoring
                          under § 141.132(b)(l), you must remain
                          on increased monitoring until you
                          qualify for a return to routine
                          monitoring under § 141.625(c). You
                          must conduct increased monitoring
                          under § 141.625 at the monitoring
                          locations in the monitoring plan
                          developed under § 141.622 beginning at
                          the date identified in § 141.620(c) for
                          compliance with this subpart and
                          remain on increased monitoring until
                          you qualify for a return to routine
                          monitoring under § 141.625(c).

                          § 141.629  Reporting and recordkeeping
                          requirements.
                           (a)  Reporting. (1) You must report the
                          following information for each
                          monitoring location to the State within
                          10 days of the end  of any quarter in
                          which monitoring is required:
                           (i) Number of samples taken during
                          the last quarter.
                           (ii) Date and results of each sample
                          taken during the last quarter.
                           (iii) Arithmetic average of quarterly
                          results for the last four quarters for each
                          monitoring location (LRAA), beginning
                          at the end of the fourth calendar quarter
                          that follows the compliance date and at
                          the end of each subsequent quarter. If
                          the LRAA calculated based on fewer
                          than four quarters of data would cause
                          the MCL to be exceeded regardless of
                          the monitoring results of subsequent
                          quarters, you must report this
                          information to the State as part of the
                          first report due following the
                          compliance date or anytime thereafter
                          that this determination is made. If you
                          are required to conduct monitoring at a
                          frequency that is less than quarterly,
                          you must make compliance calculations
 beginning with the first compliance
 sample taken after the compliance date,
 unless you are required to conduct
 increased monitoring under § 141.625.
   (iv) Whether, based on § 141.64(b)(2)
 and this subpart, the MCL was violated
 at any monitoring location.
   (v) Any operational evaluation levels
 that were exceeded during the quarter
 and, if so, the location and date, and the
 calculated TTHM and HAAS levels.
   (2) If you are a subpart H system
 seeking to qualify for or remain on
 reduced TTHM/HAA5 monitoring, you
 must report the following source water
 TOC information for each treatment
 plant that treats  surface water or ground
 water under the  direct influence of
 surface water to  the State within  10 days
 of the end of any quarter in which
 monitoring is required:
   (i) The number of source water TOC
• samples taken each month during last
 quarter.
   (ii) The date and result of each sample
 taken during last quarter.
   (iii) The quarterly average of monthly
 samples taken during last quarter or the
 result of the quarterly sample.
   (iv) The running annual average
 (RAA) of quarterly averages from the
 past four quarters.
   (v) Whether the RAA exceeded 4.0
 mg/L.
   (3) The State may choose to perform
 calculations and determine whether the
 MCL was exceeded or the system is
 eligible for reduced monitoring in lieu
 of having the system report that
 information
  (b) Recordkeeping. You must retain
 any subpart V monitoring plans and
 your subpart V monitoring results as
 required by § 141.33.

 PART 142—NATIONAL PRIMARY
 DRINKING WATER REGULATIONS
 IMPLEMENTATION

• 21. The authority citation for part 142
continues to read as follows:
  Authority: 42 tJ.S.C. 300f, 300g-l, 300g-2,
 300g-3, 300g-4, 300g-5, 300g-6, 300J-4,
 300J-9, and300j-ll.
• 22. Section 142.14 is amended by
adding paragraph (a)(8) to read as
follows:

§ 142.14  Records kept by States.
  (a) *   *  *
  (8) Any decisions made pursuant to
the provisions of 40 CFR part 141,
subparts U and V of this part.
  (i) IDSE monitoring plans, plus any
modifications required by the State,
must be kept until replaced by approved
IDSE reports.
  (ii) IDSE reports and 40/30
certifications, plus any modifications

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             Federal  Register/Vol. 71, No. 2/Wednesday,  January 4, 2006/Rules and  Regulations
                                                                       493
required by the State, must be kept until
replaced or revised in their entirety.
  (iii) Operational evaluations
submitted by a system must be kept for
10 years following submission.
• 23. Section 142.16 is amended by
adding paragraph (m) to read as follows:

§ 142.16 Special primacy requirements.
  (m) Requirements for States to adopt
40 CFR part 141, subparts U and V. In
addition to the general primacy
requirements elsewhere in this part,
including the requirements that State
regulations be at least as stringent as
federal requirements, an application for
approval of a State program revision
that adopts 40 CFR part 141, subparts U
and V, must contain a description of
how the State will implement a
procedure for addressing modification
of wholesale system and consecutive
system monitoring on a case-by-case
basis for part 141 subpart V outside the
provisions of § 141.29 of this chapter, if
the State elects to use such an authority.
The procedure must ensure that all
systems have at least one compliance
monitoring location.
*****

[FR Doc. 06-3 Filed 1-3-06; 8:45 am]
BILLING CODE 6560-50-P

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