vvEPA
Proposed Long Term 2
Enhanced Surface Water Treatment Rule
EPA is proposing a National Primary Drinking Water Regulation that requires the use of
treatment techniques, along with monitoring, reporting, and public notification requirements, for
all public water systems (PWSs) that use surface water sources, including groundwater under the
direct influence of surface water The purposes of the Long-Term 2 Enhanced Surface Water
Treatment Rule (LT2ESWTR) are to improve control of microbial pathogens, including
specifically the protozoan Cryptosporidium, in drinking water and to address risk trade-offs with
control of disinfection byproducts  The proposed rule will be published in the Federal Register
in the summer of 2003

EPA believes that implementation of the LT2ESWTR will significantly reduce levels of
Cryptosporidium in finished drinking water The intent of the LT2ESWTR is to supplement
existing microbial treatment requirements for systems where additional public health protection
is needed In addition to concern with Cryptosporidium, the LT2ESWTR is intended to ensure
that systems maintain adequate protection against microbial pathogens as they take steps to
reduce formation of disinfection byproducts (DBFs)  The LT2ESWTR will build upon the
treatment technique requirements of the Interim Enhanced Surface Water Treatment Rule
(1ESWTR) and the Long Term 1 Enhanced Surface Water Treatment Rule (LT1ESWTR).

Which public water systems  must comply with the rule?

The LT2ESWTR will apply to all public water systems that use surface water or ground water
under the direct influence of surface water (GWUDI). The rule is expected to apply to more than
14,000 systems that serve nearly 180 million Americans.

What does the rule require?

The LT2ESWTR consists of monitoring and Cryptosporidium treatment requirements for filtered
and unfiltered systems In addition, the rule has requirements pertaining to microbial inactivation
benchmarking and uncovered finished water reservoirs. These are described below.

1) Monitoring Requirements for Filtered Systems
       Monitoring requirements for large and small filtered systems and the schedule for each
       stage of monitoring are shown in the table below

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LT2ESWTR Monitoring Requirements for Filtered Systems
Public water
system size
Monitoring begins
Monitoring
duration
Monitoring parameters and sample
frequency requirements
Cry piosporidium
E. coil
Large systems
(serving 10,000 or
more people)
6 months after
promulgation of
LT2ESWTR
2 years’
minimum
sample/month 3
minimum
I sample/month 4
Small systems
(serving fewer than
10,000 people)
30 months (2 V 2 years) after
promulgation of
LT2ESWTR
1 year’
see below*
I sample every 2
weeks
‘Possible additional monitoring requirement for Crypt osporidium
if small systems exceed E colt trigger levels, then
Small systems
(serving fewer than
10,000 people)’ 2
48 months (4 years) after
promulgation of
LT2ESWTR
1 year
2 samples/month
N/A
PWSs may be eligible to use historical data in lieu of new monitoring if specified quality control criteria arc met
2 SmaIl systems are required to monitor for Cryplosporidiurn if their mean E co/i concentration exceeds 10/100 mL for systems
using takes/reservoir sources or exceeds 50/100 mL for systems using flowing stream sources
3 PWSs may collect more than I sample per month if sampling is evenly spaced over the monitoring period
4 PWSs must also report source water turbidity levels with E colt measurements
N/A = Not applicable No monitoring required
• Analyses must be conducted by approved laboratories using approved analytical
methods; see proposal for information regarding sampling location and minimum sample
volume.
• EPA wIll evaluate large system monitoring results to determine if indicator levels other
than those specified above should trigger Cryptosporidium monitoring by small filtered
systems.
• Systems must conduct a second round of monitoring beginning six years after initial bin
assignment
2) Additional Cryptosporidium Treatment Requirements for Filtered Systems
• Filtered systems will be classified in one of four possible risk categories (bins) based on
monitoring results. Additional Cryptosporidium treatment requirements, beyond the
requirements of the IESWTR or LTIESWTR, are a function of bin classification.

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Bin Classifications for Filtered Systems
Bin
Classification
Mean Cryptosporiduim Concentratio&
Additional treatment required for
conventional plants beyond IESWTRJLTI 2
Bin I
Crypto <0 075 oocystslL
No additional treatment
Bin 2
0 075 oocystsfL < Crypto < 1 0 oocystsfL
I log
Bin 3
1 0 oocysts/L < Cryplo < 3 0 oocystslL
2 0 log (with I log disinfection)
Bin 4
3 0 oocystsfL< Crypto
2 5 log (with I log disinfection)
‘Bin classification based on highest 12-month running annual average, or 2-year mean if at least 48 samples are analyzed,
average must be calculated using total oocysts Count, unadjusted for recovery (Method 1622 or 1623)
2 See proposal for information on treatment requirements for plant types other than conventional
3) Monitoring Requirements for Unfiltered Systems
Large unfiltered systems (serving at least 1 0,000 people) must conduct Cryptosporidium
sampling on the same schedule and at the same frequency as large filtered systems
• All small unfiltered systems must conduct Cryptosporidium sampling on the same
schedule and at the same frequency as small filtered systems. Small unfiltered systems
do not sample for E co/i and cannot be exempted from Cryptosporidium monitoring
through an indicator screening analysis.
4) Cryptosporidium Treatment Requirements for Unfiltered Systems
• Unfiltered systems must provide at least 2 log inactivation of Cryptosporidium, in
addition to their current requirements for 3 log inactivation of Giardia and 4 log
inactivation of viruses.
• Unfiltered systems must provide 3 log inactivation of Cryptosporidium if source water
monitoring demonstrates that their mean Cryptosporidium level is above 0.01 oocystsfL.
• Unfiltered systems must comply with their total inactivation requirements using a
minimum of 2 disinfectants.
5) Options for Meeting LT2ESWTR Crypiosporidium Treatment Requirements
• Systems must comply with Cryptosporidium treatment requirements under the
LT2ESWTR by selecting one or more options from the microbial toolbox’.
• The microbial toolbox includes the following components: watershed control program,
presedimentation with coagulation, bank filtration, intake relocation/management,
ultraviolet light, ozone, chlorine dioxide, individual and combined filter performance,
slow sand filters, membranes, bag/cartridge filters, and demonstration of performance.
• Systems must meet specified design and implementation criteria to receive presumptive
Cryptosporidium treatment credits for microbial toolbox components. See proposal for
details.

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6) Microbial Inactivation Benchmark:ng
• Ceratin systems will be required to develop a profile that characterizes current levels of
virus and Giardia inactivation throughout the plant over the course of one year
• Systems that have valid operational data from profiling conducted under the IESWTR or
LTI ES WTR are not required to collect additional data.
• Systems considering making a significant change to their disinfection practice must
calculate a baseline or benchmark of disinfection (microbial inactivation) and consult
with the State regarding the impact of the proposed change on the current disinfection
benchmark.
7) Uncovered Finished Water Reservoirs
• Systems with uncovered finished water reservoirs must cover the finished water
reservoirs or
• Systems must treat the reservoir discharge to the distribution system to achieve at least 4
log virus inactivation unless
• The State determines that existing risk mitigation is adequate Where the State makes
such a determination, systems must implement a risk mitigation plan that addresses
physical access, surface water run-off, animal and bird wastes, and ongoing water quality
assessment.
How soon will the changes take effect?
The rule will be effective 30 days after publication in the Federal Register; however, each of the
requirements has a different compliance date. The table below provides the applicable dates.
Rule Requirement
Compliance date
Cover or treat uncovered finished water reservoirs
36 months after promulgation
Large systems (serving at least 10,000 people)
Initiate Crypiosporidium monitoring’
6 months after rule promulgation
Determine bin classification 2
36 months after rule promulgation
Meet Crypiosporidium treatment requirements 3 72 months after rule promulgation
Small systems (serving fewer than 10,000 people)
Initiate E co/i monitoring
30 months after rule promulgation
Initiate Cryptospond :uin monitoring
48 months after rule promulgation
Determine bin classification 2
66 months after rule promulgation
Meet Cryplosporidium treatment requirements 3
102 months after rule promulgation
‘Filtered systems must also monitor E cot: and turbidity
2 Unfiitered systems determine their mean source water Cryptosporidium level
3 States may allow an additional 2 years for systems making capital improvements

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What is the significance of this rule?
In 1990, the Science Advisory Board (SAB) cited drinking water contamination as one of the
most important environmental risks and indicated that disease-causing microbiological
contaminants (i e., pathogens, such as, bacteria, protozoa, and viruses) are probably the greatest
remaining health risk management challenge for drinking water suppliers. While modern water
treatment systems have substantially reduced waterbome disease incidence, drinking water
contamination remains a significant health risk management challenge. The LT2ESWTR
addresses this challenge by mitigating remaining public health concerns following
implementation of the IESWTR and LT1ESWTR.
Based on available data on Cryptospor:dium occurrence, infectivity, and treatment, EPA believes
that the majority of filtered systems in compliance with the IESWTR and LTI ESWTR provide
sufficient treatment for Cryplosporidium However, there is a subset of filtered systems with
elevated source water pathogen levels where additional treatment is needed. Consequently, EPA
is proposing risk-targeted treatment technique requirements for Cryptosporidium control in
filtered systems, where additional treatment requirements relate to source water occurrence
levels. The majority of systems, which have relatively low Cryptosporidium levels, will incur no
additional treatment requirements. A subset of systems must provide from 1 .0 to 2 5 log
Cryptosporidium reduction beyond IESWTR and LT1ESWTR requirements These requirements
will achieve a more uniform level of public health protection.
Unfiltered systems are currently not required to provide any treatment for Cryptosporzdiuin.
Occurrence data indicate that unfiltered systems should provide 2 to 3 log Cryptosporidium
inactivation in order to achieve equivalent public health protection to filtered systems. Hence,
EPA is proposing Cryptosporidium treatment technique requirements for unfiltered systems.
How will this rule protect public health?
The LT2ESWTR will significantly improve the control of microbiological pathogens,
specifically Cryptosporidium, in public drinking water systems with the highest risk levels This
will substantially lower rates of endemic cryptosporidiosis, the gastrointestinal illness caused by
ingestion of Cryptosporidium, which can be severe and sometimes fatal in sensitive
subpopulations (e.g., infants, AIDS patients, the elderly). The treatment technique requirements
of this proposal are also expected to increase protection from exposure to other microbial
pathogens (e g, Giardia) that co-occur with Cryptosporidium. It will also ensure that systems
maintain protection from pathogens in cases where systems alter their disinfection practices to
meet new disinfection byproduct standards promulgated under the Stage 2 Disinfectants and
Disinfection Byproducts Rule (DBPR).
How much will this rule cost?
In estimating the costs of the LT2ESWTR, the Agency considered impacts on PWSs and States
(including territories and EPA implementation in non-primacy States) The LT2ESWTR will
result in increased costs to public water systems for implementing the components of the rule.
States will also incur implementation costs. EPA estimates that the annual cost of the rule is
$71.6 to 107 7 million (based on present value at 7%, year 2000).

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Approximately 99 percent ($70.7 to 106.8 million annualized) of the rule’s total annual costs are
imposed on drinking water utilities. States incur the remaining 1 percent ($0.9 million
annualized) of the LT2ESWTR’s total annual cost The largest costs are borne by the 23 to 36%
of systems estimated to provide additional treatment for Cryplosporidium ($60.2 to 95.9 million
annualized). All non-purchased systems will incur costs for monitoring ($5.1 to 5.6 million
annualized). Remaining costs are associated with systems that cover or treat uncovered finished
water reservoirs ($5.3 million annualized). The national estimates of annualized costs are based
on estimates of system-level costs for the rule and estimates of the number of systems expected
to incur each type of cost
The average annual household cost is estimated to be $1.91 per year. Ninety percent of
households will experience costs of less than $3.53 per year, and 99 99 percent of households are
estimated to incur annual costs of less than $120 per year. These estimates may be conservative
because systems with fewer households are likely to choose less costly improvements.
What are the benefits of this rule?
The primary benefits of the LT2ESWTR come from reductions in the risk of illness from
pathogens in drinking water, specifically Cryptosporidium. Exposure to other pathogenic
protozoa or other waterborne bacterial or viral pathogens is likely to be reduced by the
provisions of this rule as well. In addition to preventing illnesses, this rule is expected to have
other non-health related benefits. These benefits result from avoiding non-health related costs
associated with waterborne disease outbreaks
The annual monetized benefits of the proposed rule are conservatively calculated to be $283 to
1,113 million EPA estimates that implementation of the LT2ESWTR will result in a reduction
of cryptosporidiosis illness of between 179,999 and 722,000 cases per year, and a reduction in
mortalities due to cryptosporidiosis of between 26 and 101 deaths per year. Most of the avoided
deaths would be among immunocompromised and other sensitive subpopulations.
Is funding available to help systems comply with this rule?
Since 1996, the Drinking Water State Revolving Loan Fund has made more than $4.4 billion
available to States, which have used the funding to provide loans to help water systems improve
their infrastructure. Through December 31, 2000, States had made close to I ,600 loans for more
than $3 2 billion. Other federal funds for infrastructure financing are available through the U. S.
Department of Housing and Urban Development’s Community Development Block Grant
Program and the Rural Utilities Service of the U.S. Department of Agriculture EPA also
provides program management funding to States that have primary enforcement responsibility
for their drinking water programs through the Public Water Systems Supervision (PWSS) grants
program.
How did EPA consult with stakeholders in developing this rule?
In March 1999, EPA reconvened the M-DBP Federal Advisory Committee to develop
recommendations for the Stage 2 DBPR and LT2ESWTR The Committee consisted of
organizational members representing USEPA, State and local public health and regulatory

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agencies, local elected officials, Indian tribes, drinking water suppliers, chemical and equipment
manufacturers, and public interest groups. The Committee’s activities resulted in the collection
and evaluation of substantial new information related to key elements for both rules. This
information included new data on pathogen icity, occurrence, and treatment of microbial
contaminants, specifically including Cryptosporidium, as well as new data on DBP health risks,
exposure, and control. The Committee reviewed this new information and considered both the
strengths and limitations of these data, as well as the related technical and policy issues involved
in developing a Stage 2 DBPR and a LT2ESWTR under the Safe Drinking Water Act.
In September 2000 the Committee signed an Agreement in Principle reflecting the consensus
recommendations of the group. The Agreement was published by EPA in a December 29, 2000,
Federal Register notice (65 FR 83015). The proposed LT2ESWTR is consistent with the
Agreement.
On November 29, 2001, EPA posted a pre-proposal draft of the LT2ESWTR preamble and
regulatory language on an EPA Internet site (www epa.gov/safewaterl) The purpose of making
this early draft available for public review was to solicit comment on whether it was consistent
with the Agreement in Principle of the Stage 2 M-DBP Advisory Committee EPA received
comments on this pre-proposal draft from public water systems, State governments, laboratories,
and other stakeholders. While EPA did not formally respond to these comments, EPA has
carefully considered them in developing the LT2ESWTR proposal.
Where can the public get more information about this proposed rule?
For general information on the LT2ESWTR and for copies of the Federal Register notice of the
proposed regulation or technical fact sheets contact the Safe Drinking Water Hotline, at (800)
426-4791, or visit the EPA Safewater website, www epa.gov/safewater/mdbp/1t2/st2eswtr.html.
The Safe Drinking Water Hotline is open Monday through Friday, excluding Federal holidays,
from 9 00 a.m. to 5 30 p.m. Eastern Time.
Last updated September 2003
U RL http .I/www.epa gov/safewater/1t2/st2eswtr_fact pdf
Office of Ground Water and Drinking Water EPA 815-F-02-005
www epa gov/safewater September 2002

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