Stage 2 DBPR IDSE System Specific Study Factsheet

Stage 2 DBPR
IDSE System Specific Study Factsheet
WHAT Is THE STAGE 2 DBPR?
The U.S. Environmental Protection Agency (EPA) published the Stage 2 Disinfectants and Disinfection
Byproducts Rule (Stage 2 DBPR) on January 4, 2006. The Stage 2 DBPR builds on existing regulations by
requiring water systems to meet disinfection byproduct (DBP) maximum contaminant levels (MCLs) at each
monitoring site in the distribution system to better protect public health.

WHAT Is THE IDSE PROVISION OF THE STAGE 2 DBPR?

The Stage 2 DBPR includes a provision requiring all community water systems (CWS) and only nontransient
noncommunity water systems (NTNCWS) serving more than 10,000 people to conduct an initial distribution
system evaluation (IDSE). NTNCWS serving less than 10,000 are exempted from IDSE requirements, but will
need to comply with the Stage 2 DBPR compliance monitoring requirements. The goal of the IDSE is to
characterize the distribution system and identify monitoring sites where customers may be exposed to high
levels of total trihalomethanes (TTHM) and haloacetic acids (HAAS). There are four ways to comply with the
IDSE requirements: Standard Monitoring, System Specific Study (SSS), 40/30 Certification (40/30), and Very
Small System (VSS) Waiver. SSS is an option for systems that have extensive existing DBP data or have prepared
a hydraulic model that can be used to determine locations of high DBP levels in their distribution system.
Systems will have to meet minimum requirements to perform either option. This factsheet provides
information regarding the SSS option for both Existing Monitoring and for Hydraulic Modeling.
What is a System Specific Study (SSS)?

SSS - Existing Monitoring
An evaluation of a system's DBP levels based
on existing monitoring data collected
throughout the distribution system and during
the peak historical month. The rule requires a
minimum number of samples and specific
locations in the distribution system. This IDSE
option is most likely to be used by systems
that have extensive operational DBP data in
addition to Stage 1 DBPR compliance
monitoring data. Systems may use a
combination of all qualifying data (i.e.,
existing operational and compliance data) to
determine the best locations for Stage 2 DBPR
compliance monitoring.
SSS - Hydraulic Modeling
An evaluation of a system's DBP levels based on
results of an Extended Period Simulation (EPS)
hydraulic model using water age as a surrogate for
DBP formation. This IDSE option is most likely to
be used by systems that have a high level of
technical expertise and already utilize modeling
technologies outside of the IDSE process. The
model must meet the minimum requirements
presented in the rule, such as percentage of
distribution system represented by the model and
calibration. The model results are used in
conjunction with Stage 1 DBPR compliance data
and one round of monitoring during the IDSE to
select the best locations for Stage 2 DBPR
compliance monitoring.

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SYSTEM SPECIFIC STUDY REQUIREMENTS
Systems opting to conduct an SSS will need to:
• Step 1: Prepare and submit an SSS Plan by the date specified in Table 1 (below).
• Step 2: Address additional SSS requirements.
• Step 3: Prepare and submit the IDSE Report.
• Step 4: Prepare a Stage 2 DBPR compliance monitoring plan.
If you are conducting an SSS for IDSE compliance, you will be required to prepare a study plan, possibly conduct
some additional monitoring, develop an IDSE Report, and prepare a Stage 2 DBPR compliance monitoring plan.
These documents must be submitted by the deadlines listed in Table 1; however, you can submit two or all
three of the documents as one submission as long as the required elements of each document are included and
the deadline for the earliest document is met.
Table 1: SSS Compliance Dates
,, . . .. . . , i ...... m r. r. . Submit IDSE Begin Compliance
If you are a system serving: Schedule: SSS Plan Due Date: D . D ,f .. . r .
Report By: Monitoring by:
At least 100,000 people or part of a
combined distribution system serving at
least 100,000 people
50,000 to 99,999 people or part of a
combined distribution system serving 50,000
to 99,999 people
10,000 to 49,999 people or part of a
combined distribution system serving 10,000
to 49,999 people
Less than 10,000 or part of a combined
distribution system serving less than 10,000
Schedule 1
Schedule 2
Schedule 3
Schedule 4
October 1 , 2006
April 1 , 2007
October 1 , 2007
April 1 , 2008
January 1 , 2009
July 1,2009
January 1, 2010
July 1, 2010
April 1, 2012
October 1, 2012
October 1 , 201 3
October 1 , 201 3 2
1 Your schedule is defined by the largest system in your combined distribution system.
2 Systems not conducting Cryptosporidium monitoring under 40 CFR 141.701 (a)(4) must begin Stage 2 DBPR compliance monitoring by
this date. Systems conducting Cryptosporidium monitoring under 40 CFR 141.701 (a)(4) or 141.701 (a)(6) must begin Stage 2 DBPR
compliance monitoring by October 1, 2014.
STEP 1: PREPARE & SUBMIT SYSTEM SPECIFIC STUDY PLAN
THE REQUIRED ELEMENTS OF AN SSS PLAN INCLUDE:
• Population served by your system.
• System Type: Subpart H (surface water or ground water under the direct influence of surface water) or
Ground Water.
PI Distribution System Schematic showing:
• Entry Points
• Sources
• Locations and dates of all planned or completed SSS monitoring
• Locations and dates of planned Stage 1 DBPR compliance samples
Specific requirements for each type of SSS are listed on the next page. // you meet the requirements for
the IDSE Report, you may submit the SSS Plan and IDSE Report together.

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HOW TO SUBMIT AN SSS PLAN:
Submit Electronically:
Go To: www.epa.gov/safewater/disinfection/tools
and access the IDSE Tool, Plan/Report Entry.
Create an electronic SSS Plan using the template
provided in the IDSE Tool.
Attach schematic and additional information.
Submit by the Due Date presented in Table 1
(above).
Keep the confirmation number and copy of your
plan for your files.
Submit By Mai I:
Create an SSS Plan. A template can be found
in the IDSE Guidance Manual.
Attach schematic and additional information.
Mail submission to the IPMC:
US EPA-IPMC
PO Box 98
Dayton, OH 45401-0098
STEP 2: ADDRESS ADDITIONAL SYSTEM SPECIFIC STUDY REQUIREMENTS

THE SPECIFIC ELEMENTS REQUIRED FOR AN EXISTING MONITORING SYSTEM SPECIFIC STUDY PLAN:

PI Previously collected monitoring results: Data must be no more than 5 years old as of the due date of
submission and must have been analyzed by approved methods.

• Certification that:

• All compliance and operational data taken during the SSS period are included.
• Distribution system and treatment have not significantly changed since the period of SSS data.
• Samples are representative of the entire distribution system.

• Locations and frequency of sampling must meet the requirements of Table 2 and each site must be
sampled at least once during peak historical month (i.e., high TTHM, high HAAS, or high water
temperature) for each 12 months of qualifying data. If additional data is needed to meet minimum
requirements, the SSS monitoring plan must include the locations and dates for proposed SSS
monitoring.

Table 2: Monitoring Requirements for Existing Monitoring SSS
Source Water
Type
Subpart H
Ground
Population Size Total per monitoring Minimum Number of Samples
Category period TTHM HM5
<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
3
3
6
12
24
36
48
60
3
3
12
18
24
3
9
36
72
144
216
288
360
3
9
48
72
96
3
9
36
72
144
216
288
360
3
9
48
72
96

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THE SPECIFIC ELEMENTS REQUIRED FOR A HYDRAULIC MODELING SYSTEM SPECIFIC STUDY PLAN:
^ Model must be an Extended Period Simulation (EPS) model and must simulate 24-hour variation in
demand and show a consistently repeating 24-hour pattern of residence time.
• Tabular or spreadsheet data demonstrating that the model includes:
• 75 percent of pipe volume and 50 percent 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
significant conveyors of water.
• All 6-inch and larger pipes that connect remote areas of a distribution system to the main portion of
the system.
• All storage facilities with standard operations represented.
• All active pump stations with controls and all active control valves.
• Description of calibration activities undertaken including (if calibration is complete):
• A graph of predicted tank levels vs. measured tank levels for the storage facility with the highest
residence time in each pressure zone.
• 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.
• Model output showing preliminary 24-hr average residence time predictions throughout the system.
^ Timing and number of samples representative of distribution system for
at least one monitoring period of TTHM and HAAS monitoring at no less Peak H1storical Month:
than the number of locations required under standard monitoring
during the peak historical month. These samples must be taken at
locations other than existing Stage 1 DBPR compliance monitoring
locations. temperature. It is meant to
A description of how all requirements will be completed within 12 represent the "worst case"
months of plan submission scenano for DBP formatlon-
Is the month with the highest
TTHM or the highest HAA5
levels or the warmest water
STEP 3: PREPARE AND SUBMIT IDSE REPORT
The primary purpose of the IDSE Report is to provide EPA or the state with the system's recommendations for
where and at what frequency Stage 2 DBPR compliance monitoring will be conducted.
The required elements of the IDSE Report are:
• Recommendations for Stage 2 DBPR monitoring sites and dates.
• Basis (analytical results and modeling) and justification for selection of recommended Stage 2 DBPR
monitoring sites.
• TTHM and HAAS analytical results in a tabular or spreadsheet format from all Stage 1 DBPR and SSS
monitoring conducted during the period of the SSS.
• An explanation of any deviation from the approved SSS plan.

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• If any of the following changed from your study plan:

• Population served.
• System type (subpart H or ground).
• Distribution system schematic.

In addition, if you are conducting a Hydraulic Modeling SSS you must provide your final calibration information
(if not already provided with the IDSE plan) and a 24-hr time series graph of residence time for all Stage 2
DBPR monitoring sites selected. If you include the bold items above in your plan, you will not have to prepare
a separate IDSE Report.

IDSE Report can be submitted the same way as the SSS Plan, as described under Step 1 of this factsheet.

STEP 4: PREPARE STAGE 2 DBPR COMPLIANCE MONITORING PLAN

The required elements of the Stage 2 DBPR compliance monitoring plan are the compliance monitoring
locations and dates and compliance calculation procedures. If you decide to include the compliance calculation
procedures in your IDSE Report, you will not have to prepare a separate Stage 2 DBPR compliance monitoring
plan. However, if you did not include the information required for the Stage 2 DBPR compliance monitoring
plan as part of your IDSE Report, your next step will be to prepare this plan before beginning Stage 2 DBPR
compliance monitoring. If you are a Subpart H system serving more than 3,300 people, you must submit a copy
of the monitoring plan to your state before Stage 2 DBPR compliance monitoring begins. Also, systems should
check with their states in case there are state requirements, in addition to the Federal requirements, that
need to be included in the IDSE Report.

ADDITIONAL GUIDANCE MATERIALS

The following guidance materials address the IDSE requirements for the Stage 2 DBPR:

PI Initial Distribution System Evaluation Guidance Manual for the Final Stage 2 Disinfectants and
Disinfection Byproducts Rule (EPA 815-B-06-002) - This manual is a comprehensive technical guidance
document for all system sizes and types and all IDSE options.

• IDSE Tool - Is a web-based tool that walks the user through the IDSE process. A Wizard determines IDSE
requirements and selects the best IDSE option for your system. The tool creates Custom Forms your
system (based on population served and system type) can submit electronically to EPA's Information
Processing and Management Center for EPA/state review. (Available on-line at
www.epa.gov/safewater/disinfection/tools.)

For additional guidance on the Stage 2 DBPR, you may refer to the following existing and future EPA materials:

• Stage 2 DBPR Quick Reference Guides (Schedules 1-4).

• Simultaneous Compliance Guidance Manuals for the Stage 2 Rules (draft version anticipated mid-2006).

• Stage 2 Disinfectant and Disinfection Byproducts Rule: Small Entity Compliance Guide - One of the
Simple Tools for Effective Performance (STEP) Guide Series (draft version anticipated late 2006).

• Consecutive System Guidance Manual for the Final Stage 2 Disinfectants and Disinfection Byproducts
Rule (draft version anticipated late 2006).

• Operational Evaluation Guidance Manual for the Final Stage 2 Disinfectants and Disinfection Byproducts
Rule (draft version anticipated late 2006).

Materials can be downloaded from www.epa.gov/safewater/disinfection/stage2, as they become available.

For additional information, please contact the Safe Drinking Water Hotline at 1-800-426-4791,
send an email to stage2mdbp@epa.gov. or visit www.epa.gov/safewater/disinfection/stage2.

Office of Water (4606) EPA 816-F-06-022 www.epa.gov/safewater/d1s1nfect1on/stage2 June 2006

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