United States

Environmental

Protection

Agency

Office of Water

(4601)

EPA 815-B-06-002

January 2006

INITIAL DISTRIBUTION SYSTEM

EVALUATION GUIDANCE MANUAL

FOR THE FINAL STAGE 2 DISINFECTANTS

AND DISINFECTION BYPRODUCTS RULE
This page intentionally left blank.
IDSE Guidance Manual for the Final Stage 2 DBPR i January 2006

Note on the Initial Distribution System Evaluation Guidance Manual for

the Final Stage 2 Disinfectants and Disinfection Byproducts Rule

Purpose:

The purpose of this guidance manual is solely to provide technical information for water

systems and states to assist them in complying with the Initial Distribution System Evaluation

(IDSE), a component of the Stage 2 Disinfectants and Disinfection Byproducts Rule (Stage 2

DBPR). This guidance is not a substitute for applicable legal requirements, nor is it a regulation

itself. Thus, it does not impose legally-binding requirements on any party, including EPA,

states, or the regulated community. Interested parties are free to raise questions and objections

to the guidance and the appropriateness of using it in a particular situation. Although this

manual describes many methods for complying with IDSE requirements, the guidance presented

here may not be appropriate for all situations, and alternative approaches may provide

satisfactory performance. The mention of trade names or commercial products does not

constitute endorsement or recommendation for use.

Authorship:

This manual was developed under the direction of EPA’s Office of Water, and was

prepared by The Cadmus Group, Inc. and Malcolm Pirnie, Inc. Questions concerning this

document should be addressed to:

Elin Warn Betanzo and Thomas Grubbs 

U.S. Environmental Protection Agency

Mail Code 4607M

1200 Pennsylvania Avenue NW

Washington, DC 20460-0001

Tel: (202) 564-1807 (Elin Warn Betanzo)

(202) 564-5262 (Thomas Grubbs)

Fax: (202) 564-3767

Email: Betanzo.Elin@epamail.epa.gov and Grubbs.Thomas@epamail.epa.gov
IDSE Guidance Manual for the Final Stage 2 DBPR ii January 2006

Acknowledgments:

American Water Works Association

Association of Metropolitan Water Agencies

Association of State Drinking Water Agencies

Ken Bousfield—Utah Division of Drinking Water

Andrew DeGraca—San Francisco Water

Walter Grayman—W.M. Grayman Consulting

Mike Grimm—Oregon Health Department

Rich Haberman—California Department of Health Services

Mike Hotaling—City of Newport News

Doug Howie—HDR Engineering

Alexa Obolensky—Philadelphia Water Department

David Reckhow—University of Massachusetts, Amherst

Tom Schaeffer—Association of Metropolitan Water Agencies

Charlotte Smith—Charlotte Smith & Associates

Scott Summers—Colorado University

Jeffrey Swertfeger–Cincinnati Water Works

Jim Uber—University of Cincinnati

Marguerite Young—Clean Water Action
IDSE Guidance Manual for the Final Stage 2 DBPR iii January 2006

Contents

List of Exhibits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii

List of Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii

List of IDSE Forms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii

List of Checklists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

List of Worksheets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

List of IDSE Requirements Summary Sheets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x

Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi

Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xii

1.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

1.1 Getting Started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

1.1.1 What is the IDSE? What is its purpose? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

1.1.2 Do I have to conduct an IDSE? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

1.1.3 What guidance materials are available for the IDSE? . . . . . . . . . . . . . . . . . . . . 1-2

1.1.4 How can I get copies of EPA guidance materials? . . . . . . . . . . . . . . . . . . . . . . 1-4

1.1.5 How do I use this guidance manual? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

1.1.6 Whom do I call with questions? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7

1.2 Overview of IDSE Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7

1.3 IDSE Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8

1.4 Early Implementation Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8

1.5 Changes to IDSE Requirements Since the Proposed Stage 2 DBPR . . . . . . . . . . . . . 1-10

2.0 Determining Your IDSE Schedule and Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

2.1 System Characteristics that Affect IDSE Requirements . . . . . . . . . . . . . . . . . . . . . . . . 2-1

2.2 Determining Your IDSE Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

2.3 Determining Your IDSE Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4

2.4 IDSE Requirements Summary Sheets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4

3.0 Very Small System Waiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

3.1 Qualifying for the VSS Waiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

3.2 Selecting a Stage 2 DBPR Compliance Monitoring Site . . . . . . . . . . . . . . . . . . . . . . . . 3-2

3.3 Next Steps: Preparing the Stage 2 DBPR Compliance Monitoring Plan . . . . . . . . . . . 3-3

4.0 40/30 Certification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

4.1 Qualification Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

4.2 Preparing and Submitting the Certification Letter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4

4.3 Recordkeeping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4

4.4 Selecting Stage 2 Compliance Monitoring Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7

4.4.1 You Have THE SAME Number of Stage 1 Sites as Required by the Stage 2

DBPR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8

4.4.2 You Have MORE Stage 1 Sites than Required by the Stage 2 DBPR . . . . . . . 4-8

4.4.3 You Have FEWER Stage 1 Sites than Required by the Stage 2 DBPR . . . . . 4-10

4.5 Next Steps: Preparing the Stage 2 DBPR Compliance Monitoring Plan . . . . . . . . . . 4-11
IDSE Guidance Manual for the Final Stage 2 DBPR iv January 2006

5.0 System Specific Study Using Existing Monitoring Results . . . . . . . . . . . . . . . . . . . . . . . . 5-1

5.1 Qualifying for an Existing Monitoring Results SSS . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3

5.1.1 Evaluating Existing Monitoring Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3

5.1.2 Evaluating Treatment and Source Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7

5.1.3 Evaluating Distribution System Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8

5.1.4 Compiling Your Data and Calculating LRAAs . . . . . . . . . . . . . . . . . . . . . . . 5-10

5.2 Preparing Your Existing Monitoring Results SSS Plan . . . . . . . . . . . . . . . . . . . . . . . . 5-10

5.3 Selecting Stage 2 DBPR Compliance Monitoring Sites and Preparing the IDSE 

Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-27

5.3.1 Selecting Stage 2 DBPR Compliance Monitoring Locations . . . . . . . . . . . . . 5-28

5.3.2 Determining Your Stage 2 DBPR Compliance Monitoring Dates . . . . . . . . . 5-35

5.3.3 Preparing the IDSE Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-35

5.4 Recordkeeping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-49

5.5 Next Steps: Preparing the Stage 2 DBPR Compliance Monitoring Plan . . . . . . . . . . 5-49

6.0 System Specific Study Using a Distribution System Hydraulic Model . . . . . . . . . . . . . . . 6-1

6.1 Minimum Model Requirements and Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5

6.1.1 Physical System Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6

6.1.2 Demand Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6

6.1.3 Operational Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-9

6.1.4 Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10

6.2 Modeling Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-13

6.2.1 Water Age Modeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-14

6.2.2 Modeling Analysis Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-15

6.3 Determining SSS Monitoring Requirements and Schedule . . . . . . . . . . . . . . . . . . . . 6-18

6.4 Preparing your Modeling Study Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-20

6.5 Selecting SSS Monitoring Sites and Conducting Monitoring . . . . . . . . . . . . . . . . . . . 6-33

6.5.1 Select SSS Monitoring Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-40

6.5.1.1 Identify Near Entry Point Monitoring Locations . . . . . . . . . . . . . . . . . 6-33

6.5.1.2 Use Your Model to Identify Average Residence Time and High TTHM

Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-34

6.5.1.3 Use Your Model and Other Data to Identify High HAA5 Sites . . . . . 6-37

6.5.1.4 Finalize SSS Monitoring Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-38

6.5.2 Special Case: Using DBP Formation Modeling to Select Sites . . . . . . . . . . . . 6-40

6.5.3 Conducting Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-40

6.6 Selecting Stage 2 DBPR Compliance Monitoring Sites and Schedule . . . . . . . . . . . . 6-41

6.6.1 Analyzing Model Results at Monitoring Locations . . . . . . . . . . . . . . . . . . . . . 6-42

6.6.2 Analyzing SSS Monitoring Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-43

6.6.3 Comparison of Modeling and Sampling Results . . . . . . . . . . . . . . . . . . . . . . . 6-43

6.6.4 Select Final Compliance Monitoring Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-44

6.6.5 Determining Your Stage 2 DBPR Compliance Monitoring Schedule . . . . . . 6-48

6.7 Preparing the IDSE Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-48

6.8 Recordkeeping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-69

6.9 Next Steps: Preparing the Stage 2 DBPR Compliance Monitoring Plan . . . . . . . . . . 6-69
IDSE Guidance Manual for the Final Stage 2 DBPR v January 2006

7.0 Standard Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1

7.1 Selecting Standard Monitoring Sites and Preparing Your Standard Monitoring Plan . 7-2

7.1.1 Recommended Approach for Selecting Standard Monitoring Sites . . . . . . . . . 7-3

Step 1: Gather Data and Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5

Step 2: Identify Near Entry Point Standard Monitoring Sites . . . . . . . . . . . . . 7-7

Step 3: Identify Candidate Average Residence Time Sites . . . . . . . . . . . . . . . 7-9

Step 4: Identify Candidate High TTHM Sites . . . . . . . . . . . . . . . . . . . . . . . . 7-13

Step 5: Identify Candidate High HAA5 Standard Monitoring Sites . . . . . . . 7-14

Step 6: Plot Sites on a Distribution System Map . . . . . . . . . . . . . . . . . . . . . . 7-17

Step 7: Select Standard Monitoring Sites from Candidate Sites . . . . . . . . . . 7-17

Step 8: Write Justifications and a Summary of Data . . . . . . . . . . . . . . . . . . . 7-19

7.1.2 Selecting Your Peak Historical Month and Determining Standard Monitoring 

Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-21

7.1.3 Preparing Your Standard Monitoring Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-23

7.2 Conducting Standard Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-35

7.3 Selecting Stage 2 DBPR Compliance Monitoring Sites and Preparing the IDSE 

Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-37

7.3.1 Selecting Stage 2 DBPR Compliance Monitoring Locations . . . . . . . . . . . . . 7-38

7.3.2 Determining Your Stage 2 DBPR Compliance Monitoring Schedule . . . . . . 7-44

7.3.3 Preparing the IDSE Report for Standard Monitoring . . . . . . . . . . . . . . . . . . . 7-44

7.4 Recordkeeping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-61

7.5 Next Steps: Preparing the Stage 2 DBPR Compliance Monitoring Plan . . . . . . . . . . 7-61
IDSE Guidance Manual for the Final Stage 2 DBPR vi January 2006

Appendices

Appendix A Factors Affecting DBP Formation

Appendix B Stage 2 DBPR and LT2ESWTR Compliance Schedule

Appendix C TTHM and HAA5 Sampling Protocol

Appendix D Consecutive and Wholesale System Issues

Appendix E Example IDSE Existing Monitoring Results System Specific Study Plan and

Report for a Surface Water System Serving 40,000 People

Appendix F Example IDSE System Specific Study Using a Hydraulic Model for a Surface

Water System Serving 57,000 People

Appendix G Complex Modeling Analysis Example for a System with Multiple Sources

Appendix H Example IDSE Standard Monitoring Plan and Report for a Surface Water System

Serving 160,000 People

Appendix I Example IDSE Standard Monitoring Plan and Report for a Ground Water System

Serving 200,000 People
IDSE Guidance Manual for the Final Stage 2 DBPR vii January 2006

List of Exhibits

Exhibit 1.1 IDSE Tool Home Page . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

Exhibit 1.2a IDSE Guidance Manual Chapters and Appendices . . . . . . . . . . . . . . . . . . . . . . . 1-5

Exhibit 1.2b Building a Custom IDSE Guidance Manual for Your System . . . . . . . . . . . . . . 1-6

Exhibit 1.3 Staggered Schedule for the IDSE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9

Exhibit 1.4 Options for Submitting IDSE Material to EPA and States Through the IPMC 1 . 1-10

Exhibit 2.1 IDSE Schedule Number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

Exhibit 2.2 Example Letter from EPA to System on Schedule 1 . . . . . . . . . . . . . . . . . . . . . . . 2-3

Exhibit 2.3 Flowchart for Determining Your IDSE Option . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

Exhibit 2.4 List of Requirements Summary Sheets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9

Exhibit 3.1 Required Contents of Stage 2 DBPR Compliance Monitoring Plans . . . . . . . . . . 3-3

Exhibit 4.1 40/30 Criteria Compliance Dates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

Exhibit 4.2 Stage 2 Compliance Monitoring Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7

Exhibit 4.3 Typical Characteristics of High TTHM Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10

Exhibit 4.4 Required Contents of Stage 2 DBPR Compliance Monitoring Plans . . . . . . . . . 4-12

Exhibit 5.1 Qualifying Period for the Existing Monitoring Results SSS . . . . . . . . . . . . . . . . . 5-3

Exhibit 5.2 Examples of System Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9

Exhibit 5.3 Required Elements of Your SSS Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-11

Exhibit 5.4 Required Elements of Your IDSE Report for an Existing Monitoring Results 

 SSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-28

Exhibit 5.5 Protocol for Selecting Stage 2 DBPR (Subpart V) Compliance Monitoring 

 Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-31

Exhibit 5.6 Required Contents of Stage 2 DBPR Compliance Monitoring Plans . . . . . . . . . 5-50

Exhibit 6.1 Minimum Distribution System Hydraulic Model Requirements . . . . . . . . . . . . . . 6-2

Exhibit 6.2 Minimum Reporting Requirements for Modeling Study Plan . . . . . . . . . . . . . . . . 6-3

Exhibit 6.3a Sample Subdivision Layout in a Less Skeletonized Model . . . . . . . . . . . . . . . . . 6-8

Exhibit 6.3b Sample Subdivision Layout in a More Skeletonized Model . . . . . . . . . . . . . . . . 6-8

Exhibit 6.4 Example Diurnal Demand Variation Pattern . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10

Exhibit 6.5 Sample of an Acceptable Graph for Demonstration of Model Calibration . . . . . 6-13

Exhibit 6.6 Schematic of the Case Study Distribution System . . . . . . . . . . . . . . . . . . . . . . . 6-16

Exhibit 6.7 Water Age Graph for the Tank with the Highest Water Age . . . . . . . . . . . . . . . . 6-17

Exhibit 6.8 Locational Average Water Age Throughout the Study Area . . . . . . . . . . . . . . . . 6-18

Exhibit 6.9 Requirements for Modeling SSS Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-19

Exhibit 6.10 Ranking of Water Age Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-35

Exhibit 6.11 Histogram of Water Age Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-36

Exhibit 6.12 Example of Typical Water Age Variation over Time . . . . . . . . . . . . . . . . . . . . 6-43

Exhibit 6.13 Protocol for Selecting Stage 2 DBPR (Subpart V) Compliance Monitoring

 Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-47

Exhibit 6.14 Minimum Requirements for IDSE Report for a Modeling SSS . . . . . . . . . . . . 6-49

Exhibit 6.15 Required Contents of Stage 2 DBPR Compliance Monitoring Plans . . . . . . . . 6-70
IDSE Guidance Manual for the Final Stage 2 DBPR viii January 2006

Exhibit 7.1 Required Elements of Your Standard Monitoring Plan . . . . . . . . . . . . . . . . . . . . . 7-2

Exhibit 7.2 Recommended Approach to Selecting Standard Monitoring Sites . . . . . . . . . . . . 7-4

Exhibit 7.3 Data and Tools for Selecting Different Types of Standard Monitoring Sites . . . . 7-6

Exhibit 7.4 Guidelines for Using Disinfectant Residual Data . . . . . . . . . . . . . . . . . . . . . . . . 7-11

Exhibit 7.5 Typical Characteristics of High TTHM Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-13

Exhibit 7.6 Required Elements of Your IDSE Report for Standard Monitoring . . . . . . . . . . 7-37

Exhibit 7.7 Protocol for Selecting Stage 2 DBPR (Subpart V) Compliance Monitoring 

 Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-40

Exhibit 7.8 Required Contents of Stage 2 DBPR Compliance Monitoring Plans . . . . . . . . . 7-62

List of Examples

Example 2.1 Determining IDSE Requirements for a Consecutive System Serving 25,000 

People . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8

Example 4.1 Qualifying for a 40/30 Certification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3

Example 4.2 Completed 40/30 Certification Letter Using Form 1 . . . . . . . . . . . . . . . . . . . . . . 4-6

Example 5.1 Qualifying With Multiple Years of Data Collected From Different Locations . 5-6

Example 5.2 Qualifying Using Data from a One-Year Special Study . . . . . . . . . . . . . . . . . . . 5-7

Example 5.3 Selecting Stage 2 DBPR Compliance Monitoring Sites . . . . . . . . . . . . . . . . . . 5-32

Example 5.4 Maintaining a Historical Record . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-34

Example 5.5 Providing Geographic Coverage When Choosing Stage 2 Sites . . . . . . . . . . . . 5-34

Example 7.1 System with Fewer Entry Points than Required Near Entry Point Standard 

Monitoring Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-8

Example 7.2 System with More Entry Points than Required Near Entry Point Sample Sites . 7-9

Example 7.3 Average Disinfectant Residual Calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-12

Example 7.4 Selecting Stage 2 DBPR Compliance Monitoring Sites . . . . . . . . . . . . . . . . . . 7-41

Example 7.5 Maintaining a Historical Record . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-43

Example 7.6 Providing Geographic Coverage When Choosing Stage 2 Sites . . . . . . . . . . . . 7-43

List of IDSE Forms

Form 1 40/30 Certification Letter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5

Form 2 Existing Monitoring Results SSS Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-19

Form 3 IDSE Report for an Existing Monitoring Results SSS . . . . . . . . . . . . . . . . . . . . . . . . 5-41

Form 4 Modeling Study Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-27

Form 5 IDSE Report for a Modeling SSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-57

Form 6 Standard Monitoring Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-29

Form 7 IDSE Report for Standard Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-51
IDSE Guidance Manual for the Final Stage 2 DBPR ix January 2006

List of Checklists

Checklist 2.1 Minimum Requirements Checklist for an SSS Using a Distribution System 

Hydraulic Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6

Checklist 2.2 Minimum Requirements Checklist for an SSS Using Existing Monitoring 

Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7

Checklist 5.1 Minimum Requirements Checklist for an SSS Using Existing Monitoring 

Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4

List of Worksheets

Worksheet 4.1 Stage 2 DBPR Site Selection for Systems Getting the 40/30 Certification . . . 4-9

Worksheet 5.1 Stage 2 DBPR Site Selection Worksheet for an Existing Monitoring Results 

SSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-30

Worksheet 6.1 Stage 2 DBPR Site Selection Worksheet for a Modeling SSS . . . . . . . . . . . . 6-46

Worksheet 7.1 Selecting the Peak Historical Month . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-22

Worksheet 7.2 Stage 2 DBPR Site Selection Worksheet for Standard Monitoring . . . . . . . . 7-39
IDSE Guidance Manual for the Final Stage 2 DBPR x January 2006

List of IDSE Requirements Summary Sheets

Requirement Summary Sheet Page

Requirements for Very Small System Waivers 2-11

40/30 Certification Requirements - Schedule 1 2-13

40/30 Certification Requirements - Schedule 2 2-15

40/30 Certification Requirements - Schedule 3 2-17

40/30 Certification Requirements - Schedule 4 2-19

System-Specific Study Requirements - Schedule 1 2-21

System-Specific Study Requirements - Schedule 2 2-23

System-Specific Study Requirements - Schedule 3 2-25

System-Specific Study Requirements - Schedule 4 2-27

System-Specific Study Requirements - Attachment (For All Schedules) 2-29

Standard Monitoring Requirements - Schedule 1 2-31

Standard Monitoring Requirements - Schedule 2 2-33

Standard Monitoring Requirements - Schedule 3 2-35

Standard Monitoring Requirements - Schedule 4 2-37

Standard Monitoring Requirements - Attachment (For All Schedules) 2-39
IDSE Guidance Manual for the Final Stage 2 DBPR xi January 2006

Acronyms

CBI Confidential Business Information

CWS Community water system

DBP Disinfection byproduct

DBPR Disinfectants and Disinfection Byproducts Rule

EPA U.S. Environmental Protection Agency

EPS Extended period simulation

FOIA Freedom of Information Act

GIS Geographic information system

GWUDI Ground water under the direct influence of surface water

HAA Haloacetic acid

HAA5 The sum of five HAA species

HPC Heterotrophic plate count

ICR Information Collection Rule 

IDSE Initial distribution system evaluation

IPMC Information Processing and Management Center

LRAA Locational running annual average

LT2ESWTR Long Term 2 Enhanced Surface Water Treatment Rule

MCL Maximum contaminant level

M-DBP Microbial and disinfection byproduct

NOM Natural organic matter

NPDWR National Primary Drinking Water Regulation

NTNCWS Nontransient noncommunity water system

PWS Public water system

PWSID Public water system identification number

SDWA Safe Drinking Water Act

SSS System-specific study 

STEP Simple Tools for Effective Performance

SUVA Specific ultraviolet absorbance

SWTR Surface Water Treatment Rule

TCR Total Coliform Rule

THM Trihalomethane

TOC Total organic carbon

TNCWS Transient noncommunity water system

TTHM Total trihalomethanes

TTHMFP Total trihalomethane formation potential

UV Ultraviolet light

VSS Very small system
IDSE Guidance Manual for the Final Stage 2 DBPR xii January 2006

Definitions

Aquifer: a geological formation composed of rock, gravel, sand, or other porous material that

yields water to wells or springs.

Biodegradation: a biological process where HAA5s are broken down into smaller compounds by

microbes.

Booster disinfection: the practice of adding disinfectant in the distribution system to maintain

disinfectant residual concentration throughout the distribution system.

Combined distribution system: the interconnected distribution system consisting of the

distribution systems of wholesale systems and of the consecutive systems that receive finished

water. 40 CFR 141.2

Community water system: a public water system which serves at least 15 service connections

used by year-round residents or regularly serves at least 25 year-round residents. 40 CFR 141.2

Consecutive system: 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. 40 CFR 141.2

Disinfectant: any oxidant, including but not limited to chlorine, chlorine dioxide, chloramines,

and ozone added to water in any part of the treatment or distribution process, that is intended to

kill or inactivate pathogenic microorganisms. 40 CFR 141.2

Disinfectant residual concentration: the concentration of disinfectant that is maintained in a

distribution system. Disinfectant could be free chlorine (the sum of the concentrations of

hypochlorous acid (HOCl) and hypochlorite (OCl-)) or combined chlorine (chloramines). It is

used in Surface Water Treatment Rule as a measure for determining CT. 

Disinfection: a process which inactivates pathogenic organisms in water by chemical oxidants or

equivalent agents. 40 CFR 141.2

Disinfection byproduct (DBP): compound formed from the reaction of a disinfectant with

organic and inorganic compounds in the source or treated water during disinfection and

distribution.

Dual Sample set: a set of two samples collected at the same time and same location, with one

sample analyzed for TTHM and the other sample analyzed for HAA5. Dual sample sets are

collected for the purpose of conducting an IDSE under subpart U and determining compliance

with the TTHM and HAA5 MCLs under subpart V. 40 CFR 141.2

Entry Point: the point(s) where finished water first enters the distribution system from one or

more sources. Samples taken at these points represent minimum residence time in the

distribution system.
IDSE Guidance Manual for the Final Stage 2 DBPR xiii January 2006

Finished Water: 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). 40 CFR 141.2 

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 180 days, except that

the reactivation frequency for GAC10 used as a best available technology for compliance with

subpart V MCLs under §141.64(b)(2) shall be 120 days. 40 CFR 141.2 

GAC20: 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. 40 CFR

141.2 

Ground water system: public water systems that use ground water only or purchase ground water

from other systems (40 CFR 141.2). For the purposes this guidance manual, ground water

systems refers to the subset of systems that disinfect their water, or purchase disinfected ground

water, even if they do not apply any additional treatment.

Ground water under the direct influence of surface water (GWUDI): any water beneath the

surface of the ground with significant occurrence of insects or other macroorganisms, algae, or

large-diameter pathogens such as Giardia lamblia, or Cryptosporidium, or significant and

relative rapid shifts in water characteristics such as turbidity, temperature, conductivity, or pH

which closely correlate to climatological or surface water conditions. Direct influence must be

determined for individual sources in accordance with criteria established by the State. The State

determination of direct influence may be based on site-specific measurements of water quality

and/or documentation of well construction characteristics and geology with field evaluation. 40

CFR 141.2

Haloacetic acid (HAA): one of the family of organic compounds named as a derivative of acetic

acid, wherein one to three hydrogen atoms in the methyl group in acetic acid are each substituted

by a halogen atom (namely, chlorine and bromine) in the molecular structure.

Haloacetic acids (five) (HAA5): the sum of the concentrations in milligrams per liter of the

haloacetic acid compounds (monochloroacetic acid, dichloroacetic acid, trichloroacetic acid,

monobromoacetic acid, and dibromoacetic acid), rounded to two significant figures after

addition. 40 CFR 141.2

Heterotrophic plate count (HPC): a procedure for estimating the number of heterotrophic

bacteria in water, measured as the number of colony forming units per 100 mL. 

Information Processing and Management Center (IPMC): a receiving, processing, and mailing

facility with a web-based data management system that allows EPA and states to access, track,

and respond to IDSE submissions.
IDSE Guidance Manual for the Final Stage 2 DBPR xiv January 2006

Influence zone: the portions of the distribution system supplied with water from a particular

source of supply.

Locational running annual average (LRAA): the average of sample results taken at a particular

monitoring location during the previous four calendar quarters. 40 CFR 141.2 

Maximum contaminant level (MCL): the maximum permissible level of a contaminant in water

which is delivered to any user of a public water system. 40 CFR 141.2

Maximum contaminant level goal (MCLG): the maximum level of a contaminant in drinking

water at which no known or anticipated adverse effect on the health of persons would occur, and

which allows an adequate margin of safety. Maximum contaminant level goals are

nonenforceable health goals. 40 CFR 141.2

Mixing Zone: an area in the distribution system where water flowing from two or more different

sources blend.

Monitoring site: the location where samples are collected.

Non-community water system: a public water system that is not a community water system. A

non-community water system is either a “transient non-community water system (TNCWS)” or a

“non-transient non-community water system (NTNCWS) 40 CFR 141.2

Non-transient non-community water system (NTNCWS): a public water system that is not a

community water system and that regularly serves at least 25 of the same persons over 6 months

per year. 40 CFR 141.2

Population served: the retail number of people served by a water system. Systems typically

work with their State to determine population served for compliance purposes. Note that IDSE

and Stage 2 compliance monitoring requirements (e.g., number of samples and sampling

frequency) are based on the population served by the water system. IDSE and Stage 2

compliance monitoring schedules, however, are based on the largest population served by

systems in the combined distribution system. If you do not know the population of your system,

ask your state.

Public water system (PWS): a system for the provision to the public of water for human

consumption through pipes or, after August 5, 1998, other constructed conveyances, if such

system has at least fifteen service connections or regularly serves an average of at least twentyfive individuals daily at least 60 days out of the year. Such term includes: any collection,

treatment, storage, and distribution facilities under control of the operator of such system and

used primarily in connection with such system; and any collection or pretreatment storage

facilities not under such control which are used primarily in connection with such system. Such

term does not include any “special irrigation district.” A public water system is either a

“community water system” or a “noncommunity water system. 40 CFR 141.2
IDSE Guidance Manual for the Final Stage 2 DBPR xv January 2006

Residence time: the time period lasting from when the water is treated to a particular point in the

distribution system. Also referred to as water age. 

Residual disinfection: also referred to as “secondary disinfection.” The process whereby a

disinfectant (typically Chlorine or Chloramines) is added to finished water in order to maintain a

disinfection residual in the distribution system. 

State: the agency of the State or Tribal government which has jurisdiction over public water

systems. During any period when a State or Tribal government does not have primary

enforcement responsibility pursuant to Section 1413 of the Safe Drinking Water Act, the term

“State” means the Regional Administrator, U.S. Environmental Protection Agency. 40 CFR

141.2

Subpart H systems: public water systems using surface water or ground water under the direct

influence of surface water as a source that are subject to the requirements of 40 CFR 141.2 (H).

40 CFR 141.2

Surface water: all water which is open to the atmosphere and subject to surface runoff. 40 CFR

141.2

Total chlorine residual: the sum of combined chlorine (chloramine) and free available chlorine

residual.

Total trihalomethanes (TTHM): the sum of the concentration in milligrams per liter of the

trihalomethane compounds (trichloromethane [chloroform], dibromochloromethane,

bromodichloromethane, and tribromomethane [bromoform]), rounded to two significant figures. 

40 CFR 141.2

Tracer study: a procedure for estimating hydraulic properties of the distribution system, such as

residence time. Where more than one water source feeds the distribution system, tracer studies

can be used to determine the zone of influence of each source.

Transient Non-Community Water System (TNCWS): a non-community water system that does

not regularly serve at least 25 of the same persons over six months per year. 40 CFR 141.2

Trihalomethane (THM): one of the family of organic compounds named as derivatives of

methane, wherein three of the four hydrogen atoms in methane are each substituted by a halogen

atom in the molecular structure. 40 CFR 141.2

Water distribution system model: a computer program that can simulate the hydraulic, and in

some cases, water quality behavior of water in a distribution system. 

Wholesale system: 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. 40 CFR 141.2
IDSE Guidance Manual for the Final Stage 2 DBPR xvi January 2006

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IDSE Guidance Manual for the Final Stage 2 DBPR 1-1 January 2006

This chapter covers:

1.1 Getting Started (Read this Section First)

1.2 Overview of IDSE Options

1.3 IDSE Schedule 

1.4 Early Implementation Process

1.5 Changes to IDSE Requirements Since the Proposed Stage 2 DBPR

Read this Section First

1.0 Introduction

The Administrator of the EPA signed the Stage 2 Disinfectants and Disinfection

Byproducts Rule (DBPR) on December 15, 2005, and it was published in the Federal Register on

January 4, 2006 (71 FR 388). This rule applies to all community and non-transient

noncommunity water systems that provide disinfected water (other than water disinfected only

by Ultraviolet [UV] light) to their customers. The rule has two primary sections. Subpart U is

referred to as the Initial Distribution System Evaluation (IDSE) section. The requirements of

this part of the rule are discussed in this manual. Subpart V, the Stage 2 Disinfection Byproducts

Requirements, is referred to as Stage 2 Compliance Monitoring in this guidance manual. Stage 2

Compliance Monitoring Requirements are an extension of the Stage 1 DBPR. Note that systems

that are exempt from the IDSE portion of the rule may not be exempt from the Stage 2

Compliance Monitoring section.

EPA developed this Initial Distribution System Evaluation Guidance Manual to help

systems meet the IDSE requirements of the Stage 2 DBPR. System personnel should start by

reading Section 1.1 to answer basic questions about the IDSE, select the appropriate guidance

materials to meet IDSE requirements, and get instructions on how to use this manual.

1.1 Getting Started 

1.1.1 What is the IDSE? What is its purpose?

IDSEs are an important part of the Stage 2 DBPR. They are one-time studies conducted

by water systems to identify distribution system locations with high concentrations of

trihalomethanes (THMs) and haloacetic acids (HAAs). Water systems will use results from the

IDSE, in conjunction with their Stage 1 DBPR compliance monitoring data, to select compliance

monitoring locations for the Stage 2 DBPR.
IDSE Guidance Manual for the Final Stage 2 DBPR 1-2 January 2006

1.1.2 Do I have to conduct an IDSE?

You are subject to the IDSE requirements of the Stage 2 DBPR if you meet the following

criteria:

• You use a primary or residual disinfectant other than ultraviolet light (UV), or you

are a consecutive system that delivers water that has been treated with a primary or

residual disinfectant other than UV.

AND

• You are a community water system (CWS) of any size, or you are a non-transient

non-community water system (NTNCWS) that serves > 10,000 people.

IDSE requirements do not apply to NTNCWSs serving fewer than 10,000 people, although these

systems have other requirements under the Stage 2 DBPR. Transient non-community water

systems (TNCWSs) are not subject to any part of the Stage 2 DBPR. 

There are four options systems can use to comply with the IDSE requirements of the

Stage 2 DBPR:

• Qualify for a Very Small System (VSS) Waiver

• Meet 40/30 Certification requirements

• Conduct a System Specific Study (SSS) using existing monitoring results or a

distribution system hydraulic model

• Conduct Standard Monitoring

The four options are described briefly in Section 1.2 of this chapter, with further details provided

in the remainder of this guidance manual. 

1.1.3 What guidance materials are available for the IDSE?

EPA has developed two guidance manuals and an on-line tool to help you comply with

the IDSE requirement. This manual is comprehensive and includes IDSE requirements and

technical guidance for all system sizes and types and all IDSE options, designed for easy access

to specific modules. The second manual, entitled the Initial Distribution System Evaluation

Guide for Systems Serving < 10,000 People, is targeted to smaller systems and focuses on

information they are most likely to use. It provides examples to help smaller systems as they

proceed with satisfying IDSE requirements. It does not, however, discuss the IDSE SSS options.

EPA has also developed the IDSE Tool, available on-line at

http://www.epa.gov/safewater/disinfection/stage2 and on CD. The IDSE tool walks systems

through the entire IDSE process, and it can be used in place of the IDSE guidance manuals. It

contains a Wizard you can use to determine your requirements and select the best IDSE option

for your system. The tool then creates Custom Forms for your system size and type that can be

submitted electronically for EPA or state review. See Section 1.4 for more information. Exhibit

1.1 shows the IDSE Tool home page. 
IDSE Guidance Manual for the Final Stage 2 DBPR 1-3 January 2006

Exhibit 1.1 IDSE Tool Home Page

The IDSE Guidance Manual, the IDSE Guide for Systems Serving < 10,000 People, and

the IDSE Tool address only IDSE requirements and DO NOT cover other provisions of the Stage

2 DBPR. For additional guidance on implementing the Stage 2 DBPR, you can refer to the

following EPA materials:

• The Stage 2 DBPR Quick Reference Guide

• Stage 2 Disinfectant and Disinfection Byproducts Rule: Small Entity Compliance Guide – 

One of the Simple Tools for Effective Performance (STEP) Guide Series (draft version)

EPA will be releasing draft versions of additional Stage 2 DBPR guidance manuals soon,

including The Consecutive Systems Guidance Manual, The Simultaneous Compliance Guidance

Manual, and The Operational Evaluation Guidance Manual. Your state may have additional,

state-specific materials to assist you in complying with the Stage 2 DBPR.
IDSE Guidance Manual for the Final Stage 2 DBPR 1-4 January 2006

IDSE Tool

1.1.4 How can I get copies of EPA guidance materials?

• You can download guidance manuals and fact sheets from EPA’s Web site at

http://www.epa.gov/safewater/disinfection/stage2.

• You can call the Safe Drinking Water Hotline at 1-800-426-4791

• You can call the National Service Center for Environmental Publications at 1-800-

490-9198 or visit their Web site at http://www.epa.gov/ncepihom.

Also, you may wish to contact your state drinking water program office for additional guidance.

1.1.5 How do I use this guidance manual?

To help you find information quickly, EPA has designed this manual in a modular

format. While Chapters 1 and 2 contain information for all systems, Chapters 3, 4, 5, 6 and 7

each contain comprehensive requirements for a specific IDSE option. Appendices are organized

similarly. The first three appendices include general information for all systems. Appendix D

addresses consecutive and wholesale system issues. Appendices E through H provide examples

for specific IDSE options. Exhibit 1.2 shows which chapters and appendices you should use for

the different IDSE options.

EPA recommends that once you have read the introductory materials in Chapter 1, you

use the flowchart in Chapter 2 to determine the best IDSE option for your system. Then you

can go to the chapter and appendices addressing your IDSE option and skip the rest of the

manual. If you are accessing this guidance manual electronically, you can download only those

chapters and appendices that you need to build a custom manual for your system. 

Remember that the IDSE Tool does these steps for you. The IDSE Tool

Wizard asks questions about your system and, based on your answers, extracts

the appropriate requirements summary sheet and guidance manual material. 

Chapter 2 contains requirements summary sheets for each IDSE option and compliance

schedule. These sheets contain compliance deadlines for IDSE submissions and other important

information. EPA recommends that you make a copy of your requirements summary sheets (or

if you are accessing the manual electronically, print them out) and keep them handy throughout

the IDSE process. 
IDSE Guidance Manual for the Final Stage 2 DBPR 1-5 January 2006

Exhibit 1.2a IDSE Guidance Manual Chapters and Appendices

Chapters

1 Introduction

2 Determining Your IDSE Schedule and Option

3* Very Small System Waiver

4* 40/30 Certification

5* System Specific Study Using Existing Monitoring Results

6* System Specific Study Using a Distribution System Hydraulic Model

7* Standard Monitoring

Appendices

A Factors Affecting DBP Formation

B Stage 2 DBPR and LT2ESWTR Compliance Schedule

C TTHM and HAA5 Sampling Protocol

D Consecutive and Wholesale System Issues

E Example System Specific Study using Existing Monitoring Results for a Surface Water

System Serving 40,000 People

F Example System Specific Study Using a Hydraulic Model for a Surface Water System

Serving 55,000 People

G Complex Modeling Analysis Example for a System with Multiple Sources

H Example IDSE Standard Monitoring Plan and Report for a Surface Water System

Serving 160,000 People

I Example IDSE Standard Monitoring Plan and Report for a Ground Water System

Serving 200,000 People

* You need one of these Chapters for the IDSE
IDSE Guidance Manual for the Final Stage 2 DBPR 1-6 January 2006

Chapter 1

Chapter 2

Appendix A

Appendix B

PLUS

Systems qualifying for the VSS Waiver

Systems qualifying for 40/30 Certification

Systems conducting an SSS using existing

monitoring results

Systems conducting an SSS using a model

Systems conducting standard monitoring

Chapter 3

Chapter 4

Chapter 5

Appendix E

Chapter 6

Appendix C

Appendix F

Appendix G

Chapter 7

Appendix C

Appendix H

Appendix I

PLUS

Consecutive and wholesale systems only Appendix D

All Systems

Chapter 1

Chapter 2

Appendix A

Appendix B

PLUS

Systems qualifying for the VSS Waiver

Systems qualifying for 40/30 Certification

Systems conducting an SSS using existing

monitoring results

Systems conducting an SSS using a model

Systems conducting standard monitoring

Chapter 3

Chapter 4

Chapter 5

Appendix E

Chapter 6

Appendix C

Appendix F

Appendix G

Chapter 7

Appendix C

Appendix H

Appendix I

PLUS

Consecutive and wholesale systems only Appendix D

All Systems

Exhibit 1.2b Building a Custom IDSE Guidance Manual for Your System
IDSE Guidance Manual for the Final Stage 2 DBPR 1-7 January 2006

1.1.6 Whom do I call with questions?

Because compliance activities begin soon after the Stage 2 DBPR is

finalized, EPA and states will be working together to implement the IDSE. In

some cases, EPA will be your main point of contact during the first phases of the

IDSE. In other cases, your state will be your main point of contact. 

To identify your point of contact for the IDSE, visit EPA’s website at

http://www.epa.gov/safewater/disinfection/stage2. The website contains a list of contact

numbers for the IDSE by state. You can also call the EPA SDWA hotline at 1-800-426-4791 for

this information. Refer to Section 1.4 of this chapter for more information on how the IDSE will

be implemented. 

1.2 Overview of IDSE Options

There are four options available to systems to meet IDSE requirements. Your option will

depend on your technical resources, existing monitoring results, size, and preference. The four

options are described briefly below, with further details provided in the remainder of this

guidance manual. 

• Very Small System (VSS) Waiver. Systems serving fewer than 500 people that

have TTHM and HAA5 data automatically receive the VSS waiver unless they are

notified by EPA or their state that they must conduct an IDSE. Systems receiving the

VSS waiver have no further IDSE requirements.

• 40/30 Certification. Systems can fulfill the IDSE requirements by certifying that all

individual TTHM and HAA5 monitoring results for compliance with the Stage 1

DBPR are less than or equal to 0.040 mg/L for TTHM and 0.030 mg/L for HAA5

during a prescribed 2-year time period. In addition, the system must not have had any

Stage 1 DBPR monitoring violations for TTHM and HAA5 during the same period. 

The system must submit the required 40/30 certification and, unless told otherwise by

EPA or their state, they have no further requirements under the IDSE.

• System Specific Study (SSS). Systems can meet IDSE requirements using existing

monitoring results or a distribution system hydraulic model if their data or model

meet certain minimum criteria. Systems conducting an SSS must prepare an SSS

plan and IDSE report. Existing monitoring requirements were developed to be

equivalent to standard monitoring.

• Standard Monitoring. Any system can choose to conduct standard monitoring, even

if they receive a VSS, qualify for the 40/30 certification, or have enough data to

conduct an SSS. Standard monitoring entails 1 year of distribution system

monitoring at multiple locations (in addition to Stage 1 DBPR monitoring). The

required sampling frequency and minimum number of sample locations depend on
IDSE Guidance Manual for the Final Stage 2 DBPR 1-8 January 2006

population served and source water type. Systems conducting standard monitoring

must prepare a standard monitoring plan and IDSE report.

1.3 IDSE Schedule

IDSE activities begin soon after the Stage 2 DBPR is finalized. Appendix B provides the

overall schedule for the Stage 2 DBPR and Long Term 2 Enhanced Surface Water Treatment

Rule (LT2ESWTR) to show how the IDSE fits into the overall compliance schedule for both

rules. Exhibit 1.3 shows a more detailed schedule for IDSE activities only. Note that the

schedule is staggered by system size, and that the schedule for consecutive and wholesale

systems is based on the population served by the largest system in the combined distribution

system. Guidance for determining your schedule is in Chapter 2. 

1.4 Early Implementation Process

Because IDSE activities begin soon after the Stage 2 DBPR is finalized, EPA and states

will be working together to implement the IDSE. To facilitate review and processing of IDSE

submissions, EPA has created the Information Processing and Management Center (IPMC). 

The IPMC is both a receiving facility and a web-based data management system that allows EPA

and states to access, track, and respond to IDSE submissions. 

The IPMC is password protected and accessible only by EPA and state drinking water

representatives. IDSE submissions will not, however, be considered confidential business

information (CBI) and are subject to the Freedom of Information Act (FOIA). Therefore, your

IDSE submissions should not contain information that poses a security risk to your system. 

Chapters 5, 6, and 7 of this manual provide guidelines on the kinds of information you may want

to exclude from your distribution system schematic for security reasons.

One advantage of the IPMC is that it provides a one-stop location for IDSE submissions. 

Regardless of whether EPA or your state is reviewing your IDSE materials, all submissions go to

the same address. See Exhibit 1.4 on page 1-10 for ways in which you can submit IDSE

materials to the IPMC. EPA and/or your state will review your IDSE plan and report. If they

have concerns regarding your submission, they will work with you to resolve those issues during

the one year review period. 

If you have questions during the IDSE, you should visit EPA’s website at

http://www.epa.gov/safewater/disinfection/stage2 to determine the contact name and phone

number for the IDSE for your state. You can also call the Safe Drinking Water Hotline at 1-800-

426-4791 for this information.
IDSE Guidance Manual for the Final Stage 2 DBPR 1-9 

Schedule 1

Systems

serving

 >100,000 1

Schedule 2

Systems

serving

50,000-99,999 1

Schedule 3

Systems

serving

 10,000-49,999 1

1 For consecutive and wholesale systems, the schedule is based on the population served by the largest system in a combined distri2 Communication with the system is included in the EPA/state review period.

Schedule 4

Systems

serving

 <10,000 1

2006 2007 2008 2009 2

IDSE plans and

certifications due

IDSE plans and

certifications due

IDSE plans and

certifications due

IDSE plans and

certifications due

IDSE reports

due

IDSE reports

due

IDSE reports

due

ID

J F M

A

M J J A

S

O

N

D J F M

A

M J J A

S

O

N

D J F M

A

M J J A

S

O

N

D J F M

A

M J J A

S

O

N

D J F M

A

M 

EPA/state

reviews plans 2

EPA/state

reviews reports

EPA/state

reviews reports

EPA/state

reviews reports

E

rev

EPA/state

reviews plans 2

EPA/state

reviews plans 2

EPA/state

reviews plans 2

IDSE Monitoring

(Recommended)

IDSE Monitoring

(Recommended)

IDSE Monitoring

(Recommended)

IDSE Monitoring

(Recommended)

2006 2007 2008 2009 2

J F M

A

M J J A

S

O

N

D J F M

A

M J J A

S

O

N

D J F M

A

M J J A

S

O

N

D J F M

A

M J J A

S

O

N

D J F M

A

M 

Exhibit 1.3 Staggered Schedule for the IDSE
IDSE Guidance Manual for the Final Stage 2 DBPR 1-10 January 2006

Exhibit 1.4 Options for Submitting IDSE Material to EPA and States Through the

IPMC 1

Option 1 Option 2 Option 3 

Use the IDSE Tool

to submit completed

certifications, plans

and reports

electronically

Mail paper copies of 

submissions to:

E-mail electronic submissions

as attachments to:

 STAGE 2 DBPR

 US EPA-IPMC

 P O Box 98

 Dayton, OH 45401-0098

stage2mdbp@epa.gov

Notes:

1. You can use one of these three options to submit IDSE materials to the IPMC. 

The IPMC accepts a variety of electronic formats:

• Adobe PDF file (*.pdf)

• Microsoft Word (*.doc)

• WordPerfect (*.wpd)

• Image files (*.gif, *.bmp, *.jpg, *.jpeg)

• Microsoft Excel (*.xls)

• Text file (*.txt)

1.5 Changes to IDSE Requirements Since the Proposed Stage 2 DBPR

Several changes have been made to the IDSE requirements since the publication of the

proposed Stage 2 DBPR on August 18, 2003. Many of these changes are in response to public

comment received on the proposed rule and are intended to facilitate implementation. These

changes, which are discussed in more detail below, include:

• Change from plant-based to population-based monitoring for all systems

• Change in definition of consecutive systems 

• Staggered IDSE schedule

• Changes to VSS waivers

• Change in 40/30 requirements

• Clarification to the IDSE SSS option

• Elimination of Stage 2A

Change from plant-based to population-based monitoring for all systems

The Stage 2 DBPR proposal included population-based monitoring requirements for

consecutive systems that purchase all of their water. For all other systems, plant-based
IDSE Guidance Manual for the Final Stage 2 DBPR 1-11 January 2006

monitoring requirements were proposed. The plant-based approach, consistent with Stage 1

DBPR compliance monitoring requirements, is grounded in the assumption that larger systems

have more treatment plants and thus greater system complexity. While this is generally true, the

plant-based approach created disproportionately burdensome monitoring requirements for some

systems where the number of plants did not correlate with system size, such as larger systems

with only a few very large plants or smaller systems with many disinfecting wells. Moreover, a

plant-based approach can complicate monitoring of purchased water systems, particularly

complex ones with multiple connections. 

For these reasons, EPA has developed population-based compliance monitoring

requirements for all systems for the final Stage 2 DBPR. EPA believes that the new

population-based approach makes monitoring requirements simpler and more equitable for

systems of the same size and type.

Change in definition of consecutive system

For the Stage 2 DBPR proposal, the definition for consecutive systems specified the

minimum length of time (60 days) a system must receive water from a wholesale system to be

considered a consecutive system. EPA received public comments on this definition. Several

commenters expressed concerns with including a time period of water delivery that defined

whether a system was a consecutive system or wholesale system. This change was also made

due to the change to population based monitoring because it is no longer necessary to define

consecutive system entry points as it was under plant based monitoring. EPA has dropped this

requirement from the final rule and has provided some flexibility for states to determine which

systems are part of a combined distribution system (without presenting a time criterion).

Staggered IDSE schedule

EPA has modified the proposed compliance schedule to stagger deadlines for CWSs and

NTNCWSs serving 10,000 to 99,999 people to allow for a more evenly distributed workload and

greater opportunity for EPA and state involvement. The final compliance schedule includes a

formal review period for EPA and/or state review of IDSE plans and 40/30 certifications as well

as IDSE reports. The staggered schedule also provides time for analytical laboratories to build

up capacity as necessary to accommodate the sample analysis needs of systems. The new IDSE

plan and IDSE report submission dates are shown in Exhibit 1.3. It is important to note that, as

in the proposal, smaller systems may have to comply on an earlier schedule than indicated for

their individual system size if they are part of a combined distribution system that includes a

large system. This is discussed further in Chapter 2.

Changes to VSS waivers

The final rule grants a waiver from the IDSE requirements to community water systems

serving fewer than 500 people that have taken TTHM and HAA5 samples. This provision was

changed from the proposal to reflect that most small systems have sampling locations that are

representative of both high TTHM and high HAA5 because they have small and simple
IDSE Guidance Manual for the Final Stage 2 DBPR 1-12 January 2006

distributions systems. In addition, many very small systems are ground water systems which

typically have stable DBP levels (ground water systems tend to have lower DBP levels than

surface water systems). EPA recognizes, however, that 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, EPA or a state can contact a very small system and require

them to conduct an IDSE. 

Change in 40/30 requirements

The reporting requirements for the 40/30 certification option have been reduced from the

requirements in the proposed Stage 2 DBPR. 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 meets all the requirements of the 40/30 certification and to include their Stage 2

compliance monitoring recommendations in their Stage 2 compliance 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. EPA or the state 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.

Clarification to the IDSE SSS option

The final rule includes more specific requirements than the proposal regarding how

systems can use distribution system hydraulic models and existing monitoring results for the

IDSE SSS. This change was made to help systems better understand expectations under this

provision and lessen the chances of an SSS plan not being approved. The new modeling

requirements reflect that distribution system hydraulic models can appropriately identify

monitoring locations by predicting water age in distribution systems if they meet certain

minimum requirements. Existing monitoring results requirements are equivalent to Standard

Monitoring requirements, except they apply to data already collected.

Elimination of Stage 2A

The Stage 2 DBPR proposal included a phased-in approach to calculating compliance

with MCLs using a Locational Running Annual Average (LRAA), referred to as Stage 2A and

Stage 2B which coincided with the IDSE period. EPA received public comments that found this

confusing, and this provision is no longer in the final rule. What was referred to in the proposal

as Stage 2B compliance monitoring is now referred to as Stage 2 Compliance Monitoring.
IDSE Guidance Manual for the Final Stage 2 DBPR 2-1 January 2006

This chapter covers:

2.1 System Characteristics that Affect IDSE Requirements

2.2 Determining Your IDSE Schedule

2.3 Determining Your IDSE Option

2.4 IDSE Requirements Summary Sheets

2.0 Determining Your IDSE Schedule and Option

2.1 System Characteristics that Affect IDSE Requirements

Your IDSE schedule, option, and other requirements depend on your system

characteristics. In general, there are three system characteristics that drive IDSE requirements: 

• Whether you are a subpart H system or a ground water system.

• The population served by your system.

• If you are a consecutive or wholesale system, the population served by the largest

system in your combined distribution system. 

Regulatory definitions for subpart H systems, consecutive systems, wholesale systems, and

combined distribution systems are provided in the definitions section at the beginning of this

guidance manual. Appendix D provides additional discussion of important definitions for

consecutive and wholesale systems.

2.2 Determining Your IDSE Schedule

EPA has established four IDSE compliance schedules, shown graphically in Exhibit 1.3

and summarized in the table in Exhibit 2.1. If you are a consecutive or wholesale system, your

schedule is based on the population served by the largest system in your combined distribution

system. If you are not a consecutive or wholesale system, your schedule is based on the

population served by your individual system. EPA and your state have worked together to

identify which systems are part of combined distribution systems. 
1 The Stage 2 DBPR contains provisions that allow systems to modify their Stage 2 DBPR compliance

monitoring plan after their IDSE has been completed. Systems should work with their state if they believe that their

Stage 2 compliance monitoring sites should be changed after their IDSE is completed.

IDSE Guidance Manual for the Final Stage 2 DBPR 2-2 January 2006

Exhibit 2.1 IDSE Schedule Number

If you are this kind of system: You are on

IDSE

schedule

number

Your first

deadline is

Systems serving 100,000 or more people OR belonging to

a combined distribution system in which the largest system

serves 100,000 people or more

1 October 1, 2006

Systems serving 50,000 to 99,999 people OR belonging to

a combined distribution system in which the largest system

serves 50,000 to 99,999 people

2 April 1, 2007

Systems serving 10,000 to 49,999 OR belonging to a

combined distribution system in which the largest system

serves 10,000 to 49,999 people

3 October 1, 2007

Systems serving fewer than 10,000 people and not

belonging to a combined distribution system in which any

system serves 10,000 people or more

4 April 1, 2008

Every system that is subject to the Stage 2 DBPR should receive a letter from EPA or the

state with information on the Stage 2 DBPR and a determination of IDSE schedule (i.e., schedule

1, 2, 3, or 4). Exhibit 2.2 is an example of a letter sent by EPA to a system on schedule 1. 

Letters from states and letters to systems on other schedules look similar. Systems that EPA or

the state anticipates are on schedules 1 and 2 should receive a letter in February 2006. Systems

that EPA or the state anticipates are on schedules 3 and 4 should receive a letter in July 2006.

States determined your schedule based on their records on your population served and

connections to other systems. You should make sure the schedule determination in the letter is

consistent with your system size, source water type, and buying / selling relationships with other

systems before proceeding. 

Some systems may be planning treatment changes before, during, or after the IDSE. 

Most treatment plant modifications should not impact the relative formation of DBPs in your

distribution system. There are no provisions in the Stage 2 DBPR that allow the IDSE schedule

to be changed or delayed1

. Not meeting the IDSE compliance deadlines in your requirements

summary sheets results in a Tier 3 monitoring and reporting violation for your system. 
IDSE Guidance Manual for the Final Stage 2 DBPR 2-3 January 2006

Exhibit 2.2 Example Letter from EPA to System on Schedule 1

 

System Name January 31, 2006

System Address

City State Zip

 Important New Rule Roll Out 

Stage 2 Disinfectants and Disinfection Byproduct Rule (Stage 2 DBPR)

This letter applies to those systems serving 100,000 or more people OR those systems in which the largest

system in their combined distribution system serves 100,000 or more people. These systems may also be

referred to as Schedule 1 systems.

This letter is the third in a series of communications to inform you of the Stage 2 DBPR requirements. The Rule

was published in the Federal Register on January 4, 2006. The Stage 2 DBPR builds on existing regulations by

requiring water systems to meet disinfection byproduct maximum contaminant levels (MCLs) at each disinfection

byproduct monitoring site in the distribution system to better protect public health. All community water

systems (CWSs) and non-transient noncommunity water systems (NTNCWSs) that use or deliver water treated with

a primary or residual disinfectant other than ultraviolet light are subject to the Stage 2 DBPR requirements.

However, NTNCWS, serving less than 10,000 people do not have to comply with the Initial Distribution System

Evaluation (IDSE) requirements (see below for an explanation of IDSE). An electronic copy of the Stage 2 DBPR

can be downloaded from EPA’s website at www.epa.gov/safewater/disinfection/stage2. 

The first major requirement of the Stage 2 DBPR is for systems to conduct an IDSE. The purpose of the IDSE is to

identify locations in the distribution system that have the highest trihalomethane (TTHM) and highest haloacetic

acid (HAA5) concentrations. The locations in the distribution system with the highest TTHM and highest HAA5

concentrations will be used as Stage 2 DBPR compliance monitoring sites. 

EPA and State records show that your system is required to comply with Schedule 1 IDSE

requirements. These requirements are based on the information that your system:

• Serves 100,000 or more people (or those systems those systems in which the largest system in your

combined distribution system serves 100,000 or more people); and 

• Provides water that has been treated with a primary or residual disinfectant other than ultraviolet

light.

If you believe our records are incorrect please notify us at stage2mdbp@epa.gov as soon as possible.

By October 1, 2006, Schedule 1 systems will have to comply with IDSE requirements by submitting a

standard monitoring plan, system specific study plan, or a 40/30 certification. Systems that qualify for

a very small system waiver would be exempt from this IDSE requirement.

(Continued)
IDSE Guidance Manual for the Final Stage 2 DBPR 2-4 January 2006

IDSE Tool

Whom should I call if I don’t receive my letter?

To identify your point of contact for the IDSE, visit EPA’s website at 

http://www.epa.gov/safewater/disinfection/stage2. The website contains a list of contact

numbers for the IDSE by state. You can also call the EPA SDWA hotline at 1-800-426-

4791 for this information. 

2.3 Determining Your IDSE Option

There are four options available to meet the requirements of the IDSE:

• Qualify for a Very Small System (VSS) Waiver

• Meet 40/30 Certification requirements

• Conduct a System Specific Study (SSS) using existing monitoring results or a hydraulic

model

• Conduct Standard Monitoring

You can use the flowchart in Exhibit 2.3 and Checklists 2.1 and 2.2 to help you determine the right

IDSE option for your system. Example 2.1 shows how a surface water system serving 25,000

people used the information in this chapter to determine their requirements.

The IDSE Tool works through the flowchart and checklists to determine the most

suitable IDSE Option for your system. The tool is available on EPA’s website at 

http://www.epa.gov/safewater/disinfection/stage2.

2.4 IDSE Requirements Summary Sheets

EPA has prepared Requirements Summary Sheets that contain key information and

compliance deadlines for each IDSE schedule and option. A list of requirements summary sheets

and their page numbers is provided in Exhibit 2.4 and in the table of contents of this guidance

manual. EPA recommends that you make a copy of the requirements summary sheet for your

IDSE schedule and option and keep it handy throughout the IDSE process. If you are conducting

an SSS or standard monitoring, make sure you also make a copy of the Attachment with

monitoring requirements.

How does population served affect my IDSE requirements?

IDSE Schedule

• If you are a consecutive or wholesale system, your IDSE schedule is based on the population

served by the largest system in your combined distribution system and is designated in a letter

from EPA or your state.

• If you are not a consecutive or wholesale system, your IDSE schedule is based on the

population served by your system.

IDSE Monitoring

• For all systems, IDSE monitoring locations and sampling frequency are based on the

population served by your individual system.
IDSE Guidance Manual for the Final Stage 2 DBPR 2-5 January 2006

Do you

have TTHM and

HAA5 data equivalent

to w hat is required by

the Stage 1

DBPR?

For the periods listed below 1, is

Every TTHM sample < 0.040 mg/L and

Every HAA5 sample < 0.030 mg/L?

If you are on Schedules 1 or 2 – 8 consecutive

quarters starting no earlier than January 2004

If you are on Schedules 3 or 4 – 8 consecutive

quarters starting no earlier than January 2005

Have you

 had any Stage 1 TTHM

or HAA5 monitoring

violations during the

eligibility period?

You qualify for 40/30 certification.

Go to the follow ing pages:

-Systems on Schedule 1 – Page 2-13

-Systems on Schedule 2 – Page 2-15

-Systems on Schedule 3 – Page 2-17

-Systems on Schedule 4 – Page 2-19

See Chapter 4 for more information on

the 40/30 certification. Do you

have a distribution

system

model?

Does

your

model meet

all of the minimum

requirements listed in

Checklist 2.1 on

the next

page?

You are eligible for a system specific

study although you also have the option to

conduct standard monitoring. If you

plan to conduct a system specific study, go to

the follow ing pages:

-Systems on Schedule 1 – Page 2-21

-Systems on Schedule 2 – Page 2-23

-Systems on Schedule 3 – Page 2-25

-Systems on Schedule 4 – Page 2-27

See Chapters 5 and 6 for more information

on system specific studies.

You are required to conduct standard

monitoring. Go to the follow ing pages:

-Systems on Schedule 1 – Page 2-31

-Systems on Schedule 2 – Page 2-33

-Systems on Schedule 3 – Page 2-35

-Systems on Schedule 4 – Page 2-37

See Chapter 7 for more information on

standard monitoring.

Yes

Yes

Yes Yes

Yes

Yes

No

No

No

No

No

Does

your data

meet all of

the requirements in

Checklist 2.2

on Page

2-7?

Do you

have extensive

TTHM and HAA5 data

(compliance and/or

operational)?

No

Yes

Does your

system serve 500

people or

more?

Do you

have TTHM and HAA5

data as required by the

Stage 1 DBPR? You qualify for a very small system w aiver.

You do not have to do an IDSE unless EPA or

your State contacts you. Go to Page 2-11 for a summary of

your Stage 2 requirements. See Chapter 3 for more

information.

Yes

Yes

No

No

1Unless you are on reduced monitoring for Stage 1 and w ere 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.

No

Exhibit 2.3 Flowchart for Determining Your IDSE Option
IDSE Guidance Manual for the Final Stage 2 DBPR 2-6 January 2006

Checklist 2.1 Minimum Requirements Checklist for an SSS

Using a Distribution System Hydraulic Model

Yes No

G G Does your model run in extended period simulation?

G G Does it simulate 24-hr variation in demand and show a consistently repeating 24-hr pattern

of 24-hr residence time?

G G Does your model include 75% of pipe volume?

G G Does it include 50% of pipe length?

G G Does it represent all pressure zones?

G G Does your model include all 12" diameter and larger pipes?

G G Does your model include all 8" diameter 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?

G G Does it include all 6" diameter and larger pipes that connect remote areas of the

distribution system to the main portion of the system?

G G Are all storage facilities with standard operations represented in your model?

G G Are all active pump stations with controls represented in your model?

G G Does your model include all active control valves?

G G Has your model been calibrated (or do you have plans to complete calibration in the next

12 months) for the current configuration of the distribution system during periods of high

TTHM formation potential? 

G G Were all storage facilities evaluated as part of the calibration process?

If you answered yes to all of the above questions, you meet EPA’s minimum requirements for a model

SSS. Remember, though, that EPA or the state can still require you to conduct standard monitoring,

even if you meet the minimum requirements, or you can choose to conduct standard monitoring. 

Refer to Section 6.1 for additional guidance on minimum requirements.
IDSE Guidance Manual for the Final Stage 2 DBPR 2-7 January 2006

Checklist 2.2 Minimum Requirements Checklist for an SSS

Using Existing Monitoring Results

Yes No

G G Do you have at least the minimum number of distribution system monitoring locations

shown in the table below from which you collected TTHM and HAA5 samples?

G G Do you have at least the minimum number of TTHM samples and HAA5 samples shown in

the table below?

G G Was each monitoring location sampled once during the month of high TTHM, high HAA5 or

warmest water temperature for every 12 months of data?

G G Were all samples collected and analyzed in accordance with an approved EPA method

and by a certified laboratory?

G G Were all sample results collected no earlier than five years prior to your SSS plan

submission deadline?

G G Have your distribution system and treatment not changed significantly since you collected

your samples?

G G Are your existing monitoring locations representative of your entire distribution system?

If you answered yes to all of the above questions, you meet EPA’s minimum requirements for an SSS using

existing monitoring results. Remember, though, that EPA or your state can still require you to conduct standard

monitoring, even if you meet the minimum requirements, or you can choose to conduct standard monitoring. 

Refer to Section 5.1 for additional guidance on minimum requirements.

Source Water

Type

System Size Category

(Population Served)

Minimum Number of

Monitoring Locations

Minimum Number of

Samples

TTHM HAA5

Subpart H

<500 3 3 3

500-3,300 3 9 9

3,301-9,999 6 36 36

10,000-49,999 12 72 72

50,000-249,999 24 144 144

250,000-999,999 36 216 216

1,000,000-4,999,999 48 288 288

>5,000,000 60 360 360

Ground Water

<500 3 3 3

500-9,999 3 9 9

10,000-99,999 12 48 48

100,000-499,999 18 72 72

>500,000 24 96 96
IDSE Guidance Manual for the Final Stage 2 DBPR 2-8 January 2006

IDSE Tool

Example 2.1 Determining IDSE Requirements for a Consecutive System Serving

25,000 people

System X is a consecutive system serving 25,000 people. They purchase all of their water from

System Y, which is a wholesale surface water system that serves their own retail population of

110,000 people. System X received a letter from their state notifying them of the new Stage 2

DBPR and stating that they are on Schedule 1. System X called System Y right away to

confirm that they were on the same schedule.

Next, System X began working through the flowchart in Exhibit 2.3 of the IDSE guidance

manual to determine their IDSE option. 

• They serve more than 500 people and cannot qualify for the VSS waiver. 

• Their Stage 1 DBPR monitoring results for TTHM were between 45 and 70

micrograms per liter (:g/L), so they did not qualify for the 40/30 certification. 

• System X knows that System Y had been collecting TTHM and HAA5 samples

from both systems for a long time. They contacted System Y and requested

TTHM and HAA5 data collected from System X for the last five years. System

X worked closely with System Y and determined that their existing monitoring

results met the minimum requirements in Checklist 2.2. Therefore, System X

selected the SSS using existing monitoring results as their IDSE option. 

To determine which chapters of the IDSE manual they needed, System X referred to Exhibit

1.2. System X then downloaded Chapters 1, 2, and 5, and Appendices A, B, D, and E of the

IDSE guidance manual from http://www.epa.gov/safewater/disinfection/stage2 to build their

own custom manual. They made a copy of the requirements summary sheet titled “System

Specific Study Requirements - Schedule 1" and the “System Specific Study Requirements -

Attachment (For All Schedules)” sheet to keep handy throughout the IDSE process. Then they

began preparing their SSS Plan.

Note: If System X had used the IDSE tool, it would have done these steps for

them and created a custom form for their SSS Plan.
IDSE Guidance Manual for the Final Stage 2 DBPR 2-9 January 2006

Exhibit 2.4 List of Requirements Summary Sheets

Requirement Summary Sheet Page 

Requirements for Very Small System Waivers 2-11

40/30 Certification Requirements - Schedule 1 2-13

40/30 Certification Requirements - Schedule 2 2-15

40/30 Certification Requirements - Schedule 3 2-17

40/30 Certification Requirements - Schedule 4 2-19

System Specific Study Requirements - Schedule 1 2-21

System Specific Study Requirements - Schedule 2 2-23

System Specific Study Requirements - Schedule 3 2-25

System Specific Study Requirements - Schedule 4 2-27

System Specific Study Requirements - Attachment (For All Schedules) 2-29

Standard Monitoring Requirements - Schedule 1 2-31

Standard Monitoring Requirements - Schedule 2 2-33

Standard Monitoring Requirements - Schedule 3 2-35

Standard Monitoring Requirements - Schedule 4 2-37

Standard Monitoring Requirements - Attachment (For All Schedules) 2-39
IDSE Guidance Manual for the Final Stage 2 DBPR 2-10 January 2006

This page left intentionally blank.
IDSE Guidance Manual for the Final Stage 2 DBPR 2-11 January 2006

Requirements for Very Small System Waivers Page 1 of 2

This summary sheet is for systems that:

• Serve fewer than 500 people, and

• Have taken TTHM and HAA5 samples.

WHAT TO DO NOW:

You have NO further requirements for the IDSE unless EPA or your state contacts you. If EPA

or your state contacts you, they will work with you to determine an appropriate IDSE schedule

for your system. See Chapter 3 for more information.

Continue compliance monitoring for the Stage 1 DBPR until you begin compliance monitoring

for the Stage 2 DBPR.

NEXT STEPS: 

You must start taking Stage 2 DBPR compliance monitoring samples by the deadline listed on

the next page. You must prepare a Stage 2 compliance monitoring plan before you take your

first compliance sample.

If you have high levels of DBPs, you may need to make system changes to meet the

requirements of the Stage 2 DBPR. See Chapter 1, Section 1.1 of this guidance manual, for a

list of additional guidance materials for the Stage 2 DBPR. If you buy water from another public

water system, see EPA’s Consecutive System Guidance Manual for more information.

Reminder:

Your requirements for Stage 2 DBPR compliance monitoring (locations and frequency) are

based on the population served by your system and are listed on the next page.
IDSE Guidance Manual for the Final Stage 2 DBPR 2-12 January 2006

Requirements for Very Small System Waivers Page 2 of 2

Stage 2 DBPR Compliance Monitoring Deadlines

Schedule (population served)1 Year in Which You Must Begin Stage 2

Compliance Monitoring

Schedule 1 (> 100,000) 2012

Schedule 2 (50,000 - 99,999) 2012

Schedule 3 (10,000 - 49,999) 2013

Schedule 4 (< 10,000) 2013 or 20142

1

 If you are a consecutive or wholesale system, your schedule is based on the largest system in your

combined distribution system. You should have received a letter from EPA or your state with your

schedule for the Stage 2 DBPR. 

2

 2014 if Cryptosporidium monitoring is required under 141.701(a)(4) or (a)(6).

Stage 2 DBPR Compliance Monitoring Requirements

Source Water

Type

Population Size

Category1

Monitoring

Frequency2

Distribution System

Monitoring Location3

Subpart H <500 per year 2

Ground Water <500 per year 2 1 Your monitoring requirements (location and frequency) are based on the population served by your

individual system.

2

 You must monitor during the month of highest DBP concentrations. 

3

 You are required to take individual TTHM and HAA5 samples at the locations with the highest TTHM and

HAA5 concentrations, respectively. Only one location with a dual sample set per monitoring period is

needed if the highest TTHM and HAA5 concentrations occur at the same location and month.
IDSE Guidance Manual for the Final Stage 2 DBPR 2-13 January 2006

40/30 Certification Requirements - Schedule 1 Page 1 of 2

Submit 40/30

Certification by

Oct. 1, 2006

Rule Promulgation

Collect 40/30 Data for Any 8 Consecutive

Quarter Eligibility Period

Jan. 1, 2004

2004 2005 2006

IDSE Tool

This summary sheet is for systems that satisfy all of the following requirements for any 8

consecutive quarter eligibility period beginning no earlier than January 2004:

• You serve 100,000 people or more OR are part of a combined distribution system where

the largest system serves 100,000 people or more

• You have TTHM and HAA5 data equivalent to what is required by the Stage 1 DBPR

• No individual sample exceeds 0.040 mg/L for TTHM

• No individual sample exceeds 0.030 mg/L for HAA5

• Your system did not have any TTHM or HAA5 monitoring violations

WHAT TO DO NOW:

1. Prepare a certification letter Due: October 1, 2006

You must submit the certification letter to the address or e-mail provided below, or use the IDSE

Tool to prepare and submit your certification letter. Note that EPA or your state could contact

you and require more information, or require you to conduct an IDSE.

For more information and letter templates:

See Chapter 4 of this guidance manual. If you are a consecutive or wholesale

system, see Appendix D of this guidance manual. A template you can use for your

40/30 certification letter is included on Page 4-5. If you would like an electronic

template, use the IDSE Tool, available at

http://www.epa.gov/safewater/disinfection/stage2.

2. Mail your 40/30 certification letter to:

STAGE 2 DBPR

US EPA-IPMC

P O Box 98

Dayton, OH 45401-0098

Email to stage2mdbp@epa.gov or submit electronically via the IDSE tool

3. Continue compliance monitoring for the Stage 1 DBPR until you begin compliance

monitoring for the Stage 2 DBPR.
IDSE Guidance Manual for the Final Stage 2 DBPR 2-14 January 2006

40/30 Certification Requirements - Schedule 1 Page 2 of 2

NEXT STEPS:

You have additional Stage 2 DBPR requirements. You must:

• Select Stage 2 DBPR compliance monitoring sites.

• Develop a Stage 2 compliance monitoring plan before you take your first compliance

sample. If you are a subpart H system and you serve more than 3,300 people, you need

to submit your plan to the state.

• Begin annual or quarterly Stage 2 compliance monitoring during the period starting with

April 2012, according to your Stage 2 compliance monitoring plan.

See Chapter 1, Section 1.1 of this guidance manual for a list of additional guidance materials

for the Stage 2 DBPR.

Reminder:

Your requirements for Stage 2 compliance monitoring are based on the population of your

system and are listed below.

Stage 2 DBPR Compliance Monitoring Requirements

Source

Water

Type

Population Size

Category1

Monitoring

Frequency2

Distribution System Monitoring Location 

Total per

monitoring

period3

Highest

TTHM

Locations

Highest

HAA5

Locations

Existing Stage

1 DBPR

Compliance

Locations

Subpart H 

<500 per year 2 1 1 ...............

500-3,300 per quarter 2 1 1 ...............

3,301-9,999 per quarter 2 1 1 ...............

10,000-49,999 per quarter 4 2 1 1

50,000-249,999 per quarter 8 3 3 2

250,000-999,999 per quarter 12 5 4 3

1,000,000-4,999,999 per quarter 16 6 6 4

$ 5,000,000 per quarter 20 8 7 5

Ground

Water

<500 per year 2 1 1 ...............

500-9,999 per year 2 1 1 ...............

10,000-99,999 per quarter 4 2 1 1

100,000-499,999 per quarter 6 3 2 1

$ 500,000 per quarter 8 3 3 2

1

 Your monitoring requirements (location and frequency) are based on the population served by your system. 2

 All systems must monitor during month of highest DBP concentrations. 3

 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 HAA5 concentrations, respectively. Only one location with a dual sample set per monitoring period is

needed if highest TTHM and HAA5 concentrations occur at the same location (and month, if monitored annually).
IDSE Guidance Manual for the Final Stage 2 DBPR 2-15 January 2006

40/30 Certification Requirements - Schedule 2 Page 1 of 2

Submit 40/30

Certification by

April 1, 2007

Rule Promulgation

Collect 40/30 Data for Any 8 Consecutive

Quarter Eligibility Period

Jan. 1, 2004

2004 2005 2006 2007

IDSE Tool

This summary sheet is for systems that satisfy all of the following requirements for any 8

consecutive quarter eligibility period beginning no earlier than January 2004:

• You serve 50,000-99,999 people OR are part of a combined distribution system where

the largest system serves 50,000-99,999 people

• You have TTHM and HAA5 data equivalent to what is required by the Stage 1 DBPR

• No individual sample exceeds 0.040 mg/L for TTHM

• No individual sample exceeds 0.030 mg/L for HAA5

• Your system did not have any TTHM or HAA5 monitoring violations

WHAT TO DO NOW:

1. Prepare a certification letter Due: April 1, 2007

You must submit the certification letter to the address or e-mail provided below, or use the IDSE

Tool to prepare and submit your certification letter. Note that EPA or your state could contact

you and require more information, or require you to conduct an IDSE.

For more information and letter templates:

See Chapter 4 of this guidance manual. If you are a consecutive or wholesale system, see

Appendix D of this guidance manual. A template you can use for your 40/30

certification letter is included on Page 4-5. If you would like an electronic template,

use the IDSE Tool, available at http://www.epa.gov/safewater/disinfection/stage2.

2. Mail your 40/30 certification letter to:

STAGE 2 DBPR

US EPA-IPMC

P O Box 98

Dayton, OH 45401-0098

Email to stage2mdbp@epa.gov or submit electronically via the IDSE tool

3. Continue compliance monitoring for the Stage 1 DBPR until you begin compliance

monitoring for the Stage 2 DBPR.
IDSE Guidance Manual for the Final Stage 2 DBPR 2-16 January 2006

40/30 Certification Requirements - Schedule 2 Page 2 of 2

NEXT STEPS:

You have additional Stage 2 DBPR requirements. You must:

• Select Stage 2 compliance monitoring sites.

• Develop a Stage 2 compliance monitoring plan before you take your first compliance

sample. If you are a subpart H system and you serve more than 3,300 people, you need

to submit your plan to the state.

• Begin annual or quarterly Stage 2 compliance monitoring during the period starting with

October 2012, according to your Stage 2 compliance monitoring plan.

See Chapter 1, Section 1.1 of this guidance manual for a list of additional guidance materials

for the Stage 2 DBPR.

Reminder:

Your requirements for Stage 2 compliance monitoring are based on the population of your

system and are listed below.

Stage 2 DBPR Compliance Monitoring Requirements

Source

Water

Type

Population Size

Category1

Monitoring

Frequency2

Distribution System Monitoring Location 

Total per

monitoring

period3

Highest

TTHM

Locations

Highest

HAA5

Locations

Existing Stage

1 DBPR

Compliance

Locations

Subpart 

H

<500 per year 2 1 1 ...............

500-3,300 per quarter 2 1 1 ...............

3,301-9,999 per quarter 2 1 1 ...............

10,000-49,999 per quarter 4 2 1 1

50,000-249,999 per quarter 8 3 3 2

250,000-999,999 per quarter 12 5 4 3

1,000,000-4,999,999 per quarter 16 6 6 4

$ 5,000,000 per quarter 20 8 7 5

Ground

Water

<500 per year 2 1 1 ...............

500-9,999 per year 2 1 1 ...............

10,000-99,999 per quarter 4 2 1 1

100,000-499,999 per quarter 6 3 2 1

$ 500,000 per quarter 8 3 3 2

1

 Your monitoring requirements (location and frequency) are based on the population served by your system. 2

 All systems must monitor during month of highest DBP concentrations. 3

 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 HAA5 concentrations, respectively. Only one location with a dual sample set per monitoring period is

needed if highest TTHM and HAA5 concentrations occur at the same location (and month, if monitored annually).
IDSE Guidance Manual for the Final Stage 2 DBPR 2-17 January 2006

40/30 Certification Requirements - Schedule 3 Page 1 of 2

Submit 40/30

Certification by

Oct. 1, 2007

Rule Promulgation

Collect 40/30 Data for Any 8 Consecutive

Quarter Eligibility Period

Jan. 1, 2005

2005 2006 2007

IDSE Tool

This summary sheet is for systems that satisfy all of the following requirements for any 8

consecutive quarter eligibility period beginning no earlier than January 2005:

• You serve 10,000-49,999 people OR are part of a combined distribution system where the

largest system serves 10,000-49,999 people

• You have TTHM and HAA5 data equivalent to what is required by the Stage 1 DBPR

• No individual sample exceeds 0.040 mg/L for TTHM

• No individual sample exceeds 0.030 mg/L for HAA5

• Your system did not have any TTHM or HAA5 monitoring violations

WHAT TO DO NOW:

1. Prepare a certification letter Due: October 1, 2007

You must submit the certification letter to the address or e-mail provided below, or use the IDSE

Tool to prepare and submit your certification letter. Note that EPA or your state could contact

you and require more information, or require you to conduct an IDSE.

For more information and letter templates:

See Chapter 4 of this guidance manual. If you are a consecutive or wholesale

system, see Appendix D of this guidance manual. A template you can use for your

40/30 certification letter is included on Page 4-5. If you would like an electronic

template, use the IDSE Tool, available at

http://www.epa.gov/safewater/disinfection/stage2.

2. Mail your 40/30 certification letter to:

STAGE 2 DBPR

US EPA-IPMC

P O Box 98

Dayton, OH 45401-0098

Email to stage2mdbp@epa.gov or submit electronically via the IDSE tool

3. Continue compliance monitoring for the Stage 1 DBPR until you begin compliance

monitoring for the Stage 2 DBPR.
IDSE Guidance Manual for the Final Stage 2 DBPR 2-18 January 2006

40/30 Certification Requirements - Schedule 3 Page 2 of 2

NEXT STEPS:

You have additional Stage 2 DBPR requirements. You must:

• Select Stage 2 compliance monitoring sites.

• Develop a Stage 2 compliance monitoring plan before you take your first compliance

sample. If you are a subpart H system and you serve more than 3,300 people, you need to

submit your plan to the state.

• Begin annual or quarterly Stage 2 compliance monitoring during the period starting with

October 2013, according to your Stage 2 compliance monitoring plan.

See Chapter 1, Section 1.1 of this guidance manual for a list of additional guidance materials for

the Stage 2 DBPR.

Reminder:

Your requirements for Stage 2 compliance monitoring are based on the population of your system

and are listed below.

Stage 2 DBPR Compliance Monitoring Requirements

Source

Water Type

Population Size

Category1

Monitoring

Frequency2

Distribution System Monitoring Location 

Total per

monitoring

period3

Highest

TTHM

Locations

Highest

HAA5

Locations

Existing Stage 1

DBPR

Compliance

Locations

Subpart 

H

<500 per year 2 1 1 ...............

500-3,300 per quarter 2 1 1 ...............

3,301-9,999 per quarter 2 1 1 ...............

10,000-49,999 per quarter 4 2 1 1

50,000-249,999 per quarter 8 3 3 2

250,000-999,999 per quarter 12 5 4 3

1,000,000-4,999,999 per quarter 16 6 6 4

$ 5,000,000 per quarter 20 8 7 5

Ground

Water

<500 per year 2 1 1 ...............

500-9,999 per year 2 1 1 ...............

10,000-99,999 per quarter 4 2 1 1

100,000-499,999 per quarter 6 3 2 1

$ 500,000 per quarter 8 3 3 2

1 Your monitoring requirements (location and frequency) are based on the population served by your system.

2 All systems must monitor during month of highest DBP concentrations. 

3 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 HAA5 concentrations, respectively. Only one location with a dual sample set per monitoring period is

needed if highest TTHM and HAA5 concentrations occur at the same location (and month, if monitored annually).
IDSE Guidance Manual for the Final Stage 2 DBPR 2-19 January 2006

Submit 40/30

Certification by

April 1, 2008

Rule Promulgation

Collect 40/30 Data for Any 8 Consecutive

Quarter Eligibility Period

Jan. 1, 2005

2005 2006 2007 2008

40/30 Certification Requirements - Schedule 4 Page 1 of 2

IDSE Tool

This summary sheet is for systems that satisfy all of the following requirements for any 8

consecutive quarter eligibility period beginning no earlier than January 2005:

• You serve fewer than 10,000 people OR are part of a combined distribution system where

the largest system serves fewer than 10,000 people

• You have TTHM and HAA5 data equivalent to what is required by the Stage 1 DBPR

• No individual sample exceeds 0.040 mg/L for TTHM

• No individual sample exceeds 0.030 mg/L for HAA5

• Your system did not have any TTHM or HAA5 monitoring violations

WHAT TO DO NOW:

1. Prepare a certification letter Due: April 1, 2008

You must submit the certification letter to the address or e-mail provided below, or use the IDSE

Tool to prepare and submit your certification letter. Note that EPA or your state could contact

you and require more information, or require you to conduct an IDSE.

For more information and letter templates:

See Chapter 4 of this guidance manual. If you are a consecutive or wholesale

system, see Appendix D of this guidance manual. A template you can use for your

40/30 certification letter is included on Page 4-5. If you would like an electronic

template, use the IDSE Tool, available at

http://www.epa.gov/safewater/disinfection/stage2.

2. Mail your 40/30 certification letter to:

STAGE 2 DBPR

US EPA-IPMC

P O Box 98

Dayton, OH 45401-0098

Email to stage2mdbp@epa.gov or submit electronically via the IDSE tool

3. Continue compliance monitoring for the Stage 1 DBPR until you begin compliance

monitoring for the Stage 2 DBPR.
IDSE Guidance Manual for the Final Stage 2 DBPR 2-20 January 2006

40/30 Certification Requirements - Schedule 4 Page 2 of 2

NEXT STEPS:

You have additional Stage 2 DBPR requirements. You must:

• Select Stage 2 compliance monitoring sites.

• Develop a Stage 2 compliance monitoring plan before you take your first compliance

sample. If you are a subpart H system and you serve more than 3,300 people, you need to

submit your plan to the state.

• Begin annual or quarterly Stage 2 compliance monitoring during the period starting with

October 2013 or October 2014, according to your Stage 2 compliance monitoring plan.

See Chapter 1, Section 1.1 of this guidance manual for a list of additional guidance materials for

the Stage 2 DBPR.

Reminder:

Your requirements for Stage 2 compliance monitoring are based on the population of your system

and are listed below.

Stage 2 DBPR Compliance Monitoring Requirements

Source

Water

Type

Population Size

Category1

Monitoring

Frequency2

Distribution System Monitoring Location 

Total per

monitoring

period3

Highest

TTHM

Locations

Highest

HAA5

Locations

Existing Stage 1

DBPR

Compliance

Locations

Subpart 

H

<500 per year 2 1 1 ...............

500-3,300 per quarter 2 1 1 ...............

3,301-9,999 per quarter 2 1 1 ...............

10,000-49,999 per quarter 4 2 1 1

50,000-249,999 per quarter 8 3 3 2

250,000-999,999 per quarter 12 5 4 3

1,000,000-4,999,999 per quarter 16 6 6 4

$ 5,000,000 per quarter 20 8 7 5

Ground

Water

<500 per year 2 1 1 ...............

500-9,999 per year 2 1 1 ...............

10,000-99,999 per quarter 4 2 1 1

100,000-499,999 per quarter 6 3 2 1

$ 500,000 per quarter 8 3 3 2 1

 Your monitoring requirements (location and frequency) are based on the population served by your system. 2

 All systems must monitor during month of highest DBP concentrations. 3

 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 HAA5 concentrations, respectively. Only one location with a dual sample set per monitoring period is

needed if highest TTHM and HAA5 concentrations occur at the same location (and month, if monitored annually).
IDSE Guidance Manual for the Final Stage 2 DBPR 2-21 January 2006

System Specific Study Requirements - Schedule 1 Page 1 of 2

Rule Promulgation

Oct. 1, 2007 Sept. 30, 2008

Submit IDSE

Report by

Jan. 1, 2009

Submit System

Specific Study Plan

by Oct. 1, 2006

Conduct Any

Additional Monitoring

(recommended)

2006 2007 2008 2009

IDSE Tool

This summary sheet is for systems that serve 100,000 people or more OR are part of a combined

distribution system where the largest system serves 100,000 people or more.

WHAT TO DO NOW:

1. Develop a System Specific Study Plan Due: October 1, 2006

For guidance on how to develop your SSS Plan:

• If you are using existing monitoring results, see Chapter 5. Your minimum

data requirements are also listed on the attachment on Page 2-29.

• If you are using a distribution system hydraulic model, see Chapter 6.

• Chapters 5 and 6 contain plan templates. If you would like an electronic

template, see the IDSE Tool:

http://www.epa.gov/safewater/disinfection/stage2.

Mail your SSS Plan to:

STAGE 2 DBPR

US EPA-IPMC

P O Box 98

Dayton, OH 45401-0098 

Email to stage2mdbp@epa.gov or submit electronically via the IDSE tool

EPA or your state will review your SSS plan and contact you before October 1, 2007 to

either let you know it has been approved or discuss necessary changes. If you do not hear

anything by this deadline, consider your SSS plan approved and proceed with your plans. 

2. Conduct Any Additional Monitoring Oct. 1, 2007 - Sept. 30, 2008

Systems using existing monitoring results may take additional samples during the SSS. 

Monitoring should be done according to the approved SSS Plan. Systems using models are

required to complete one period of monitoring.
IDSE Guidance Manual for the Final Stage 2 DBPR 2-22 January 2006

System Specific Study Requirements - Schedule 1 Page 2 of 2

WHAT TO DO NOW (cont’d):

3. Select Stage 2 Compliance Monitoring Sites and Develop

IDSE Report for the SSS Due: January 1, 2009

The number of Stage 2 compliance monitoring sites required for your system is listed on the

attachment on Page 2-30. For guidance on how to select your sites and write your IDSE report:

• If you are using existing monitoring data, see Chapter 5, Section 5.3.

• If you are using a distribution system hydraulic model, see Chapter 6, Section 6.6 and

Section 6.7.

EPA or your state will review your IDSE report and contact you before April 1, 2009 to either

let you know your Stage 2 compliance monitoring sites and schedule have been approved or to

discuss necessary changes. If you do not hear anything by this deadline, consider your report

approved and start preparing for Stage 2 compliance monitoring.

4. Continue compliance monitoring for the Stage 1 DBPR until you begin compliance

monitoring for the Stage 2 DBPR.

NEXT STEPS: 

You will have additional requirements for Stage 2 compliance. Your system will need to:

• If you have high levels of DBPs, you may need to make system changes before April 1,

2012 to meet the requirements of the Stage 2 DBPR. If you buy water, see the

Consecutive System Guidance Manual for more information.

• Develop a Stage 2 compliance monitoring plan before you take your first compliance

sample. If you are a subpart H system and you serve more than 3,300 people, you need

to submit your plan to the state.

• Begin annual or quarterly Stage 2 compliance monitoring during the period starting with

April 2012, according to your Stage 2 compliance monitoring plan.

Reminder: 

Your system's monitoring requirements for both the IDSE and Stage 2 compliance monitoring

are based on the population of your system and are listed the attachment on Pages 2-29 and 2-30.
IDSE Guidance Manual for the Final Stage 2 DBPR 2-23 January 2006

System Specific Study Requirements - Schedule 2 Page 1 of 2

Rule Promulgation

April 1, 2008 March 31, 2009

Submit IDSE

Report by

July 1, 2009

Submit System

Specific Study Plan

by April 1, 2007

Conduct Any

Additional Monitoring

(recommended)

2006 2007 2008 2009

IDSE Tool

This summary sheet is for systems that serve 50,000-99,999 people OR are part of a combined

distribution system where the largest system serves 50,000-99,999 people.

WHAT TO DO NOW:

1. Develop a System Specific Study Plan Due: April 1, 2007

For guidance on how to develop your SSS Plan:

• If you are using existing monitoring results, see Chapter 5. Your minimum data 

 requirements are also listed on the attachment on Page 2-29.

• If you are using a distribution system hydraulic model, see Chapter 6.

• Chapters 5 and 6 contain plan templates. If you would like an electronic

template, see the IDSE Tool:

http://www.epa.gov/safewater/disinfection/stage2.

Mail your SSS Plan to:

STAGE 2 DBPR

US EPA-IPMC

P O Box 98

Dayton, OH 45401-0098 

Email to stage2mdbp@epa.gov or submit electronically via the IDSE tool

EPA or your state will review your SSS plan and contact you before April 1, 2008 to either

let you know it has been approved or discuss necessary changes. If you do not hear anything by

this deadline, consider your SSS plan approved and proceed with your plans. 

2. Conduct Any Additional Monitoring Apr. 1, 2008 - March 31, 2009

Systems using existing monitoring results may take additional samples during the SSS. 

Monitoring should be done according to the approved SSS Plan. Systems using models are

required to complete one period of monitoring.
IDSE Guidance Manual for the Final Stage 2 DBPR 2-24 January 2006

System Specific Study Requirements - Schedule 2 Page 2 of 2

WHAT TO DO NOW (cont’d):

3. Select Stage 2 Compliance Monitoring Sites and Develop

IDSE Report for the SSS Due: July 1, 2009

The number of Stage 2 compliance monitoring sites required for your system is listed on the

attachment on Page 2-30. For guidance on how to select your sites and write your IDSE report:

• If you are using existing monitoring data, see Chapter 5, Section 5.3.

• If you are using a distribution system hydraulic model, see Chapter 6, Section 6.6 and

Section 6.7.

EPA or your state will review your IDSE report and contact you before October 1, 2009 to

either let you know your Stage 2 compliance monitoring sites and schedule have been approved

or to discuss necessary changes. If you do not hear anything by this deadline, consider your

report approved and start preparing for Stage 2 compliance.

4. Continue compliance monitoring for the Stage 1 DBPR until you begin compliance

monitoring for the Stage 2 DBPR.

NEXT STEPS: 

You will have additional requirements for Stage 2 compliance. Your system will need to:

• If you have high levels of DBPs, you may need to make system changes before October

1, 2012 to meet the Stage 2 MCLs. If you buy water, see the Consecutive System

Guidance Manual for more information.

• Develop a Stage 2 compliance monitoring plan before you take your first compliance

sample. If you are a subpart H system and you serve more than 3,300 people, you need

to submit your plan to the state. 

• Begin annual or quarterly Stage 2 compliance monitoring during the period starting with

October 2012, according to your Stage 2 compliance monitoring plan.

Reminder: 

Your system's monitoring requirements for both the IDSE and Stage 2 compliance monitoring

are based on the population of your system and are listed the attachment on Pages 2-29 and 2-30.
IDSE Guidance Manual for the Final Stage 2 DBPR 2-25 January 2006

System Specific Study Requirements - Schedule 3 Page 1 of 2

Rule Promulgation

Oct. 1, 2008 Sept. 30, 2009

Submit IDSE

Report by

Jan. 1, 2010

Submit System

Specific Study Plan

by Oct. 1, 2007

Conduct Any

Additional Monitoring

(recommended)

2006 2007 2008 2009 2010

IDSE Tool

This summary sheet is for systems that serve 10,000-49,999 people OR are part of a combined

distribution system where the largest system serves 10,000-49,999 people.

WHAT TO DO NOW:

1. Develop a System Specific Study Plan Due: October 1, 2007

For guidance on how to develop your SSS Plan:

• If you are using existing monitoring results, see Chapter 5. Your minimum data

requirements are also listed on the attachment on Page 2-29.

• If you are using a distribution system hydraulic model, see Chapter 6.

• Chapters 5 and 6 contain plan templates. If you would like an electronic

template, see the IDSE Tool:

http://www.epa.gov/safewater/disinfection/stage2.

Mail your SSS Plan to:

STAGE 2 DBPR

US EPA-IPMC

P O Box 98

Dayton, OH 45401-0098 

Email to stage2mdbp@epa.gov or submit electronically via the IDSE tool

EPA or your state will review your SSS plan and contact you before October 1, 2008 to

either let you know it has been approved or discuss necessary changes. If you do not hear

anything by this deadline, consider your SSS plan approved and proceed with your plans. 

2. Conduct Any Additional Monitoring Oct. 1, 2008 - Sept. 30, 2009

Systems using existing monitoring results may take additional samples during the SSS. 

Monitoring should be done according to the approved SSS Plan. Systems using models are

required to complete one period of monitoring.
IDSE Guidance Manual for the Final Stage 2 DBPR 2-26 January 2006

System Specific Study Requirements - Schedule 3 Page 2 of 2

WHAT TO DO NOW (cont’d):

3. Select Stage 2 Compliance Monitoring Sites and Develop

IDSE Report for the SSS Due: January 1, 2010

The number of Stage 2 compliance monitoring sites required for your system is listed on the

attachment on Page 2-30. For guidance on how to select your sites and write your IDSE report:

• If you are using existing monitoring data, see Chapter 5, Section 5.3.

• If you are using a distribution system hydraulic model, see Chapter 6, Section 6.6 and

Section 6.7.

EPA or your state will review your IDSE report and contact you before October 1, 2010 to

either let you know your Stage 2 compliance monitoring sites and schedule have been approved

or to discuss necessary changes. If you do not hear anything by this deadline, consider your

report approved and start preparing for Stage 2 compliance.

4. Continue compliance monitoring for the Stage 1 DBPR until you begin compliance

monitoring for the Stage 2 DBPR.

NEXT STEPS: 

You will have additional requirements for Stage 2 compliance. Your system will need to:

• If you have high levels of DBPs, you may need to make system changes before October

1, 2013 to meet the Stage 2 MCLs. If you buy water, see the Consecutive System

Guidance Manual for more information.

• Develop a Stage 2 compliance monitoring plan before you take your first compliance

sample. If you are a subpart H system and you serve more than 3,300 people, you need

to submit your plan to the state.

• Begin annual or quarterly Stage 2 compliance monitoring during the period starting with

October 2013, according to your Stage 2 compliance monitoring plan.

Reminder: 

Your system's monitoring requirements for both the IDSE and Stage 2 compliance monitoring

are based on the population of your system and are listed the attachment on Pages 2-29 and 2-30.
IDSE Guidance Manual for the Final Stage 2 DBPR 2-27 January 2006

System Specific Study Requirements - Schedule 4 Page 1 of 2

Rule Promulgation

April 1, 2009 March 31, 2010

Submit IDSE

Report by

July 1, 2010

Submit System

Specific Study Plan

by April 1, 2008

Conduct Any

Additional Monitoring

(recommended)

2006 2007 2008 2009 2010

IDSE Tool

This summary sheet is for systems that serve fewer than 10,000 people OR are part of a

combined distribution system where the largest system serves fewer than 10,000 people.

WHAT TO DO NOW:

1. Develop a System Specific Study Plan Due: April 1, 2008

For guidance on how to develop your SSS Plan:

• If you are using existing monitoring results, see Chapter 5. Your minimum data

requirements are also listed on the attachment on Page 2-29.

• If you are using a distribution system hydraulic model, see Chapter 6.

• Chapters 5 and 6 contain plan templates. If you would like an electronic

template, see the IDSE Tool:

http://www.epa.gov/safewater/disinfection/stage2.

Mail your SSS Plan to:

STAGE 2 DBPR

US EPA-IPMC

P O Box 98

Dayton, OH 45401-0098

Email to stage2mdbp@epa.gov or submit electronically via the IDSE tool

EPA or your state will review your SSS plan and contact you before April 1, 2009 to either

let you know it has been approved or discuss necessary changes. If you do not hear anything by

this deadline, consider your SSS plan approved and proceed with your plans. 

2. Conduct Any Additional Monitoring Apr. 1, 2009 - March 31, 2010

Systems using existing monitoring results may take additional samples during the SSS. 

Monitoring should be done according to the approved SSS Plan. Systems using models are

required to complete one period of monitoring.
IDSE Guidance Manual for the Final Stage 2 DBPR 2-28 January 2006

System Specific Study Requirements - Schedule 4 Page 2 of 2

WHAT TO DO NOW:

3. Select Stage 2 Compliance Monitoring Sites and Develop

IDSE Report for the SSS Due: July 1, 2010

The number of Stage 2 compliance monitoring sites required for your system is listed on the

attachment on Page 2-30. For guidance on how to select your sites and write your IDSE report:

• If you are using existing monitoring data, see Chapter 5, Section 5.3.

• If you are using a distribution system hydraulic model, see Chapter 6, Section 6.6 and

Section 6.7.

EPA or your state will review your IDSE report and contact you before October 1, 2010 to

either let you know your Stage 2 compliance monitoring sites and schedule have been approved

or to discuss necessary changes. If you do not hear anything by this deadline, consider your

report approved and start preparing for Stage 2 compliance.

4. Continue compliance monitoring for the Stage 1 DBPR until you begin compliance

monitoring for the Stage 2 DBPR.

NEXT STEPS: 

You will have additional requirements for Stage 2 compliance. Your system will need to:

• If you have high levels of DBPs, you may need to make system changes before October

1, 2013 to meet the Stage 2 MCLs. If you buy water, see the Consecutive System

Guidance Manual for more information.

• Develop a Stage 2 compliance monitoring plan before you take your first compliance

sample. If you are a subpart H system and you serve more than 3,300 people, you need

to submit your plan to the state.

• Begin annual or quarterly Stage 2 compliance monitoring during the period starting with

October 2013 or October 2014, according to your Stage 2 compliance monitoring plan.

 Reminder: 

Your system's monitoring requirements for both the IDSE and Stage 2 compliance monitoring

are based on the population of your system and are listed the attachment on Pages 2-29 and 2-30.
IDSE Guidance Manual for the Final Stage 2 DBPR 2-29 

System Specific Study Requirements - Attachment (For All Schedules

Minimum Sample Requirements for the SSS using Existing Monitoring Resu

Source Water

Type

Population Size

Category 1

Number of

Monitoring

Locations

Number of TTHM 

Samples

Number o

Samp

Subpart H <500 3 3 3

500-3,300 3 9 93,301-9,999 6 36 3610,000-49,999 12 72 7250,000-249,999 24 144 144250,000-999,999 36 216 2161,000,000-4,999,999 48 288 288$5,000,000 60 360 360

Ground Water <500 3 3 3

500-9,999 3 9 910,000-99,999 12 48 48100,000-499,999 18 72 72

$500,000 24 96 96

1 Your minimum sample requirements (locations and frequency) are based on the population served by your sys
IDSE Guidance Manual for the Final Stage 2 DBPR 2-30 

System Specific Study Requirements - Attachment (For All Schedules

Stage 2 Compliance Monitoring Requirements

Source

Water

Type

Population Size

Category1

Monitoring

Frequency2

Distribution System Monitoring Loca

Total per

monitoring 

period 3

Highest TTHM

Locations

Highest HAA5

Locations

Subpart

H

<500 per year 2 1 1 

500-3,300 per quarter 2 1 1 3,301-9,999 per quarter 2 1 1 10,000-49,999 per quarter 4 2 1 50,000-249,999 per quarter 8 3 3 250,000-999,999 per quarter 12 5 4 1,000,000-4,999,999 per quarter 16 6 6 $5,000,000 per quarter 20 8 7 

Ground

Water

<500 per year 2 1 1 500-9,999 per year 2 1 1 10,000-99,999 per quarter 4 2 1 100,000-499,999 per quarter 6 3 2 $500,000 per quarter 8 3 3 

1 Your monitoring requirements (location and frequency) are based on the population served by your system. 2 All systems must monitor during month of highest DBP concentrations. 3 Systems on quarterly monitoring must take dual sample sets every 90 days at each monitoring location, except for subpar

500-3,300. Systems on annual monitoring and subpart H systems serving 500-3,300 are required to take individual TTHM 

(instead of a dual sample set) at the locations with the highest TTHM and HAA5 concentrations, respectively. Only one locaset per monitoring period is needed if highest TTHM and HAA5 concentrations occur at the same location (and month, if mo
IDSE Guidance Manual for the Final Stage 2 DBPR 2-31 January 2006

Standard Monitoring Requirements - Schedule 1 Page 1 of 2

Rule Promulgation

Oct. 1, 2007 Sept. 30, 2008

Submit IDSE

Report by

Jan. 1, 2009

Submit Standard

Monitoring Plan

by Oct. 1, 2006

Conduct Standard

Monitoring

(recommended)

2006 2007 2008 2009

IDSE Tool

This summary sheet is for systems that serve 100,000 people or more OR are part of a combined

distribution system where the largest system serves 100,000 people or more.

WHAT TO DO NOW:

1. Develop Standard Monitoring Plan Due: October 1, 2006

• See Chapter 7, Section 7.1.3 for guidance on how to develop your IDSE Standard

Monitoring Plan. Your monitoring requirements are also listed on the

attachment on Page 2-39. 

• Chapter 7 contains plan templates. If you would like an electronic

template, see the IDSE Tool:

http://www.epa.gov/safewater/disinfection/stage2.

Mail your standard monitoring plan to:

STAGE 2 DBPR

US EPA-IPMC

P O Box 98

Dayton, OH 45401-0098 

E-mail to stage2mdbp@epa.gov or submit electronically via the IDSE tool

EPA or your state will review your standard monitoring plan and contact you before

October 1, 2007 to either let you know it has been approved or discuss necessary changes. If

you do not hear anything by this deadline, consider your plan approved and start monitoring. 

2. Conduct Standard Monitoring Oct. 1, 2007 - Sept. 30, 2008

Monitoring should be done according to your standard monitoring plan. 
IDSE Guidance Manual for the Final Stage 2 DBPR 2-32 January 2006

Standard Monitoring Requirements - Schedule 1 Page 2 of 2

WHAT TO DO NOW (cont’d):

3. Select Stage 2 Compliance Monitoring Sites and Develop

IDSE Standard Monitoring Report Due: January 1, 2009

• See Chapter 7, Section 7.3 for guidance on how to select Stage 2 compliance monitoring

sites and write the IDSE report. The number of Stage 2 compliance monitoring sites

required for your system is listed on the attachment on Page 2-40.

• EPA or your state will review your IDSE report and contact you before April 1,

2009 to either let you know your Stage 2 compliance monitoring sites and schedule have

been approved or to discuss necessary changes. If you do not hear anything by this

deadline, consider your plan approved and start preparing for Stage 2 compliance. 

4. Continue compliance monitoring for the Stage 1 DBPR until you begin compliance

monitoring for the Stage 2 DBPR.

NEXT STEPS: 

You will have additional requirements for Stage 2 compliance. Your system will need to do the

following:

• If you have high levels of DBPs, you may need to make system changes before April 1,

2012 to meet the Stage 2 MCLs. If you buy water, see the Consecutive System Guidance

Manual for more information.

• Develop a Stage 2 compliance monitoring plan before you take your first compliance

sample. If you are a subpart H system and you serve more than 3,300 people, you need

to submit your plan to the state. 

• Begin annual or quarterly Stage 2 compliance monitoring during the period starting with

April 2012, according to your Stage 2 compliance monitoring plan.

Reminder: 

Your system's monitoring requirements for both the IDSE and Stage 2 compliance monitoring

are based on the population of your system and are listed in the attachment on Pages 2-39 and 2-

40.
IDSE Guidance Manual for the Final Stage 2 DBPR 2-33 January 2006

Standard Monitoring Requirements - Schedule 2 Page 1 of 2

Rule Promulgation

April 1, 2008 March 31, 2009

Submit IDSE

Report by

July 1, 2009

Submit Standard

Monitoring Plan

by April 1, 2007

Conduct Standard

Monitoring

(recommended)

2006 2007 2008 2009

IDSE Tool

This summary sheet is for systems that serve 50,000-99,999 people OR are part of a combined

distribution system where the largest system serves 50,000-99,999 people.

WHAT TO DO NOW:

1. Develop Standard Monitoring Plan Due: April 1, 2007

• See Chapter 7, Section 7.1.3 for guidance on how to develop your IDSE Standard

Monitoring Plan. Your monitoring requirements are also listed on the

attachment on Page 2-39. 

• Chapter 7 contains plan templates. If you would like an electronic

template, see the IDSE Tool:

http://www.epa.gov/safewater/disinfection/stage2.

Mail your standard monitoring plan to:

STAGE 2 DBPR

US EPA-IPMC

P O Box 98

Dayton, OH 45401-0098 

E-mail to stage2mdbp@epa.gov or submit electronically via the IDSE tool

EPA or your state will review your standard monitoring plan and contact you before April

1, 2008 to either let you know it has been approved or discuss necessary changes. If you do not

hear anything by this deadline, consider your plan approved and start monitoring. 

2. Conduct Standard Monitoring Apr. 1, 2008 - March 31, 2009

Monitoring should be done according to your standard monitoring plan. 
IDSE Guidance Manual for the Final Stage 2 DBPR 2-34 January 2006

Standard Monitoring Requirements - Schedule 2 Page 2 of 2

WHAT TO DO NOW (cont’d):

3. Select Stage 2 Compliance Monitoring Sites and Develop

IDSE Standard Monitoring Report Due: July 1, 2009

• See Chapter 7, Section 7.3 for guidance on how to select Stage 2 compliance monitoring

sites and write the IDSE report. The number of Stage 2 compliance monitoring sites

required for your system is listed on the attachment on Page 2-40.

• EPA or your state will review your IDSE report and contact you before October 1,

2009 to either let you know your Stage 2 compliance monitoring sites and schedule have

been approved or to discuss necessary changes. If you do not hear anything by this

deadline, consider your plan approved and start preparing for Stage 2 compliance. 

4. Continue compliance monitoring for the Stage 1 DBPR until you begin compliance

monitoring for the Stage 2 DBPR.

NEXT STEPS: 

You will have additional requirements for Stage 2 compliance. Your system will need to do the

following:

• If you have high levels of DBPs, you may need to make system changes before October

1, 2012 to meet the Stage 2 MCLs. If you buy water, see the Consecutive System

Guidance Manual for more information.

• Develop a Stage 2 compliance monitoring plan before you take your first compliance

sample. If you are a subpart H system and you serve more than 3,300 people, you need

to submit your plan to the state. 

• Begin annual or quarterly Stage 2 compliance monitoring during the period starting with

October 2012, according to your Stage 2 compliance monitoring plan.

Reminder: 

Your system's monitoring requirements for both the IDSE and Stage 2 compliance monitoring

are based on the population of your system and are listed in the attachment on Pages 2-39 and 2-

40.
IDSE Guidance Manual for the Final Stage 2 DBPR 2-35 January 2006

Standard Monitoring Requirements - Schedule 3 Page 1 of 2

Rule Promulgation

Oct. 1, 2008 Sept. 30, 2009

Submit IDSE

Report by

Jan. 1, 2010

Submit Standard

Monitoring Plan

by Oct. 1, 2007

Conduct Standard

Monitoring

(recommended)

2006 2007 2008 2009 2010

IDSE Tool

This summary sheet is for systems that serve 10,000-49,999 people OR are part of a combined

distribution system where the largest system serves 10,000-49,999 people.

WHAT TO DO NOW:

1. Develop Standard Monitoring Plan Due: October 1, 2007

• See Chapter 7, Section 7.1.3 for guidance on how to develop your IDSE Standard

Monitoring Plan. Your monitoring requirements are also listed on the

attachment on Page 2-39. 

• Chapter 7 contains plan templates. If you would like an electronic

template, see the IDSE Tool:

http://www.epa.gov/safewater/disinfection/stage2.

Mail your standard monitoring plan to:

STAGE 2 DBPR

US EPA-IPMC

P O Box 98

Dayton, OH 45401-0098 

E-mail to stage2mdbp@epa.gov or submit electronically via the IDSE tool

EPA or your state will review your standard monitoring plan and contact you before

October 1, 2008 to either let you know it has been approved or discuss necessary changes. If

you do not hear anything by this deadline, consider your plan approved and start monitoring. 

2. Conduct Standard Monitoring Oct. 1, 2008 - Sept. 30, 2009

Monitoring should be done according to your IDSE Standard Monitoring Plan. 
IDSE Guidance Manual for the Final Stage 2 DBPR 2-36 January 2006

Standard Monitoring Requirements - Schedule 3 Page 2 of 2

WHAT TO DO NOW (cont’d):

3. Select Stage 2 Compliance Monitoring Sites and Develop 

IDSE Standard Monitoring Report Due: January 1, 2010

• See Chapter 7, Section 7.3 for guidance on how to select Stage 2 compliance monitoring

sites and write the IDSE report. The number of Stage 2 compliance monitoring sites

required for your system is listed on the attachment on Page 2-40.

• EPA or your state will review your IDSE report and contact you before October 1,

2010 to either let you know your Stage 2 compliance monitoring sites and schedule have

been approved or to discuss necessary changes. If you do not hear anything by this

deadline, consider your plan approved and start preparing for Stage 2 compliance. 

4. Continue compliance monitoring for the Stage 1 DBPR until you begin compliance

monitoring for the Stage 2 DBPR.

NEXT STEPS: 

You will have additional requirements for Stage 2 compliance. Your system will need to do the

following:

• If you have high levels of DBPs, you may need to make system changes before October

1, 2013 to meet the Stage 2 MCLs. If you buy water, see the Consecutive System

Guidance Manual for more information.

• Develop a Stage 2 compliance monitoring plan before you take your first compliance

sample. If you are a subpart H system and you serve more than 3,300 people, you need

to submit your plan to the state.

• Begin annual or quarterly Stage 2 compliance monitoring during the period starting with

October 2013, according to your Stage 2 compliance monitoring plan.

Reminder: 

Your system's monitoring requirements for both the IDSE and Stage 2 compliance monitoring

are based on the population of your system and are listed in the attachment on Pages 2-39 and 2-

40.
IDSE Guidance Manual for the Final Stage 2 DBPR 2-37 January 2006

Standard Monitoring Requirements - Schedule 4 Page 1 of 2

Rule Promulgation

April 1, 2009 March 31, 2010

Submit IDSE

Report by

July 1, 2010

Submit Standard

Monitoring Plan

by April 1, 2008

Conduct Standard

Monitoring

(recommended)

2006 2007 2008 2009 2010

IDSE Tool

This summary sheet is for systems that serve fewer than 10,000 people OR are part of a

combined distribution system where the largest system serves fewer than 10,000 people.

WHAT TO DO NOW:

1. Develop Standard Monitoring Plan Due: April 1, 2008

• See Chapter 7, Section 7.1.3 for guidance on how to develop your IDSE

Standard Monitoring Plan. Your monitoring requirements are also listed

on the attachment on Page 2-39. 

• Chapter 7 contains plan templates. If you would like an electronic

template, see the IDSE Tool:

http://www.epa.gov/safewater/disinfection/stage2.

Mail your standard monitoring plan to:

STAGE 2 DBPR

US EPA-IPMC

P O Box 98

Dayton, OH 45401-0098 

E-mail to stage2mdbp@epa.gov or submit electronically via the IDSE tool

EPA or your state will review your standard monitoring plan and contact you before April

1, 2009 to either let you know it has been approved or discuss necessary changes. If you do not

hear anything by this deadline, consider your plan approved and start monitoring. 

2. Conduct Standard Monitoring Apr. 1, 2009 - March 31, 2010

Monitoring should be done according to your standard monitoring plan. 
IDSE Guidance Manual for the Final Stage 2 DBPR 2-38 January 2006

Standard Monitoring Requirements - Schedule 4 Page 2 of 2

WHAT TO DO NOW (cont’d):

3. Select Stage 2 Compliance Monitoring Sites and Develop 

IDSE Standard Monitoring Report Due: July 1, 2010

• See Chapter 7, Section 7.3 for guidance on how to select Stage 2 compliance monitoring

sites and write the IDSE report. The number of Stage 2 compliance monitoring sites

required for your system is listed on the attachment on Page 2-40.

• EPA or your state will review your IDSE report and contact you before October 1,

2010 to either let you know your Stage 2 compliance monitoring sites and schedule have

been approved or to discuss necessary changes. If you do not hear anything by this

deadline, consider your plan approved and start preparing for Stage 2 compliance.

4. Continue compliance monitoring for the Stage 1 DBPR until you begin compliance

monitoring for the Stage 2 DBPR.

NEXT STEPS: 

You will have additional requirements for Stage 2 compliance. Your system will need to do the

following:

• If you have high levels of DBPs, you may need to make system changes before October

1, 2013 to meet the Stage 2 MCLs. If you buy water, see the Consecutive System

Guidance Manual for more information.

• Develop a Stage 2 compliance monitoring plan before you take your first compliance

sample. If you are a subpart H system and you serve more than 3,300 people, you need

to submit your plan to the state. 

• Begin annual or quarterly Stage 2 compliance monitoring during the period starting with

October 2013 or October 2014, according to your Stage 2 compliance monitoring plan.

Reminder: 

Your system's monitoring requirements for both the IDSE and Stage 2 compliance monitoring

are based on the population of your system and are listed in the attachment on Pages 2-39 and 2-

40.
IDSE Guidance Manual for the Final Stage 2 DBPR 2-39 

Standard Monitoring Requirements - Attachment (For All Schedules) 

IDSE Standard Monitoring Requirements

Source

Water

Type

Population Size Category1

Monitoring Periods

and Frequency of

Sampling

Distribution System Monitoring Locatio

Total per

monitoring

period

Near Entry

Points

Average

Residence Time

High TT

Locati

Subpart H

<500 consecutive systems one (during peak

historical month)3

2 1 .................. 1 

<500 non-consecutivesystems

2 .................. .................. 1 

500-3,300 consecutivesystems

four (every 90 days)

2 1 .................. 1 

500-3,300 non-consecutivesystems

2 .................. .................. 1 

3,301-9,999 4 .................. 1 2 10,000-49,999

six (every 60 days)

81 2 3 

50,000-249,999 16 345250,000-999,999 24 4681,000,000-4,999,999 32 6 8 10 

$5,000,000 40 8 10 12 

Ground

Water

<500 consecutive systems one (during peak

historical month)3

2 1 .................. 1 

<500 non-consecutivesystems

2 .................. .................. 1 

500-9,999

four (every 90 days)

2 .................. .................. 1 

10,000-99,999 6 112100,000-499,999 8 113

$500,000 12 224

1 Your monitoring requirements (locations and frequency) are based on the population served by your system. 2 A dual sample set (i.e., a TTHM and an HAA5 sample) must be taken at each monitoring location during each monitoring period. 3 The peak historical month is the month with the highest TTHM or HAA5 levels or the warmest water temperature.
IDSE Guidance Manual for the Final Stage 2 DBPR 2-40 

Standard Monitoring Requirements - Attachment (For All Schedules

Stage 2 Compliance Monitoring Requirements

Source

Water

Type

Population Size

Category1

Monitoring

Frequency2

Distribution System Monitoring Loca

Total per

monitoring

period3

Highest TTHM

Locations

Highest HAA5

Locations

Subpart

H

<500 per year 2 1 1 500-3,300 per quarter 2 1 1 3,301-9,999 per quarter 2 1 1 10,000-49,999 per quarter 4 2 1 50,000-249,999 per quarter 8 3 3 250,000-999,999 per quarter 12 5 4 1,000,000-4,999,999 per quarter 16 6 6 

$5,000,000 per quarter 20 8 7 

Ground

Water

<500 per year 2 1 1 500-9,999 per year 2 1 1 10,000-99,999 per quarter 4 2 1 100,000-499,999 per quarter 6 3 2 

$500,000 per quarter 8 3 3 

1 Your monitoring requirements (locations and frequency) are based on the population served by your system. 2 All systems must monitor during month of highest DBP concentrations. 3 Systems on quarterly monitoring must take dual sample sets every 90 days at each monitoring location, except for subpar

500-3,300. Systems on annual monitoring and subpart H systems serving 500-3,300 are required to take individual TTHM a

(instead of a dual sample set) at the locations with the highest TTHM and HAA5 concentrations, respectively. Only one locaset per monitoring period is needed if highest TTHM and HAA5 concentrations occur at the same location (and month, if mo
IDSE Guidance Manual for the Final Stage 2 DBPR 3-1 January 2006

This chapter covers:

3.1 Qualifying for the VSS Waiver 

3.2 Selecting a Stage 2 Compliance Monitoring Site

3.3 Next Steps: Preparing the Stage 2 DBPR Compliance Monitoring Plan

3.0 Very Small System Waiver

EPA recognizes that very small systems typically have small distribution systems where

the high total trihalomethane (TTHM) and high haloacetic acid-five (HAA5) levels occur at the

same location. For this reason, systems serving fewer than 500 people are automatically exempt

from IDSE requirements as long as the criteria in Section 3.1 are met, and EPA or your state

does not require otherwise.

If you meet the very small system (VSS) waiver criteria and EPA or your state does

not notify you that you need to conduct an IDSE, your system has NO further

requirements for the IDSE. You will continue Stage 1 compliance monitoring until Stage 2

compliance monitoring starts. If you are in a combined distribution system, you must start

Stage 2 compliance monitoring based on the schedule of the system with the largest population

in your combined distribution system. If you are not in a combined distribution system, you

must start Stage 2 compliance monitoring in 2013 (2014 if you must monitor for

Cryptosporidium under the Long Term 2 Enhanced Surface Water Treatment Rule). See

Chapter 2 for more information on determining your schedule. Refer to Appendix D if you are a

consecutive or wholesale system for specific issues that you should consider.

This chapter discusses the requirements for VSS waivers. These requirements are also

outlined on your requirements summary sheet in Chapter 2 of this manual.

3.1 Qualifying for the VSS Waiver

How can I qualify for the waiver?

To automatically qualify for the VSS waiver, you must serve fewer than 500 people and

have taken TTHM and HAA5 samples. VSS eligibility is not dependent on your Stage 1 DBPR

compliance monitoring or other TTHM or HAA5 data results. The results do not have to be

below any particular level for you to receive the waiver.

As long as you have TTHM and HAA5 data, you are qualified for the VSS Waiver. You have

NO further requirements for the IDSE unless EPA or your state tells you otherwise.
IDSE Guidance Manual for the Final Stage 2 DBPR 3-2 January 2006

Many systems will have Stage 1 DBPR compliance monitoring data that will allow them

to automatically qualify, including those on reduced monitoring. Some systems in combined

distribution systems, however, may not have conducted Stage 1 DBPR compliance monitoring. 

These systems can still meet the waiver criteria if they have TTHM and HAA5 data. Below is

guidance for systems that have compliance data and those that have operational TTHM and

HAA5 data

• Systems with Compliance Data: If you have Stage 1 DBPR compliance data and

have submitted TTHM and HAA5 results to your state, you have NO further

requirements unless you hear otherwise from EPA or your state. 

• Systems with Operational Data: If you have not conducted compliance

monitoring under the Stage 1 DBPR but have other TTHM and HAA5 data, you

should contact EPA or your state to determine if this data is sufficient to qualify

for the waiver. Some of the criteria that the reviewer might use to evaluate your

data are: 

- Were samples analyzed by approved methods?

- Were samples analyzed at a certified laboratory?

- Are the sites located in areas of maximum residence time?

- Were samples taken during the month of warmest water temperature?

Consecutive systems that do not have any TTHM and HAA5 data for their system should check

with their wholesaler to determine if the wholesaler collected any TTHM and HAA5 data in their

system. 

What if EPA or my state contacts me and requires me to conduct an IDSE?

Remember that even if you qualify for the VSS waiver, EPA or your state may require

you to conduct an IDSE. IDSE sampling requirements for systems serving < 500 people are

minor compared to requirements for medium and large systems. Standard monitoring for

systems serving < 500 people consists of preparing a monitoring plan, taking dual sample sets at

two distribution system locations during the peak historical month, and completing an IDSE

report. Refer to the EPA document, IDSE Guide for Systems Serving < 10,000 People, for

guidance on conducting standard monitoring. 

3.2 Selecting a Stage 2 DBPR Compliance Monitoring Site

All systems serving <500 people are required to take one TTHM sample at the location

with the highest TTHM concentration, and one HAA5 sample at the location with the highest

HAA5 concentration. You can collect a dual sample set at one location if the highest TTHM

and HAA5 concentrations occur at the same sample location and during the same month. 
IDSE Guidance Manual for the Final Stage 2 DBPR 3-3 January 2006

EPA recommends that you consider using your Stage 1 monitoring location for Stage 2

DBPR compliance monitoring it if meets these criteria. If you did not have a Stage 1 compliance

monitoring location, you should work with your state to select the best Stage 2 compliance

monitoring location(s). The high TTHM site will typically be an area of high residence time,

located at an extreme end or isolated portion of the distribution system. The high HAA5 site will

often be at the same location, unless you have difficulty maintaining a distribution system

residual.

You should not select high HAA5 sites in locations that regularly or in the summer months have

free chlorine residuals less than 0.2 mg/L or with chloramine residuals less than 0.5 mg/L. 

3.3 Next Steps: Preparing the Stage 2 DBPR Compliance Monitoring Plan

As the final step before you can begin compliance monitoring for the Stage 2 DBPR, you

must develop a Stage 2 DBPR compliance monitoring plan. The plan will be similar to your

Stage 1 DBPR monitoring plan in that it will identify how you intend to sample for compliance

with Stage 2. You do not need to submit the monitoring plan to EPA or your state, but you must

keep it on file for state and public review. Note that Stage 1 DBPR compliance monitoring

requirements are in effect until you begin Stage 2 DBPR compliance monitoring.

Exhibit 3.1 contains the minimum requirements for what must be included in your Stage

2 DBPR compliance monitoring plan. Because compliance monitoring plans are not addressed

as part of the IDSE provisions of the Stage 2 DBPR, EPA has not included detailed guidance

for developing Stage 2 compliance monitoring plans in this guidance manual. EPA plans to

develop other manuals and training that specifically address the compliance monitoring

provisions of the Stage 2 DBPR.

See EPA’s website at http://www.epa.gov/safewater/disinfection/stage2 for an up-to-date

inventory of Stage 2 DBPR guidance manuals and training materials, or call the Safe Drinking

Water Hotline at 1-800-426-4791.

Exhibit 3.1 Required Contents of Stage 2 DBPR Compliance Monitoring Plans

All Systems Additional Requirements for Consecutive and

Wholesale Systems 1

• Monitoring locations

• Monitoring dates

• Compliance calculation

procedures

• If your state has used its special primacy authority to

modify your monitoring requirements, you must

include monitoring plans for other systems in your

combined distribution system

1. See Appendix D of this manual for guidance specifically for consecutive and wholesale systems.
IDSE Guidance Manual for the Final Stage 2 DBPR 3-4 January 2006

This page intentionally left blank.
IDSE Guidance Manual for the Final Stage 2 DBPR 4-1 January 2006

This chapter covers:

4.1 Qualification Criteria

4.2 Preparing and Submitting the Certification Letter

4.3 Recordkeeping

4.4 Selecting Stage 2 Compliance Monitoring Sites

4.5 Next Steps: Preparing the Stage 2 DBPR Compliance Monitoring

Plan

4.0 40/30 Certification

Systems can qualify for the IDSE 40/30 certification if they have measured consistently

low total trihalomethane (TTHM) and haloacetic acid-five (HAA5) levels during Stage 1 DBPR

compliance monitoring. The term " 40/30" refers to a system having all individual Stage 1

DBPR compliance samples less than or equal to 0.040 milligrams per liter (mg/L) for TTHM and

0.030 mg/L for HAA5 during a specific time period. 

If you qualify for the 40/30 certification and comply with the certification

requirements, and EPA or your state does not notify you that you need to conduct an IDSE,

your system has NO further requirements for the IDSE. Your next steps will be to prepare a

compliance monitoring plan and start monitoring for the Stage 2 DBPR. You must continue

with Stage 1 DBPR monitoring until you begin Stage 2 monitoring.

If you have not already done so, complete the flowchart in Exhibit 2.3 of this guidance

manual before reading this chapter. The flowchart directs you to a 2-page Requirements

Summary Sheet which contains compliance dates and additional requirements for complying

with the Stage 2 DBPR. You should keep your requirements summary sheet handy as you work

through this chapter.

This chapter provides guidance on how to prepare and submit a 40/30 certification letter

and select Stage 2 DBPR compliance monitoring sites. If you are a consecutive or wholesale

system, refer to Appendix D for specific issues that you should consider.
IDSE Guidance Manual for the Final Stage 2 DBPR 4-2 January 2006

4.1 Qualification Criteria

To be eligible for 40/30 certification, you must meet all of the following requirements for

the 8 consecutive quarter eligibility period shown in Exhibit 4.1:

• You have TTHM and HAA5 data equivalent to what is required by the Stage 1 DBPR

for your system (e.g., quarterly, annual, or every third year)

• No individual sample exceeds 0.040 mg/L for TTHM

• No individual sample exceeds 0.030 mg/L for HAA5

• Your system did not have any TTHM or HAA5 monitoring violations

Exhibit 4.1 40/30 Criteria Compliance Dates

Schedule1

Stage 1 DBPR 

Data Eligibility Period2

40/30 Certification

Deadline

1 8 consecutive calendar quarters

 starting no earlier than January 2004

October 1, 2006

2 April 1, 2007

3 8 consecutive calendar quarters

 starting no earlier than January 2005

October 1, 2007

4 April 1, 2008

Notes:

1. Your schedule is defined by population served by your system or by the largest system in your combined

distribution system. See Chapter 2 for more information.

2. If you were not required to sample during this period, use data from the 12-month period prior to the eligibility

period shown.

Example 4.1 is an example of a system determining whether they meet the 40/30 criteria.

If you don’t have Stage 1 compliance data, EPA or your state may allow you to use

operational TTHM and HAA5 data to qualify for 40/30 certification if your sampling and

analysis met the general intent of Stage 1 DBPR compliance. Some of the criteria that EPA or

your state might use to evaluate your data are below. 

• Were samples analyzed by EPA approved methods?

• Were samples analyzed at a certified laboratory?

• Is the number of sites adequate to represent the distribution system?

• Are the sites located appropriately (average and maximum residence time)?

• Were samples taken during the month of warmest water temperature?

• Were samples taken at the appropriate frequency (monthly, quarterly or annually)?
IDSE Guidance Manual for the Final Stage 2 DBPR 4-3 January 2006

Depending on the 8 consecutive quarter eligibility period upon which you are basing

your certification, you may be sampling right before your certification deadline. If this is the

case, you will not know whether you have met the eligibility criteria for 40/30 certification until

these last samples are analyzed. If your TTHM or HAA5 results exceed the 40/30 threshold near

the end of the period, you must conduct an IDSE through standard monitoring or a system

specific study (SSS). The deadlines for submittal of a standard monitoring plan or a SSS plan

are the same as the 40/30 certification deadline shown in Exhibit 4.1. Systems may want to

consider preparing a standard monitoring plan if they are concerned that they might exceed the

40/30 levels at the end of the eligibility period.

Remember that even if you meet the eligibility criteria and submit the certification, EPA

or your state may still require you to conduct an IDSE using standard monitoring or an SSS. If

this occurs, you may need to work with EPA or your state to determine a schedule for

completing a standard monitoring or SSS plan and submitting an IDSE report. 

Example 4.1 Qualifying for a 40/30 Certification

A ground water system serving 8,000 people with two wells has been sampling annually at

two locations in their distribution system under the Stage 1 DBPR. Because they do not buy

or sell water, this system is on schedule 4. The table below shows their TTHM and HAA5

data for their eligibility period. 

July 21, 2005 July 24, 2006 July 23, 2007

TTHM

(mg/L)

HAA5

(mg/L)

TTHM

(mg/L)

HAA5

(mg/L)

TTHM

(mg/L)

HAA5

(mg/L)

Stage 1 Site 1 0.033 0.015 0.037 0.020 0.035 0.021

Stage 1 Site 2 0.040 0.022 0.035 0.021 0.037 0.019

No individual sample exceeded 0.040 mg/L for TTHM or 0.030 mg/L for HAA5. The system

does not have any TTHM or HAA5 monitoring violations during the eligibility period. The

system determines that they meet the criteria for the 40/30 certification and they submit their

certification for the period of January 1, 2006 to December 31, 2007 by their deadline of April

1, 2008.
IDSE Guidance Manual for the Final Stage 2 DBPR 4-4 January 2006

IDSE Tool

4.2 Preparing and Submitting the Certification Letter

At a minimum, you must prepare and submit a statement certifying that you meet the

eligibility criteria in Section 4.1. Your certification should also contain basic system information

including population served by your system, your system type (subpart H or ground water,

community or non-community), and contact information. EPA has developed a 40/30

Certification Letter Form (Form 1), shown on the next page, that can be used by any system to

prepare a certification letter. This form is also available electronically as part of the IDSE Tool. 

Example 4.2 is a completed certification form for a hypothetical system.

The IDSE Tool creates a custom 40/30 certification form for your system and

submits the completed letter to EPA and your state for you. The tool is available

on EPA’s website at http://www.epa.gov/safewater/disinfection/stage2.

You must submit your certification letter by the deadline in Exhibit 4.1. You should

submit the certification to the Information Processing and Management Center (IPMC) for

review by EPA or your state. See Section 1.4 of this guidance manual for information on how to

submit your letter to the IPMC. If you do not submit either a 40/30 certification, standard

monitoring, or study plan by this deadline, you will incur a monitoring and reporting violation. 

You can submit the letter as early as you want after you have met the requirements.

EPA or your state may require you to submit additional information listed below:

• Stage 1 compliance monitoring results

• A distribution system schematic

• Recommended Stage 2 compliance monitoring locations 

If the reviewer wants to request additional information or to have you conduct an IDSE, they

will contact you. However, you may not receive a confirmation that your 40/30 certification has

been accepted. If you do not hear from EPA or your state within 12 months after the submission

deadline, you can assume your certification has been accepted.

4.3 Recordkeeping

You must retain a complete copy of your 40/30 certification letter

on file for 10 years after you submit it to EPA or your state. You must also

make your 40/30 certification letter and any notification from EPA or your

state available for review by your state or the public.
IDSE Guidance Manual for the Final Stage 2 DBPR 4-5 January 2006

Form 1: 40/30 Certification Letter Page 1 of 1

STAGE 2 DBPR

US EPA-IPMC

P O Box 98

Dayton, OH 45401-0098

System Information

PWS Name:_____________________ PWS ID:_______________________

Street Address:___________________ Population Served:________________ 

City:___________________________

State:___________________________

Zip:____________________________

Source Water Type: 9Ground 9Subpart H 

System Type: 9CWS 9NTNCWS

Combined Distribution System: 9Wholesale 9Consecutive 9Neither 

Contact Person

Name: _______________________ Title: ____________________

Phone Number:__________________ Fax Number (if available):____________

Email Address (if available):_______________________

Certification

I hereby certify that each individual Stage 1 DBPR compliance sample collected from ________

to _____________ was less than or equal to 0.040 mg/L for TTHM and 0.030 mg/L for HAA5. I

understand that to be eligible, each individual sample must be equal to or below these values. I

also certify that this PWS collected all required Stage 1 samples and did not have any Stage 1

monitoring violations during this time period. 

Signature:_________________ Date:______________________
IDSE Guidance Manual for the Final Stage 2 DBPR 4-6 January 2006

Example 4.2 Completed 40/30 Certification Letter Using Form 1

STAGE 2 DBPR

US EPA-IPMC

P O Box 98

Dayton, OH 45401-0098

System Information

PWS Name: Hometown PWS ID: US 1234567 

Street Address: 987 Main Street Population Served: 25,976 

City: Hometown 

State: XX 

Zip: 12345 

Source Water Type: 9Ground TSubpart H 

System Type: TCWS 9NTNCWS

Combined Distribution System: 9Wholesale 9Consecutive TNeither 

Contact Person

Name: Jim Smith Title: Certified Operator 

Phone Number: 987-6543 Fax Number (if available):____________

Email Address (if available): J.smith@hometown.gov 

Certification

I hereby certify that each individual Stage 1 DBPR compliance sample collected from March

2005 to February 2007 was less than or equal to 0.040 mg/L for TTHM and 0.030

mg/L for HAA5. I understand that to be eligible, each individual sample must be equal to or

below these values. I also certify that this PWS collected all required Stage 1 samples and did

not have any Stage 1 monitoring violations during this time period. 

Signature: Date: May 13, 2007 
IDSE Guidance Manual for the Final Stage 2 DBPR 4-7 January 2006

4.4 Selecting Stage 2 Compliance Monitoring Sites 

The required number and type of sites for Stage 2 DBPR compliance monitoring are

based on your source water type and the population served by your system. Monitoring

requirements are summarized on the second page of your Requirements Summary Sheet in

Chapter 2 and presented again here in Exhibit 4.2. Keep in mind that even if you qualify for

reduced monitoring under Stage 2 compliance monitoring, you must still select the required

number of monitoring sites as shown in Exhibit 4.2 and include them in your Stage 2 compliance

monitoring plan (see Section 4.5 for a summary of compliance monitoring plan requirements).

Due to the change from plant-based monitoring under the Stage 1 DBPR to populationbased monitoring for the Stage 2 DBPR, you may have the same number, more, or fewer

monitoring sites for Stage 2 compared to Stage 1. Compare your required number of Stage 2

DBPR sites to the total number of Stage 1 DBPR monitoring sites for all plants in your system. 

Depending on your findings, go to the appropriate subsection (4.4.1, 4.4.2, or 4.4.3) for guidance

on selecting Stage 2 DBPR compliance monitoring sites.

Exhibit 4.2 Stage 2 Compliance Monitoring Requirements

Source Water

Type Population Size Category Monitoring Frequency1

Total Number of

Distribution System

Monitoring Locations 2

Subpart H

<500 per year 2

500-3,300 per quarter 2

3,301-9,999 per quarter 2

10,000-49,999 per quarter 4

50,000-249,999 per quarter 8

250,000-999,999 per quarter 12

1,000,000-4,999,999 per quarter 16

$5,000,000 per quarter 20

Ground Water

<500 per year 2

500-9,999 per year 2

10,000-99,999 per quarter 4

100,000-499,999 per quarter 6

$500,000 per quarter 8 1

 All systems must monitor during the month of highest DBP concentration. 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 HAA5 concentrations, respectively. Only one location with a dual sample set per monitoring period is

needed if highest TTHM and HAA5 concentrations occur at the same location (and month, if monitored annually).
IDSE Guidance Manual for the Final Stage 2 DBPR 4-8 January 2006

For systems collecting quarterly data:

LRAA = (Q1 + Q2+ Q3 + Q4) / 4

For systems collecting annual data

(once/year):

LRAA = result for warmest

temperature month

4.4.1 You Have THE SAME Number of Stage 1 Sites as Required by the Stage 2 DBPR

If the number of Stage 1 DBPR monitoring locations in your system is exactly the same

as the required number of Stage 2 DBPR monitoring locations, continue to use all of your Stage

1 DBPR sites for Stage 2 DBPR compliance monitoring. 

4.4.2 You Have MORE Stage 1 Sites than Required by the Stage 2 DBPR

If you have more Stage 1 sites than you need for Stage 2 DBPR monitoring (this could be

the case if you have multiple treated entry points in your system), you must select the sites with

highest DBP levels for Stage 2 monitoring. You must alternate your site selection between

locations representing high TTHM levels and high HAA5 levels, starting with high TTHM.

To identify locations representing high TTHM levels and high HAA5 levels, EPA

recommends that you use Stage 1 DBPR monitoring results. Specifically, you can use the 4-Step

process outlined below:

Step 1: Calculate the locational running annual

average (LRAA) TTHM and HAA5

concentrations at each Stage 1 DBPR

monitoring site. You should use data

for the most recent calendar year, as

long as this year is generally

representative of typical system

conditions. 

Step 2: Select the site with the highest TTHM

LRAA as your first high TTHM site

Step 3: Select the site with the highest HAA5 LRAA not previously selected as your first

high HAA5 site

Step 4: Repeat Steps 2 and 3, selecting the next highest sites for TTHM and HAA5

respectively, until the total number of selected sites equals the number of sites

required for Stage 2 DBPR compliance monitoring (as shown in Exhibit 4.2)

You can use the site selection Worksheet 4.1 to organize your Stage 1 DBPR data and select

Stage 2 DBPR monitoring sites. If you use this form, you should consider keeping it as part of

your Stage 2 DBPR monitoring plan (see Section 4.5).
IDSE Guidance Manual for the Final Stage 2 DBPR 4-9 January 2006

Worksheet 4.1 Stage 2 DBPR Site Selection for Systems Getting 

the 40/30 Certification Page 1 of 1

Instructions: Enter the site ID and LRAAs for each Stage 1 DBPR monitoring location. You

may want to sort your entries in order by TTHM LRAA or HAA5 LRAA values. 

As you work through the site selection protocol, fill in the “Stage 2 Site Type” column each

time you select a site to indicate whether the site is a high TTHM or high HAA5 site. This will

help you to track which sites have already been selected and can help you ensure that you

select the required number of each type of site.

Stage 1 DBPR

Monitoring Site ID

LRAA

TTHM (mg/L) HAA5 (mg/L) Stage 2 Site Type*

Example 0.032 0.025 1st high TTHM

* Enter high TTHM or high HAA5 site
IDSE Guidance Manual for the Final Stage 2 DBPR 4-10 January 2006

4.4.3 You Have FEWER Stage 1 Sites than Required by the Stage 2 DBPR

If you do not have enough Stage 1 sites to meet Stage 2 DBPR monitoring requirements

(this could be the case if you are a large system with very few treatment plants), you must select

additional sites. You must identify additional locations by alternating selection of locations

representing high TTHM and high HAA5. Remember that you will need to provide a

justification for the new site selection in your Stage 2 compliance monitoring plan discussed in

Section 4.5 below.

General guidelines for selecting candidate locations for high TTHM and high HAA5 sites

are provided below. Guidance for final site selection considering other factors follows. If you

would like more information about formation of disinfection by-products, refer to Appendix A. 

In addition, Chapter 7 provides a more in-depth discussion of how to select sites that represent

high levels of TTHM or HAA5.

High TTHM sites

In general, higher water temperatures and increased water age lead to higher TTHM

concentrations. Exhibit 4.3 provides typical characteristics of high TTHM sites. Storage

facilities in a distribution system typically increase water age. Therefore, if your system has

storage tanks or reservoirs, you should locate high TTHM sites downstream of those tanks. In

addition, sites near dead ends and sparsely populated residential areas can be likely sites for high

TTHM. Be sure to locate the sites before or at the last group of customers on a dead end line. 

Samples taken at the very end of a dead end line are not representative of the water received by

customers. 

Exhibit 4.3 Typical Characteristics of High TTHM Sites

High TTHM sites are often located: 

• hydraulically downstream of storage facilities

• near the ends of the distribution system, at or before the last group of customers

• in hydraulic dead-ends, where flow of water is low or stagnant

• prior to the last fire hydrant

Sample sites should not be located:

• at a dead-end where there are no customers.

• prior to booster disinfection with chlorine 
IDSE Guidance Manual for the Final Stage 2 DBPR 4-11 January 2006

High HAA5 Sites

As with TTHM, higher temperatures and increased residence time can lead to higher

HAA5 concentrations. However, HAA5 can biodegrade where biological activity is present and

disinfectant residual levels are low or non-existent. Therefore, you should consider locating high

HAA5 sites where disinfectant residuals are significantly less than the system average

(indicating a long residence time), but avoid areas that have very low or no residual. When

booster disinfection is applied, the disinfectant residual will increase despite advanced water age. 

HAA5 levels are likely to increase after a booster disinfectant is applied due to the greater

concentration of disinfectant available to react with DBP precursors and the lack of biological

activity in these areas. Therefore, if your system practices booster disinfection, you should

locate high HAA5 sites after booster disinfection is applied.

You should not select high HAA5 sites in locations that regularly or in the summer months have

free chlorine residuals less than 0.2 mg/L or with chloramine residuals less than 0.5 mg/L. 

Final Site Selection

Once you have considered the likely high TTHM and HAA5 locations in your

distribution system, you will choose the best locations for monitoring. Consider the following

issues when making these choices. 

• Select sites that provide the best geographic and hydraulic representation. 

• Make sure that you have located sites in as many key areas as possible. These would

include isolated portions of the distribution system, areas downstream of tanks, areas

downstream of booster chlorination, and within each pressure zone. 

• Consider site access issues as each selected site must remain accessible over the long

term.

4.5 Next Steps: Preparing the Stage 2 DBPR Compliance Monitoring Plan

As the final step before you can begin compliance monitoring for the Stage 2 DBPR, you

must develop a Stage 2 DBPR compliance monitoring plan. The plan will be similar to your

Stage 1 DBPR monitoring plan in that it will identify how you intend to sample for compliance

with Stage 2. You must keep your plan on file for state and public review. If you are a subpart

H system serving > 3,300 people, you must also submit your plan to EPA or your state prior to

when you are required to start monitoring.

Exhibit 4.4 contains the minimum requirements for what must be included in your Stage

2 DBPR compliance monitoring plan. Because compliance monitoring plans are not addressed

as part of the IDSE provisions of the Stage 2 DBPR, EPA has not included detailed guidance

for developing Stage 2 compliance monitoring plans in this guidance manual. EPA plans to

develop other manuals and training that specifically address the compliance monitoring

provisions of the Stage 2 DBPR.
IDSE Guidance Manual for the Final Stage 2 DBPR 4-12 January 2006

See EPA’s website at http://www.epa.gov/safewater/disinfection/stage2 for an up-to-date

inventory of Stage 2 DBPR guidance manuals and training materials, or call the Safe Drinking

Water Hotline at 1-800-426-4791.

Exhibit 4.4 Required Contents of Stage 2 DBPR Compliance Monitoring Plans

All Systems Additional Requirements for

Systems Getting the 40/30

Certification

Additional Requirements

for Consecutive and

Wholesale Systems 1

• Monitoring

locations

• Monitoring dates

• Compliance

calculation

procedures

• If you had FEWER Stage 1

DBPR compliance monitoring

sites than required by the

Stage 2 DBPR, you must

include the rationale for

identifying locations as having

high levels of TTHM or HAA5

• If your state has used its

special primacy authority

to modify your

monitoring requirements,

you must include

monitoring plans for

other systems in your

combined distribution

system

1. See Appendix D of this manual for guidance specifically for consecutive and wholesale systems.
This chapter covers:

5.1 Qualifying for an Existing Monitoring Results SSS

5.2 Preparing Your SSS Plan

N Form 2: Existing Monitoring Results SSS Plan

5.3 Selecting Stage 2 DBPR Compliance Monitoring Sites and Preparing the

IDSE Report

N Form 3: IDSE Report for an Existing Monitoring Results SSS

5.4 Recordkeeping

5.5 Next Steps: Preparing the Stage 2 DBPR Compliance Monitoring Plan 

5.0 System Specific Study Using Existing Monitoring Results

This system specific study (SSS) allows systems to avoid duplicating field monitoring

efforts under the Initial Distribution System Evaluation (IDSE) if they already have significant

existing total trihalomethane (TTHM) and haloacetic acid-five (HAA5) data. Some systems may

have operational TTHM and HAA5 data beyond what is required by the Stage 1 Disinfectants

and Disinfection Byproducts Rule (DBPR) that will allow them to qualify for this IDSE option. 

Other small and medium systems with many plants may be able to qualify using their Stage 1

DBPR data (these systems may have more data for Stage 1 than will be required by the Stage 2

DBPR because of the change from plant-based to population-based monitoring requirements). 

Section 5.1 provides the minimum requirements systems must meet to qualify for the existing

monitoring SSS.

If you have not already done so, you should complete the flowchart in Exhibit 2.3 of this

guidance manual. The flowchart will help you select the most appropriate IDSE option for your

system and will direct you to a 2-page Requirements Summary Sheet for your schedule. You

will also be directed to the System Specific Study Requirements - Attachment sheet containing

detailed requirements for Stage 2 compliance monitoring (e.g., number of samples and sampling

frequency). You should keep these sheets handy as you work through this chapter. 

This chapter provides guidelines for compiling results, preparing an Existing Monitoring

Results SSS Plan, selecting Stage 2 DBPR compliance monitoring sites, and preparing the IDSE

report. Appendix E supports this chapter by providing an example SSS plan and report for a

surface water system serving 40,000 people. 

It is important that consecutive and wholesale systems communicate with each other

throughout the IDSE process. If you are a consecutive or wholesale system, refer to Appendix

D for specific issues that you should consider.

If you plan to conduct an SSS using existing monitoring results, you must submit an SSS

study plan for state or EPA review in accordance with the schedule on your requirements

summary sheet found in Chapter 2. You have the option of submitting the SSS plan and IDSE
IDSE Guidance Manual for the Final Stage 2 DBPR 5-2 January 2006

report together (which must include selection of Stage 2 DBPR compliance monitoring sites) by

the study plan deadline if all monitoring is complete. If you choose this option, you have no

further requirements under the IDSE unless you are contacted by EPA or your state.

Alternatively, you may submit the SSS plan first, conduct additional monitoring, then submit

your IDSE report for the existing monitoring results SSS by the report deadline in your

requirements summary sheet. Below is a discussion of when you should use each of these two

options.

Option 1: Submitting a Completed Study Plan and IDSE Report at the Same Time

You should consider Option 1 if:

• You have at least as much data as the minimum requirements.

• You believe that your existing data provides good coverage of your system and

adequately identifies locations of high TTHM and HAA5.

You need to:

• Select Stage 2 DBPR compliance monitoring locations based on your existing

monitoring results.

• Submit both the SSS plan and IDSE report by the deadline for the SSS plan

provided on your requirements summary sheet.

Option 2: Submitting a Separate SSS Plan and IDSE Report

You should consider Option 2 if:

• You believe that Stage 1 compliance monitoring data collected during the IDSE

period can help select Stage 2 compliance monitoring sites.

• You have additional operational monitoring planned that will aid you in selecting

Stage 2 DBPR compliance monitoring sites.

• Your existing data does not provide good geographic coverage of your system.

You need to:

• Submit the SSS plan by the deadline provided on your requirements summary

sheet. 

• Conduct additional monitoring by the date listed in your requirements summary

sheet.

• Select Stage 2 DBPR compliance monitoring sites based on existing and new

monitoring results.

• Submit your IDSE report by the deadline in your requirements summary sheet.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-3 January 2006

5.1 Qualifying for an Existing Monitoring Results SSS

Checklist 5.1 on the next page contains the minimum requirements your system must

meet to qualify for an SSS using existing monitoring results. The data you use to meet the

minimum number of monitoring locations and number of samples must meet the criteria

presented in the checklist. Remember, though, that EPA or your state can still require you to

conduct standard monitoring even if you qualify for the existing monitoring results SSS. 

The following sections provide additional guidance for evaluating your data, source

water conditions, and distribution system conditions to determine if you qualify.

5.1.1 Evaluating Existing Monitoring Data

 You must have collected at least the total number of TTHM and HAA5 samples as

shown in Checklist 5.1. You must also have sampled from the minimum number of locations

shown for your system size and source water type. Your existing monitoring results must

include your Stage 1 DBPR compliance monitoring data. All of the data you use to count

towards these minimum numbers must meet the criteria in the checklist. All data must have been

collected within five years prior to your SSS plan deadline as listed on your requirements

summary sheet found in Chapter 2. See Exhibit 5.1 for the five-year qualifying periods for each

Stage 2 DBPR schedule.

Exhibit 5.1 Qualifying Period for the Existing Monitoring Results SSS

Schedule1 SSS Plan Deadline

Five-Year Qualifying Period for Existing

Monitoring Results

1 October 1, 2006 October 1, 2001 - October 1, 2006

2 April 1, 2006 April 1, 2001 - April 1, 2006

3 October 1, 2007 October 1, 2002 - October 1, 2007

4 April 1, 2008 April 1, 2003 - April 1, 2008

Note:

1. Your schedule is defined by population served by your system or by the largest system in your combined

distribution system. You should have received a letter from EPA or your state with your schedule for the Stage 2

DBPR. See Chapter 2 for more information.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-4 January 2006

Checklist 5.1 Minimum Requirements Checklist for an SSS

Using Existing Monitoring Results

Yes No

G G Do you have at least the minimum number of distribution system monitoring locations

shown in the table below from which you collected TTHM and HAA5 samples?

G G Do you have at least the minimum number of TTHM samples and HAA5 samples shown in

the table below?

G G Was each monitoring location sampled once during the peak historical month for TTHM,

HAA5, or warmest water temperature for every 12 months of qualifying data submitted?

G G Were all qualifying samples collected and analyzed in accordance with an approved EPA

method and by a certified laboratory?

G G Were all sample results collected no earlier than five years prior to your SSS plan

submission deadline?

G G Have your distribution system and treatment not changed significantly since you collected

your samples?

G G Are your existing monitoring locations representative of your entire distribution system?

If you answered yes to all of the above questions, you meet EPA’s minimum requirements for an SSS using

existing monitoring results. Remember, though, that EPA or your state can still require you to conduct standard

monitoring, even if you meet the minimum requirements, or you can choose to conduct standard monitoring. 

Source Water

Type

System Size Category

(Population Served)

Minimum Number of

Monitoring Locations

Minimum Number of

Samples

TTHM HAA5

Subpart H

<500 3 3 3

500-3,300 3 9 9

3,301-9,999 6 36 36

10,000-49,999 12 72 72

50,000-249,999 24 144 144

250,000-999,999 36 216 216

1,000,000-4,999,999 48 288 288

>5,000,000 60 360 360

Ground Water

<500 3 3 3

500-9,999 3 9 9

10,000-99,999 12 48 48

100,000-499,999 18 72 72

>500,000 24 96 96
IDSE Guidance Manual for the Final Stage 2 DBPR 5-5 January 2006

Each location must have been sampled once during the peak historical month for

TTHM, HAA5, or warmest water temperature for every 12 months of qualifying data. You

should identify your month of high TTHM, high HAA5 or warmest water temperature by

reviewing your compliance or other operational data. If you have more than one source in your

system, you should base the peak historical month on the source associated with the highest

TTHM or HAA5 formation.

If you have monthly or quarterly TTHM or HAA5 data, EPA recommends that you use

these results to identify your peak historical month. You can also evaluate water temperature

data to identify the peak historical month for each year. If the peak historical month for TTHM,

HAA5, or water temperature is different in different years, you should select the month that is

most reflective of your system’s normal operating and climatological conditions and use that

month throughout your analysis. You should document the basis for your peak historical month

for TTHM, HAA5, or warmest water temperature in your SSS Plan (See Section 5.2 for

guidance on preparing your SSS plan).

Your existing monitoring results for TTHM and HAA5 must have been collected and

analyzed in accordance with an approved EPA method. See Appendix C of this manual for

information on sample collection and approved methods. Your results must have been generated

by a certified laboratory. 

If you have several years worth of data during your five-year qualifying period, you can

use different locations sampled in different years to qualify, as long as the data meet all other

criteria for the SSS. Alternatively, you can qualify exclusively with data from one 12-month

period, as long as the 12-month period is within five years prior to your SSS plan deadline. If

you have data that spans more than 12 months, but not 24 months, the data from one peak

historical month can only be used to qualify one 12-month period of data. For example, if you

have collected data from January 2004 through June 2005 and August is your peak historical

month, you may only use data from one 12-month period (e.g., January 2004-January 2005 or

June 2004-June 2005) to count toward your minimum requirements. See Examples 5.1 and 5.2

for how hypothetical systems used their existing monitoring results to qualify for the SSS. 

As you evaluate your data, keep in mind that you are required to include all of your

Stage 1 DBPR compliance monitoring data and all other operational TTHM and HAA5

data collected during the time period beginning with the first reported result and ending

with the most recent Stage 1 DBPR results. This includes data that may not meet qualifying

criteria such as samples analyzed by a non-certified laboratory. You must submit this data even

though it does not count toward your minimum number of locations and samples. You should

verify that the qualifying data you submit meet the minimum numbers and criteria for an existing

monitoring results SSS.

See Section 5.1.4 and the instructions for filling out Form 2 in Section 5.2 of this manual

for suggestions for compiling your data.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-6 January 2006

Example 5.1 Qualifying With Multiple Years of Data Collected From Different

Locations

A surface water system serving 9,000 people has extensive operational DBP data from their

distribution system. Because they purchase water from a wholesale system serving 110,000

people, they are on Schedule 1 for the IDSE, and their SSS plan is due on October 1, 2006. 

The system samples quarterly at one location under the Stage 1 DBPR. Below is a description

of their TTHM and HAA5 data from their system during the qualifying period (October 1,

2001 - October 1, 2006)

Peak Historical Month for

TTHM, HAA5 or water

temperature:

August, based on high TTHM and water temperature

Special Monitoring Program,

January 2002 through

December 2003:

Collected TTHM and HAA5 samples quarterly at 4

locations. Monitored during peak historical month for

2002 and 2003. 

Total qualifying samples = 32 TTHM

 32 HAA5 

Special Monitoring Program,

January 2004 through

December 2005:

Collected TTHM and HAA5 samples twice per year at 1 of

the previous 4 locations plus 1 new location. Monitored

during peak historical month in 2004 and 2005. 

Total qualifying samples = 8 TTHM

 8 HAA5

Stage 1 Compliance

Monitoring, January 2004

through December 2005:

Collected one TTHM and HAA5 sample per quarter at the

Stage 1 DBPR compliance monitoring site. Monitored

during peak historical month in 2004 and 2005. 

Total qualifying samples = 8 TTHM

 8 HAA5

Total Monitoring Locations = 6 (4+1+1)

Total qualifying samples = 48 (32+8+8) TTHM

 48 (32+8+8) HAA5

The system has made no significant changes to treatment or the distribution system since the

data were collected. They used certified laboratories and approved methods for all data

collected. This system qualifies for the SSS using existing monitoring results. They plan to

submit both their SSS plan and IDSE report by their plan deadline (October 1, 2006).
IDSE Guidance Manual for the Final Stage 2 DBPR 5-7 January 2006

Example 5.2 Qualifying Using Data from a One-Year Special Study

A subpart H water system serving 90,000 people serves a geographically diverse community. 

They have three springs that are ground water under the direct influence of surface water

(GWUDI) and are each treated at the spring. The system currently monitors quarterly for the

Stage 1 DBPR at 12 distribution system monitoring locations.

This system conducted a detailed study of TTHM and HAA5 levels in their system in

calendar year 2003. They monitored quarterly at 16 different locations in their system (in

addition to Stage 1 DBPR compliance monitoring locations) and collected a total of 64

TTHM and HAA5 samples. Also during 2003, the system conducted quarterly monitoring at

12 sites for Stage 1 DBPR compliance, generating a total of 48 TTHM and HAA5 results. 

Dual samples were taken at each site during the peak historical month of July during calendar

year 2003. 

Total monitoring locations = 28 (16+12)

Qualifying samples in 2003 = 112 (64+48) TTHM

 = 112 HAA5

Qualifying samples in 2004 = 48 TTHM

 = 48 HAA5

Qualifying samples in 2005 = 48 TTHM

 = 48 HAA5

Qualifying samples in 2006 = 48 TTHM

 = 48 HAA5

Total qualifying samples = 256 (112+48+48+48) TTHM

256 (112+48+48+48) HAA5

The system has made no significant changes to treatment or the distribution system since the

data were collected. They used certified laboratories and approved methods for all data

collected. This system qualifies for the SSS using existing monitoring results. They plan to

submit both their SSS plan and IDSE report by their plan deadline (by April 1, 2007). 

5.1.2 Evaluating Treatment and Source Conditions

The monitoring results used for your SSS should reflect the source water(s) and treatment

configuration in place at the time that your SSS is completed. Within the period of the SSS data,

temporary changes, such as regular maintenance, rehabilitation, and upgrades of plant processes

are generally acceptable. Temporary changes to disinfection practices are also generally

acceptable within the period of the SSS data. Regular, repeating, and seasonal changes in supply
IDSE Guidance Manual for the Final Stage 2 DBPR 5-8 January 2006

or treatment are allowable during the SSS qualifying period and should be reflected in data

submitted.

If you made permanent changes to your system that significantly affected relative DBP

formation in the distribution system, only existing monitoring results representing conditions

after the change should be used for your SSS. Treatment changes that affected the magnitude

of TTHM and HAA5 levels in the distribution system, but that are unlikely to have changed the

DBP formation rate and relative levels of TTHMs and HAA5s in different parts of the system,

are acceptable. For example, improved control of an existing coagulation process or minor

changes in coagulation pH that reduce average levels of DBP precursors are acceptable. If

treatment process or source changes have occurred and data collected prior to the change are

utilized in an SSS, then the use of the data should be justified. An explanation of the change and

a demonstration that the change is unlikely to have significantly affected the relative TTHM and

HAA5 levels in the distribution system should be provided. See Appendix A for more

information on factors affecting DBP formation.

5.1.3 Evaluating Distribution System Conditions 

Your qualifying data must reflect the overall distribution system hydraulic operation and

large-scale movement of water through your system at the time you submit your SSS plan or

report. Normal daily and seasonal changes in system operation during the data collection period

for the SSS are acceptable. Supply points, pressure zones, large transmission mains, pump

stations, storage tanks, and large wholesale and retail customers should generally be consistent

throughout the data collection period for the SSS and submittal of your study plan and IDSE

report, but do not have to remain exactly the same. A steady increase in water demand over time

that occurs in many systems due to growth is acceptable during the data collection period for the

SSS, if it did not result in major changes in water flow pattern and age within the distribution

system.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-9 January 2006

Exhibit 5.2 Examples of System Changes1

Temporary Changes that do not

Significantly Impact DBP Formation

Permanent Changes that are Generally

Considered Cutoff Points for Using 

Existing Data

• Regular maintenance, rehabilitation,

and upgrades of plant processes

• Short duration switches to free

chlorine for secondary disinfection:

• to control nitrification in a

chloraminated system

• for short duration emergencies

• for special disinfection

operations

• Adding booster chlorination in the distribution

system

• Addition of a new water source

• Addition or removal of a very high water use

customer (industrial, institutional, or

wholesale)

• Addition, deletion, or replacement of mains or

storage tanks that significantly change water

flow patterns 

• Large main looping projects that significantly

change water flow patterns 1

 Note that this list is not comprehensive—you should use best professional judgement to determine if a modification

to your treatment or distribution system should be considered a cutoff point for the use of existing monitoring

results.

Significant distribution system changes that should be considered as cutoff points for the

use of existing monitoring results include:

• Major, permanent changes in plant production rates, installation or removal of

high service or booster pump stations, or pump operation schemes that

significantly change the location of influence zones of treatment plants and

mixing zones within the distribution system.

• Major, permanent changes in water use patterns or system hydraulics.

Specific examples of these types of changes are shown in Exhibit 5.2.

This list is not comprehensive—you should use best professional judgement to determine

if a modification to your distribution system should be considered a cutoff point for the use of

existing monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-10 January 2006

IDSE Tool

5.1.4 Compiling Your Data and Calculating LRAAs

You must include all of your existing TTHM and HAA5 data (Stage 1 compliance and

operational data) from the first monitoring date that you included through the most recent Stage

1 DBPR compliance monitoring results in your SSS plan and certify that you have not omitted

any data. The Stage 2 DBPR requires all data to be submitted to confirm that there were no

significant or permanent changes to source water quality (swings or shifts) during the monitoring

period that might affect the selection of appropriate Stage 2 compliance monitoring sites. 

To organize your data for submission, compile your data into a table or spreadsheet

format. You may wish to use the tables in the SSS plan form in this chapter. You should note

which location IDs are Stage 1 compliance locations. If your locations were monitored at

different time intervals (e.g., twice / year vs. quarterly), consider organizing your data such that

data from your peak historical month lines up vertically. 

You should select a repeating 12-month period for your data analysis, and calculate the

annual average at each monitoring site for that time period for every 12-month period of

qualifying data submitted. See the instructions for filling out Form 2 in Section 5.2 for more

suggestions on how to organize your data.

5.2 Preparing Your Existing Monitoring Results SSS Plan

Every system that conducts an SSS using existing monitoring results must prepare and

submit an SSS study plan. You should submit the plan to the Information Processing and

Management Center (IPMC) for review by EPA or your state. See Section 1.4 of this guidance

manual for information on how to submit your plan to the IPMC.

EPA has developed an Existing Monitoring Results SSS Form (Form 2), presented in

this section and available electronically as part of the IDSE Tool. You are not required to use

this form; however, if you choose not to use it, refer to Exhibit 5.3 for a list of the minimum

elements you must include in your SSS study plan. 

The IDSE Tool creates a custom form for your system and provides

links to technical guidance from this manual. The tool is available on EPA’s

website at http://www.epa.gov/safewater/disinfection/stage2. 

Your deadline for submitting your study plan can be found on your requirements

summary sheet in Chapter 2. If EPA or your state does not approve or request modifications to

your plan, or notify you that your plan is still under review within 12 months after the deadline

for plan submission, you may consider the plan approved. 
IDSE Guidance Manual for the Final Stage 2 DBPR 5-11 January 2006

Exhibit 5.3 Required Elements of Your SSS Plan

• The population served by your system.

• Your system type (subpart H or ground water).

• All stage 1 DBPR monitoring results and other monitoring results generated

during the time period beginning with the first reported result and ending with

the most recent Stage 1 DBPR compliance results. 

• Certification that the reported monitoring results include all compliance and noncompliance results generated during the time period beginning with the first

reported result and ending with the most recent Stage 1 result.

• Certification that the samples were representative of the entire distribution

system and that the treatment and distribution system have not changed

significantly since the samples were collected.

• A distribution system schematic showing entry points, sources, storage facilities,

and locations and dates of all completed and planned (if applicable) compliance

and non-compliance monitoring.

• Identification of your peak historical month for TTHM, HAA5 or warmest water

temperature.

The Existing Monitoring Results SSS Plan Form (Form 2) includes the following

sections:

I. General Information

II. SSS Requirements

III. Peak Historical Month

IV. Previously Collected Monitoring Results

V. Certification of Data

VI. Proposed SSS Monitoring Dates

VII. Distribution System Schematic

VIII. Attachments

Sections of the form with an asterisk (*) are required by the Stage 2 DBPR. An example of a

completed form is provided in Appendix E of this guidance manual.

I. General Information

I.A. PWS Information* - Important definitions for classifying your system are

provided in the definitions section at the beginning of this guidance manual. If

you have any questions on this section, contact EPA or your state.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-12 January 2006

PWSID - Enter your PWSID identification number here. This number is typically

assigned by your state.

PWS Name - Enter the name of your system here. 

PWS Address - Enter the primary mailing address for your water system here.

Population Served - Enter the number of people served by your PWS. 

Remember, this is your RETAIL population served, not including the population

served by consecutive systems that purchase water from you.

System Type - Put a check mark in the appropriate box to identify whether your

system is a CWS or a NTNCWS. Definitions for CWS and NTNCWS can be

found in the definitions section at the beginning of this guidance manual.

Source Water Type - Put a check mark in the appropriate box to identify whether

your system is a subpart H system or a ground water system. If you use any

surface water or GWUDI as a source, mark the subpart H box. Definitions for

subpart H system (including GWUDI) and ground water system can be found in

the definitions section at the beginning of this guidance manual.

Buying/Selling Relationships - Put a check mark in the appropriate box to identify

whether your system is a consecutive system, a wholesale system, or neither. If

you are both a consecutive and wholesale system (e.g., you buy and sell water),

check both boxes. Definitions for consecutive system and wholesale system can

be found in the definitions section at the beginning of this guidance manual and

in Appendix D.

I.B. Date Submitted* - Enter either the date that you are submitting the form

electronically, putting it in the mailbox, or dropping it off with an express

delivery service. Be sure to submit your SSS study plan before the deadline

found on your requirements summary sheet.

I.C. PWS Operations - This section asks questions about your system to help inform

EPA and state personnel during the plan review process.

Residual Disinfectant Type - Put a check mark in the appropriate box to identify

the type of disinfectant you most often use to maintain a residual in your

distribution system (not necessarily the same disinfectant used for primary

disinfection at the treatment plant). If you use chloramine but switch to free

chlorine for a short time, you should still check chloramine only. If you use

chloramine and chlorine regularly in your system (e.g, 4 months of free chlorine

and 8 months of chloramines), check both chlorine and chloramine. If you

maintain your residual with a disinfectant other than chlorine or chloramines (e.g.,
IDSE Guidance Manual for the Final Stage 2 DBPR 5-13 January 2006

chlorine dioxide), you should place a check next to the box marked “Other” and

enter the type of disinfectant you use in the blank next to “Other”.

Number of Disinfected Sources - Enter the total number of sources that deliver

disinfected water to your distribution system. If you connect to a single

wholesale system at a number of locations in your distribution system, consider

this one purchased source. Multiple wells that are disinfected at a common

treatment plant should also be considered one source. Do not count wells that are

not disinfected or are disinfected by UV only.

I.D. Contact Person* - Enter the contact information of the person who is submitting

the form. This should be the person who will be available to answer questions

from EPA and/or the state reviewers.

II. SSS Requirements*

II.A. Minimum Number of Monitoring Locations - Refer to the System Specific Study

Requirements - Attachment sheet in Chapter 2. Copy the numbers from the “SSS

Existing Data - Minimum Sample Requirements” table for the number of

monitoring locations that corresponds to your source type and the population

served by your system.

II.B. Minimum Number of Required Samples - Refer to the System Specific Study

Requirements - Attachment sheet in Chapter 2. Copy the numbers from the “SSS

Existing Data - Minimum Sample Requirements” table for the number of TTHM

and HAA5 samples that corresponds to your source type and the population

served by your system.

II.C. IDSE Schedule - Enter the schedule for your system based on the letter sent to

you from EPA or your state. See Chapter 2 for more information on the letter.

III. Peak Historical Month

III.A. Peak Historical Month for TTHM, HAA5 or Warmest Water Temperature* -

Enter the month that you determined to be your peak historical month for TTHM,

HAA5 or warmest water temperature for your existing monitoring results.

III.B. If Multiple Sources, Source Used to Determine Peak Historical Month - If your

system has only one source, write “N/A” here. If you have more than one source,

write the name of the source you used as the basis for determining peak historical

month. For example, if a system has one surface water, one ground water, and

one purchased ground water source, it is likely that they relied heavily on data

from the surface water source to select their peak historical month. This system

would write “surface water source” in the blank provided.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-14 January 2006

III.C. Peak Historical Month Based On - Put a check mark in the appropriate box to

identify whether your system used TTHM, HAA5, or warmest water temperature

to determine the peak historical month. If more than one were used, check as

many as necessary. If you used data other than TTHM, HAA5 and temperature

data to select your peak historical month (e.g., you used TOC data and/or water

age data), describe how you used additional data here. 

IV. Previously Collected Monitoring Results*

IV.A. Where were your TTHM and HAA5 samples analyzed? - Put a check mark in the

appropriate box to identify whether your system analyzed TTHM and HAA5

samples in an in-house laboratory or sent the samples to a certified laboratory for

analysis.

If you analyzed your TTHM and HAA5 samples in an in-house laboratory, check

the appropriate box to identify whether your laboratory is certified. If you sent

your TTHM and HAA5 samples to a certified laboratory, enter the name of the

laboratory in the blank. If you used more than one laboratory (e.g., if you used

different laboratories for operational and compliance samples), list both

laboratories, or check “in-house” and list the name of the laboratory if applicable.

IV.B. What method was used to analyze your TTHM and HAA5 samples? Put a check

mark in the appropriate box to indicate the analytical method used to measure

TTHM and HAA5. If more than one method was used (e.g., if you used different

methods for operational and compliance samples), check more than one method. 

If you do not know what method was used, contact your laboratory.

IV.C. TTHM Results - Enter the TTHM results for each monitoring site for each

monitoring period in which you collected data. Attach additional copies of this

page if needed. Alternatively, you can use your own format and submit all

monitoring results in an attachment. Guidelines for using the data tables in this

section of Form 2 to report results are provided below. 

• If you have multiple years of data at a monitoring location: Select a

repeating 12-month period for your data analysis. You may choose the

calendar year, fiscal year, or other 12-month period. While you can select

any 12-month period, you must include one sample for the peak historical

month for every 12 months of qualifying data submitted. List each

12-month period in a separate row and indicate the 12-month period

during which the data were collected. List multiple years of data for each

monitoring location before continuing to the next monitoring location.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-15 January 2006

• If you have data from one 12-month period at a monitoring location:

Use the 12-month period for which you have collected data, even if you

used a different time period for other monitoring locations. 

Enter the site ID for each location, and note which site IDs are Stage 1

compliance locations. If your locations were monitored at different time intervals

(e.g., twice/year vs. quarterly), consider organizing your data such that data from

your peak historical month lines up vertically. For each sample result, enter the

date on which sampling was conducted. 

In the column marked “Data Qualifies (yes/no),” indicate whether the data in the

row are qualifying data. To be considered qualifying data, the samples must be

analyzed by a certified laboratory using an approved method, and each location

must be sampled during the peak historical month identified in III.A for each

12-month period of data submitted. See Section 5.1.1 for more information.

Calculate the LRAA for each 12-month period of qualifying data submitted and

enter it in the last column in the table. If you did not monitor on a regular basis,

compute quarterly averages first, then use these values to calculate your LRAA. 

If you took a sample once during the peak historical month, then your LRAA is

the single result from your peak historical month.

Appendix E provides an example of how you can present your data.

Remember, you must include all Stage 1 DBPR compliance results and

operational results generated during the time period beginning with the first result

reported for the SSS and ending with the most recent Stage 1 DBPR results. 

IV.D. HAA5 Results - Enter the HAA5 results for each monitoring site for each

monitoring period in which you collected data. For each sample result, enter the

date on which sampling was conducted. Attach additional copies of this page if

needed. Alternatively, you can use your own format and submit all monitoring

results in an attachment.

Use the same 12-month periods you used to report TTHM data under IV.C. Refer

to IV.C. for suggestions on how to organize and report your data.

Remember, you must include all Stage 1 DBPR compliance results and

operational results generated during the time period beginning with the first result

reported for the SSS and ending with the most recent Stage 1 DBPR results.

V. Certification of Data* - Carefully read the criteria listed in this section and review your 

system data to verify that each statement is true. If all statements are true, sign your

name and enter the date in the spaces provided.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-16 January 2006

VI. Proposed SSS Monitoring Schedule* - Skip this section if you are submitting your

IDSE report at the same time as your SSS plan. Complete it only if you plan to conduct

monitoring during the SSS period. 

Enter the ID for each monitoring site in the table (verify that these match the IDs you

enter on your schematic), and enter your proposed sampling schedule. The entry can be a

specific date or week and can be in a number of different formats. For example:

• 7/9/07

• 2nd week in Nov ‘07

• Week of 7/9/07 

Be sure to include dates for Stage 1 DBPR monitoring to be conducted during the SSS

period. Remember that at least one monitoring period must be during the peak historical

month identified in Section III.A. for each 12 months of qualifying data. Attach

additional sheets as needed.

VII. Distribution System Schematic* - Attach a distribution system schematic to your SSS

plan. Your schematic must include the locations of entry points, sources, storage

facilities, Stage 1 compliance monitoring sites, and monitoring sites for your existing

results.

SSS plans will not be considered confidential business information (CBI) and are subject

to the Freedom of Information Act (FOIA). Therefore, your distribution system

schematic should not contain information that poses a security risk to your system. 

EPA suggests that you consider one of the following options for submitting distribution

system schematics:

• Option 1: Distribution system schematic with no landmarks or addresses

indicated. Show locations of sources, entry points, storage facilities, Stage 1

compliance monitoring locations, and monitoring sites for your existing results

(required). Also include pressure zone boundaries and locations of pump stations. 

Provide map scale.

• Option 2: City map without locations of pipes indicated. Show locations of

sources, entry points, storage facilities, Stage 1 compliance monitoring locations,

and monitoring sites for your existing results (required). Also include boundaries

of the distribution system, pressure zone boundaries and locations of pump

stations. Provide map scale.

Schematics should be as clear and easy to read as possible. They should typically be

submitted on a scale of between 1:4,000 and 1:8,000; however, larger-scale drawings are

acceptable as long as systems components can still be clearly shown. All sizes from 81⁄2

inches x 11 inches to larger, plan-sized sheets are acceptable. If electronic versions are

submitted, use one of the following file types:
IDSE Guidance Manual for the Final Stage 2 DBPR 5-17 January 2006

• Adobe PDF file (*.pdf)

• Microsoft Word (*.doc)

• WordPerfect (*.wpd)

• Image file (*.gif, *.bmp, *.jpg, *.jpeg)

VIII. Attachments - Put a check mark in each of the boxes corresponding to any attachments

that you have included in your report. A distribution system schematic is required. Refer

to Section VII for details.

If you submit your study plan electronically, you also have the option to submit

attachments in hard copy. Include a note in your electronic study plan explaining that 

attachments are being submitted in hard copy, and mail the hard copy to the IPMC

mailing address in your Requirements Summary Sheet. The IPMC will match the hard

copy submission with your electronic submission when it is received.

Enter the total number of pages in your monitoring plan (including attachments) in the

blank at the bottom of this section. This will allow EPA or your state to ensure that all

pages were received.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-18 January 2006

This page intentionally left blank.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-19 January 2006

Form 2: Existing Monitoring Results SSS Plan Page 1 of 8

I. GENERAL INFORMATION

A. PWS Information* B. Date Submitted*

 PWSID:

PWS Name:

PWS Address:

City: State: Zip:

Population Served:

System Type: Source Water Type: Buying / Selling Relationships:

~ CWS ~ Subpart H ~ Consecutive System 

~ NTNCWS ~ Ground ~ Wholesale System 

 ~ Neither 

C. PWS Operations

Residual Disinfectant Type: ~ Chlorine ~ Chloramines ~ Other_____________

Number of Disinfected Sources: ____Surface____GWUDI____Ground____Purchased

D. Contact Person*

Name:

Title:

Phone #: Fax #:

E-mail: 

II. SSS REQUIREMENTS*

A. Minimum Number of Monitoring Locations 

B. Minimum Number of Required Samples

 TTHM HAA5

C. IDSE Schedule

 ~ Schedule 1 ~ Schedule 2 ~ Schedule 3 ~ Schedule 4
IDSE Guidance Manual for the Final Stage 2 DBPR 5-20 January 2006

Form 2: Existing Monitoring Results SSS Plan Page 2 of 8

III. PEAK HISTORICAL MONTH

A. Peak Historical Month* 

B. If Multiple Sources, Source Used to Determine Peak Historical Month

(write “N/A” if only one source in your system)

________________________________________________________________

C. Peak Historical Month Based On (check as many as needed)

~ High TTHM ~ High HAA5 ~ Warmest Water temperature

If you used other information to select your peak historical month, explain here 

(attach additional sheets if needed)

IV. PREVIOUSLY COLLECTED MONITORING RESULTS*

A. Where were your TTHM and HAA5 samples analyzed?

~ In-House 

Is your in-house laboratory certified? ~ Yes 

~ No

~ Certified Laboratory

Name of certified laboratory:

B. What method(s) was used to analyze your TTHM and HAA5 samples?

 TTHM HAA5

~ EPA 502.2 ~ EPA 552.1

~ EPA 524.2 ~ EPA 552.2

~ EPA 551.1 ~ EPA 552.3

~ SM 6251 B
IDSE Guidance Manual for the Final Stage 2 DBPR 5-21 

Form 2: Existing Monitoring Results SSS Plan IV. PREVIOUSLY COLLECTED MONITORING RESULTS (continued)*C. TTHM Results

Site ID1

12-

monthperiod

Data

Qualifies

(yes/no) 

Data Type TTHM (mg/L) 

Sample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample Result

1 Verify that site IDs match the site IDs on your distribution system schematic.

Attach additional sheets as needed for previously collected compliance and operational monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-22 

Form 2: Existing Monitoring Results SSS Plan IV. PREVIOUSLY COLLECTED MONITORING RESULTS (continued)*C. TTHM Results

Site ID1

12-

monthperiod

Data

Qualifies

(yes/no) 

Data Type TTHM (mg/L) 

Sample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample Result

1 Verify that site IDs match the site IDs on your distribution system schematic.

Attach additional sheets as needed for previously collected compliance and operational monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-23 

Form 2: Existing Monitoring Results SSS Plan IV. PREVIOUSLY COLLECTED MONITORING RESULTS (continued)*D. HAA5 Results

Site ID1

12-

monthperiod

Data

Qualifies

(yes/no) 

Data Type HAA5 (mg/L) 

Sample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample Result

1 Verify that site IDs match the site IDs on your distribution system schematic.

Attach additional sheets as needed for previously collected compliance and operational monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-24 

Form 2: Existing Monitoring Results SSS Plan IV. PREVIOUSLY COLLECTED MONITORING RESULTS (continued)*D. HAA5 Results

Site ID1

12-

monthperiod

Data

Qualifies

(yes/no) 

Data Type HAA5 (mg/L) 

Sample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample Result

1 Verify that site IDs match the site IDs on your distribution system schematic.

Attach additional sheets as needed for previously collected compliance and operational monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-25 January 2006

Form 2: Existing Monitoring Results SSS Plan Page 7 of 8

V. CERTIFICATION OF DATA*

I hereby 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 Stage 1 DBPR results.

• The samples are representative of the entire distribution system.

• Treatment and the distribution system have not changed significantly since the

samples were collected.

Signature:

Date:

VI. PROPOSED SSS MONITORING SCHEDULE*

Skip if you are submitting your IDSE Report at the same time as your plan

SSS Site ID 

(from map) 1

Projected Sampling Date (date or week) 2

period 1 period 2 period 3 period 4 period 5 period 6

 

1

 Verify that site IDs match IDs on your distribution system schematic (See Section VII of this

form). Attach additional copies of this sheet if necessary.

2

 period = monitoring period. Can list exact date or week (e.g., week of 7/9/07)
IDSE Guidance Manual for the Final Stage 2 DBPR 5-26 January 2006

Form 2: Existing Monitoring Results SSS Plan Page 8 of 8

VII. DISTRIBUTION SYSTEM SCHEMATIC*

ATTACH a schematic of your distribution system. 

Distribution system schematics are not confidential and should not contain information that

poses a security risk to your system. EPA recommends that you use one of two options: 

Option 1: Distribution system schematic with no landmarks or

addresses indicated. Show locations of sources, entry points, storage

facilities, operational monitoring locations, and Stage 1 compliance

monitoring locations (required). Also include pressure zone boundaries and

locations of pump stations. Provide map scale. 

Option 2: City map without locations of pipes indicated. Show

locations of sources, entry points, storage facilities, operational monitoring

locations, and Stage 1 compliance monitoring locations (required). Also

include boundaries of the distribution system, pressure zone boundaries

and locations of pump stations. Provide map scale.

VIII. ATTACHMENTS

~ Additional sheets for explaining how you selected the peak historical month

 (Section III).

~ Additional sheets for previously collected monitoring results (Section IV).

~ Additional sheets for proposed monitoring dates (Section VI).

~ Distribution system schematic* (Section VII).

Total Number of Pages in Your Plan: __________

Note: Fields with an asterisk (*) are required by the Stage 2 DBPR.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-27 January 2006

IDSE Tool

5.3 Selecting Stage 2 DBPR Compliance Monitoring Sites and Preparing the

IDSE Report

If you submitted your study plan separate from your IDSE report, EPA or your state will

review the plan. If EPA or your state does not approve or request modifications to your plan, or

notify you that your plan is still under review within 12 months after the deadline for plan

submission, you may consider the plan approved. Follow your approved study plan as you

complete SSS monitoring.

Every system that conducts an existing monitoring results SSS must use results from

their SSS to select Stage 2 DBPR compliance monitoring sites. You must follow a specific

protocol, as laid out in the Stage 2 DBPR, to evaluate data and select compliance sites unless

you decide to recommend alternative Stage 2 compliance monitoring sites to your state or EPA.

This section presents the required protocol for selecting Stage 2 DBPR compliance monitoring

sites and provides guidance for preparing an IDSE report. 

You must include all additional monitoring results taken during the period of the SSS

and recommended Stage 2 compliance monitoring sites in your IDSE Report. You should

submit your IDSE report to the Information Processing and Management Center (IPMC) for

review by EPA or your state. See Section 1.4 of this guidance manual for information on how to

submit your plan to the IPMC. 

You must submit the report by the deadline in your requirements summary sheet

identified in chapter 2. As discussed on page 5-2 of this chapter, you have the option of

submitting your IDSE report with the SSS plan by the plan deadline. In this case, all monitoring

results must be included in your study plan.

EPA has developed a form for the IDSE Report for an Existing

Monitoring Results SSS (Form 3), presented in Section 5.3.3 and available

electronically as part of the IDSE Tool. You are not required to use this form;

however, if you choose not to use it, refer to Exhibit 5.4 for a list of the minimum

elements you must include in your IDSE report. An example of a completed report

can be found in Appendix E. The IDSE Tool is available on EPA’s website at

http://www.epa.gov/safewater/disinfection/stage2.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-28 January 2006

Exhibit 5.4 Required Elements of Your IDSE Report for an Existing Monitoring

Results SSS

• All additional Stage 1 DBPR monitoring results and other monitoring results

generated during the time period of the SSS in tabular or spreadsheet format.

• Recommendations and justifications of Stage 2 DBPR monitoring sites and

sampling dates.

• If changed from your approved study plan, 

- Distribution system schematic

- Population

- System type (subpart H or ground water).

• An explanation of any deviations from your approved study plan

5.3.1 Selecting Stage 2 DBPR Compliance Monitoring Locations

Section 5.1.4 provided guidance on compiling data for each Stage 1 compliance site and

each operational site. These results should have been included in your SSS plan. Calculate the

LRAAs for all sites that were monitored since you submitted your SSS plan, including your

Stage 1 monitoring sites. If you are submitting your IDSE report at the same time as your SSS

plan, you do not need to make additional calculations.

You will be starting with the LRAA results for each monitoring location to select Stage 2

compliance monitoring sites. If you have multiple years of data at the same monitoring location,

use the year of data with the highest LRAA for each site. If you monitored at different

frequencies at different locations or in different years, consider using your peak historical month

data to evaluate your monitoring locations. If you do this, ensure your analysis and resulting

recommendation is clear in your justification for each monitoring location. EPA recommends

that you use Worksheet 5.1 to organize your data and select Stage 2 DBPR compliance

monitoring sites. 

As noted in the worksheet, you must use the site selection protocol in Exhibit 5.5 to

select your Stage 2 compliance monitoring locations. The number of required Stage 2

compliance monitoring sites for your system can be found on page 2 of the System Specific

Study Requirements - Attachment sheet in Chapter 2. Use qualifying data only as you work

through the protocol. If you complete all steps in the protocol and need additional compliance

monitoring sites for the Stage 2 DBPR, repeat the protocol until the required number of sites has

been selected. If you arrive at Step 3 or Step 7 and have no more Stage 1 DBPR sites from

which to select, continue to the next step. Example 5.3 shows how a system uses the protocol to

select their Stage 2 compliance monitoring sites.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-29 January 2006

Additional Factors to Consider During Selection of Stage 2 Compliance Monitoring Sites

You may select alternate sites other than those identified using the protocol, but you

must justify the alternate locations in your IDSE report. 

In general, TTHM and HAA5 LRAAs are the most important factors in site selection. 

However, the Stage 2 rule allows for some flexibility in this process. As you work through the

site selection protocol, you should consider other factors that may lead you to select a site with a

similar or slightly lower LRAA. If you do not use your highest TTHM and HAA5 LRAAs to

select your Stage 2 compliance monitoring sites, you must provide justification for your

selection in your IDSE report. The following conditions are possible reasons why you may

select a site with a slightly lower LRAA over another site:

• The site provides more complete geographic coverage of the entire distribution

system

• The site allows you to maintain a historical record

• Sampling at that site provides the opportunity to collect other water quality or

operational data (e.g., chloramine systems may want to collect nitrate or nitrite

data at that site)

EPA recognizes that a slight difference between LRAAs measured at two sites may not

be meaningful given the normal variability that may occur at a site over time. As a result, the

selection of a Stage 2 compliance monitoring site with a slightly lower LRAA may be acceptable

if other factors, such as those listed above, favor the site with the lower LRAA. Examples 5.4

and 5.5 illustrate situations in which hypothetical systems might select Stage 2 DBPR

compliance monitoring sites using criteria other than the site selection protocol. When two sites

have the same LRAA, you should also consider the factors listed above to select the best site for

your Stage 2 compliance monitoring.

You may want to discuss additional site characteristics that make the location suitable for

Stage 2 compliance monitoring. Some characteristics you might consider including in your

justifications are as follows:

• Peak historical month data

• Pipe size, or range of pipe sizes in the area

• Relationship to storage facilities

• Estimated water age, if available

• Source of water (if the distribution system is served by more than one source)

It is possible that EPA or your state may not concur with your justification and may require you

to select different Stage 2 compliance monitoring sites.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-30 January 2006

Worksheet 5.1 Stage 2 DBPR Site Selection Worksheet for an Existing

Monitoring Results SSS Page 1 of 1

Instructions:

1) Enter the number of required Stage 2 DBPR compliance monitoring sites based on your

System Specific Study Requirements - Attachment summary sheet from Chapter 2. 

2) Enter the Site ID and LRAA for each Stage 1 compliance monitoring location and each

operational monitoring location. You may want to sort your entries in order by TTHM

LRAA or HAA5 LRAA values. 

3) As you work through the site selection protocol in Exhibit 5.5, fill in the “Stage 2 Site

Type” column each time you select a site to indicate whether the site is a high TTHM, high

HAA5, Existing Stage 1 DBPR Compliance Monitoring Site, or selected using criteria other

than the protocol. 

No. of Stage 2 DBPR Compliance Monitoring Sites Required

 Highest TTHM Highest HAA5 Existing Stage 1 TOTAL

Site ID

LRAA

Stage 2 DBPR Site

TTHM (mg/L) HAA5 (mg/L) Type*

Example 0.075 0.045 Highest TTHM

* Enter Highest TTHM, Highest HAA5, or existing Stage 1 DBPR
IDSE Guidance Manual for the Final Stage 2 DBPR 5-31 January 2006

Exhibit 5.5 Protocol for Selecting Stage 2 DBPR (Subpart V)

Compliance Monitoring Sites

Steps1

[required by rule]

Stage 2 Compliance Monitoring Sites

Selected 2

1 Select the location with the highest TTHM LRAA 1st highest TTHM site

2 Select the remaining location with the highest HAA5 LRAA 1st highest HAA5 site

3 For subpart H systems: Select the remaining existing Stage 1

DBPR average residence time compliance monitoring location

with the highest HAA5 LRAA

For ground water systems: Select the remaining existing Stage 1

DBPR maximum residence time compliance monitoring location

with the highest HAA5 LRAA

Skip this step if you have no more Stage 1 DBPR sites

1st Stage 1 DBPR site

4 Select the remaining location with the next highest TTHM

LRAA.

2nd highest TTHM site

5 Select the remaining location with the next highest TTHM LRAA 3rd highest TTHM site

6 Select the remaining location with the next highest HAA5 LRAA 2nd highest HAA5 site

7 For subpart H systems: Select the remaining existing Stage 1

DBPR average residence time compliance monitoring location

with the highest TTHM LRAA

For ground water systems: Select the remaining existing Stage 1

DBPR maximum residence time compliance monitoring location

with the highest TTHM LRAA

Skip this step if you have no more Stage 1 DBPR

2nd Stage 1 DBPR site

8 Select the remaining location with the next highest HAA5 LRAA 3rd highest HAA5 site

If you need more Stage 2 DBPR compliance monitoring locations, Go back to Step 1 of this protocol and repeat the

steps until you have selected the required number of total sites.

1. All steps are based on your calculated LRAAs for your operational sites and Stage 1 DBPR compliance

monitoring sites. This means that your existing Stage 1 DBPR sites can be selected in steps other than 3 or 7. Stop

when you reach your required number of Stage 2 DBPR compliance monitoring sites.

2. You cannot select the same site as a highest TTHM and a highest HAA5 compliance monitoring site. 
IDSE Guidance Manual for the Final Stage 2 DBPR 5-32 January 2006

Example 5.3 Selecting Stage 2 DBPR Compliance Monitoring Sites

A consecutive system serving 15,000 people has completed an existing monitoring

results SSS for the IDSE. This system purchases disinfected ground water from a number of

ground water systems drawing from the same aquifer. Based on state determination, the

system has two Stage 1 DBPR compliance monitoring sites. According to the System

Specific Study - Attachment sheet in Chapter 2, the system must select the following four

Stage 2 compliance monitoring sites from operational monitoring and Stage 1 DBPR sites: 

• 2 highest TTHM sites,

• 1 highest HAA5 site, and 

• 1 maximum residence time site from the existing Stage 1 DBPR data.

The table below lists the maximum TTHM and HAA5 LRAAs for the Stage 1 DBPR

compliance monitoring sites and operational monitoring data submitted for the existing

monitoring results SSS.

Site Number and

Description

Maximum TTHM LRAA

(mg/L)

Maximum HAA5 LRAA

(mg/L)

Stage 1 DBPR Compliance Monitoring Results:

1 0.058 0.031

2 0.052 0.046

Operational Monitoring Results:

3 0.053 0.040

4 0.056 0.032

5 0.051 0.042

6 0.047 0.038

7 0.045 0.036

8 0.049 0.039

9 0.038 0.034

10 0.035 0.026

11 0.021 0.015

12 0.022 0.019
IDSE Guidance Manual for the Final Stage 2 DBPR 5-33 January 2006

Example 5.3 Selecting Stage 2 DBPR Compliance Monitoring Sites (cont.)

The water system used the site selection protocol in Exhibit 5.5 to select their compliance

monitoring sites.

Go to Step 1: Select the Highest TTHM LRAA Site

Site 1 has the highest TTHM LRAA and is selected as the first high TTHM site.

Go to Step 2: Select the Highest HAA5 LRAA Site

Site 2 has the highest HAA5 LRAA and has not already been selected. Therefore,

Site 2 is chosen as the first high HAA5 site.

Go to Step 3: Select the Stage 1 Maximum Residence Time Site with the Highest HAA5 LRAA

There are no remaining Stage 1 sites to select from. Skip this step and go to Step 4.

Go to Step 4: Select the Next Highest TTHM LRAA Site

Site 4 has the next highest TTHM LRAA and is therefore chosen as the next highest

TTHM site.

Go to Step 5: Select the Next Highest TTHM LRAA Site

Site 3 has the next highest TTHM LRAA and is therefore chosen as the next highest

TTHM site.

Final Inventory of Stage 2 DBPR Compliance Monitoring Sites*

Highest TTHM: Site 1, Site 3, Site 4 (3 sites)

Highest HAA5: Site 2 (1 site)

Existing Stage 1 DBPR Site (as described in Step 3): No sites

TOTAL Sites = 4

*Note that the requirements on the previous page are for 2 highest TTHM sites, 1 highest

HAA5 site, and 1 maximum residence time site from existing Stage 1 DBPR data. However,

because the two Stage 1 DBPR sample sites were the highest TTHM site and the highest

HAA5 site, these sites were selected during the first two steps of the selection protocol. As a

result, there were no remaining Stage 1 DBPR sites to choose from during Step 3. Step 3 was

skipped and the remaining two Stage 2 compliance sites were chosen using Steps 4 and 5.

Based on the data collected, the system seems to have chosen its Stage 1 DBPR sites well in

terms of sampling at locations with the highest TTHM and HAA5 levels. 
IDSE Guidance Manual for the Final Stage 2 DBPR 5-34 January 2006

A

B

C

Water Treatment Plant

Example 5.5 Providing Geographic Coverage When Choosing Stage 2 Sites

In general, two representative high TTHM sites should not be located in the same

general area of the distribution system. Consider the following example:

The two highest TTHM LRAAs in the

distribution system are from adjacent historical

sample sites (sites A and B). The site with the third

highest TTHM LRAA is on the far side of the

distribution system (site C). In this case, consider

selecting sites A and C or B and C as Stage 2 sites

for a broader geographical coverage of the

distribution system.

Example 5.4 Maintaining a Historical Record

A ground water system serves 90,000 people and must select four Stage 2 compliance

sites. The system has already selected one highest TTHM site, one highest HAA5 site, and

one Stage 1 maximum residence time site with the highest HAA5 LRAA. The fourth site to

be selected is a high TTHM site which must be selected from the Stage 1 DBPR sites and

operational sites not yet selected. The table below lists three remaining high-TTHM sites

Site Number and Description

LRAA

TTHM (mg/L) HAA5

(mg/L)

4 (operational site) 0.072 0.051

8 (operational site) 0.065 0.056

9 (Stage 1 DBPR max residence time site) 0.070 0.051

Among the three remaining high sites, Site 4 has the highest TTHM LRAA. However, 

the Stage 1 DBPR site has only slightly lower TTHM LRAA than operational Site 4. The

system chooses the Stage 1 DBPR site over site 4 for the Stage 2 high TTHM site to

maintain the historical DBP record at that site.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-35 January 2006

IDSE Tool

5.3.2 Determining Your Stage 2 DBPR Compliance Monitoring Dates

The first step in selecting your Stage 2 DBPR compliance monitoring dates is to select

the peak historical month. According to the Stage 2 DBPR, you must conduct Stage 2 DBPR

compliance monitoring during the peak historical month for TTHM or HAA5. You should use

the peak historical month selected in your SSS plan unless new data suggest another month. If

your high TTHM and high HAA5 data occur in different months, you should consider which

contaminant is of more concern. If one contaminant clearly shows a higher overall trend and is

closer to the MCL, you should choose the month in which that contaminant is highest. 

You must conduct Stage 2 DBPR compliance monitoring during the peak historical

month. If you are a ground water system that serves more than 9,999 people or you are a surface

water system that serves more than 499 people, you must also conduct Stage 2 compliance

sampling at 90 day intervals before and/or after the peak historical month. 

The intent of the required time interval is to ensure that samples are representative of the

quality of water over an extended period and do not over-emphasize either high or low

concentrations of TTHM or HAA5 that might occur seasonally. For example, a system on

quarterly monitoring could sample in the third full week of every third month. It is not

necessary to sample all sites on the same day.

5.3.3 Preparing the IDSE Report

Every system that conducts an SSS for Existing Monitoring must prepare and submit an

IDSE Report for an Existing Monitoring Results SSS. You should submit the report to the

Information Processing and Management Center (IPMC) for review by EPA or your state. See

Section 1.4 of this guidance manual for information on how to submit your report to the IPMC. 

EPA has developed a form for the IDSE Report for an Existing Monitoring SSS

(Form 3), presented in this section and available electronically as part of the IDSE Tool. You

are not required to use this form; however, if you choose not to use it, refer to Exhibit 5.4 for a

list of the minimum elements you must include in your IDSE report. 

The IDSE Tool creates a custom form for your system and provides links

to technical guidance from this manual. The tool is available on EPA’s website at

http://www.epa.gov/safewater/disinfection/stage2.

Before you begin Stage 2 DBPR compliance monitoring, you will also be required to

prepare a Stage 2 DBPR compliance monitoring plan. In addition, if you are a subpart H system

serving >3,300 people, you must submit a copy of your Stage 2 compliance monitoring plan to

the state. If you include compliance calculation procedures in your IDSE report, the report can
IDSE Guidance Manual for the Final Stage 2 DBPR 5-36 January 2006

meet the requirement of the plan, and you do not have to prepare or submit a separate plan. As a

guide for specifying your compliance calculation procedures, refer to the Stage 1 DBPR,

141.133(b), and your Stage 1 compliance monitoring plan. Check with your state, as they may

have different requirements under the Stage 2 DBPR. If you are a consecutive or wholesale

system, your state may choose to use its special primacy authority to modify your Stage 2

compliance monitoring requirements. In this case, you should check with the state to see if they

are going to use this authority. You should develop your IDSE report for the total number of

required Stage 2 compliance locations for your system. 

The IDSE report for an Existing Monitoring Results SSS form includes the following

sections:

I. General Information

II. Stage 2 DBPR Requirements

III. Additional SSS and Stage 1 Compliance Monitoring Results

IV. Justification of Stage 2 DBPR Compliance Monitoring Sites

V. Peak Historical Month 

VI. Proposed Stage 2 Compliance Monitoring Schedule

VII. Distribution System Schematic

VIII. Attachments

If you are submitting an SSS plan and IDSE report at the same time, you must submit the

portions listed in bold above. The rest of this section provides guidance on the completion of

this form.

I. General Information

I.A. PWS Information* - If nothing has changed since you completed your modeling

study plan, copy information from your plan into this section. If your system

characteristics have changed, see Section 5.2 of this chapter for guidance on

completing this section.

I.B. Date Submitted* - Enter either the date that you are submitting the form

electronically, putting it in the mailbox, or dropping it off with an express

delivery service. Be sure to submit your IDSE report before the deadline found

on your requirements summary sheet.

I.C. PWS Operations - This section asks questions about your system to help inform

EPA and state personnel during the plan review process. If nothing has changed

since you completed your modeling study, copy information from your plan into

this section. If your system characteristics have changed, see Section 5.2 of this

chapter for guidance on completing this section. 
IDSE Guidance Manual for the Final Stage 2 DBPR 5-37 January 2006

I.D. Contact Person* - Enter the contact information of the person who is submitting

the report. This should be the person who will be available to answer questions

from EPA and/or the state reviewers. 

II. Stage 2 DBPR Requirements*

II.A. Number of Required Stage 2 DBPR Compliance Monitoring Sites - Refer to the

System Specific Study Requirements - Attachment in Chapter 2. Copy the

numbers from the “Stage 2 Compliance Monitoring Requirements” table that

correspond to your source type and the population served by your system. 

II.B. IDSE Schedule -This should be the same schedule you entered for your modeling

study plan. See Section 5.2 of this chapter for guidance. 

II.C. Required Stage 2 DBPR Compliance Monitoring Frequency - Refer to the

System-Specific Study Requirements - Attachment in Chapter 2. Locate the

monitoring frequency from the “Stage 2 Compliance Monitoring Requirements”

table that corresponds to your source type and the population served by your

system. Put a check mark in the box corresponding to that monitoring frequency.

III. Additional SSS and Stage 1 Compliance Monitoring Results*

Skip this section if you are submitting your IDSE Report at the same time as your

SSS plan. If you are submitting additional data with your IDSE report, complete

this section. See the instructions for Form 2 part IV in Section 5.2 of this

guidance manual..

IV. Justification of Stage 2 DBPR Compliance Monitoring Sites*

Enter the site ID from the distribution schematic and the site type (whether it is

highest TTHM, highest HAA5, Stage 1 DBPR, or a site selected using criteria

other than the site selection protocol). An example of how you might justify a

site is given below. For example:

2nd Highest TTHM Site

An example of how you might justify a site that was not selected using the

protocol is below:

Among the three remaining high TTHM sites, operational Site 4 has the highest

TTHM LRAA. However, Stage 1 DBPR Site 7 has only a slightly lower TTHM

LRAA than operational Site 4. Therefore, we choose Stage 1 DBPR Site 7 over

operational site 4 to maintain the historical DBP record.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-38 January 2006

Note that there is only space for 8 monitoring sites on this sheet. If you are a

subpart H system serving more than 249,999 people you are required to monitor 

at more than 8 sites. Therefore, you will need to attach additional sheets.

V. Peak Historical Month

V.A. Peak Historical Month* - Enter the month that you determined to be your peak

historical month for TTHM or HAA5.

V.B. Is Your Peak Historical Month the Same as in Your System Specific Study Plan?

- Put a check mark in the appropriate box to identify whether your system used

the same peak historical month as in your SSS plan. If you selected a new peak

historical month based on additional monitoring or other data, explain the basis

for your selection here.

VI. Proposed Stage 2 DBPR Compliance Monitoring Schedule*

Enter the ID for each Stage 2 DBPR compliance monitoring site in the table (verify that

these match the IDs you enter in Section IV and on your schematic). Enter your

proposed sampling schedule for the number of monitoring periods identified in Section

II.C. The entry can be a specific date or week and can be in a number of different

formats. For example:

• 7/9/07

• 2nd week in Nov ‘07

• Week of 7/9/07 

Remember that at least one monitoring period must be during the peak historical month

identified in Section V.A. Note that there is only space for 8 monitoring sites on this

sheet. If you are a subpart H system serving more than 249,999 people you are required

to monitor at more than 8 sites. Therefore, you will need to attach additional sheets.

VII. Distribution System Schematic*

If you are submitting an IDSE report at the same time as your SSS plan, skip this section. 

A distribution system schematic is required only if it has changed from your SSS plan. If

it has changed, you must attach a distribution system schematic. See Section 5.2 of this

manual for guidance. 

VIII. Attachments - Put a check mark in each of the boxes corresponding to any attachments

that you have included in your report.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-39 January 2006

Note that there is only space for 8 Stage 2 DBPR compliance monitoring sites and

monitoring schedule in Sections IV and VI. If you are a subpart H system serving more

than 249,999 people, you are required to monitor at more than 8 sites. Therefore, you

will need to attach additional sheets.

Note that a schematic is required only if it has changed from your approved SSS study

plan. 

If you deviated from your approved study plan, you must attach an explanation of all

deviations.

If you submit your IDSE report electronically, you also have the option to submit

attachments in hard copy. Include a note in your electronic IDSE report explaining that 

attachments are being submitted in hard copy, and mail the hard copy to the IPMC

mailing address in your Requirements Summary Sheet. The IPMC will match the hard

copy submission with your electronic submission when it is received.

If you are a subpart H system serving >3,300 people, you must submit a copy of your

Stage 2 compliance monitoring plan to the state. If you include compliance calculation

procedures in your IDSE report, the report can meet the requirement of the plan, and you

do not have to prepare or submit a separate plan. As a guide for specifying your

compliance calculation procedures, refer to the Stage 1 DBPR, 141.133(b), and your

Stage 1 compliance monitoring plan. Check with your state, as they may have different

requirements under the Stage 2 DBPR. 

Enter the total number of pages in your IDSE report (including attachments) in the blank

at the bottom of this section. This will allow EPA or your state to ensure that all pages

were received.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-40 January 2006

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IDSE Guidance Manual for the Final Stage 2 DBPR 5-41 January 2006

Form 3: IDSE Report for an Existing Monitoring

Results SSS Page 1 of 7

I. GENERAL INFORMATION

(Skip this section if you are submitting the plan and report at the same time)

A. PWS Information* B. Date Submitted*

 PWSID:

PWS Name:

PWS Address:

City: State: Zip:

Population Served:

System Type: Source Water Type: Buying / Selling Relationships:

~ CWS ~ Subpart H ~ Consecutive System 

~ NTNCWS ~ Ground ~ Wholesale System 

 ~ Neither 

C. PWS Operations

Residual Disinfectant Type: ~ Chlorine ~ Chloramines ~ Other _____________

Number of Disinfected Sources: ___Surface ___GWUDI ___Ground ___Purchased

D. Contact Person*

Name:

Title:

Phone #: Fax #:

E-mail: 

II. STAGE 2 DBPR REQUIREMENTS*

A. Number of Required Stage 2 DBPR Compliance Monitoring Sites TOTAL

 Highest TTHM Stage 1 DBPR Highest HAA5
IDSE Guidance Manual for the Final Stage 2 DBPR 5-42 January 2006

Form 3: IDSE Report for an Existing Monitoring

Results SSS Page 2 of 7

II. STAGE 2 DBPR REQUIREMENTS (continued)*

B. IDSE Schedule C. Required Stage 2 DBPR Compliance Monitoring

Frequency

 ~ Schedule 1 ~ During peak historical month (1 monitoring period)

 ~ Schedule 2 ~ Every 90 days (4 monitoring periods)

 ~ Schedule 3

 ~ Schedule 4

III. ADDITIONAL SSS AND STAGE 1 COMPLIANCE MONITORING RESULTS*

(Skip this section if you are submitting the plan and report at the same time)

A. Where were your TTHM and HAA5 samples analyzed?

~ In-House

Is your in-house laboratory certified? ~ Yes ~ No

~ Certified Laboratory

Name of certified laboratory:

B. What method(s) was used to analyze your TTHM and HAA5 samples?

 TTHM HAA5

~ EPA 502.2 ~ EPA 552.1

~ EPA 524.2 ~ EPA 552.2

~ EPA 551.1 ~ EPA 552.3

~ SM 6251 B
IDSE Guidance Manual for the Final Stage 2 DBPR 5-43 

Form 3: IDSE Report for an Existing Monitoring Results SSS III. ADDITIONAL SSS AND STAGE 1 DBPR MONITORING RESULTS (Continued)*C. TTHM Results

Site ID1

12-

monthperiod

Data

Qualifies

(yes/no) 

Data Type TTHM (mg/L) 

Sample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample Result

1 Verify that site IDs match the site IDs in your SSS Plan.

Attach additional sheets as needed for SSS and Stage 1 DBPR results.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-44 

Form 3: IDSE Report for an Existing Monitoring Results SSS III. ADDITIONAL SSS AND STAGE 1 DBPR MONITORING RESULTS (Continued)*D. HAA5 Results

Site ID1

12-

monthperiod

Data

Qualifies

(yes/no) 

Data Type HAA5 (mg/L) 

Sample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample Result

1 Verify that site IDs match the site IDs in your SSS Plan.

Attach additional sheets as needed for SSS and Stage 1 DBPR results.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-45 January 2006

Form 3: IDSE Report for an Existing Monitoring Results

SSS Page 5 of 7

IV. JUSTIFICATION OF STAGE 2 DBPR COMPLIANCE MONITORING SITES*

Stage 2

Compliance

Monitoring

Site ID

Site Type Justification

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

Attach additional copies of this sheet if you need more room.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-46 January 2006

Form 3: IDSE Report for an Existing Monitoring

Results SSS Page 6 of 7

V. PEAK HISTORICAL MONTH

A. Peak Historical Month* 

B. Is Your Peak Historical Month the Same as in Your SSS Plan?

~ Yes ~ No

If no, explain how you selected your new peak historical month (attach

additional sheets if needed):

VI. PROPOSED STAGE 2 DBPR COMPLIANCE MONITORING SCHEDULE*

Stage 2

Compliance

Monitoring

Site ID

Projected Sampling Date (date or week)1

period 1 period 2 period 3 period 4

 

1

 period = monitoring period. Complete for the number of monitoring periods from

Section II.C.

Attach additional copies of this sheet if you need more room.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-47 January 2006

Form 3: IDSE Report for an Existing Monitoring

Results SSS Page 7 of 7

VII. DISTRIBUTION SYSTEM SCHEMATIC*

(Skip this section if you are submitting the plan and report at the same time)

ATTACH a schematic of your distribution system if it has changed since you submitted

your Existing Monitoring Results SSS Plan (Form 2). 

VIII. ATTACHMENTS

~ Additional sheets for Additional SSS Monitoring Results (Section III).

~ Additional sheets for Stage 2 DBPR Monitoring Sites (Section IV). REQUIRED if you 

 are a subpart H system serving more than 249,999 people.

~ Additional sheets for explaining how you selected the peak historical month (Section

 V).

~ Additional sheets for proposed compliance monitoring dates (Section VI). REQUIRED if 

 you are a subpart H system serving more than 249,999 people.

~ Explanation of deviations from approved study plan.

~ Distribution system schematic* (Section VII). REQUIRED if it has changed from your 

 approved SSS plan.

~ Compliance calculation procedures (for Stage 2 Compliance Monitoring Plan).

Total Number of Pages in Your Report: __________

Note: Fields with an asterisk(*) are required by the Stage 2 DBPR.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-48 January 2006

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IDSE Guidance Manual for the Final Stage 2 DBPR 5-49 January 2006

5.4 Recordkeeping

The IDSE SSS report must be kept on file for 10 years after

the date it is submitted. If EPA or your state modifies the

recommendations made in your report or approves alternative

Stage 2 DBPR compliance monitoring locations, you must also

keep a copy of EPA or your state’s notification on file for 10 years

after the date of the notification. You must make your IDSE

report and any notification available for review by your state or

the public.

The SSS plan, including any modifications by EPA or your

state, must also be kept on file for as long as you are required to

retain your IDSE SSS report. You must make the plan and any

modifications available for review by your state or the public.

5.5 Next Steps: Preparing the Stage 2 DBPR Compliance Monitoring Plan 

As the final step before you can begin compliance monitoring for the Stage 2 DBPR, you

must develop and implement a Stage 2 DBPR monitoring plan by the deadline provided in

your requirements summary sheet. The plan will be similar to your Stage 1 DBPR monitoring

plan in that it will identify how you intend to sample for compliance with Stage 2. You must

keep your plan on file for state and public review. If you are a subpart H system serving >

3,300 people, you must submit your plan to EPA or your state prior to when you are required to

start monitoring.

Exhibit 5.6 contains the minimum requirements for what must be included in your Stage 2

DBPR compliance monitoring plan. Because compliance monitoring plans are not addressed as

part of the IDSE provisions of the Stage 2 DBPR, EPA has not included detailed guidance for

developing Stage 2 compliance monitoring plans in this guidance manual. EPA plans to

develop other manuals and training that address the compliance monitoring provisions of the

Stage 2 DBPR.

See EPA’s website http://www.epa.gov/safewater/disinfection/stage2 for an up-to-date

inventory of Stage 2 DBPR guidance manuals and training materials, or call the Safe Drinking

Water Hotline at 1-800-426-4791.
IDSE Guidance Manual for the Final Stage 2 DBPR 5-50 January 2006

Exhibit 5.6 Required Contents of Stage 2 DBPR Compliance Monitoring Plans

All Systems Additional Requirements for Consecutive and

Wholesale Systems 1

• Monitoring locations

• Monitoring dates

• Compliance calculation

procedures

• If your state has used its special primacy

authority to modify your monitoring

requirements, you must include monitoring plans

for other systems in your combined distribution

system

1. See Appendix D of this manual for guidance specifically for consecutive and wholesale systems
IDSE Guidance Manual for the Final Stage 2 DBPR 6-1 January 2006

6.0 System Specific Study Using a Distribution System Hydraulic Model

One of two options for the system specific study (SSS) involves the use of a detailed,

comprehensive, and well-calibrated distribution system hydraulic model to help select Stage 2

DBPR compliance monitoring locations. Systems using a distribution system hydraulic model

will be required to submit a modeling study plan and IDSE Report describing the modeling

analysis, selection of monitoring sites, and sampling data.

Distribution system hydraulic models can be used for the SSS provided the minimum

model requirements are met. An overview of requirements is given in Exhibit 6.1 and detailed

guidance is provided in Section 6.1 The option of using a distribution system hydraulic model is

intended to allow systems that have models to use their existing technical resources to perform

the IDSE. For many systems, developing a detailed and well-calibrated distribution system

hydraulic model from scratch and training staff to use it could cost more than conducting

standard monitoring (see Chapter 7). If the model will be used for other purposes after the

completion of the SSS, such as optimizing system operations and prioritizing capital

improvements, then the cost of the model development may be justified. If a system’s existing

model does not meet the minimum requirements in Exhibit 6.1 at the beginning of the IDSE

period, the system may be able to upgrade the model to complete the modeling SSS or instead

use it in combination with other data and/or analyses for selecting sites for standard monitoring

(see Chapter 7). Exhibit 6.2 includes a list of minimum reporting requirements for the modeling

SSS. 

This chapter covers:

6.1 Minimum Model Requirements and Calibration

6.2 Modeling Analysis 

6.3 Determining SSS Monitoring Requirements and Schedule

6.4 Preparing your Modeling Study Plan

N Form 4: Modeling Study Plan

6.5 Selecting SSS Monitoring Sites and Conducting Monitoring

6.6 Selecting Stage 2 DBPR Compliance Monitoring Sites and Schedule

6.7 Preparing the IDSE Report

N Form 5: IDSE Report for a Modeling SSS

6.8 Recordkeeping

6.9 Next Steps: Preparing the Stage 2 DBPR Compliance Monitoring

Plan 
IDSE Guidance Manual for the Final Stage 2 DBPR 6-2 January 2006

Exhibit 6.1 Minimum Distribution System Hydraulic Model Requirements

To meet the minimum model requirements, your model must include:

Physical System Data

• At least 50 percent of total pipe length in the distribution system.

• At least 75 percent of the pipe volume in the distribution system.

• All 12-inch diameter and larger pipes.

• All 8-inch diameter and larger pipes that connect pressure zones, mixing 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 diameter and larger pipes that connect remote areas of a distribution

system to the main portion of the system or are known or expected to be significant

conveyors of water.

• All storage facilities, with controls or settings applied to govern the open/closed

status of the facility that reflect standard operations.

• All active pump stations, with realistic controls or settings applied to govern their

on/off status that reflect standard operations.

• All active control valves or other system features that could significantly affect the

flow of water through the distribution system (e.g., interconnections with other

systems, pressure reducing valves between pressure zones).

Demand Data

• Extended period simulation with representative diurnal variations in demand

< Represent total system demand for the peak month of TTHM formation

Calibration

• A calibration verification using data for the peak month of TTHM formation and

current system configuration

< Operational controls to represent typical operation during the peak month of

TTHM formation

• Evaluation of actual system performance compared to modeled performance at all

storage facilities in the system

• Ability to complete all required calibration no later than 12 months after your

required plan submission date

Modeling Analysis

• The ability to simulate water age during the peak month of TTHM formation using

a sufficient simulation length to overcome initial conditions and produce a

consistent, repeating pattern of 24-hour water age
IDSE Guidance Manual for the Final Stage 2 DBPR 6-3 January 2006

Exhibit 6.2 Minimum Reporting Requirements for Modeling Study Plan

The following information must be provided in your Modeling Study Plan. You may use

the Modeling Study Plan Form (Form 4) found in this chapter or the IDSE tool to help you

prepare your submission.

1. Tabular or spreadsheet data demonstrating that your model meets the physical system

data requirements in Exhibit 6.1. 

2. A description of all calibration activities undertaken (or to be undertaken). This must

include, 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.

< A time series graph of water age results for the storage facility with the highest

residence time in your system showing predictions for the entire EPS simulation

period (i.e. from time zero until the time it takes for the model to reach a

consistently repeating pattern of residence time).

3. Preliminary results of the modeling analysis showing showing 24-hour average water

age predictions throughout the distribution system.

4. Timing and number of samples planned for at least one period of TTHM and HAA5

monitoring at a number of locations no less than that required for your system under

standard monitoring during the month of high TTHM.

5. Description of how all requirements will be completed no later than 12 months after

your required plan submission date.

6. Distribution system schematic showing entry points and their sources, storage facilities,

and locations of all completed SSS monitoring and all subpart L compliance monitoring. 

7. Population served and system type (subpart H or ground water). 

Notes: 

< You must respond to any state or EPA inquiries regarding your model and your

SSS plan submission. 

< If you have already completed your required monitoring, it is highly recommended

that you submit your IDSE report at the same time as your study plan.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-4 January 2006

For the purposes of the modeling SSS, water age is used as a surrogate for TTHM

concentration. Thus, the minimum requirements for the modeling SSS are focused only on the

hydraulic component of distribution system models. A well-calibrated water quality model may

provide a better understanding of the behavior of the distribution system, leading to superior

selections of Stage 2 DBPR compliance monitoring locations compared to hydraulic models

without water quality calibration. However, proper calibration of the water quality component

can be a difficult task and is typically done with much less accuracy than calibration of the

hydraulic component. In addition, the data needed to properly calibrate and verify the water

quality concentrations predicted by the model may exceed data collection requirements under the

IDSE standard monitoring option. If systems decide to use water quality modeling, they are

encouraged to provide information on the water quality calibration to EPA or the state in

addition to the required information for the underlying hydraulic components of the model.

A variety of public domain and commercial software packages are available for

distribution system modeling. Public domain software includes EPANET and PipelineNET,

which are both available for free download. EPANET is available from

www.epa.gov/ORD/NRMRL/wswrd/epanet.html and PipelineNET is available from

http://eh2o.saic.com/iwqss/. Systems should verify that the software used to model the

distribution system can provide the output required to demonstrate the model’s calibration and

performance (Section 6.1). 

If you have not already done so, you should complete the flowchart in Exhibit 2.3 of this

guidance manual. The flowchart will direct you to a 2-page Requirements Summary Sheet for

your schedule. You will also be directed to the System Specific Study Requirements -

Attachment sheet containing detailed requirements for Stage 2 compliance monitoring (e.g.,

number of samples and sampling frequency). You should keep these sheets handy as you work

through this chapter. It is important that consecutive and wholesale systems communicate

with each other throughout the IDSE process. If you are a consecutive or wholesale system,

refer to Appendix D for specific issues that you should consider.

If you plan to conduct an SSS using a model, you must submit a modeling study plan for

state or EPA review in accordance with the schedule on your requirements summary sheet. You

have the option of submitting the modeling study plan and IDSE report together (which must

include selection of Stage 2 DBPR compliance monitoring sites) by the study plan deadline if all

required elements have been completed. If you choose this option, you have no further

requirements under the IDSE unless you are contacted by EPA or your state. Below is a list of

conditions under which you should consider submitting the report at the same time as the plan,

and conditions under which you would want to submit your modeling study plan first, then your

report at the end of the IDSE monitoring period. 

Option 1: Submitting a Completed Modeling Study Plan and IDSE Report at the Same Time

You should consider Option 1 if:

• You have completed calibration of your model, and

• You have completed one monitoring period of additional TTHM and HAA5

monitoring meeting the criteria in Section 6.3.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-5 January 2006

You need to:

• Submit both the modeling study plan and the IDSE report by the deadline for the

modeling study plan that is provided on your requirements summary sheet. 

Option 2: Submitting a Separate Modeling Study Plan and IDSE Report

You should consider Option 2 if:

• You have not completed calibration of your model, or

• You have not completed one monitoring period of additional TTHM and HAA5

monitoring meeting the criteria in Section 6.3.

You need to:

• Submit the modeling study plan by the deadline for the modeling study plan on your

requirements summary sheet.

• Conduct additional monitoring and/or perform calibration by the date listed in your

requirements summary sheet.

• Submit the IDSE report for a modeling SSS by the deadline in your requirements

summary sheet.

6.1 Minimum Model Requirements and Calibration

Exhibit 6.1 summarizes the minimum model requirements for the SSS. In general, a

system’s distribution system hydraulic model should be more comprehensive for the purpose of

an SSS than models typically used for long-range capital improvement program analysis of

transmission capacity (e.g., master planning). A calibrated hydraulic model intended for detailed

distribution system design or operational studies is likely to be adequate. A well-calibrated

water quality model is also likely to be acceptable. In either case, the model must be an

extended period simulation (EPS) model. Also, the model must be calibrated for the peak

month for TTHM formation. Consequently, the model will need to incorporate operational

and demand conditions for the peak month for TTHM formation. See Section 6.3 for guidance

on selecting the peak month.

Distribution systems are always changing (e.g., population growth, new industrial users,

aging of mains), so it is important that the model reflect system conditions and demand at the

time of the SSS. If your model is not current, it must be updated and calibrated before it could

be considered adequate for the SSS. Your model must be calibrated for the current configuration

of the distribution system.

Sections 6.1.1 through 6.1.4 provide additional guidelines to help you determine if your

model meets the minimum requirements. Note that the guidelines in this section are not

comprehensive—every distribution system is unique. Systems should always use their best

professional judgment when determining model adequacy for the SSS. You should note that

EPA or your state can still require you to conduct standard monitoring even if you meet
IDSE Guidance Manual for the Final Stage 2 DBPR 6-6 January 2006

minimum requirements. AWWA Manual M32, Computer Modeling of Water Distribution

Systems, 2nd Edition, 2005, may be a useful reference that goes into greater detail on the

distribution system modeling presented in this chapter. 

6.1.1 Physical System Data

Most distribution system models do not include every pipe in a distribution system. 

Typically, small pipes near the periphery of the system and other pipes that affect relatively few

customers are excluded to a greater or lesser extent depending on the intended use of the model. 

This process is called skeletonization. Models including only transmission networks (e.g. pipes

larger than 12 inches in diameter only) are highly skeletonized while models including many

smaller diameter distribution mains (e.g. 4 to 6 inches in diameter) are less skeletonized. In

general, water moves quickly through larger transmission piping and slower through the smaller

distribution mains. Therefore, the simulation of water age or water quality requires that the

smaller mains be included in the model to fully capture the residence time and potential water

quality degradation between the treatment plant and the customer. Increases in computing

capabilities are making it possible to include many more pipes in hydraulic models than was

previously feasible.

To be used for the purposes of conducting the SSS, the model should be relatively

detailed (less skeletonized) and include the majority of pipes in the distribution system. 

Minimum requirements for physical system data are provided in Exhibit 6.1.

System inventory information can be used to determine the adequacy of the model,

including pipe information in GIS or on water atlas maps. Documentation of the ability of the

model to meet the minimum requirements must be submitted with the modeling study plan. 

Most modeling software provides the ability to calculate and export data on the total length of

the pipes within the model. GIS, water system inventory data, or water atlas sheets can be used

to calculate the length of pipes that exist in the distribution system but are not included in the

model. Systems should use their best professional judgment in the estimation of the coverage of

the distribution system that is included in the model. An example of these calculations is

provided in Appendix F.

6.1.2 Demand Data

A key set of input data to a hydraulic model is the demand data used to simulate

consumption of water throughout the system. The demand data dictates the flow through each

pipe and therefore is an important part of the model. Water demand should be allocated among

the nodes in the model in a manner that reflects the actual spatial distribution of such demand

throughout the system, with a level of detail appropriate for the system size. A proper demand

allocation will help ensure that the model provides a realistic simulation of water flow

throughout the system.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-7 January 2006

In general, it is desirable to have demand allocated to as many nodes as possible in the

model. The calculation of water age at nodes on dead end mains with zero demand is not

accurate because the water age will equal the simulation time at each time step, so often model

results will show the highest water age at dead ends. While this is a realistic representation of

the distribution system, you should take these results into consideration when selecting sampling

locations. Much of the modeling and GIS software available contains tools to assist with

demand allocation based on geocoding of customer accounts, processing of census population

data, or spatial analysis of land use patterns. Alternatively, it is possible to allocate customer

demands manually based on system knowledge of meter locations, meter reader routes, or zone

flow meters.

To ensure that your model is calibrated well for the period of high TTHM formation

potential, include all significant users in the system in your model. Many skeletonized models

will exclude dead ends in the system even though they may serve a subdivision or other area

with a sizable number of customers. Systems should make an effort to include dead end pipes

that serve significant populations to capture the full system demand as well as any potential

degradation of water quality within the dead end area. Exhibit 6.3a shows a typical subdivision

layout with dead ends that are not included in the model (more skeletonized) and Exhibit 6.3b

shows that model with all pipes included (less skeletonized).

Systems with rapidly changing populations and water usage should verify that the

demands in the hydraulic model reflect the distribution system conditions under which the SSS

will be evaluated. Particular attention should be paid to large users in the system, which are

often industrial or institutional and can have a significant impact on flows. Seasonal trends in

demand variation should also be considered so that the model reflects the correct water usage for

the month with the highest TTHM formation potential (see Section 6.3 for more information on

determining peak month for TTHM formation). For example, many commercial properties have

automatic irrigation systems that operate during summer months only and some systems may

have seasonal users such as campgrounds or swimming pools.

System water loss should also be reflected in the demands in the hydraulic model. Many

systems calculate a non-revenue water percentage based on the difference between their monthly

production records and customer billing data. This water loss should be included in the model. 

Many systems apply a constant rate of water loss across their system by using a global demand

multiplier. However, if more detailed information on losses is available, such as measured losses

in a particular zone in the system, that data could be used to allocate the total water loss to

specific areas in the model.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-8 January 2006

Exhibit 6.3a Sample Subdivision Layout in a Less Skeletonized Model

Exhibit 6.3b Sample Subdivision Layout in a More Skeletonized Model

Diurnal Demand Variation

The prediction of water age or water quality requires an extended period simulation

(EPS). To run a hydraulic model EPS, demand patterns showing the variation in usage over time

are required. Therefore, models must not only include realistic base demands but must also

reflect the variation in demand over time. For water age or water quality simulation in the

modeling SSS, a minimum of a 24-hour EPS is required and therefore this discussion will refer

to diurnal demand variations. 
IDSE Guidance Manual for the Final Stage 2 DBPR 6-9 January 2006

Residential customers typically show a diurnal variation of water use with a peak in the

morning (before work) and in the evening (after work), with little use during the night. Large

users, such as industries, may use water on a different schedule than residential users. For

example, a factory running full production 24 hours per day will not decrease its water usage

during the night. In order to simulate realistic water movement throughout the distribution

system and calibrate your model, capture the different patterns of usage, particularly for large

users. Systems are encouraged to verify the diurnal water usage patterns for large users and to

include separate demand variation categories for these users if they differ from a typical

residential user.

Diurnal curves will also vary by season. For example, residential use will often increase

in the evening and night hours during the summer due to lawn watering. Other systems may

experience seasonal population shifts that will affect the demand patterns. 

Demand patterns can be derived from a mass balance calculation using water production

and pumping records, tank levels, and other operational data. Most reference books on hydraulic

modeling include an explanation of diurnal demand variation calculations. The pattern is a

series of multipliers that represent the ratio of instantaneous demand to the average daily demand

at a given point in time. The average of all multipliers is equal to 1.0. Exhibit 6.4 shows an

example of a diurnal demand variation pattern.

The IDSE requires modeling of the peak month of TTHM formation and therefore

systems must ensure that their model adequately simulates demand variation during that month

for the purposes of the SSS. In addition to diurnal demand patterns, the total demand in the

model must match the typical demand for the peak month of TTHM formation. The base

demand in the model may need to be adjusted by using a global demand multiplier to better

represent the peak month of TTHM formation. See Section 6.3 for guidance on selecting the

peak month for TTHM formation.

6.1.3 Operational Controls

Another important feature of a good EPS model is the ability to simulate system

operation using controls. Controls are used within the model to turn on or off pumps, open or

close valves, and perform other operations to mimic the real-life operations that occur in a

system. The ability of the model to simulate the actual operation of the system requires the

specification of controls.

Hydraulic modeling software offers several options for controls. In general, controls are

either time-based or logical. Time-based controls perform a specific operation (e.g. turn on a

pump) at a specified time in the simulation. Logical controls perform a given operation based on

an evaluation of conditions in the system (e.g. turn on a pump when the tank is half empty). For

large systems, a series of conditions must often be met before a change in status of operation can

occur. To simulate these cases, complex logical controls can be created in the model. 
IDSE Guidance Manual for the Final Stage 2 DBPR 6-10 January 2006

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

0 4 8 12 16 20 24

Hour

Multiplier

Average = 1.0

Exhibit 6.4 Example Diurnal Demand Variation Pattern

The simulation of water age and water quality throughout a distribution system is heavily

impacted by the modeled behavior at the storage facilities. The behavior of the storage facilities

is in turn greatly affected by the operational rules used to control levels and fill rates. Therefore

it is important that systems ensure that the controls used in the hydraulic model provide a

simulation of true system operation.

For the SSS using a distribution system model, you must simulate the conditions during

the period with the highest TTHM formation potential in your model. 

6.1.4 Calibration

Once a base model for a distribution system has been developed, the model must be

calibrated to match the simulated system performance to actual operating conditions. 

Calibration is generally an iterative process where model parameters are adjusted until

simulation results match field conditions. Systems must demonstrate that their model is either

calibrated using data collected during the peak month for TTHM formation or, if previously
IDSE Guidance Manual for the Final Stage 2 DBPR 6-11 January 2006

calibrated to a different time period, can satisfactorily simulate operation during the period with

the highest TTHM formation potential through model verification. Calibration of a model for

steady-state simulations only is not adequate for the modeling SSS. The model must be

calibrated in extended period simulation for at least a 24-hour period. Because storage facilities

have such a significant impact upon water age and reliability of water age predictions throughout

the distribution system, you must compare and evaluate the model predictions versus the actual

water levels of all storage facilities in the system to meet calibration requirements. However,

you are only required to submit the graph for the storage facility with the highest water age in

each pressure zone.

Calibration is never exact and there are no official calibration standards or guidelines in

the United States. There is general agreement in the modeling profession that the extent of

calibration should reflect the intended uses of the model. For example, a more rigorous model

calibration would be necessary when the model is used to make detailed design calculations

versus general master planning, where a larger margin of error in calibration may be acceptable. 

Calibration performed several years ago for the purposes of general master planning is not 

acceptable for the modeling SSS. For more information regarding the calibration of distribution

system hydraulic models, refer to Modeling Water Quality in Drinking Water Distribution

Systems (Clark and Grayman, 1998), Advanced Water Distribution Modeling and Management

(Walski et al., 2003), or other reference books.

Calibration Data Collection

Calibration data will vary by system depending on the type and number of facilities

involved. In general, calibration data will include:

• Flow and discharge pressure at each pump and/or pumping facility

• Water level in each storage facility (elevated and ground storage)

• Pressure data, either at facilities or other locations in the distribution system

• Flow tests at hydrants

• Friction factor (C-factor) tests

• System-wide demand and diurnal pattern information 

Many systems collect operational data using supervisory control and data acquisition

(SCADA) systems, chart recorders, or other types of dataloggers. It is important to obtain

operational data over a 24-hour time period so that the EPS model can be calibrated for each

time step. This data must represent the actual operating conditions during the peak historical

month for TTHM formation. 

Field studies may also be conducted to obtain flow test and friction factor test data. If

possible, such tests should coincide with operational data collection to provide a robust data set. 

Reference books can provide instructions for conducting these tests.

If the model was previously calibrated to a time that does not coincide with the peak

month for TTHM formation (e.g., calibrated to an average day in March and the peak month for
IDSE Guidance Manual for the Final Stage 2 DBPR 6-12 January 2006

TTHM formation is August), additional data will need to be collected to verify the performance

of the model during the peak month for TTHM formation. 

The operation of storage facilities in distribution systems has a significant impact on

water retention and potential for water quality degradation. Therefore, a simulation of the

behavior of all storage facilities during the peak month for TTHM formation is required as part

of the modeling SSS. The ability of the calibrated model to predict actual water levels in all

storage facilities must be verified.

In your modeling study plan you are required to describe your calibration process to

verify the adequacy of the model for the purposes of the SSS. If your model is not calibrated at

the time you submit your Modeling SSS Plan, you must describe the calibration activities that

are proposed to take place. You will then be required to submit your final calibration

documentation as part of your IDSE report. If you have already completed your calibration, you

must include the following in your modeling study plan:

• A model results graph of water level versus time for the storage facility with the

highest water age in each pressure zone of the system. If a pressure zone has no

storage facilities located within its boundaries, no graph is required for that zone. 

The graph must include both simulated (model) and observed (actual) water levels

during the period of highest TTHM formation potential. The submitted graph should

show results for a minimum simulation length of 24 hours, with time increments no

greater than 1 hour. An example of an acceptable graph is shown in Exhibit 6.5.

• 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 EPS simulation

period (i.e., from time zero until the time it takes for the model to reach a consistently

repeating pattern of residence time). An example of an acceptable graph is shown in

Exhibit 6.7. This graph will be produced as part of your water age modeling analysis. 

Guidance on conducting the water age modeling analysis is given in Section 6.2.

If your model simulation results do not match the observed water level variations in the

storage facility but you feel that your model is sufficiently calibrated to be used in the SSS,

additional justification should be provided in your modeling study plan. 
IDSE Guidance Manual for the Final Stage 2 DBPR 6-13 January 2006

Exhibit 6.5 Sample of an Acceptable Graph for Demonstration of Model

Calibration

6.2 Modeling Analysis

Using your calibrated hydraulic model of the distribution system, a water age simulation

must be run and analyzed to show 24 hour average residence time predictions throughout the

distribution system. Consecutive systems and systems with multiple sources with different water

quality should consider how the water age entering the distribution system and differing DBP

formation potential will influence model predictions and analysis. Appendix G discusses

approaches that can be used to analyze hydraulic models in these situations. 

If your model calibration is not complete, a preliminary modeling analysis using the

existing model must be conducted and submitted with your modeling study plan. All required

calibration activities must then be completed within 12 months of your required plan

submission date. Documentation of your calibration along with the final modeling analysis

using the calibrated model must then be submitted as part of your IDSE Report. If your model is

calibrated, you should submit your final water age results in your modeling study plan (see

Section 6.4 for guidance).

The following sections provide guidance for the modeling analysis and the completion of

the modeling study plan.

Water Elevation for Tank 1

140.0

142.0

144.0

146.0

148.0

150.0

152.0

154.0

156.0

158.0

160.0

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42

Time (hours)

Water Elevation (ft)

Actual Model
IDSE Guidance Manual for the Final Stage 2 DBPR 6-14 January 2006

6.2.1 Water Age Modeling

For the modeling SSS, water age is being used as a surrogate for TTHM concentration. 

A water age analysis can be conducted using a hydraulic model without additional input of water

quality data. This simulation option calculates the length of time that each parcel of water has

been in the system after leaving the source(s). The water age calculation is highly dependent on

the operational controls in the model (e.g., tank water levels used to control pump settings). 

Therefore, the model must be set up to match the operating conditions during the peak month for

TTHM formation. This may require adjustments to model demands and controls.

Each water age simulation begins with an initial age of zero at all model nodes. The

water age increases as the simulation time increases until fresh water from the source arrives at a

given node. Nodes with zero or very small demand, especially at dead ends, will not receive

fresh water and therefore will not have an accurate simulation of water age. Similarly, the water

age for tanks will be equal to the simulation time until the entire volume of the tank has been

refreshed with water from the source. Depending on operating conditions in the simulation, this

may take as long as several weeks. 

To overcome the effects of the initial conditions in a water age analysis, ensure that the

simulation runs for a sufficient length of time. The required length of the water age simulation

will vary depending on system characteristics, but can be approximated by the time it would take

to fully turn over all water in the worst case storage facility. The average water age for a given

storage facility is approximately equal to the inverse of the percent turnover. For example, a

tank with an average daily volume turnover of 33% has an average water age of 3 days (100/33 =

3); a tank with an average daily volume turnover of 25% has an average water age of 4 days

(100/25 = 4). However, hydraulic models have limited ability to account for tank mixing

characteristics. Storage facilities with poor mixing characteristics may have water that is

significantly older than the average water age.

An appropriate simulation time should generate a consistent, repeating pattern of water

age in the storage facility with the highest average water age. An example of a repeating pattern

is shown in the case study example in Section 6.2.2. Once the simulation has been completed,

only results from the stable, repeating portion of the simulation (e.g., the last 24 hours) should be

used in subsequent analyses. The intent of using a long simulation time for water age is not to

replicate multiple different days of operation of the system but only to overcome the effects of

initial water age settings (zero at all nodes) on the results. 

Because of the length of the simulation for water age, controls should be checked to

ensure that they will perform properly throughout the simulation. Time-based controls that refer

to the simulation time (e.g. turn on Pump 1 at hour 11) will need to be adjusted to cover the full

length of the simulation. Many software packages have an option to use clock time rather than

simulation time for controls. The use of clock time (e.g. turn on Pump 1 at clock time 11) will

repeat the operation on each day of the simulation at the same time while the use of simulation

time will only perform the operation only once during the entire run. Logical controls (e.g. turn

on Pump 1 when Tank 1 level is 20 feet) will generally perform fine in a longer simulation, but

should be checked.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-15 January 2006

Water age simulation is also sensitive to the time step used for calculations. In most

software packages this is referred to as the water quality time step. In general, the accuracy of

the simulation increases as the time step is decreased. However, the use of very small time steps

can result in longer processing time for larger models. A time step on the order of 1 to 5 minutes

is generally good for water age simulation, depending on the system configuration. Trial runs

with different time steps can be conducted to determine if the water age simulation is sensitive to

the time step selected.

Once the water age simulation is completed, the model results from the stable (repeating)

part of the simulation can be used to calculate an average water age at each node in the

distribution system. If your model calibration is not complete, the results of a modeling analysis

showing the preliminary (over 24 hours) water age results throughout the distribution system

must be submitted with your model study plan. In this case, the modeling analysis must be

verified after model calibration and the revised results must be submitted with your IDSE report. 

If your model calibration is complete, you should submit your final water age results with the

model study plan (in lieu of the preliminary results). In either case, EPA recommends that you

submit water age results in tabular format to minimize security risks to your system. 

6.2.2 Modeling Analysis Example

This case study is based on the NET3.NET example from the EPANET 2 modeling

package. This package can be downloaded from: 

www.epa.gov/ORD/NRMRL/wswrd/epanet.html. The same analysis can be completed using

most modeling software packages, although the exact process may differ slightly.

The system, shown in Exhibit 6.6, contains two sources and three storage tanks. The

treatment plant at the LAKE source operates only from 6 AM to 8 PM while pumping from the

RIVER source is controlled by the level in Tank 1. The sources have similar DBP

concentrations and formation potentials and therefore can be considered to have the same effect

on the final concentrations observed in the distribution system. For a more complex example for

a system with different source characteristics, see Appendix G.

The model was already calibrated for summer conditions. The system data were then

modified to reflect the demands and operating conditions that were expected to occur during the

peak month for TTHM formation. This required the following change to the Simple Control rule

(time based) that was applied to the hours of operation for the pump at the LAKE source (Link

10):

Link 10 OPEN AT CLOCKTIME 6 AM

Link 10 CLOSED AT CLOCKTIME 8 PM

The calibration was verified for the peak month for TTHM formation by producing the

tank level graph depicted in Exhibit 6.5. The fit in this graph verifies that the previous

calibration is adequate to simulate operations during the peak month of TTHM formation.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-16 January 2006

Exhibit 6.6 Schematic of the Case Study Distribution System 

Water age simulations were then completed using increasing simulation durations (e.g.,

120 hours, 240 hours, etc.) until it was apparent that the water age in the storage tanks had

equilibrated. The default water quality time step of 5 minutes was used for each of these

simulations. The largest tank, Tank 3, was found to take the longest time to equilibrate. Exhibit

6.7 shows the time history of water age in this tank over an 840 hour simulation period.

LAKE Source Tank 3 

Tank 1 

RIVER Source 

Tank 2 
IDSE Guidance Manual for the Final Stage 2 DBPR 6-17 January 2006

Exhibit 6.7 Water Age Graph for the Tank with the Highest Water Age

To make sure that this result was not sensitive to the water quality time step used, an

additional run was made using a reduced time step. Results from the smaller time step matched

those for the 5 minute time step.

Next, an analysis was conducted to find the average water age at each location in the

network. To do this, the following modifications were made to the network’s data:

1. the water quality time step was kept at 5 minutes

2. the simulation duration was kept at 840 hours

3. the Report Start Time was set to 792 hours (i.e., 48 hours before the end of the

simulation)

4. the Statistic being reported by the program was set to AVERAGE (so that the average

age over the last 48 hours of the simulation would be reported).

The resulting average water age throughout the network is displayed graphically in

Exhibit 6.8. EPA suggests that you submit your 24 hour average residence time predictions in

tabular format without identifying all nodes on your distribution system schematic to avoid

creating a security risk for your system. An example of this is provided in Appendix F. 

However, you will probably want to rely on graphic output (e.g., Exhibit 6.8) as you evaluate

your model to select SSS monitoring locations as described in Section 6.3. 
IDSE Guidance Manual for the Final Stage 2 DBPR 6-18 January 2006

Exhibit 6.8 Locational Average Water Age Throughout the Study Area

6.3 Determining SSS Monitoring Requirements and Schedule 

As part of the SSS using a distribution system hydraulic model, you must collect TTHM

and HAA5 samples from the distribution system during the peak month for TTHM formation. 

The number of monitoring locations must equal or exceed the required number of locations

required for IDSE standard monitoring. Stage 1 DBPR compliance monitoring locations can not

be selected as locations for your SSS monitoring. The types of locations (near entry point, high

TTHM, high HAA5, and average residence time) must also match the requirements for IDSE

standard monitoring. See Exhibit 6.9 to determine your monitoring location criteria according to

your system size and source water type.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-19 January 2006

Exhibit 6.9 Requirements for Modeling SSS Sampling

Source

Water

Type

Population Size Category1

Distribution System Monitoring Locations2

Total

Number of

Samples

Near

Entry

Points

Average

Residence

Time

High TTHM

Locations

High HAA5

Locations

Subpart H

<500 consecutive systems 2 1 .......... 1 ..........

<500 non-consecutive systems 2 .......... .......... 1 1

500-3,300 consecutive systems 2 1 .......... 1 ..........

500-3,300 non-consecutive

systems

2 .......... .......... 1 1

3,301-9,999 4 .......... 1 2 1

10,000-49,999 8 1 2 3 2

50,000-249,999 16 3 4 5 4

250,000-999,999 24 4 6 8 6

1,000,000-4,999,999 32 6 8 10 8

$5,000,000 40 8 10 12 10

Ground

Water

<500 consecutive systems 2 1 .......... 1 ..........

<500 non-consecutive systems 2 .......... .......... 1 1

500-9,999 2 .......... .......... 1 1

10,000-99,999 6 1 1 2 2

100,000-499,999 8 1 1 3 3

$500,000 12 2 2 4 4 1 Your monitoring requirements (locations and frequency) are based on the population served by your system. 2

 A dual sample set (i.e., a TTHM and an HAA5 sample) must be taken at each monitoring location during each monitoring period.

You should review all available compliance, study, or operational data to determine the

peak historical month for TTHM formation for your system. If you have monthly or quarterly

TTHM monitoring data, EPA recommends that you use this data as the basis for your historical

month. If you do not have monthly or quarterly data, EPA recommends that you select the

month with warmest water temperature as your peak month for TTHM formation. In some

cases, you may find data in addition to TTHM and temperature data helpful in selecting your

peak historical month. For example, some systems may regularly see an increase in total organic

carbon (TOC) levels in the spring or fall. If your TTHM monitoring does not capture a seasonal

increase in TOC, you may want to consider the month with highest TOC when selecting your

peak historical month. 

You should include the basis for selecting your peak month for TTHM formation in your

Modeling Study Plan (see Section 6.4 for guidance on completing the modeling study plan). 

Systems have different requirements for describing sampling plans in their modeling

study plans depending on whether they have completed calibration of their models.

• If you have not completed model calibration you must provide the number of samples

you plan to take and the planned sampling month in your modeling study plan.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-20 January 2006

IDSE Tool

• If your calibration and modeling analysis are complete but sampling is not yet done,

you should indicate the proposed SSS sampling locations on your distribution

schematic in your modeling study plan. 

• If you have completed calibration and sampling, you must indicate the sampled

locations on your distribution schematic in your study plan. You should strongly

consider submitting the IDSE report along with your modeling study plan. 

Note that sampling must be completed by the deadline in your requirements summary sheet.

6.4 Preparing your Modeling Study Plan

After you have verified that your model meets the criteria in Section 6.1.1 through 6.1.4

and have determined the number and timing of your SSS samples, you are ready to prepare your

modeling study plan. Every system that conducts a modeling SSS must prepare and submit a

modeling study plan. You should submit your plan to the Information Processing and

Management Center (IPMC) for review by EPA or your state. See Section 1.4 of this guidance

manual for information on how to submit your plan to the IPMC. 

EPA has developed a Modeling Study Plan Form (Form 4), presented in this section

and available electronically as part of the IDSE Tool. You are not required to use this form;

however, if you choose not to use it, refer to Exhibit 6.2 for a list of the minimum elements you

must include in your modeling study plan.

The IDSE Tool creates a custom form for your system and provides

links to technical guidance from this manual. The tool is available on EPA’s

website at http://www.epa.gov/safewater/disinfection/stage2 .

If your model is not calibrated but you plan to calibrate your model and complete the

modeling analysis as part of the SSS, you must submit your plan with a description of the

proposed calibration work to be done. You must also indicate how all requirements will be

completed within 12 months of your required plan submission date and provide a description of

how you intend to use your model to select monitoring locations. This will allow time to correct

deficiencies that might become apparent during the calibration process. A preliminary water age

analysis must also be conducted with your existing model and submitted as part of the plan (if

your model is calibrated, this should be your final water age analysis). If your model does not

meet the requirements in Exhibit 6.1 and you are unable to address all of the questions on Form

4, you should provide information about how you plan to address those issues during the SSS.

Your deadline for submitting your study plan can be found on your requirements

summary sheet in Chapter 2. If EPA or your state does not approve or request modifications to

your plan, or notify you that your plan is still under review within 12 months after the deadline

for plan submission, you may consider the plan approved. If you have not yet completed

calibration of your model, you must continue calibrating your model while your plan is
IDSE Guidance Manual for the Final Stage 2 DBPR 6-21 January 2006

being reviewed to meet the requirement that all required calibration must be completed no

later than 12 months after your plan submission deadline. 

Form 4 includes the following sections:

I. General Information

II. IDSE Requirements

III. Model Description

IV. Peak Month for TTHM Formation

V. Modeling Information

VI. Planned Stage 1 Compliance Monitoring Schedule

VII. Distribution System Schematic

VIII. Attachments

Sections of the form with an asterisk (*) are required by the Stage 2 DBPR. An example of a

completed modeling study plan using this form is provided in Appendix F.

I. General Information

I.A. PWS information* - Important definitions for classifying your system are

provided in the definitions section at the beginning of this guidance manual. If

you have any questions on this section, contact EPA or your state.

PWSID - Enter your PWSID identification number here. This number is typically

assigned by your state.

PWS Name - Enter the name of your system here. 

PWS Address - Enter the primary mailing address for your water system here.

Population Served - Enter the number of people served by your PWS. 

Remember, this is your RETAIL population served, not including the population

served by consecutive systems that purchase water from you.

System Type - Put a check mark in the appropriate box to identify whether your

system is a CWS or a NTNCWS. Definitions for CWS and NTNCWS can be

found in the definitions section at the beginning of this guidance manual.

Source Water Type - Put a check mark in the appropriate box to identify whether

your system is a subpart H system or a ground water system. If you use any

surface water or GWUDI as a source, mark the subpart H box. Definitions for

subpart H system (including GWUDI) and ground water system can be found in

the definitions section at the beginning of this guidance manual.

Buying/Selling Relationships - Put a check mark in the appropriate box to identify

whether your system is a consecutive system, a wholesale system, or neither. If
IDSE Guidance Manual for the Final Stage 2 DBPR 6-22 January 2006

you are both a consecutive and wholesale system (e.g., you buy and sell water),

check both boxes. Definitions for consecutive system and wholesale system can

be found in the definitions section at the beginning of this guidance manual and

in Appendix D.

I.B. Date submitted* - Enter either the date that you are submitting the form

electronically, putting it in the mailbox, or dropping it off with an express

delivery service. Be sure to submit your modeling study plan before the deadline

found on your requirements summary sheet.

I.C. PWS Operations - This section asks questions about your system to help inform

EPA and state personnel during the plan review process.

Residual Disinfectant Type - Put a check mark in the appropriate box to identify

the type of disinfectant you most often use to maintain a residual in your

distribution system (not necessarily the same disinfectant used for primary

disinfection at the treatment plant). If you use chloramine but switch to free

chlorine for a short time, you should still check chloramine only. If you use

chloramine and chlorine regularly in your system (e.g, 4 months of free chlorine

and 8 months of chloramines), check both chlorine and chloramine. If you

maintain your residual with a disinfectant other than chlorine or chloramines (e.g.,

chlorine dioxide), you should place a check next to the box marked “Other” and

enter the type of disinfectant you use in the blank next to “Other”.

Number of Disinfected Sources - Enter the total number of sources that deliver

disinfected water to your distribution system. If you connect to a single

wholesale system at a number of locations in your distribution system, consider

this one source. Multiple wells that are disinfected at a common treatment plant

should also be considered one source. Do not count wells that are not disinfected

or are disinfected by UV only.

I.D. Contact Person* - Enter the contact information of the person who is submitting

the form. This should be the person who will be available to answer questions

from EPA and/or the state reviewers.

II. IDSE Requirements*

II.A. SSS Monitoring - Copy the required number of samples from the table in Exhibit

6.9 that corresponds to your source type and the population served by your

system. 

II.B. IDSE Schedule - Enter the schedule for your system based on the letter that you

received from EPA or your state. See Chapter 2 for more information on the

letter.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-23 January 2006

II.C. SSS Monitoring Frequency - You are required to monitor during the peak month

of TTHM formation. If you plan to conduct additional monitoring, describe it

here. 

III. Model Description

III.A. Yes/No Questions* These questions refer to the physical data contained in your

model. Circle Y or N to indicate if your model complies with the requirements.

III.B. Model Development and Calibration* Provide a description of the history of

development and calibration of your model. Describe what the model has been

used to do, such as evaluating operational scenarios, capital improvements

planning, or water quality assessment. Discuss the types of decisions that were

based on results from the model. An example of this type of description is:

The model was developed in 2004 using GIS data for the water system. The

model was calibrated to maximum day flow conditions during July 2004. The

calibrated model has been used by our staff to identify improvements needed to

serve a new subdivision and to change our tank operating procedures to minimize

water age and maintain chlorine residual.

III.C. Demand Data For each question, provide a brief description of the data and

methods used to assign customer demands to the model.

III.D. Calibration Activities* For each question, provide a brief description of the data

and methods used to calibrate your model. If your model is not currently

calibrated but you propose to calibrate the model as part of the SSS, provide a

description of the calibration effort you plan to undertake to ensure that

calibration is completed within 12 months of your required plan submission date.

If calibration is complete:

• Submit a graph that documents your model calibration by showing

simulated tank levels versus observed levels for the storage facility with

the highest water age in each pressure zone of your system (see Exhibit

6.5 for an example)*.

IV. Peak Month for TTHM Formation

IV.A. Peak Month for TTHM Formation* - Enter the month that you determined to be

your peak month for TTHM formation. See Section 6.3 for guidelines for

selecting your peak month for TTHM formation.

IV.B. Justification of Peak Month for TTHM Formation - Describe how you determined

in which month TTHM formation is highest in your system. You should describe

the types of data used to reach your conclusion.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-24 January 2006

V. Modeling Information* - For each question, provide a brief description of the methods

used (or planned) to perform modeling for water age. 

• If your model calibration has been completed, the modeling analysis should be

described in this section. Submit a graph of water age versus time for the entire

simulation duration for the tank with the highest overall water age in the system*

• If your model calibration is not complete, a preliminary modeling analysis must be

conducted with your existing model and the results must be submitted with your SSS

plan. In this case, the modeling analysis must be verified after model calibration and

revised results must be submitted with your IDSE report. 

All systems must submit model output showing preliminary (or final) average water age

results over a 24-hour period as part of their modeling study plan. The 24-hour period

used for the average water age results table should represent a simulation time after the

model has achieved a stable, repeating water age pattern (e.g. the last 24 hours of the

simulation). EPA recommends that you submit this in tabular format to not pose a

security risk to your system.

VI. Planned Stage 1 DBPR Compliance Monitoring Schedule* - Enter the projected

sampling schedule for the number of Stage 1 DBPR monitoring periods in which you will

conduct Stage 1 DBPR monitoring during your system specific study. Verify that site

IDs in this table match the IDs on your distribution system schematic. If you are required

to monitor at more than 8 Stage 1 DBPR locations you will need to attach additional

sheets. You may also want to attach your Stage 1 DBPR monitoring plan.

VII. Distribution System Schematic* - Attach a distribution system schematic to your study

plan. The schematic must include the location of entry points and their sources, all

storage facilities, and locations of completed SSS monitoring (if applicable) and all

subpart L compliance monitoring. If you have not selected your SSS sample sites, you

must show these sites on a revised version of the schematic when you submit your IDSE

report. 

Modeling study plans will not be considered confidential business information (CBI) and

are subject to the Freedom of Information Act (FOIA). Therefore, your distribution

system schematic should not contain information that poses a security risk to your

system. EPA suggests that you submit a Distribution system schematic with no

landmarks or addresses indicated. In addition to the required information indicated

above, you should also include pressure zone boundaries, locations of pump stations, and 

the map scale. 

Schematics should be as clear and easy to read as possible. They should typically be

submitted on a scale of between 1:4,000 and 1:8,000; however, larger-scale drawings are

acceptable as long as systems components can still be clearly shown. All sizes from 81⁄2

inches x 11 inches to larger, plan-sized sheets are acceptable. If electronic versions are

submitted, use one of the following file types:
IDSE Guidance Manual for the Final Stage 2 DBPR 6-25 January 2006

• Adobe PDF file (*.pdf)

• Microsoft Word (*.doc)

• WordPerfect (*.wpd)

• Image file (*.gif, *.bmp, *.jpg, *.jpeg)

VIII. Attachments - Put a check mark in each of the boxes corresponding to any attachments

that you have included in your report. 

Note that some of the attachments are required by the Stage 2 DBPR:

• Distribution System Schematic* 

• Tabular or spreadsheet documentation that your model meets minimum requirement*

• Graph of predicted tank levels vs. measured tank levels for the storage facility with

the highest residence time in each pressure zone* (Required if calibration is

complete)

• Time series graph of water age at the longest residence time storage facility in the

distribution system showing the predictions for the entire EPS simulation period*

(Required if calibration is complete)

• Model output showing preliminary 24 hour average water age predictions for all

nodes throughout the distribution system* (Required for all submissions. If your

model is calibrated, this should be your final water age predictions.)

If you submit your study plan electronically, you also have the option to submit

attachments in hard copy. Include a note in your electronic study plan explaining that 

attachments are being submitted in hard copy, and mail the hard copy to the IPMC

mailing address in your Requirements Summary Sheet. The IPMC will match the hard

copy submission with your electronic submission when it is received.

Enter the total number of pages in your study plan (including attachments) in the blank at

the bottom of this section. This will allow EPA or your state to ensure that all pages

were received.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-26 January 2006

This page intentionally left blank.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-27 January 2006

Form 4: Modeling Study Plan Page 1 of 6

I. GENERAL INFORMATION 

A. PWS Information* B. Date Submitted* ___________

 PWSID:

 PWS Name:

PWS Address:

City: State: Zip:

Population Served:

System Type: Source Water Type: Buying / Selling Relationships:

~ CWS ~ Subpart H ~ Consecutive System 

~ NTNCWS ~ Ground ~ Wholesale System

 ~ Neither

C. PWS Operations 

Residual Disinfectant Type: ~ Chlorine ~ Chloramines ~ Other:_____________

 Number of Disinfected Sources: ___ Surface ___GWUDI ____ Ground ___ Purchased

D. Contact Person*

Name:

Title:

Phone #: Fax #:

E-mail: 

II. IDSE REQUIREMENTS*

A. SSS Monitoring B. Schedule C. SSS Monitoring Frequency

Number of Samples

per Monitoring Period

~ During peak month of TTHM formation

(1 monitoring period) ~ Schedule 1

Number of Monitoring

Periods

~ Schedule 2

 ~ Schedule 3 ~ Additional (describe) 

 Total ~ Schedule 4 
IDSE Guidance Manual for the Final Stage 2 DBPR 6-28 January 2006

Form 4: Modeling Study Plan Page 2 of 6

III. MODEL DESCRIPTION

A. Answer Yes or No to the following questions*

(provide documentation in attached sheets)

1. Is your model an Extended Period Simulation model? Y / N

2. Does your model meet the minimum requirements described

below? Attach tables or spreadsheets to demonstrate that your

model meets these requirements.

Include 75% of pipe volume Y / N

Include 50% of pipe length Y / N

Include all pressure zones Y / N

Include all pipes 12" and larger Y / N

Include all 8" 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

Y / N

Include all 6" and larger pipes that connect remote areas

of a distribution system to the main portion of the system

Y / N

Include all storage facilities with standard operations

represented in the model

Y / N

Include all active pump stations with realistic controls Y / N

Include all active control valves Y / N

3. Is your model (or will it be) calibrated to simulate actual water

levels at all storage facilities and represent the current distribution

system configuration during the period of high TTHM formation?

Y / N

4. If calibration is complete, does the model simulate 24 hour

variation in demand and show a consistently repeating 24 hour

pattern of residence time?

 Y / N

B. Provide a history of your model development and calibration*, including

dates (attach additional sheets if needed)
IDSE Guidance Manual for the Final Stage 2 DBPR 6-29 January 2006

Form 4: Modeling Study Plan Page 3 of 6

III. MODEL DESCRIPTION (Continued)

C. How was demand data assigned to the model? (attach additional sheets if

needed)

1. What method was used to assign

demands throughout the system?

2. How did you estimate diurnal demand

variation? How did you determine

total system demand?

3. How many demand categories did

you use?

4. How did you address large water

users?

D. Describe all calibration activities* If your model is not currently calibrated,

describe how calibration will be completed within 12 months of the required

plan submission date using the questions 1-8 as guidance (attach additional

sheets if needed).

1. When was the model last calibrated?

2. What types of data were used in the

calibration?

3. When was the calibration data

collected?

4. What field tests have been performed

to collect calibration data?
IDSE Guidance Manual for the Final Stage 2 DBPR 6-30 January 2006

Form 4: Modeling Study Plan Page 4 of 6 

III. MODEL DESCRIPTION (Continued)

D. (Continued)

5.

How did you determine friction

factors (C-factors)?

6. Was the calibration completed for

the peak month for TTHM formation? 

If not, was the model performance

verified for the peak month for TTHM

formation?

7.

How well do actual tank levels

correlate with predicted tank levels

during the peak month for TTHM

formation? 

See Attachments (Section VIII) for

additional submission

requirements.

8.

If you are using a water quality

model, what parameters are

modeled? How was the model

calibrated?

IV. PEAK MONTH FOR TTHM FORMATION

 A. Peak Month For TTHM Formation* 

 B. Justification of Peak Month for TTHM Formation

Describe how your system determined which month is the peak month for TTHM

formation (attach additional sheets if needed):
IDSE Guidance Manual for the Final Stage 2 DBPR 6-31 January 2006

Form 4: Modeling Study Plan Page 5 of 6 

V. MODELING INFORMATION *

How was the SSS modeling performed? (attach additional sheets as needed)

1. Was modeling done for the operating

conditions during the peak month for

TTHM formation?

2. How were operational controls

represented in the model?

3. How was water age simulated during

the peak month for TTHM formation

(time steps, length of simulation,

etc.)? If not yet done, indicate how

this will be addressed in the IDSE

report. 

4. What are the average water age

results for your distribution system? 

See Attachments (Section VIII) for

additional submission

requirements.

VI. PLANNED STAGE 1 DBPR COMPLIANCE MONITORING SCHEDULE*

 

Stage 1 DBPR

Monitoring Site

ID (from map) 1

Projected Sampling Date (date or week) 2

Period 1 Period 2 Period 3 Period 4

1 Verify that site IDs match IDs on your distribution system schematic (See Section VII of

this form). Attach additional copies if you are required to monitor at more than 8 Stage 1

DBPR sites.

2 period = monitoring period. Complete for the number of periods in which you must conduct

Stage 1 DBPR monitoring during IDSE monitoring. Can list exact date or week (e.g., week

of 7/9/07)
IDSE Guidance Manual for the Final Stage 2 DBPR 6-32 January 2006

Form 4: Modeling Study Plan Page 6 of 6

VII. DISTRIBUTION SYSTEM SCHEMATIC*

ATTACH a schematic of your distribution system. 

Distribution system schematics are not confidential and should not contain information that

poses a security risk to your system. EPA recommends that you submit the following:

Distribution system schematic with no landmarks or addresses indicated. Show

locations of sources, entry points, storage facilities, locations of completed monitoring,

and Stage 1 compliance monitoring locations (required). Also include pressure zone

boundaries and locations of pump stations. Provide map scale. 

VIII. ATTACHMENTS

~ Distribution System Schematic* (Section VII).

~ Tabular or spreadsheet documentation that your model meets minimum

requirements* (Section III.A).

~ Additional sheets for explaining your model (Section III.B).

~ Graph of predicted tank levels vs. measured tank levels for the storage facility

with the highest residence time in each pressure zone* (Section III.D). 

Required if calibration is complete.

~ Time series graph of water age at the longest residence time storage facility in

the distribution system showing the predictions for the entire EPS simulation

period* (Section V). Required if calibration is complete.

~ Additional sheets for explaining how you selected the peak historic month for

TTHM formation (Section IV).

~ Model output showing preliminary 24 hour average water age predictions for all

nodes throughout the distribution system* (Required for all submissions. If your

model is calibrated, this should be your final water age predictions.) (Section V).

~ Additional sheets describing the planned Stage 1 DBPR Compliance Monitoring 

Schedule (Section VI).

Total Number of Pages in Your Plan _____

Note: All items marked with an asterisk (*) are required by the rule.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-33 January 2006

6.5 Selecting SSS Monitoring Sites and Conducting Monitoring

If EPA or your state does not approve or request modifications to your plan, or notify you

that your plan is still under review within 12 months after the deadline for plan submission, you

may consider the plan approved. Follow your approved study plan as you select SSS

monitoring sites and conduct monitoring. Once your calibration and modeling analysis is

completed (Sections 6.1.4 and 6.2) the next step is to select your SSS monitoring locations using

the model results and supplemental data. After the locations are selected, you will collect

samples during the peak month of TTHM formation and use this data, along with your model

results, to select your Stage 2 DBPR Sites. 

6.5.1 Select SSS Monitoring Locations

As discussed in Section 6.3, systems should determine the number of SSS monitoring

locations for their system type and size based on the information provided in Exhibit 6.9. 

You should keep track of your decision making process as you select SSS monitoring

locations and then select Stage 2 DBPR compliance monitoring locations because it will help

you justify your Stage 2 compliance monitoring site selection. When you prepare your IDSE

report, you will be required to provide justification for the selection of each Stage 2 DBPR

compliance monitoring site based on model results, monitoring results and additional data

analysis.

Depending on your system size and source water type, you will select up to four different

kinds of SSS monitoring sites: near entry point sites, average residence time sites, high TTHM

sites, and high HAA5 sites. Guidance for near entry point sites is provided in Section 6.5.1.1. 

Section 6.5.1.2 provides guidelines for using water age estimates from your model to select

average residence time and high TTHM sites. Section 6.5.1.3 provides additional considerations

for selecting high HAA5 sites. Lastly, Section 6.5.1.4 provides a discussion of overarching

issues for consideration when you select your final SSS monitoring sites. 

6.5.1.1 Identify Near Entry Point Monitoring Locations

Data from sites near the entry points to the distribution system represent minimum

residence time and can be used as a baseline for interpreting changes in water quality as water

travels through the system. EPA recommends that you use the following procedure to select

near entry point monitoring sites.

Step 1. Determine How Many Near Entry Point Sites You Need for SSS Monitoring

Determine how many near entry point monitoring sites you are required to have by

referring to Exhibit 6.9. Remember that SSS sampling requirements for models are based on the

population served by your individual system, not the largest population in your combined

distribution system. 
IDSE Guidance Manual for the Final Stage 2 DBPR 6-34 January 2006

Step 2. Determine How Many Entry Points are in Your System

For the purposes of the IDSE, entry points are the locations where disinfected water

enters your distribution system. Entry points can convey treated surface water, disinfected water

from wells, or purchased water from a wholesale system (as long as it has been disinfected). 

Entry points generally include seasonal or intermittent connections. If a well is not disinfected

or is disinfected using ultraviolet light (UV) only, you should not consider it an entry point for

the purposes of the IDSE.

Step 3. Compare Results from Step 1 to Step 2

• If the number of near entry point sites required matches the number of entry points in

your system, select a sampling location near each entry point.

• If your system has FEWER entry points than required near entry point SSS

monitoring locations, you must replace the unassigned near entry point sites with

high TTHM and HAA5 sites to maintain the required total number of SSS monitoring

sites for models. If you have an odd number of unused near entry point sites, select

an additional high TTHM site. See Chapter 7, Section 7.1.1 of this guidance manual

for an example of how systems used this procedure to replace near entry point sites

with high TTHM and high HAA5 sites. 

• If your system has MORE entry points than required near entry point SSS monitoring

locations, you must take samples near entry points to the distribution system having

the highest annual water flows. Section 7.1.1 of this guidance manual also includes

an example of selecting entry points with the highest annual water flows.

The Stage 2 DBPR does not define near entry point sites explicitly. EPA recommends

that you locate your near entry point sites between the entrance to the distribution system and

no later than first customer. If you are a consecutive system, a sample tap at the master meter

would be an appropriate near entry point site. If you do not have a sample tap at your master

meter, consider using the first customer as your near entry point site.

6.5.1.2 Use Your Model to Identify Average Residence Time and High TTHM Locations

Identifying Average Residence Time Sites

Average residence time is the average age of water delivered to customers in a

distribution system. Average residence time is not simply one-half the maximum residence time. 

Ideally, it should be a flow-weighted or population-weighted estimate. The model results for

water age/DBP concentration can be used to determine the average residence time for your

system. One option for doing this is to list the water age/DBP concentration results in ranked

order for the entire system, as shown in Exhibit 6.10. This will help you to plot a histogram of

the results as shown in Exhibit 6.11. A histogram plot sorts the water age results into groups and

shows the percentage of nodes with water ages falling within the given range. From the

histogram it can be seen that the greatest number of nodes have water ages falling in the 20 hour
IDSE Guidance Manual for the Final Stage 2 DBPR 6-35 January 2006

bin (bin range = 15 to 25 hours) and therefore the most frequently occurring water age is 20

hours. Using this method, 20 hours would be a reasonable average water age estimate for the

system.

Exhibit 6.10 Ranking of Water Age Results

Rank Node ID Water Age (hours)

1 RIVER 0

2 LAKE 0

3 10 0.03

4 60 0.08

...

25 267 10.36

26 275 10.39

27 159 10.54

...

47 197 12.26

48 211 14.70

49 181 14.87

...

71 149 30.58

72 247 30.62

73 231 31.31

...

95 Tank 2 122.41

96 131 135.44

97 Tank 3 189.26
IDSE Guidance Manual for the Final Stage 2 DBPR 6-36 January 2006

Exhibit 6.11 Histogram of Water Age Results

Identify High TTHM Sites

It is not the intent of IDSE monitoring to identify sites with maximum daily or hourly

TTHM concentrations. Instead, you should choose candidate sites to represent areas of the

distribution system that you expect to have high average TTHM concentrations as compared to

other areas in the system. Increased water age typically leads to higher TTHM concentrations. 

This principle is the basis of the guidance provided for selecting high TTHM sites using your

model. If you choose to consider additional factors in identifying high TTHM locations, Section

7.1.1 Step 4 describes typical water quality characteristics of high TTHM sites.

High TTHM sites can be identified by ranking the average water age results for nodes in

the model. For model results that directly simulate TTHM concentration, nodes can be ranked

by concentration to identify representative high locations. Areas in the distribution system

where water is mixed or blended from two different supply points can result in an area of

stagnant water, often with high water age and potential for high TTHM concentration. You

should select sites from your model with the highest water age or TTHM concentration.

Color coded maps such as those shown in the case study example in Section 6.2.2 can be

helpful in interpreting the model results to identify representative high TTHM locations. Many

software and GIS packages can be used to plot water age/TTHM concentration results along with

other water quality data to produce a graphical representation of the system.

0.00

5.00

10.00

15.00

20.00

25.00

30.00

35.00

40.00

45.00

50.00

0 10 20 30 40 50 60 70 80 90 100 More

Average Water Age (hours)

% of Nodes
IDSE Guidance Manual for the Final Stage 2 DBPR 6-37 January 2006

You should also consider the following issues as you use your model to select high

TTHM locations:

• Water age at zero-demand nodes, particularly dead ends, may not be accurate. 

• The accuracy of water age estimates from a model generally decreases as the model

moves from large diameter mains to small diameter mains to subdivision piping and

dead-ends. This is due to the increasing uncertainty in water usage rates as the

system moves away from large, aggregate demands to smaller demands exerted by a

few customers or a single customer.

If the model is skeletonized, the model results for high water age/TTHM concentration

areas should be compared to maps of the actual distribution system piping and to actual customer

locations in those areas before sample locations are selected. You should try to assure that the

sample location is representative of the actual distribution system, not the model, in cases where

actual pipes may not all be included in the model in the high residence time areas. 

6.5.1.3 Use Your Model and Other Data to Identify High HAA5 Sites

As with high TTHM SSS monitoring sites, it is not the intent of IDSE monitoring to

identify sites with maximum daily or hourly HAA5 concentrations. Instead, you should choose 

 high HAA5 SSS monitoring sites to represent areas of the distribution system that you expect to

have high average HAA5 concentrations as compared to other areas in the system. Higher

temperatures and increased residence time can lead to higher HAA5 concentrations. However,

 HAA5 can biodegrade when disinfectant residual levels are low or non-existent. Therefore, a

high HAA5 site will not necessarily be the site with the longest residence time. This principle is

the basis for the guidance provided for selecting candidate sites. If you choose to consider

additional factors in identifying high HAA5 locations, Section 7.1.1 Step 5 describes typical

water quality characteristics of high HAA5 sites. You may use the 3-step procedure below to

select high HAA5 sites.

Step 1: Identify areas with high water age

Similar to high TTHM sites, the sites with high water age can be identified by ranking

the water age results for nodes in the model. For model results that simulate HAA5 formation,

nodes can be ranked by concentration to identify representative high locations. Areas in the

distribution system where water is mixed or blended from two different supply points can result

in an area of stagnant water, often with high water age. You should select sites from your model

with the representative high water age or HAA5 concentration that were not already selected as

high TTHM sites. The next paragraph will provide guidance on eliminating those locations

where biodegradation is likely.

Color coded maps such as those shown in the case study example in Section 6.2.2 can be

helpful in interpreting the model results to identify representative high HAA5 locations. Many

software and GIS packages can be used to plot water age/HAA5 concentration results along with

other water quality data to produce a graphical representation of the system.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-38 January 2006

Step 2: Eliminate sites where you suspect biodegradation

Analysis of disinfectant residual is important in determining potential for biodegradation

of HAA5. Sources of disinfectant residual data may include regular compliance monitoring sites

(e.g., SWTR or Stage 1 DBPR compliance monitoring sites), operational sample sites, or special

sites sampled in response to customer complaints. 

Low disinfectant residuals relative to the system average generally indicate longer

residence times, and may correlate with higher HAA5 concentrations. However, you should

eliminate any areas that regularly or typically in the summer months have free chlorine residuals

less than 0.2 mg/L or with chloramine residuals less than 0.5 mg/L. Sites with residuals below

these minimum levels are more likely to have significant biological activity and are therefore

more likely to have biodegradation of HAA5. Because disinfectant residuals typically decay

faster during the summer, a review of data from the summer months may be more useful in

identifying areas with consistently low residuals. HPC data may also be helpful in determining

whether biodegradation of HAA5 is occurring in your system.

Step 3. Verify Sites Using a Map

If the model is skeletonized, the model results for high water age/DBP concentration

areas should be compared to maps of the actual distribution system piping and to actual customer

locations in those areas before sample locations are selected. Systems should try to assure that

the sample location is representative of the actual distribution system, not the model, in cases

where actual pipes may not all be included in the model in the high residence time areas.

6.5.1.4 Finalize SSS Monitoring Locations

To finalize the selection of SSS monitoring locations, you should plot all your sites on a

map and check that the sites meet all the criteria shown in the following steps. Color-coding and

other mapping options may be helpful in this process.

Step 1: Confirm that sites match expectations

The purpose of this step is to confirm that your sites cover key areas. The following

questions may be useful as you evaluate all SSS monitoring sites together on the map:

• Are high TTHM SSS monitoring sites located in the extremities of the distribution

system? 

• Are high HAA5 SSS monitoring sites located in the extremities where there are no

indications of biological activity or low disinfectant residual? 

• Are high TTHM and HAA5 SSS monitoring sites generally downstream of storage

facilities and booster disinfection stations?
IDSE Guidance Manual for the Final Stage 2 DBPR 6-39 January 2006

• Are there any other areas where you suspect water age is high that are not represented

with a high TTHM (and possibly high HAA5) SSS monitoring site?

Step 2. Consider geographic coverage and other factors to finalize site selection

The following issues should be considered in making final choices for SSS monitoring

sites:

• Look for geographic representation. Select sites that are geographically diverse

from the other SSS monitoring sites and existing Stage 1 compliance monitoring

locations. EPA recommends that you locate at least one of the high TTHM SSS

monitoring sites in a remote area of the distribution system. If your distribution

system contains hydraulically isolated portions, you should represent as many of

these as possible with at least one SSS site. If you are only required to select one

high TTHM site, it is strongly recommended that you locate this site far away from

the treatment plant, near the last group of customers (but prior to the last fire

hydrant).

• Look for hydraulic representation. Select SSS monitoring sites in hydraulically

different areas. Even if sites are geographically near each other, they may represent

different pressure zones. You should also select sites that represent mixing zones if

multiple sources with different water quality characteristics are used.

• Use sites that “multi-task”. Prioritize sites that meet the multiple siting criteria and

those identified based on more than one data source. For example, a candidate high

TTHM SSS monitoring site based on water age model results that has low

disinfectant residual historically, is near the edge of the distribution system and is

downstream of a tank would be an excellent SSS monitoring site.

• Select sites that are projected to have high water age during the time of the day

when sampling is normally done.

• Consider site access. Try to select SSS monitoring sites for which access will not be

an issue. Each site should remain accessible over the long term in case the site is

selected for Stage 2 DBPR compliance monitoring.

• Select the best site in an area with several choices. If you have more than enough

sites in a given area of the distribution system and no other data favors one over the

other, use historical TTHM or HAA5 data (if available) to prioritize sites. For

example, if disinfectant residual data are the same for three sites over the same

periods, then the DBP data can be used to select a high TTHM/HAA5 SSS

monitoring site. Remember that you cannot use Stage 1 DBPR compliance

monitoring sites as SSS monitoring sites.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-40 January 2006

6.5.2 Special Case: Using DBP Formation Modeling to Select Sites

DBP modeling results using chemical constituent reactions can also be used to assist in

selection of the SSS sampling locations. Systems should note that any DBP modeling would be

used in addition to completing the modeling SSS requirements for analysis and submittal of

water age results. 

Most modeling software packages provide an option to model decay/formation of

chemical constituents including DBPs with user-specified kinetic coefficients. To calibrate a

model for a chemical constituent, field and laboratory tests are necessary to identify the kinetic

coefficients (e.g. THM formation rate coefficient and limiting concentration) and to verify the

results at different locations in the distribution system.

For a DBP formation simulation, the necessary input data includes:

• the DBP concentration leaving the source

• a first-order rate constant based on laboratory tests

• an ultimate formation potential (maximum concentration) of the DBP

As with the water age analysis, DBP modeling will begin each simulation with a zero

concentration at every node unless the user specifies an initial concentration. Historical data

could be used to determine initial concentrations throughout the distribution system. A long

simulation, similar to one required for water age, could also be used to ensure that the results are

not impacted by the initial concentration.

TTHM and HAA5 are usually modeled separately in distribution systems because they

often have different formation rate constants and initial concentrations. HAAs may biodegrade

in the distribution system but there is currently no mechanism in the modeling software to

simulate both the formation and degradation simultaneously. In that case, HAA modeling may

be better suited to general predictions of maximum possible concentration in the absence of

degradation and may not calibrate well to actual field data.

6.5.3 Conducting Monitoring

This section presents sampling requirements and tips for sample collection for

conducting monitoring for your SSS model.

REMINDER: you must continue to collect samples and comply with the Stage 1 DBPR during

the IDSE. Results from SSS monitoring should not be used for making Stage 1 compliance

determinations.

You must collect a dual sample set (i.e., two samples) at each location during the peak

month for TTHM formation. One sample must be analyzed for TTHM and the other must be

analyzed for HAA5. Two samples are required because the analytical methods used for the two
IDSE Guidance Manual for the Final Stage 2 DBPR 6-41 January 2006

groups of contaminants require different sample preservation methods. You must use EPAapproved methods for analysis of your TTHM and HAA5 samples. More information on EPAapproved methods can be found in Appendix C.

As you conduct SSS monitoring, you should keep in mind the following tips for sample

collection:

• Use appropriate sample bottles. You should use sample bottles that already contain

the appropriate dechlorinating agent and preservative for sample collection. You

should contact your lab for a recommended sampling and preservation protocol. A

typical sampling protocol can be found in Appendix C.

• Flush your sample tap. If you collect samples from a tap, you should open the cold

water tap and allow the line to flush until the water temperature has stabilized

(usually about 3-5 minutes). If you collect a sample at a hydrant or blow-off, the

flushing time only needs to be long enough to purge the connecting line to the main. 

The purpose of this step is to ensure the sample does not represent stagnant water that

has been sitting for a long time in the water line between the street and the faucet. 

The sample should represent the water flowing through the distribution system at the

chosen sampling point. 

• Collect cold water samples. If you collect indoor samples you should collect them

from a cold water line.

• Collect additional water quality data. You may wish to collect additional water

quality data, such as disinfectant residual and temperature data, at the time of DBP

sample collection. This information can be helpful as you interpret monitoring

results (e.g., unusually low residual at a location could mean unusually high residence

time).

• Re-sample if a sample is lost or broken. If a sample bottle is lost or broken after

sample collection, you should re-sample as soon as possible after the loss occurs. 

Only the lost sample needs to be recollected, not the entire sample set that was

collected together. Make sure to note the loss of sample and resample date as a

deviation in your IDSE report.

6.6 Selecting Stage 2 DBPR Compliance Monitoring Sites and Schedule

The purpose of the IDSE is to select Stage 2 DBPR compliance monitoring locations that

reflect sites with representative high TTHM and HAA5 concentrations in the distribution system. 

After completion of the modeling analysis, selection of SSS monitoring locations and sampling

during one monitoring period, the Stage 2 DBPR compliance monitoring sites must be selected

for use in future compliance monitoring. 
IDSE Guidance Manual for the Final Stage 2 DBPR 6-42 January 2006

This section provides technical guidance for selecting Stage 2 Compliance Monitoring

Sites. Justification for each site is required to be submitted in the IDSE report for a modeling

SSS (See Section 6.7).

6.6.1 Analyzing Model Results at Monitoring Locations

To assist in the final selection of Stage 2 DBPR sampling locations, model results should

be examined for each SSS monitoring location and each Stage 2 DBPR compliance monitoring

location . It is recommended that you plot water age versus time for a minimum period of 24

hours at a time in the simulation when results have stabilized and are repeatable (e.g. last 24

hours of the simulation period) for each monitoring location. Note that you are required to

submit a graph of water age for each monitoring location that is selected as a Stage 2 DBPR

compliance monitoring site as part of the IDSE Report. As with all model analyses in the SSS,

the typical operations in the peak month for TTHM formation must be represented. An example

of an acceptable graph is given in Exhibit 6.12.

IMPORTANT NOTE: For security reasons, the graphs of water age for each selected Stage 2

compliance monitoring site should not be identified by site location number. A blind numbering

system should be used on each graph that you can discuss with EPA or your state if they contact

you with questions about your IDSE report.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-43 January 2006

Exhibit 6.12 Example of Typical Water Age Variation over Time

6.6.2 Analyzing SSS Monitoring Results

You must calculate the locational running annual average (LRAA) for each SSS

monitoring site and Stage 1 DBPR compliance monitoring site in order to select Stage 2 DBPR

compliance monitoring sites. The LRAA for each SSS monitoring site is equivalent to the single

sample result taken during the peak month for TTHM formation (unless you conducted

additional sampling). The LRAA for each Stage 1 DBPR compliance monitoring site should be

the LRAA for the year in which you were required to complete SSS monitoring. It will be based

on either one or four data points depending on your Stage 1 compliance monitoring frequency. 

You should consider using a spreadsheet to store your data and calculate your LRAAs.

6.6.3 Comparison of Modeling and Sampling Results

As part of the site selection process, you should compare modeling results to sampling

results. Because of the dynamic nature of distribution systems, it is not expected that every

sample will exactly match the model results. However, the sample data should generally

demonstrate that the SSS monitoring locations correspond to the areas of the distribution system

they were chosen to represent. Sampling results that do not fit with the predicted water age or

DBP modeling results should be noted. This check is intended to look for trends that indicate the
IDSE Guidance Manual for the Final Stage 2 DBPR 6-44 January 2006

selected sites may not be appropriate and determine whether additional model analysis should be

completed. For example, if many of the average residence time sites have TTHM concentrations

that are significantly greater than at the high TTHM sites, this may indicate a problem with the

model predictions. In this case it would be appropriate to revisit the model analysis to make sure

the completed sampling represents high TTHM and HAA5 concentrations in the distribution

system. 

Systems should explain any discrepancies between the modeling and sampling results

and describe any follow-up actions taken to investigate. In this case, systems should consider

the following scenarios when analyzing their modeling and sampling results:

• The time of sample collection should be noted and compared to the water age graph

to determine if the sample time coincided with the time of maximum water age. DBP

concentrations can vary over time and while the average simulated concentration

might be considered high, the concentration at certain times of the day may be

relatively low. 

• Operational events such as main breaks and flushing can change the typical flow

patterns in a system and thereby affect the DBP concentrations. 

• Additional field data collected during the sampling period (e.g. chlorine residual,

heterotrophic plate count) may help to explain discrepancies between modeling and

sampling results. 

• Systems may choose to resample at the site(s).

• Verify that the model represents the current configuration of the distribution system. 

Unexpected sampling results may indicate inconsistencies in the model.

6.6.4 Select Final Compliance Monitoring Sites

You must first use the site selection protocol in Exhibit 6.13 to identify Stage 2

compliance monitoring locations based on your LRAAs. The number of required Stage 2

compliance monitoring sites for your system can be found on page 2 of the System Specific

Study Requirements - Attachment sheet in Chapter 2. If you complete all steps in the protocol

and need additional compliance monitoring sites for the Stage 2 DBPR, repeat the protocol until

the required number of sites has been selected. If you arrive at Step 3 or Step 7 and have no

more Stage 1 DBPR sites from which to select, continue to the next step. You can also use

Worksheet 6.1 to help you organize your data.

You should compare Stage 2 sites selected using the protocol to model results for water

age. In general, TTHM and HAA5 results and modeled water age are the most important factors

in site selection. You should consider both predicted average water age and the 24-hour

variation in water age. If you are choosing between two sites where one has large variations in

water age throughout the day and the other is relatively consistent, you should select the site with

consistent water age. Sites with discrepancies between model results and SSS monitoring results

can be selected as Stage 2 DBPR compliance monitoring sites if justification is provided in the

IDSE report.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-45 January 2006

The Stage 2 DBPR allows you to consider additional factors when selecting Stage 2

compliance monitoring locations. As you work through the site selection protocol, you should

consider other factors that may lead you to select a site with a similar or slightly lower water age

and/or LRAA. For example:

• The site provides more complete geographic coverage of the entire distribution

system

• The site allows you to maintain a historical record

• Sampling at that site provides the opportunity to collect other water quality or

operational data (e.g., chloramine systems may want to collect nitrate or nitrite data at

that site)

Your IDSE report must include the basis (analytical results and modeling) and

justification you used to select these Stage 2 DBPR compliance monitoring sites. This is

particularly important for sites where there was a discrepancy between the model and the

monitoring results. You should first explain why you selected the site for SSS monitoring, and

then why you selected the site for Stage 2 compliance monitoring using modeling results and

sample data. An example of how you might justify a site is given below. 

This site has the highest water age of all nodes and had the highest TTHM levels of all

samples collected during our SSS monitoring. Therefore, it was selected as our first high

TTHM site.

It is possible that EPA or your state may not concur with your justification and may require you

to select different Stage 2 compliance monitoring sites.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-46 January 2006

Worksheet 6.1 Stage 2 DBPR Site Selection Worksheet for a 

Modeling SSS Page 1 of 1

Instructions:

1) Enter the number of required Stage 2 DBPR compliance monitoring sites based on your

System Specific Study Requirements - Attachment summary sheet from Chapter 2. 

2) Enter the Site ID and LRAA for each SSS monitoring and Stage 1 compliance monitoring

location. You may want to sort your entries in order by TTHM LRAA or HAA5 LRAA

values. 

3) As you work through the site selection protocol in Exhibit 6.13, fill in the “Stage 2 Site

Type” column each time you select a site to indicate whether the site is a high TTHM, high

HAA5, Existing Stage 1 DBPR Compliance Monitoring Site, or selected using criteria other

than the protocol. 

No. of Stage 2 DBPR Compliance Monitoring Sites Required

 Highest TTHM Highest HAA5 Existing Stage 1 TOTAL

Site ID

LRAA

Stage 2 DBPR Site

Type*

TTHM

(mg/L)

HAA5 

(mg/L)

Example 0.075 0.045 Highest TTHM

* Enter Highest TTHM, Highest HAA5, or existing Stage 1 DBPR
IDSE Guidance Manual for the Final Stage 2 DBPR 6-47 January 2006

Exhibit 6.13 Protocol for Selecting Stage 2 DBPR (Subpart V) Compliance

Monitoring Sites

Steps1

[required by rule]

Stage 2 Compliance Monitoring

Sites Selected 2

1 Select the location with the highest TTHM LRAA 1st highest TTHM site

2 Select the remaining location with the highest HAA5

LRAA 

1st highest HAA5 site

3 For subpart H systems: Select the remaining existing

Stage 1 DBPR average residence time compliance

monitoring location with the highest HAA5 LRAA

For ground water systems: Select the remaining

existing Stage 1 DBPR maximum residence time

compliance monitoring location with the highest

HAA5 LRAA

Skip this step if you have no more Stage 1 DBPR sites

1st Stage 1 DBPR site

4 Select the remaining location with the next highest

TTHM LRAA.

2nd highest TTHM site

5 Select the remaining location with the next highest

TTHM LRAA

3rd highest TTHM site

6 Select the remaining location with the next highest

HAA5 LRAA

2nd highest HAA5 site

7 For subpart H systems: Select the remaining existing

Stage 1 DBPR average residence time compliance

monitoring location with the highest TTHM LRAA

For ground water systems: Select the remaining

existing Stage 1 DBPR maximum residence time

compliance monitoring location with the highest

TTHM LRAA

Skip this step if you have no more Stage 1 DBPR

2nd Stage 1 DBPR site

8 Select the remaining location with the next highest

HAA5 LRAA

3rd highest HAA5 site

If you need more Stage 2 DBPR compliance monitoring locations, Go back to Step 1 of this

protocol and repeat the steps until you have selected the required number of total sites.

1. All steps are based on your calculated LRAAs for your SSS monitoring sites and Stage 1 DBPR compliance

monitoring sites. This means that your existing Stage 1 DBPR sites can be selected in steps other than 3 or 7. Stop

when you reach your required number of Stage 2 DBPR compliance monitoring sites.

2. You cannot select the same site as a highest TTHM and a highest HAA5 compliance monitoring site. 
IDSE Guidance Manual for the Final Stage 2 DBPR 6-48 January 2006

IDSE Tool

6.6.5 Determining Your Stage 2 DBPR Compliance Monitoring Schedule

The first step in determining your Stage 2 DBPR compliance monitoring schedule is to

select your peak historical month. You should use the peak month for TTHM formation selected

in your SSS modeling plan unless new data suggest another month. Refer to Section 6.3 for

more information on determining peak historical month.

You must conduct Stage 2 DBPR compliance monitoring during the peak historical

month. If you are a ground water system that serves more than 9,999 people or you are a surface

water system that serves more than 499 people, you must also conduct Stage 2 compliance

sampling at 90 day intervals before and/or after the peak historical month. 

The intent of the required time interval is to ensure that samples are representative of the

quality of water over an extended period and do not over-emphasize either high or low

concentrations of TTHM or HAA5 that might occur seasonally. For example, a system on

quarterly monitoring could sample in the third full week of every third month. It is not

necessary to sample all sites on the same day.

6.7 Preparing the IDSE Report

Every system that conducts a modeling SSS must prepare and submit an IDSE Report. If

you will have completed all requirements of the IDSE by your plan submittal deadline, you may

submit completed forms or documentation for both the Modeling SSS Plan and IDSE Report for

a Modeling SSS at the same time. You should submit the report to the Information Processing

and Management Center (IPMC) for review by EPA or your state. See Section 1.4 of this

guidance manual for information on how to submit your report to the IPMC. 

EPA has developed an IDSE Report for a Modeling SSS Form (Form 5), presented in

this section and available electronically as part of the IDSE Tool. You are not required to use

this form; however, if you choose not to use it, refer to Exhibit 6.14 for a list of the minimum

elements you must include in your IDSE report. If any information has changed since submittal

of your modeling study plan, revised information must be submitted with the report. A major

component of the modeling study plan is to report on the final calibration of the hydraulic model

and its suitability for use in the required modeling analysis. If you use Form 5 in this section,

your IDSE report will contain all required information about your model. 

The IDSE Tool creates a custom form for your system and provides

links to technical guidance from this manual. The tool is available on EPA’s

website at http://www.epa.gov/safewater/disinfection/stage2.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-49 January 2006

Exhibit 6.14 Minimum Requirements for IDSE Report for a Modeling SSS

If you do not choose to use the IDSE Report for a Modeling SSS Form (Form 5), the

following information must be provided in your IDSE Report:

• Analytical results from Stage 1 DBPR compliance monitoring and SSS monitoring

in a tabular or spreadsheet format.

• An updated system schematic, if changed from your modeling study plan

(Required if you did not indicate SSS monitoring locations in your study plan).

• Final information on model requirements, calibration, and modeling analysis, if

changed or new since submittal of your study plan, including tables and graphs.

• A 24-hour time series graph of residence time for each Stage 2 DBPR compliance

monitoring location selected.

• Selected Stage 2 DBPR compliance monitoring locations and timing, including the

basis (analytical results and modeling) and justification for selection of those

locations.

• Population served and system type (subpart H or ground water) if changed from

your modeling study plan.

• An explanation of any deviations from your approved study plan.

Before you begin Stage 2 DBPR compliance monitoring, you will also be required to

prepare a Stage 2 DBPR compliance monitoring plan. In addition, if you are a subpart H system

serving >3,300 people, you must submit a copy of your Stage 2 compliance monitoring plan to

the state. If you include compliance calculation procedures in your IDSE report, the report can

meet the requirement of the plan, and you do not have to prepare or submit a separate plan. As a

guide for specifying your compliance calculation procedures, refer to the Stage 1 DBPR,

141.133(b), and your Stage 1 compliance monitoring plan. Check with your state, as they may

have different requirements under the Stage 2 DBPR. If you are a consecutive or wholesale

system, your state may choose to use its special primacy authority to modify your Stage 2

compliance monitoring requirements. In this case, you should check with the state to see if they

are going to use this authority. You should develop your IDSE report for the total number of

required Stage 2 compliance locations for your system. 
IDSE Guidance Manual for the Final Stage 2 DBPR 6-50 January 2006

The IDSE Report for a Modeling SSS Form (Form 5) includes the following sections:

I. General Information

II. SSS and Stage 2 DBPR Requirements

III. Modeling Information

IV. SSS Monitoring Location Selection

V. SSS and Stage 1 DBPR Compliance Monitoring Results

VI. Selection of Stage 2 DBPR Compliance Monitoring Locations

VII. Justification of Stage 2 DBPR Compliance Monitoring Sites

VIII. Peak Historical Month

IX. Proposed Stage 2 DBPR Compliance Monitoring Dates

X. Distribution System Schematic

XI. Attachments

If you are submitting an SSS plan and IDSE report at the same time, you must submit the

portions listed in bold above. Sections of the form with an asterisk (*) are required by the Stage

2 DBPR. An example of a complete IDSE report for a modeling SSS using this form is in

Appendix F.

I. General Information

I.A. PWS Information* - If nothing has changed since you completed your modeling

study plan, copy information from your plan into this section. If your system

characteristics have changed, see Section 6.4 of this chapter for guidance on

completing this section. 

I.B. Date Submitted* - Enter either the date that you are submitting the form

electronically, putting it in the mailbox, or dropping it off with an express

delivery service. Be sure to submit your IDSE report before the deadline found

on your requirements summary sheet.

I.C. PWS Operations - This section asks questions about your system to help inform

EPA and state personnel during the plan review process. If nothing has changed

since you completed your modeling study, copy information from your plan into

this section. If your system characteristics have changed, see Section 6.4 of this

chapter for guidance on completing this section. 

I.D. Contact Person* - Enter the contact information of the person who is submitting

the report. This should be the person who will be available to answer questions

from EPA and/or state reviewers. 
IDSE Guidance Manual for the Final Stage 2 DBPR 6-51 January 2006

II. SSS and Stage 2 DBPR Requirements*

II.A. Number of Required Stage 2 DBPR Compliance Monitoring Sites - Refer to the

System Specific Study Requirements - Attachment in Chapter 2. Copy the

numbers from the table that correspond to your source type and the population

served by your system. 

II.B. IDSE Schedule - This should be the same schedule you entered for your

modeling study plan. See Section 6.3 of this chapter for guidance. 

II.C. Stage 2 DBPR Compliance Monitoring Frequency - Refer to the System Specific

Study Requirements - Attachment in Chapter 2. From the “Stage 2 Compliance

Monitoring Requirements” table, locate the monitoring frequency that

corresponds to your source type and the population served by your system. Put a

check mark in the box corresponding to that monitoring frequency.

II.D. Number of Required SSS Samples - Enter the number of samples you were

required to collect during the peak month for TTHM formation.

III. Modeling Information

Systems with an approved model calibration as part of their modeling study plan do not

need to complete this section. If any of your information submitted as part of the

modeling study plan has changed, provide updated information in this section.

III.A. How was demand data assigned to the model? For each question, provide a brief

description of the data and methods used to assign customer demands to the

model.

III.B. Describe all calibration activities undertaken.* For each question, provide a brief

description of the data and methods used to calibrate your model.

If you did not complete calibration prior to your study plan submittal or if

your calibration has changed, submit a graph that documents your model

calibration by showing simulated tank levels versus observed levels for the

storage facility with the highest water age in each pressure zone of your system

(see Exhibit 6.5 for an example)*. 

Systems with an approved model calibration as part of their modeling study plan

do not need to complete this section.

III.C. How was the SSS modeling performed?* 

Systems with an approved model analysis as part of their modeling study plan do

not need to complete this section unless their information has changed. 
IDSE Guidance Manual for the Final Stage 2 DBPR 6-52 January 2006

Systems who conducted their water age modeling analysis after submitting their

modeling study plan should answer all questions.

• Submit model output showing final average water age results over a

24-hour period*. The 24-hour period used for the average water age

results table should represent a simulation time after the model has

achieved a stable, repeating water age pattern (e.g. the last 24 hours of the

simulation). EPA recommends that you submit this in tabular format to

not pose a security risk to your system.

• Submit a graph of water age versus time for the entire simulation

duration for the tank with the highest overall water age in the

system*. 

IV. SSS Monitoring Location Selection - Provide an explanation of the approach used to

analyze water age results to select SSS monitoring locations. Describe how sites were

ranked for water age (e.g. percentile, highest to lowest, etc.). Include any additional data

that was used to assist in the analysis, such as residual disinfectant concentration. 

Describe practical considerations such as accessibility, coverage of geographic areas, or

coverage of hydraulic zones that factored into the decision. 

V. SSS and Stage 1 DBPR Compliance Monitoring Results*

V.A. TTHM Results - Enter the TTHM results for each monitoring site for each

monitoring period in which you collected data. For each sample result, enter the

date on which sampling was conducted. You should enter all SSS monitoring

results as well as all Stage 1 DBPR compliance monitoring results collected

during the IDSE period. If you collected samples during a single monitoring

period, your LRAAs for those sites will be the same as the monitoring results. 

For each site ID, identify the location type (High TTHM, High HAA5, Average,

Entry Point).

V.B. HAA5 Results - Enter the HAA5 results for each monitoring site for each

monitoring period in which you collected data. For each sample result, enter the

date on which sampling was conducted. You should enter all SSS monitoring

results as well as all Stage 1 DBPR compliance monitoring results collected

during the IDSE period. If you collected samples during a single monitoring

period, your LRAAs for those sites will be the same as the monitoring results. 

For each site ID, identify the location type (High TTHM, High HAA5, Average,

Entry Point).

 

 V.C. Where were your TTHM and HAA5 samples analyzed? - Put a check mark in the

appropriate box to identify whether your system analyzed TTHM and HAA5

samples in an in-house laboratory or sent the samples to a certified laboratory for

analysis.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-53 January 2006

If you analyzed your TTHM and HAA5 samples in an in-house laboratory, check

the appropriate box to identify whether your laboratory is certified. If you sent

your TTHM and HAA5 samples to a certified laboratory, enter the name of the

laboratory in the blank. If you used more than one laboratory (e.g., if you used

different laboratories for SSS samples and Stage 1 DBPR compliance samples),

list both laboratories, or check “in-house” and list the name of the laboratory if

applicable.

V.D. What method(s) was used to analyze your TTHM and HAA5 samples? Put a

check mark in the appropriate box to indicate the analytical method used to

measure the TTHM and HAA5 concentrations of your SSS and Stage 1 DBPR

compliance samples. If more than one method was used (e.g., if you used

different laboratories for SSS samples and Stage 1 DBPR compliance samples),

check more than one method. If you do not know what method was used, contact

your laboratory.

VI. Selection of Stage 2 DBPR Compliance Monitoring Locations - Describe the

comparison of sampling and modeling results. Provide a description of the comparison

between sampling and modeling results, including any follow-up investigations done to

resolve discrepancies. See Section 6.3.3 for more information.

• You must submit a graph of water age versus time for each site selected*. You

should show the selected sites on the distribution system schematic and assign each

site a unique site ID (see Section XI). For security reasons, the graphs of water age

for each selected Stage 2 compliance monitoring site should not be identified by site

location number. A blind numbering system should be used on each graph, which 

you can discuss with EPA or your state if they contact you with questions about your

IDSE report.

VII. Justification of Stage 2 DBPR Compliance Monitoring Sites* - Enter the site ID from

the distribution schematic and the site category (highest TTHM, highest HAA5, or Stage

1 DBPR). You must provide a justification for each site including the modeling and

sampling results that led you to select it. See Section 6.4.4 of this manual for guidance. 

For example, a justification for a highest HAA5 site might be:

High average water age, high HAA5 results during monitoring, measurable residual in

historical TCR data, located in East Pressure Zone

Note that there is only space for 8 monitoring sites on this sheet. If you need more space,

attach additional sheets.

VIII. Peak Historical Month

VIII.A Peak Historical Month for TTHM and HAA5* - Enter the month that you

determined to be your peak historical month for TTHM and HAA5.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-54 January 2006

VIII.B Is Your Peak Historical Month the Same as Your Peak Month for TTHM

Formation in Your Modeling Study Plan? - Put a check mark in the appropriate

box to identify whether your system is using the same peak. If your SSS

monitoring results or other factors prompted you to select a different peak month.

explain how you selected a new peak month. Note that the modeling SSS was

based on using the peak month for TTHM formation for the modeling analysis. 

However, compliance with Stage 2 DBPR is based on the peak historical month

for TTHM and HAA5. You should use the same peak historical month that you

used for your SSS monitoring unless you have convincing data to do otherwise.

IX. Proposed Stage 2 DBPR Compliance Monitoring Schedule* - Enter the ID for each

Stage 2 DBPR compliance monitoring site in the table (these should match the ID’s you

enter in Section VII and on your schematic). Enter your proposed sampling schedule for

the number of monitoring periods identified in Section II.C. The entry can be a specific

date or week and can be in a number of different formats. For example:

• 7/9/07

• 2nd week in Nov ‘07

• Week of 7/9/07 

Remember that at least one monitoring period must be during the peak historical month

identified in Section VIII.A. Note that there is only space for 8 monitoring sites on this

sheet. If you are a subpart H system serving more than 249,999 people you are required

to monitor at more than 8 sites. Therefore, you will need to attach additional sheets.

X. Distribution System Schematic* A distribution system schematic is required only if it

has changed from your approved modeling study plan. If it has changed, you must attach

a distribution system schematic. If you did not show your SSS monitoring locations

on the distribution system schematic you submitted with your model study plan, you

must submit a revised distribution system schematic. See Section 6.4 of this manual

for guidance. 

XI. Attachments - Put a check mark in each of the boxes corresponding to any attachments

that you have included in your report.

Note that there is only space for 8 monitoring sites in Section V and Section VII. If you

need additional space you can attach additional sheets.

Note that some of the attachments are required by the rule.

If you deviated from your approved study plan, you must attach an explanation of all

deviations.

If you submit your IDSE report electronically, you also have the option to submit

attachments in hard copy. Include a note in your electronic IDSE report explaining that 

attachments are being submitted in hard copy, and mail the hard copy to the IPMC
IDSE Guidance Manual for the Final Stage 2 DBPR 6-55 January 2006

mailing address in your Requirements Summary Sheet. The IPMC will match the hard

copy submission with your electronic submission when it is received.

If you are a subpart H system serving >3,300 people, you must submit a copy of your

Stage 2 compliance monitoring plan to the state. If you include compliance calculation

procedures in your IDSE report, the report can meet the requirement of the plan, and you

do not have to prepare or submit a separate plan. As a guide for specifying your

compliance calculation procedures, refer to the Stage 1 DBPR, 141.133(b), and your

Stage 1 compliance monitoring plan. Check with your state, as they may have different

requirements under the Stage 2 DBPR. 

Enter the total number of pages in your IDSE report (including attachments) in the blank

at the bottom of this section. This will allow EPA or your state to ensure that all pages

were received.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-56 January 2006

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IDSE Guidance Manual for the Final Stage 2 DBPR 6-57 January 2006

Form 5: IDSE Report for a Modeling SSS Page 1 of 11

I. GENERAL INFORMATION

(Skip this section if you are submitting the plan and report at the same time)

A. PWS Information* B. Date Submitted* 

 PWSID:

PWS Name:

PWS Address:

City: State: Zip:

Population Served:

System Type: Source Water Type: Buying / Selling Relationships:

~ CWS ~ Subpart H ~ Consecutive System 

~ NTNCWS ~ Ground ~ Wholesale System 

 ~ Neither

C. PWS Operations

Residual Disinfectant Type: ~ Chlorine ~ Chloramines ~ Other:__________

Number of Disinfected Sources: ___ Surface ___GWUDI ___Ground ___Purchased

D. Contact Person*

Name:

Title:

Phone Number: Fax:

E-mail: 

II. SSS AND STAGE 2 DBPR REQUIREMENTS*

A. Number of Required Stage 2 DBPR Compliance Monitoring Sites TOTAL

 Highest TTHM: Stage 1 DBPR: 

 Highest HAA5: 

B. IDSE Schedule C. Stage 2 DBPR Compliance Monitoring Frequency

 ~ Schedule 1 ~ Once during peak historical month

 ~ Schedule 2 ~ Every 90 days (4 monitoring periods)

 ~ Schedule 3 D. Number of Required SSS Samples

 ~ Schedule 4 ______ TOTAL
IDSE Guidance Manual for the Final Stage 2 DBPR 6-58 January 2006

Form 5: IDSE Report for a Modeling SSS Page 2 of 11

III. MODELING INFORMATION

(Skip this section if you submitted a modeling study plan with an approved model calibration

and your information has not changed, or if you are submitting your plan and report at the

same time)

A. How was demand data assigned to the model? (attach additional sheets if

needed)

1. What method was used to assign

demands throughout the system?

2. How did you estimate diurnal

demand variation? How did you

determine total system demand?

3. How many demand categories did

you use?

4. How did you address large water

users?

B. Describe all calibration activities undertaken* (attach additional sheets if

needed)

1. When was the model last calibrated?

2. What types of data were used in the

calibration?

3. When was the calibration data

collected?

4. What field tests have been

performed to collect calibration data?
IDSE Guidance Manual for the Final Stage 2 DBPR 6-59 January 2006

Form 5: IDSE Report for a Modeling SSS Page 3 of 11

III. MODELING INFORMATION (Continued)

5. How did you determine friction

factors (C-factors)?

6. Was the calibration completed for

the peak month for TTHM

formation? If not, was the model

performance verified for the peak

month for TTHM formation?

7. How well do actual tank levels

correlate with predicted tank levels

during the peak month for TTHM

formation? 

Submit a graph of predicted tank

levels vs. measured tank levels

for the storage facility with the

highest water age in each

pressure zone.*

8. If you are using a water quality

model, what parameters are

modeled? How was the model

calibrated?
IDSE Guidance Manual for the Final Stage 2 DBPR 6-60 January 2006

Form 5: IDSE Report for a Modeling SSS Page 4 of 11

III. MODELING INFORMATION (Continued)

C. How was the SSS modeling performed?* (attach additional sheets as needed)

1. Was modeling done for the

operating conditions during the

peak month for TTHM formation*?

2. How were operational controls

represented in the model?

3. How was water age simulated

during the peak month for TTHM

formation (time steps, length of

simulation, etc.)? 

4. What are the average water age

results for your distribution

system? 

Submit final model output

showing 24-hour average

residence time throughout the

distribution system*.

Submit graph of water age at

the longest residence time

storage facility in the

distribution system showing

the predictions for the entire

EPS simulation period*.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-61 January 2006

Form 5: IDSE Report for a Modeling SSS Page 5 of 11 

IV. SSS MONITORING LOCATION SELECTION

How were the SSS monitoring locations selected? (attach additional sheets as needed)

1.

What model results were used as

the basis for selection? 

2.

What criteria were used in selecting

average residence time, high

TTHM, and high HAA5 sites?

3. What additional data was used in

the analysis, and how was it used?

4. How did you look at practical

considerations like accessibility of

sampling locations?

5. How did you verify that your

selected sampling locations

corresponded to the selected node

in your model?
IDSE Guidance Manual for the Final Stage 2 DBPR 6-62 January 2006

Form 5: IDSE Report for a Modeling SSS Page 6 of 11

V. SSS AND STAGE 1 DBPR COMPLIANCE MONITORING RESULTS*

A. TTHM Results

Site ID &

Category

Data Type TTHM (mg/L) LRAA

Sample Date

Sample Result

Sample Date

Sample Result

Sample Date

Sample Result

Sample Date

Sample Result

Sample Date

Sample Result

Sample Date

Sample Result

Sample Date

Sample Result

Sample Date

Sample Result

Sample Date

Sample Result

Sample Date

Sample Result

Sample Date

Sample Result

Sample Date

Sample Result

Attach additional sheets as needed for SSS and Stage 1 DBPR results.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-63 January 2006

Form 5: IDSE Report for a Modeling SSS Page 7 of 11

V. SSS AND STAGE 1 DBPR COMPLIANCE MONITORING RESULTS* (Continued)

B. HAA5 Results 

Site ID &

Category

Data Type HAA5 (mg/L) LRAA

Sample Date

Sample Result

Sample Date

Sample Result

Sample Date

Sample Result

Sample Date

Sample Result

Sample Date

Sample Result

Sample Date

Sample Result

Sample Date

Sample Result

Sample Date

Sample Result

Sample Date

Sample Result

Sample Date

Sample Result

Sample Date

Sample Result

Sample Date

Sample Result

Attach additional sheets as needed for SSS and Stage 1 DBPR results.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-64 January 2006

Form 5: IDSE Report for a Modeling SSS Page 8 of 11

V. SSS AND STAGE 1 DBPR COMPLIANCE MONITORING RESULTS* (Continued)

C. Where were your TTHM and HAA5 samples analyzed?

~ In-House

Is your in-house laboratory certified? ~ Yes ~ No

~ Certified Laboratory

Name of certified laboratory:

D. What method(s) was used to analyze your TTHM and HAA5 samples?

 TTHM HAA5

~ EPA 502.2 ~ EPA 552.1 ~ EPA 552.2

~ EPA 524.2 ~ EPA 552.3 ~ SM 6251 B

~ EPA 551.1

VI. SELECTION OF STAGE 2 DBPR COMPLIANCE MONITORING LOCATIONS

Describe the comparison of sampling and modeling results (attach additional sheets as

needed):

1.

How well did the sampling results

correspond to the modeling

results?

2.

For samples that did not match

well with model results, what

follow-up investigations were

performed?

3.

Were additional samples

collected? (Include data on table

in Section IV)

4.

Submit a graph of water age

versus time for each selected

sampling location*.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-65 January 2006

Form 5: IDSE Report for a Modeling SSS Page 9 of 11

VII. JUSTIFICATION OF STAGE 2 DBPR COMPLIANCE MONITORING SITES*

Stage 2

Compliance

Monitoring

Site ID

Site Type Justification

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

Attach additional copies of this sheet if you need more room.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-66 January 2006

Form 5: IDSE Report for a Modeling SSS Page 10 of 11

VIII. PEAK HISTORICAL MONTH

A. Peak Historical Month* 

B. Is Your Peak Historical Month the Same as your Peak Month in Your

Modeling Study Plan?

~ Yes ~ No

If no, explain how you selected your new peak historical month 

(attach additional sheets if needed):

IX. PROPOSED STAGE 2 COMPLIANCE MONITORING SCHEDULE*

Stage 2

Compliance

Monitoring

Site ID

Projected Sampling Date (date or week)1

period 1 period 2 period 3 period 4

 

1

 period = monitoring period. Complete for the number of monitoring periods from

Section II.C.

Attach additional copies of this sheet if you need more room.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-67 January 2006

Form 5: IDSE Report for a Modeling SSS Page 11 of 11

X. DISTRIBUTION SYSTEM SCHEMATIC*

(Skip this section if you submitted a modeling study plan and your distribution system

schematic was complete and has not changed from your approved modeling study plan, or if

you are submitting the plan and report at the same time)

ATTACH a schematic of your distribution system. If your schematic has changed or if

you did not show your SSS monitoring locations on the distribution system schematic

you submitted with your model study plan (Form 4), you must submit a revised

distribution system schematic. 

XI. ATTACHMENTS

~ Tabular or spreadsheet documentation that your model meets minimum calibration

requirements if updated since approved modeling study plan* (Section III). 

~ Additional sheets for explaining model information/results, including required graphs if

not submitted as part of an approved modeling study plan* (Section III). 

~ Additional sheets for sampling results, if needed (Section V).

~ Additional sheets for selection of Stage 2 DBPR compliance monitoring sites 

(Section VI).

~ Graph of water age versus time for all Stage 2 DBPR sites selected* (Section VI). 

~ Additional sheets for justification of Stage 2 DBPR Compliance Monitoring Sites, if

needed (Section VII). REQUIRED if you are a subpart H system serving more

than 249,999 people.

~ Additional sheets for explaining how you selected the peak historical month (Section

VIII). 

~ Additional sheets for proposed compliance monitoring schedule (Section IX). 

REQUIRED if you are a subpart H system serving more than 249,999 people.

~ Explanation of deviations from approved study plan.

~ Distribution system schematic* (Section X). REQUIRED if it has changed from

your approved model study plan or if monitoring locations were not shown.

~ Compliance calculation procedures (for Stage 2 Compliance Monitoring Plan). 

Total Number of Pages in Your Report: ______

Note: All items marked with an asterisk (*) are required by the rule.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-68 January 2006

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IDSE Guidance Manual for the Final Stage 2 DBPR 6-69 January 2006

6.8 Recordkeeping

The IDSE report for a modeling SSS must be kept on file for

10 years after the date it is submitted. If EPA or your state modifies

the recommendations made in your report or approves alternative

Stage 2 DBPR compliance monitoring locations, you must also keep

a copy of EPA or your state’s notification on file for 10 years after

the date of the notification. You must make your IDSE report and

any notification available for review by your state or the public.

The modeling study plan, including any modifications by

EPA or your state, must also be kept on file for as long as you are

required to retain your IDSE report for a modeling SSS. You must

make the plan and any modifications available for review by your state or the public.

6.9 Next Steps: Preparing the Stage 2 DBPR Compliance Monitoring Plan 

As the final step before you can begin compliance monitoring for the Stage 2 DBPR, you

must develop and implement a Stage 2 DBPR monitoring plan by the deadline provided in

your requirements summary sheet. The plan will be similar to your Stage 1 DBPR monitoring

plan in that it will identify how you intend to sample for compliance with Stage 2. You must

keep your plan on file for state and public review. If you are a subpart H system serving >

3,300 people, you must submit your plan to EPA or your state prior to when you are required to

start monitoring.

Exhibit 6.15 contains the minimum requirements for what must be included in your

Stage 2 DBPR compliance monitoring plan. Because compliance monitoring plans are not

addressed as part of the IDSE provisions of the Stage 2 DBPR, EPA has not included detailed

guidance for developing Stage 2 compliance monitoring plans in this guidance manual. 

EPA plans to develop other manuals and training that address the compliance monitoring

provisions of the Stage 2 DBPR.

See EPA’s website http://www.epa.gov/safewater/disinfection/stage2 for a up-to-date

inventory of Stage 2 DBPR guidance manuals and training materials, or call the Safe Drinking

Water Hotline at 1-800-426-4791.
IDSE Guidance Manual for the Final Stage 2 DBPR 6-70 January 2006

Exhibit 6.15 Required Contents of Stage 2 DBPR Compliance Monitoring Plans

All Systems Additional Requirements for Consecutive and

Wholesale Systems 1

• Monitoring locations

• Monitoring dates

• Compliance calculation

procedures

• If your state has used its special primacy

authority to modify your monitoring

requirements, you must include monitoring plans

for other systems in your combined distribution

system

1. See Appendix D of this manual for guidance specifically for consecutive and wholesale systems

References

R.M. Clark and W.M. Grayman. 1998. "Modeling Water Quality in Drinking Water Systems”, AWWA, Denver, CO



T.M. Walski, D.V. Chase, D.A. Savic, W. Grayman, S. Beckwith, E. Koelle. 2003. “Advanced Water Distribution 

Modeling and Management”, Haestad Methods, Waterbury CT: Haestad Press. 
IDSE Guidance Manual for the Final Stage 2 DBPR 7-1 January 2006

This chapter covers:

7.1 Selecting Standard Monitoring Sites and Preparing Your Standard

Monitoring Plan

N Form 6: Standard Monitoring Plan

7.2 Conducting Standard Monitoring

7.3 Selecting Stage 2 DBPR Compliance Monitoring Sites and Preparing the

IDSE Report

N Form 7: IDSE Report for Standard Monitoring

7.4 Recordkeeping

7.5 Next Steps: Preparing the Stage 2 DBPR Compliance Monitoring Plan

7.0 Standard Monitoring

Standard monitoring is one year of increased distribution system monitoring to find

locations with high total trihalomethane (TTHM) and haloacetic acid-five (HAA5)

concentrations. Results from standard monitoring will be used in conjunction with results from

Stage 1 compliance monitoring to select Stage 2 compliance monitoring locations. Any system

can conduct standard monitoring to meet the IDSE requirements of the Stage 2 Disinfectants and

Disinfection Byproducts Rule (DBPR).

If you have not already done so, you should complete the flowchart in Exhibit 2.3 of this

guidance manual. Depending on your system size and available data, you may have another

option for complying with IDSE requirements. The flowchart will help you select the most

appropriate IDSE option for your system and will direct you to a 2-page Requirements

Summary Sheet for your schedule. You will also be directed to the Standard Monitoring

Requirements - Attachment sheet containing detailed requirements for standard monitoring and

Stage 2 compliance monitoring (e.g., number of samples and sampling frequency). You should

keep these sheets handy as you work through this chapter. 

This chapter provides guidelines on how to select standard monitoring sites, prepare a

standard monitoring plan, conduct standard monitoring, select Stage 2 DBPR compliance

monitoring sites, and prepare the IDSE report. Appendices H and I support this chapter by

providing example standard monitoring plans and reports. Guidance for standard monitoring is

also available in the EPA manual, Initial Distribution System Evaluation Guide for Systems

Serving < 10,000 People. This guide is specifically targeted to small systems and contains an

example monitoring plan and report for a small surface water system.

It is important that consecutive and wholesale systems communicate with each other

throughout the IDSE process. If you are a consecutive or wholesale system, refer to Appendix

D for specific issues that you should consider.
IDSE Guidance Manual for the Final Stage 2 DBPR 7-2 January 2006

IDSE Tool

IMPORTANT: Results from IDSE standard monitoring should not be used to determine

compliance with maximum contaminant levels (MCLs) of the Stage 1 DBPR. Results must,

however, be included in the range of levels that you report in your Consumer Confidence Report. 

During the entire IDSE period, you must continue to monitor according to your Stage 1 DBPR

monitoring plan and comply with Stage 1 DBPR MCLs at your Stage 1 sites.

7.1 Selecting Standard Monitoring Sites and Preparing Your Standard

Monitoring Plan

Every system that conducts IDSE standard monitoring must prepare and submit a

Standard Monitoring Plan. You should submit the plan to the Information Processing and

Management Center (IPMC) for review by EPA or your state. See Section 1.4 of this guidance

manual for information on how to submit your plan to the IPMC.

This section contains EPA’s recommended technical approach for selecting standard

monitoring sites. It also contains the recommended approach for selecting the peak historical

month and scheduling standard monitoring. Lastly, this section provides guidance on

completing the IDSE standard monitoring plan.

EPA has developed a Standard Monitoring Plan Form (Form 6),

presented in Section 7.1.3 and available electronically as part of the IDSE Tool. 

You are not required to use this form; however, if you choose not to use it, refer to

Exhibit 7.1 for a list of the minimum elements you must include in your standard

monitoring plan. The IDSE Tool is available on EPA’s website at

http://www.epa.gov/safewater/disinfection/stage2. 

Exhibit 7.1 Required Elements of Your Standard Monitoring Plan

• The population served by your system

• Your system type (subpart H or ground water)

• A distribution system schematic showing 

- entry points

- sources 

- storage facilities

- locations and dates of all projected standard monitoring and Stage 1 DBPR

compliance samples

• Peak historical month

• Justification of standard monitoring site selection and a summary of data you

relied on to justify standard monitoring site selection
IDSE Guidance Manual for the Final Stage 2 DBPR 7-3 January 2006

7.1.1 Recommended Approach for Selecting Standard Monitoring Sites

You are required to select up to four types of standard monitoring sites for the IDSE: 

• near entry point 

• average residence time

• high TTHM

• high HAA5

Before you continue reading this chapter of the manual, you should use the IDSE Standard

Monitoring Table in the Standard Monitoring Requirements - Attachment sheet from Chapter 2

to determine how many of each type of site is required for your system. Remember that IDSE

standard monitoring requirements (i.e., the number of monitoring sites and sampling frequency)

are based on the population served by your individual system, not the largest population in your

combined distribution system. 

EPA’s recommended 8-Step technical approach for selecting standard monitoring sites

is summarized below and depicted graphically in Exhibit 7.2. The remainder of this section

contains detailed guidance for each of these eight steps.

1. Gather water quality data and system operating information including Stage 1

and historic DBP data from the last several years. You may also want to use advanced

tools (e.g., hydraulic model, tracer study data) if available. 

2. Use data sources and tools to select near entry point sites. 

3. Use data sources and tools to select candidate average residence time sites. Try to

identify at least twice as many candidate sites as are required for standard monitoring. 

4. Use data sources and tools to select candidate high TTHM sites. Try to identify at

least twice as many candidate sites as are required for standard monitoring. 

5. Use data sources and tools to select candidate high HAA5 sites. Try to identify at

least twice as many candidate sites as are required for standard monitoring. 

6. Plot the near entry point sites and all candidate sites on a map of your

distribution system. You should include your Stage 1 DBPR compliance

monitoring sites on the map so that you do not inadvertently select them as standard

monitoring sites. You may want to color-code candidate sites (e.g., by type of site or

data source).

7. Consider geographic coverage and other factors to select standard monitoring sites

from candidate sites.

8. Write your justifications for site selection and summary of data that you relied on

to select standard monitoring sites.
IDSE Guidance Manual for the Final Stage 2 DBPR 7-4 January 2006

Step 1: Gather Data 

and Tools

-Water quality data

-System information

-Advanced tools

Step 2: Select 

Near Entry 

Point Sites

Step 3: Select 

Candidate Sites

for

Average Residence 

Time

Step 4: Select 

Candidate Sites

for

High TTHM

Step 5: Select 

Candidate Sites

for

High HAA5

Step 7: Select 

Standard

Monitoring Sites

Step 8: Write 

justification and 

summary of data

Also plot Stage 1 compliance 

monitoring sites. 

Plot near entry point and 

candidate sites. 

Step 6: Plot

Candidate Sites 

Step 1: Gather Data 

and Tools

-Water quality data

-System information

-Advanced tools

Step 2: Select 

Near Entry 

Point Sites

Step 3: Select 

Candidate Sites

for

Average Residence 

Time

Step 4: Select 

Candidate Sites

for

High TTHM

Step 5: Select 

Candidate Sites

for

High HAA5

Step 7: Select 

Standard

Monitoring Sites

Step 8: Write 

justification and 

summary of data

Also plot Stage 1 compliance 

monitoring sites. 

Plot near entry point and 

candidate sites. 

Step 6: Plot

Candidate Sites 

Also plot Stage 1 compliance 

monitoring sites. 

Plot near entry point and 

candidate sites. 

Step 6: Plot

Candidate Sites 

Exhibit 7.2 Recommended Approach to Selecting Standard Monitoring Sites

Remember that Stage 1 DBPR compliance monitoring sites cannot be used as standard

monitoring sites.
IDSE Guidance Manual for the Final Stage 2 DBPR 7-5 January 2006

Step 1: Gather Data and Tools

There are many kinds of data and tools that can be useful in selecting standard

monitoring sites. Exhibit 7.3 shows the types of information typically available to water systems

and for which types of sites they should be used. 

One of the most important tools you can use to select standard monitoring sites is an upto-date, detailed map of your distribution system. When you submit your standard monitoring

plan, you are required to include a schematic of your distribution system showing all entry

points, sources and storage facilities. Other useful map features include the layout of pipes,

locations pump stations, pressure zone boundaries, locations of large users, and population

density information. For security reasons, EPA recommends that you remove any information

that could pose a security risk from your standard monitoring plan submittal. You may wish to

use a separate, working version of your distribution system map for selecting sites, then transfer

your information to a less detailed map for your standard monitoring plan submittal.

It is important that you consider available water quality data from your distribution

system when selecting standard monitoring sites. In general, your water quality data should be

less than 10 years old and should represent current system configurations to the extent possible. 

Most systems have collected disinfectant residual data from their distribution system, and this

data can be very useful for selecting standard monitoring locations. EPA has provided additional

guidelines for evaluating disinfectant residual data in Step 3.

Systems with multiple entry points that have different source water characteristics may

find source water data quite useful for selecting standard monitoring sites. For instance, if a

system has one surface water source and one ground water source, entry point sampling may

indicate the surface water source produces much higher TTHM and HAA5 levels than the

ground water source. Therefore, the water system may use this information to justify why a

significant proportion of distribution system sample sites are served by the surface water plant. 

Some systems, such as those that serve resort communities, have dramatic fluctuations in

flow as well as population. If your system experiences widely varying demands on a seasonal

basis, you should evaluate data and operational information for different seasons separately. 

When you are selecting sites, make sure that you select sites that represent the different operating

scenarios of your system. 
IDSE Guidance Manual for the Final Stage 2 DBPR 7-6 January 2006

Exhibit 7.3 Data and Tools for Selecting Different Types of 

Standard Monitoring Sites

Type of Information Type of Standard Monitoring Site

Near Entry

Point

Average

Residence Time

High 

TTHM

High

HAA5

System Configuration

Pipe layout, location of storage facilities x xx

Location of sources x x xx

Pressure Zones x xx

Information on Population Density x xx

Locations of Large Customers x

Water Quality and Operational Data

Disinfectant Residual Data x xx

Stage 1 DBP Data x x

Other DBP Data x x

Microbiological Monitoring Data (e.g., HPC) x

Tank Level Data, Pump Run Times x xx

Customer Billing Records x xx

Advanced Tools

Water Distribution System Model x xx

Tracer Study x xx

Water distribution system models (e.g., hydraulic models and water quality models) and

tracer studies can be very useful in selecting average residence time and high TTHM and HAA5

sites. Hydraulic models can be used to estimate typical residence time at various locations in

your distribution system. A tracer study can provide a snapshot of water age at different

locations in your distribution system. These tools have limitations, however, and should be used

with caution. Some general guidelines are provided below. 

• If your hydraulic model has not been recently calibrated or is highly skeletonized,

you may want to rely on other types of information for selecting sites, or use

modeling results in conjunction with other data. 

• It is important that the hydraulic model and tracer study represent the current

distribution system configuration. If your system has undergone major changes (e.g.,
IDSE Guidance Manual for the Final Stage 2 DBPR 7-7 January 2006

new tank, new pump station, major system improvement projects) since the model

was developed or the tracer study was conducted, consider using other data and tools

to select standard monitoring sites.

Chapter 6 provides detailed guidelines on using distribution system hydraulic models for the

IDSE and includes a list of technical references. Several books on distribution system modeling

also contain information on tracer studies, such as the AWWA Manual M32, Computer

Modeling of Water Distribution Systems, 2nd Edition, 2005 and Advanced Water Distribution

Modeling and Management (Walski et al., 2003).

A key resource available to many systems is the experience and knowledge of water

system personnel. Because distribution system operations and configuration are not always

well documented, experienced operations personnel can provide valuable insights to the site

selection process.

Step 2: Identify Near Entry Point Standard Monitoring Sites

Data from sites near the entry points to the distribution system represent minimum

residence time and can be used as a baseline for interpreting changes in water quality as water

travels through the system. EPA recommends that you use the following procedure to select

near entry point standard monitoring sites.

Step 2a. Determine How Many Near Entry Point Sites You Need for Standard Monitoring

Determine how many near entry point standard monitoring sites you are required to have

by referring to the Standard Monitoring Requirements - Attachment sheet in Chapter 2. 

Remember that IDSE monitoring requirements (i.e., the number of monitoring sites and

sampling frequency) are based on the population served by your individual system, not the

largest population in your combined distribution system. Note the special requirements for small

consecutive systems to monitor at their consecutive system entry point.

Step 2b. Determine How Many Entry Points are in Your System

For the purposes of the IDSE, entry points are the locations where disinfected water

enters your distribution system. Entry points can convey treated surface water, disinfected water

from wells, or purchased water from a wholesale system (as long as it has been disinfected). 

Entry points generally include seasonal or intermittent connections. If a well is not disinfected

or is disinfected using ultraviolet light (UV) only, you should not consider it an entry point for

the purposes of the IDSE.

Step 2c. Compare Results from Step 2a to Step 2b

• If the number of near entry point sites required matches the number of entry points in

your system, select a standard monitoring location near each entry point.
IDSE Guidance Manual for the Final Stage 2 DBPR 7-8 January 2006

Example 7.1 System with Fewer Entry Points than Required Near Entry Point

Standard Monitoring Sites

A system has one surface water source and serves 260,000 people. According to the

Standard Monitoring Requirements - Attachment sheet in Chapter 2, the system must select

4 near-entry point sites, 6 average residence time sites, 8 high TTHM sites, and 6 high HAA5

sites. However, the system has only one source with one entry point. This system must select

its 1 near entry point site. Then it must replace the remaining 3 near entry point sites as

follows: 2 high TTHM sites and 1 high HAA5 site. The system must therefore collect a total

of 10 high TTHM sites, 7 high HAA5 sites, and 6 average residence time sites to go along

with its 1 near entry point site.

• If your system has FEWER entry points than required near entry point standard

monitoring locations, you must replace the unassigned near entry point sites with

high TTHM and HAA5 standard monitoring sites to maintain the required total

number of standard monitoring sites for the IDSE. If you have an odd number of

unused near entry point sites, select an additional high TTHM site. See Example 7.1

for how a hypothetical system used this procedure to replace near entry point sites

with high TTHM and high HAA5 sites for standard monitoring. 

• If your system has MORE entry points than required near entry point standard

monitoring locations, you must take samples near entry points to the distribution

system having the highest annual water flows.

Annual flows may be calculated based on measured flows if your system has a flow

meter for each entry point location, pump or hour meter records, or other means. If

you have a totalizing flow meter at an entry point, you may use the most recent year’s

readings from each meter if the measurements are representative of normal operating

conditions. For entry points where a totalizing water meter is not available, you may

use pump records or other water meter records to estimate the annual flow. You

should begin by determining the average daily flow for each entry point. Then

multiply the average daily flow at each entry point by the number of days that the

entry point was in use to determine the annual flow. See Example 7.2 on the next

page for how a hypothetical system used this procedure. Consecutive systems may

need to check with wholesalers or check records of billings/deliveries from

wholesalers.

The Stage 2 DBPR does not define near entry point sites explicitly. EPA recommends

that you locate your near entry point sites between the entrance to the distribution system and 

no later than first customer. If you are a consecutive system, a sample tap at the master meter

would be an appropriate near entry point site. If you do not have a sample tap at your master

meter, consider using the first customer as your near entry point site.
IDSE Guidance Manual for the Final Stage 2 DBPR 7-9 January 2006

Example 7.2 System with More Entry Points than Required Near Entry Point

Sample Sites

A system has two ground water sources and serves 15,000 people. According to the

Standard Monitoring Requirements - Attachment sheet in Chapter 2, the system must select 1

near entry point site. For the most recent year, approximately 70 percent of the system’s water

came from Well A and the remaining 30 percent came from Well B. This system should

locate its near entry point site near Well A because this source has the higher annual flow.

Step 3: Identify Candidate Average Residence Time Sites

Average residence time is the average age of water delivered to customers in a

distribution system. Average residence time is not simply one-half the maximum residence time. 

Ideally, it should be a flow-weighted or population-weighted estimate. EPA recognizes that

locating average residence time sites can be complex. A system map, used in conjunction with

disinfectant residual data and possibly hydraulic modeling (if available) can help you to identify

areas that represent average water age.

EPA recommends that you use tools and data sources available to select at least twice as

many candidate average residence time sites as required for standard monitoring. You may want

to map and color-code your candidate sites as you select them to ensure that your distribution

system is fully represented. Later, you can use additional criteria to select the most

representative standard monitoring sites from these candidate sites (see Step 7). 

Step 3a: Use a Hydraulic Model or Tracer Study Data, if Available 

One of the best ways to identify candidate average residence time sites is by using a

hydraulic model. If run in extended period simulation mode, the model should be able to

provide estimates of typical residence time for each node in the model. See Chapter 6 for more

information on estimating residence time using hydraulic models. Also refer to Step 1 for

cautions on using model results.

A tracer study can provide a snapshot of water age at different locations in your

distribution system. You can use tracer study results along with information on population

density and locations of large users (see Step 3c) to identify the average residence time of water

in your distribution system. Remember, though, that tracer studies done in the past may no

longer be representative of your system. 
IDSE Guidance Manual for the Final Stage 2 DBPR 7-10 January 2006

Step 3b: Examine Disinfectant Residual Data

You can identify approximate average residence time locations in your distribution

system by calculating the average disinfectant residual concentration in your system and

identifying sites with residual concentrations near the average. When calculating average

disinfectant residual, it is important that you use data from sites that are representative of the

entire distribution system. One way to do this is by examining disinfectant residual data

collected at TCR monitoring sites. These data should be useful since the TCR requires that

monitoring sites represent water throughout the distribution system. Note that if you have

booster disinfection, then residual data collected after those locations will skew this analysis. 

That data should be omitted.

See the guidelines in Exhibit 7.4 for using disinfectant residual data. If you believe that

your residual data correlates well with water age, you can use the following analysis to help

identify sites with average residence time (also see Example 7.3):

1) Calculate an average disinfectant residual at each of the TCR sites using data from

the months with the warmest water temperatures. Chlorine decay is more pronounced

in warmer temperatures so it is more common to see larger changes in chlorine

residual from one point to the next.

2) Using averages from the individual sites, calculate an overall average distribution

system residual concentration. 

3) Those sites with an average residual close to the distribution system average can be

considered representative of average residence time in the distribution system. Select

sites in areas with high population densities with disinfectant residuals close to the

system average.

Caution for systems using chloramines 

Chloramines are generally more stable than chlorine and may result in only small measured

differences throughout the distribution system. In this case, the method described above may not

be effective for locating average residence time sites because the change in disinfectant residual

concentration is not significant. 
IDSE Guidance Manual for the Final Stage 2 DBPR 7-11 January 2006

Exhibit 7.4 Guidelines for Using Disinfectant Residual Data

When should I use disinfectant residual data?

Disinfectant residual in the distribution system generally decays as water age increases. 

Residual concentrations typically decay faster in the warmer months, and the magnitude of

decay is more pronounced for free chlorine residuals compared to chloramine residuals. 

 Disinfectant residual can be helpful in locating areas of average and maximum

residence time in the distribution system. This information can be used to select candidate

average residence time, high TTHM, and high HAA5 sites.

Because disinfectant residual decay can be caused by factors other than residence time,

you should be careful when interpreting your data. Other reasons why you might see a loss in

disinfectant residual are listed below.

• Certain types of pipe material can exert a disinfectant residual demand. In

particular, unlined cast iron pipe can cause residuals to decline. 

• Residual decline can be caused by corrosion byproducts and sediment. Customer

complaints may indicate that these are occurring in your distribution system.

• Bacteriological activity can result in a significant depletion of disinfectant residual. 

HPC data is useful for determining whether this is a concern in your distribution

system.

What are the sources of disinfectant residual data?

Residual data can be from TCR sites, Stage 1 sites, operational sample sites, or sites

sampled following customer complaints. 

Which data should I use to help identify candidate average residence time sites?

If you are using residual data to help identify sites with average water age, make sure

that data is from locations distributed throughout the system. You may want to use only data

from TCR sites, since these sites should be geographically representative of your system.

Make sure you don’t over emphasize a particular area. You should also use data from the

warmest months that show the biggest differences in residual levels.

What if I don’t have residual data throughout the system?

You may wish to take more residual data. Take care to ensure that the data is

comparable in terms of analytical method, distribution system configuration, and time of the

year to the data to which it will be compared.
IDSE Guidance Manual for the Final Stage 2 DBPR 7-12 January 2006

 Monthly Average (mg/L)

Jun Jul Aug

#1 1.4 1.3 1.6 1.4

#2 0.7 0.9 0.7 0.8

#3 1.0 0.9 1.2 1.0

#4 0.6 0.6 0.7 0.6

#5 0.9 1.2 1.4 1.2

#6 0.4 0.5 0.4 0.4

#7 0.2 0.3 0.6 0.4

#8 1.5 1.7 1.7 1.6

#9 0.9 0.7 0.8 0.8

#10 0.5 0.3 0.8 0.5

Distribution 

System Ave

0.8 0.8 1.0 0.9

Site Average 

(mg/L) Site ID

Example 7.3 Average Disinfectant Residual Calculation

A system with June, July, and August as its warmest months has free chlorine residual

data at 10 sites. The residual concentrations are recorded below, and the averages for each

site and the system as a whole are calculated as shown. Note that sites #2, #3, and #9 have

average chlorine residual concentrations close to the system average. These sites are good

candidate average residence time sites.

Step 3c: Use Billing Records and a Map or Schematic

You can use billing records and information on population density, together with a map

of your system, to rule out locations for average residence time sites. You should examine your

customer billing records to determine where your large customers are located. The portions of

the distribution system serving large water users will likely have low water age and will not be

good candidate sites for average residence time. The portions of the distribution system that are

sparsely population will likely have high water age and will also not be good candidates for

average residence times. You should consider the locations of storage tanks and the sizes of

distribution system mains to the extent possible.

If your system does not have any large individual customers, you should consider

locating your candidate sites in moderately developed areas in the approximate geographic

center of the distribution system.
IDSE Guidance Manual for the Final Stage 2 DBPR 7-13 January 2006

Step 4: Identify Candidate High TTHM Sites

It is not the intent of IDSE monitoring to identify sites with maximum daily or hourly

TTHM concentrations. Instead, you should choose candidate sites to represent areas of the

distribution system where you expect to find the highest TTHM levels throughout the year. 

In general, higher water temperatures and increased water age lead to higher TTHM

concentrations in distribution systems. Exhibit 7.5 provides typical characteristics of high

TTHM sites, and Appendix A provides additional background information on TTHM formation. 

Steps 4a through 4c below discuss how different types of data can be used to select

candidate high TTHM sites. Each tool and data source has its own limitations; EPA

recommends that you use all of the tools and data sources available to select at least twice as

many candidate high TTHM sites than required for standard monitoring. Later, you will use

additional criteria to select the best standard monitoring sites from these candidate sites and

determine whether all standard monitoring sites are representative of the entire distribution

system (see Step 7). You may also want to map and color-code your candidate sites as you

select them to ensure that your distribution system is fully represented. 

Step 4a: Use a Hydraulic Model or Tracer Study Data, if Available

Calibrated, system specific hydraulic models can be very useful in identifying locations

of maximum water age that would be good candidate high TTHM sites. If run in extended

period simulation mode, the model should provide estimates of typical residence time for each

node in the model. You should select candidate sites near the nodes with the longest residence

times, provided that they are prior to the last fire hydrant and before or at the last group of

customers. Chapter 6 of this guidance manual provides more details on estimating residence

time using hydraulic models. Also refer to Step 1 for cautions on using model results.

Exhibit 7.5 Typical Characteristics of High TTHM Sites

High TTHM sites are often located

• hydraulically downstream of storage facilities and booster disinfection

• in hydraulic dead-ends, where flow of water is low or stagnant

• near the ends of the distribution system, at or before the last group of customers

Sample sites should not be located

• at a dead-end where there are no customers.

• prior to booster disinfection with chlorine 

• after the last hydrant or blow-off point
IDSE Guidance Manual for the Final Stage 2 DBPR 7-14 January 2006

A tracer study can provide a snapshot of water age at different locations in the

distribution system. The locations with highest water age typically should make good candidate

high TTHM sites. Remember, though, that tracer studies done in the past may no longer be

representative of your system. 

Step 4b. Use Residual Disinfectant Data

Low disinfectant residuals relative to the system average may indicate longer residence

times, and may correlate with higher TTHM concentrations. Because disinfectant residuals

typically decay faster during the summer, a review of data from the summer months may be

useful in identifying areas with consistently low residuals that are good candidate high TTHM

sites. You should evaluate residual data with caution, however, because disinfectant residual

decay can be caused by factors other than water age (e.g., corrosion, bacteriological activity). 

See Exhibit 7.4 for guidelines on using disinfectant residual data as indicators of water age. 

When booster disinfection is applied, the disinfectant residual will increase despite

advanced water age. TTHM levels are likely to increase after a booster disinfectant is applied

due to the greater concentration of disinfectant available for reaction with DBP precursors. 

Therefore, if your system practices booster disinfection, you should locate high TTHM standard

monitoring sites after booster disinfection is applied.

Step 4c: Use a Map or Schematic and Infrastructure Data

If your system practices booster disinfection, you should locate candidate sites

downstream of your booster disinfection stations. 

If your system has storage tanks or reservoirs, you should locate candidate high TTHM

sites hydraulically downstream of those tanks. Storage facilities in a distribution system increase

water age. During tank drain cycles, water age immediately downstream of a storage facility

may be significantly (e.g., several days or more) older than “fresh” water upstream of the storage

facility. As a result, areas of a distribution system receiving water that has been stored may have

higher TTHM concentrations than areas that do not receive any stored water.

You should also locate candidate sites near dead ends, particularly those that are on

smaller lines, far from major transmission lines. Sparsely populated residential areas can be

good candidate sites for high TTHM. However, be sure to locate the candidate sites before or at

the last group of customers on a dead end line. Samples taken at the very end of a dead end line

are not representative of the water received by customers.

Step 5: Identify Candidate High HAA5 Standard Monitoring Sites

As with high TTHM standard monitoring sites, it is not the intent of IDSE monitoring to

identify sites with maximum daily or hourly HAA5 concentrations. Instead, you should choose

high HAA5 standard monitoring sites to represent areas of the distribution system where you

expect to find the highest HAA5 levels throughout the year. 
IDSE Guidance Manual for the Final Stage 2 DBPR 7-15 January 2006

Higher temperatures and increased residence time can lead to higher HAA5

concentrations. However, microorganisms can consume HAA5, causing levels to decrease. This

is know as biodegradation. Biodegradation is more likely to occur when disinfectant residual

levels are low or non-existent, particularly in warmer months. Therefore, high HAA5 sites may

be located closer to the entrance to the distribution system rather than locations with very high

water age. See Appendix A for more information on HAA5 formation.

Steps 5a through 5e below discuss how different types of data can be used to select

candidate high HAA5 sites. Each tool and data source has its own limitations. EPA

recommends that you use all of the tools and data sources available to select twice as many

candidate high HAA5 sites than required for standard monitoring. Later, you will use additional

criteria to select the best standard monitoring sites from these candidate sites (see Step 7). You

may also want to map and color-code your candidate sites as you select them to ensure that your

distribution system is fully represented. 

Remember that high HAA5 sites must be different from high TTHM sites for IDSE standard

monitoring.

Step 5a: Review Historical HAA5 Data to Identify Trends

One way to determine if HAA5 biodegrades in your system is to examine Stage 1 DBPR

monitoring or other HAA5 data. You should evaluate the data over time at different locations in

the distribution system to look for trends. Consider evaluating your data to answer the following

questions:

• Are the highest HAA5 values typically in the summer months?

• Are the highest HAA5 values at maximum residence time locations?

• Do the highest HAA5 generally occur at the same time of year and locations as high

TTHM values?

If you answered “yes” to all of these questions, it is unlikely that you are experiencing

biodegredation of HAA5 at your existing monitoring sites. If you answered “no” to any of these

questions, HAA5 compounds may be degrading in your system due to biological activity. In

this case you should focus on selecting sites with lower water age compared to sites you selected

for high TTHM. It is important that you also evaluate disinfectant residual data and

microbiological monitoring data (e.g., HPC data), if available, to determine whether a

monitoring location is appropriate. 

Step 5b. Use a Hydraulic Model or Tracer Study

Calibrated, system specific hydraulic models can be very useful for identifying locations

of maximum residence time. If run in extended period simulation mode, the model should

provide estimates of typical residence time for each node in the model. Chapter 6 of this
IDSE Guidance Manual for the Final Stage 2 DBPR 7-16 January 2006

guidance manual provides more details on estimating residence time using hydraulic models. 

Also refer to Step 1 for cautions on using model results.

You should consider selecting high HAA5 candidate sites near the nodes with the longest

residence times, provided that they are prior to the last fire hydrant and before or at the last

group of customers. You should examine chlorine residual data and HPC data if available to

ensure that these locations are not susceptible to biodegradation (see Steps 5c and 5d). However,

if you have determined that biodegradation is occurring in your distribution system in step 5a,

you should focus on sites with lower water age.

A tracer study can provide a snapshot of water age at different locations in the

distribution system. The locations with highest water age typically should make good candidate

sites, unless disinfectant residual levels are too low. Remember, though, that tracer studies done

in the past may no longer be representative of your system. 

Step 5c. Use Residual Disinfectant Data

Low disinfectant residuals relative to the system average may indicate longer residence

times, and may correlate with higher HAA5 concentrations (unless biodegradation is occurring

in the distribution system as discussed in step 5a). Sites with very low or non-existent residuals,

however, are more likely to have biodegradation of HAA5 and would not be good candidate high

HAA5 sites.

You should not select high HAA5 sites in locations that regularly or in the summer months have

free chlorine residuals less than 0.2 mg/L or with chloramine residuals less than 0.5 mg/L. 

Because disinfectant residuals typically decay faster during the summer, a review of data

from the summer months may be useful in identifying areas with consistent disinfectant residuals

that are good candidate high HAA5 sites. You should consider locating candidate high HAA5

sites where disinfectant residuals are less than the system average, but still regularly above 0.2

mg/L for free chlorine systems and above 0.5 mg/L for chloramine systems. 

When booster disinfection is applied, the disinfectant residual will increase despite

advanced water age. HAA5 levels are likely to increase after a booster disinfectant is applied

due to the greater concentration of disinfectant available for reaction with DBP precursors and

decreased potential for biodegradation. Therefore, if your system practices booster disinfection,

you should locate high HAA5 standard monitoring sites after booster disinfection is applied.

Step 5d. Use Heterotrophic Plate Count Data, if Available

In addition to disinfectant residual data, HPC data can be extremely useful for identifying

areas in your distribution system that are biologically active. If locations in the distribution

system have high HPC levels compared to other locations (particularly in the summer months),

they should be excluded as candidate high HAA5 sites. 
IDSE Guidance Manual for the Final Stage 2 DBPR 7-17 January 2006

Step 5e. Use a Map or Schematic and Infrastructure Data

Geographic locations for high HAA5 sites depend on whether your system experiences 

biodegredation in the distribution system. See Step 5a for guidance on evaluating historical

HAA5 data for trends, and Steps 5c and 5d to evaluate other data to assess the potential for

biodegredation. 

If you do not believe that HAA5 biodegrades in your system, follow the same general

guidelines for locating high TTHM sites for locating high HAA5 sites (see Step 4c). If you do

believe that HAA5 biodegrades in your system, you should consider locating HAA5 sites in

areas with lower water age in the center regions of your system where you maintain high

disinfectant residuals. 

Step 6: Plot Sites on a Distribution System Map 

A key step in selecting standard monitoring sites from candidate sites is plotting all

candidate sites on a map of your distribution system. If you have not already done so, locate all

Stage 1 DBPR compliance monitoring locations, near entry point sites, and candidate average

residence time, high TTHM, and high HAA5 sites on your water distribution map. Consider

color coding the sites by the site type. 

As noted in Step 1, your map should also contain the system attributes that will be useful

in identifying representative standard monitoring sites, such as:

• Layout of pipes

• Storage facilities

• Pumping stations

• Booster disinfection stations

• Pressure zone boundaries

If possible, your map should also include the location of large water users, areas of significant

development, and areas with relatively few customers.

Step 7: Select Standard Monitoring Sites from Candidate Sites

As described in the previous sections, various data sources and tools can be used to

identify standard monitoring sites. If you followed the recommended procedures, you should

have more candidate sites than are required for standard monitoring. This will allow you to

select a final set of standard monitoring locations that represents the entire distribution system,

considering the whole picture in addition to the specific characteristics you examined in steps 3

through 6. How should you prioritize the data and combine data sources and tools to select

standard monitoring sites? This section addresses this question by providing general guidelines

for (1) evaluating sites and determining if they meet expectations, and (2) narrowing down the

candidate sites to standard monitoring sites. Remember that you must write a justification for

each standard monitoring site and a summary of data considered (see Step 8), to be included in
IDSE Guidance Manual for the Final Stage 2 DBPR 7-18 January 2006

your IDSE standard monitoring plan. You may want to consider how you will write your

justifications as you examine your candidate sites.

You should always visually confirm that standard monitoring sites, in combination with

existing Stage 1 DBPR monitoring sites, provide geographic coverage of the distribution system. 

You should also visually confirm that standard monitoring sites are in expected areas of high and

average residence time (as predicted by a hydraulic model or other data source). You should

confirm that you are not missing key areas that may not have been sampled in the past. If you

have GIS capabilities, queries can be extremely useful in automating the site selection process. 

Experienced systems operations personnel can provide valuable input during this process.

The following are general guidelines for choosing standard monitoring sites from the list

of candidate sites identified. 

Step 7a. Evaluate Sites. Do They Meet Expectations?

The purpose of this step is to confirm that your candidate sites cover key areas and to add

candidate sites if appropriate. The following questions may be useful as you evaluate all

candidate sites together on the map:

• Are candidate high TTHM sites located in the extremities of the distribution system? 

• Are candidate high TTHM sites generally downstream of storage facilities and

booster disinfection stations (if booster disinfection is practiced)?

• Are candidate high HAA5 sites in areas where you can regularly maintain

disinfectant residual levels greater than 0.2 mg/L for chlorine and 0.5 mg/L for

chloramine?

• Are there any other areas where you suspect water age is high that are not represented

by a candidate high TTHM (and possibly high HAA5) site?

Step 7b. Select Standard Monitoring Sites

Now that you have plotted the candidate sites on the map, you will need to choose the

best locations to represent each type of site. The following issues should be considered when

making these choices:

• Look for geographic representation. Select sites that are geographically diverse

from the other standard monitoring sites and existing Stage 1 compliance monitoring

locations. EPA recommends that you locate at least one of the high TTHM standard

monitoring sites in a remote area of the distribution system. If your distribution

system contains hydraulically isolated portions, you should represent as many of

these as possible with at least one standard monitoring site. If you are only required

to select one high TTHM site, it is strongly recommended that you locate this site far
IDSE Guidance Manual for the Final Stage 2 DBPR 7-19 January 2006

away from the treatment plant, near the last group of customers (but prior to the last

fire hydrant).

• Look for hydraulic representation. Select standard monitoring sites in

hydraulically different areas. Even if sites are geographically near each other, they

may represent different pressure zones. You should also select sites that represent

mixing zones if multiple sources with different water quality characteristics are used.

• Use sites that “multi-task.” Prioritize sites that meet the multiple siting criteria and

those identified based on more than one data source. For example, a candidate high

TTHM site that has low disinfectant residual, is near the edge of the distribution

system and is downstream of a tank would be an excellent standard monitoring site.

• Consider site access. Select standard monitoring sites for which access will not be

an issue. Sites should remain accessible over the long term.

• Use existing TTHM and HAA5 monitoring data to prioritize choices. If you have

more than enough sites in a given area of the distribution system and no other data

favors one over the other, use existing TTHM or HAA5 monitoring results (if

available) to prioritize sites. For example, if disinfectant residual data are the same

for three sites over the same periods, then the DBP data can be used to select a high

TTHM or HAA5 standard monitoring site. Remember that you cannot use Stage 1

DBPR compliance monitoring sites as standard monitoring sites.

Step 8: Write Justifications and a Summary of Data

Your final steps in selecting standard monitoring sites are to write a justification for each

site and write the summary of data you used to justify your site selection. 

Step 8a. Write Justification for Each Standard Monitoring Site

You must write a justification for each standard monitoring site. Justifications should

document the key site characteristics that led you to select the site for standard monitoring. They

should be brief, but as specific as possible. Some characteristics you should consider including

in your justifications are as follows:

• Pipe size, or range of pipe sizes in the area

• Relationship to storage facilities

• Estimated water age, if available

• Source of water (if the distribution system is served by more than one source)

• Range of disinfectant residual concentrations (if lower in the summer, provide

summer values)

• For HAA5 sites, range of HPC levels, if available
IDSE Guidance Manual for the Final Stage 2 DBPR 7-20 January 2006

Not all systems will have all data types in this list; include the information that is available to

your system in your justification. Hypothetical examples of justifications for each type of

standard monitoring site are below. Additional examples of justifications are provided in

Appendices H and I of this guidance manual and in the EPA manual, Initial Distribution System

Evaluation Guide for Systems Serving < 10,000 People. 

• High TTHM site: This site is served by our surface water source and is at the end of

one of our pressure zones. It is hydraulically downstream of Tank X, one of our

largest storage facilities. The site is a gas station in a residential area with

predominantly 4 and 6 inch pipes. Chlorine residuals at this site are below system

average, ranging from 1.2 to 1.5 mg/L in the summer.

• High HAA5 site: This site is served by our surface water source and is located on an

8-inch pipe in a commercial area. It is in an area of average to high water age that

has a history of high chlorine residual concentrations (2 to 2.2 mg/L in the summer). 

HPC levels for this site have historically been low compared to the rest of the system

(< 500). 

• Average residence time site: This site is in the geographic center of Pressure Zone 2

and has a chlorine residual level close to the system average (1.5 mg/L). 

• Near entry point: This site is our finished water sampling location for Surface Water

Treatment Plant X. We have more entry points than required near entry point sites,

so we selected this entry point because it has the highest average daily flow

compared to our other sources.

Step 8b. Write a Summary of Data

You must provide a summary of data you relied on to justify standard monitoring

location selections. You should describe the water quality data you reviewed, map features you

considered, ranges of relevant water quality data, and water sources and seasonal operations if

applicable, and tools you used to select your standard monitoring sites. An example summary is

provided below. Additional examples of data summaries are provided in Appendices H and I of

this guidance manual and in the EPA manual, Initial Distribution System Evaluation Guide for

Systems Serving < 10,000 People. 

We used our up-to-date water distribution system map to plot data and select sites. Our

map shows locations and sizes of all pipes, storage tanks, booster pumping stations, and

sources. We noted the location of large users and new developments. We analyzed

disinfectant residual collected at TCR sites in 2004 and 2005 and plotted average

concentrations from the summer months on our map. Summer disinfectant levels ranged

from 2.5 mg/L at the plant to 0.3 mg/L in the distribution system. The distribution system

average was between 0.9 and 1.1 mg/L. We also indicated average TTHM and HAA5

concentrations for our Stage 1 DBPR sites for 2005 data. TTHM concentrations ranged

from 0.035 mg/L through 0.085 mg/L and HAA5 concentrations ranged from 0.015 mg/L

through 0.037 mg/L. 
IDSE Guidance Manual for the Final Stage 2 DBPR 7-21 January 2006

We reviewed our tank level data and determined average water age inside the tank to

help identify areas with higher water age. We have some water age information from a

tracer study of our distribution system done in 1995. We have estimated the highest

water age in the distribution system to be approximately 4.5 days. We also highlighted

two problem areas that our operations staff say are places where we get repeat customer

complaints and low residuals. 

7.1.2 Selecting Your Peak Historical Month and Determining Standard Monitoring

Schedule

Determining Peak Historical Month

The Stage 2 DBPR defines the peak historical month as the month with the highest

TTHM or HAA5 levels or the warmest water temperature. It is meant to represent “worst case”

conditions when DBPs are the highest. You must review available compliance, study, or

operational data to determine the peak historical month for TTHM or HAA5 levels or warmest

water temperature. You can use Worksheet 7.1 on the next page to determine your peak

historical month. 

In some cases, you may find data in addition to TTHM, HAA5, and temperature data

helpful in selecting your peak historical month. As described in Appendix A, key factors

affecting TTHM and HAA5 formation are temperature, water age, and concentration of DBP

precursors (i.e., organic compounds that react with disinfectants to produce DBPs). Some

systems may regularly see an increase in total organic carbon (TOC) levels in the spring or fall. 

If your TTHM and HAA5 monitoring does not capture a seasonal increase in TOC, you may

want to consider the month with highest TOC when selecting your peak historical month. 

Seasonal changes in water age in your distribution system can be another influencing

factor in determining the worst-case conditions when DBPs are the highest. For example, some

systems may experience a decrease in peak usage in the fall, thereby increasing residence time in

the distribution system. The water temperature in the fall may not be as high as it was in the

summer months, but it still may be relatively high, such that increased residence time

significantly increases TTHM and HAA5 formation. In this scenario, you should consider water

age when selecting your peak historical month.

If you based the selection of your peak historical month on data other than TTHM,

HAA5, and temperature, you should document the basis for selection in your IDSE standard

monitoring plan.
IDSE Guidance Manual for the Final Stage 2 DBPR 7-22 January 2006

Worksheet 7.1 Selecting the Peak Historical Month Page 1 of 1

A. Do you have more than one water source (e.g., treatment plant

or consecutive system entry point) in your system? G Yes G No

If Yes, you should identify the source associated with the highest

TTHM and HAA5 levels in your system based on your Stage 1

DBPR monitoring data. You should use data from this source for

selecting your peak historical month. Continue to STEP B

If No, continue to STEP B

B. Do you have monthly or quarterly TTHM and HAA5 data? G Yes G No

If Yes, you should determine in which month your TTHM and HAA5 levels are the

highest.

What if the highest TTHM and/or HAA5 levels occur at different times during

different years? You should choose the year of data that is most representative

of typical system operating and weather conditions.

What if the highest TTHM and HAA5 levels occur in different months? You

should consider which contaminant is of more concern. If one contaminant

clearly shows a higher overall trend and is closer to the MCL, you should

choose the month in which that contaminant is highest. 

Choose the month with the highest TTHM and HAA5 levels as your peak

historical month. Stop here. 

If No, continue to STEP C

C. Use temperature data to select your peak historical month

Calculate the average water temperature for each summer month to identify the

month of warmest water temperature. If available, use data from several years to

determine when the warmest water temperature occurs. If warmest

temperature occurs in different months in different years, select the year(s)

that are most typical of climatological and water quality data and water use

for your region. 

Remember, in your standard monitoring plan you should indicate the source used to

select your peak historical month and the basis for selecting it (high TTHM, high

HAA5, and/or temperature)
IDSE Guidance Manual for the Final Stage 2 DBPR 7-23 January 2006

IDSE Tool

Determining Standard Monitoring Schedule

You must take one round of standard monitoring samples during the peak historical

month. If you serve more than 499 people, you must also conduct sampling at equal intervals

before and/or after the peak historical month, based on your required sampling frequency. You

can find your required sampling frequency on the Standard Monitoring Requirements -

Attachment sheet in Chapter 2. Be sure to plan your monitoring so that all sampling is complete

by the deadline on your requirements summary sheet in Chapter 2. 

The intent of the required time interval is to ensure that samples represent the quality of

water over an extended period and do not over-emphasize either high or low concentrations of

TTHM or HAA5 that may occur seasonally. For example, a system on quarterly monitoring

could sample in the third full week of every third month. You should keep in mind holidays

and sampling schedules for other water quality programs when determining your standard

monitoring schedule.

7.1.3 Preparing Your Standard Monitoring Plan

Every system that conducts IDSE standard monitoring must prepare and submit an

Standard Monitoring Plan. You should submit the plan to the Information Processing and

Management Center (IPMC) for review by EPA or your state. See Section 1.4 of this guidance

manual for information on how to submit your plan to the IPMC.

EPA has developed a Standard Monitoring Plan Form (Form 6), presented in this

section and available electronically as part of the IDSE Tool. You are not required to use this

form; however, if you choose not to use it, refer to Exhibit 7.1 on page 7-3 for a list of the

minimum elements you must include in your standard monitoring plan. 

The IDSE Tool creates a custom form for your system and provides

links to technical guidance from this manual. The tool is available on EPA’s

website at http://www.epa.gov/safewater/disinfection/stage2.

Your deadlines for submitting your standard monitoring plan and conducting standard

monitoring can be found on your requirements summary sheet in Chapter 2. If EPA or your state

does not approve or request modifications to your plan, or notify you that your plan is still under

review within 12 months after the deadline for plan submission, you may consider the plan

approved. 
IDSE Guidance Manual for the Final Stage 2 DBPR 7-24 January 2006

The standard monitoring plan form includes the following sections:

I. General Information

II. IDSE Requirements

III. Selecting Standard Monitoring Sites

IV. Justification of Standard Monitoring Sites

V. Peak Historical Month and Standard Monitoring Schedule

VI. Planned Stage 1 DBPR Compliance Monitoring Schedule

VII. Distribution System Schematic

VIII. Attachments

Sections of the form with an asterisk (*) are required by the Stage 2 DBPR. Examples of

completed standard monitoring plans using this form are provided in Appendices H and I of this

guidance manual and in the EPA manual, Initial Distribution System Evaluation Guide for

Systems Serving < 10,000 People. The rest of this section provides guidance on the completion

of this form.

I. General Information

I.A. PWS Information* - Important definitions for classifying your system are

provided in the definitions section at the beginning of this guidance manual. If

you have any questions on this section, contact EPA or your state.

PWSID - Enter your PWSID identification number here. This number is typically

assigned by your state.

PWS Name - Enter the name of your system here. 

PWS Address - Enter the primary mailing address for your water system here.

Population Served - Enter the number of people served by your PWS. 

Remember, this is your RETAIL population served, not including the population

served by consecutive systems that purchase water from you.

System Type - Put a check mark in the appropriate box to identify whether your

system is a CWS or a NTNCWS. Definitions for CWS and NTNCWS can be

found in the definitions section at the beginning of this guidance manual.

Source Water Type - Put a check mark in the appropriate box to identify whether

your system is a subpart H system or a ground water system. If you use any

surface water or GWUDI as a source, mark the subpart H box. Definitions for

subpart H system (including GWUDI) and ground water system can be found in

the definitions section at the beginning of this guidance manual.

Buying/Selling Relationships - Put a check mark in the appropriate box to identify

whether your system is a consecutive system, a wholesale system, or neither. If
IDSE Guidance Manual for the Final Stage 2 DBPR 7-25 January 2006

you are both a consecutive and wholesale system (e.g., you buy and sell water),

check both boxes. Definitions for consecutive system and wholesale system can

be found in the definitions section at the beginning of this guidance manual and

in Appendix D.

I.B. Date Submitted* - Enter either the date that you are submitting the form

electronically, putting it in the mailbox, or dropping it off with an express

delivery service. Be sure to submit your standard monitoring plan before the

deadline found on your requirements summary sheet.

I.C. PWS Operations - This section asks questions about your system to help inform

EPA and state personnel during the plan review process.

Residual Disinfectant Type - Put a check mark in the appropriate box to identify

the type of disinfectant you most often use to maintain a residual in your

distribution system (not necessarily the same disinfectant used for primary

disinfection at the treatment plant). If you use chloramine but switch to free

chlorine for a short time, you should still check chloramine only. If you use 

chloramine and chlorine regularly in your system (e.g, 4 months of free chlorine

and 8 months of chloramines), check both chlorine and chloramine. If you

maintain your residual with a disinfectant other than chlorine or chloramines (e.g.,

chlorine dioxide), you should place a check next to the box marked “Other” and

enter the type of disinfectant you use in the blank next to “Other”.

Number of Disinfected Sources - Enter the total number of sources that deliver

disinfected water to your distribution system. If you connect to a single

wholesale system at a number of locations in your distribution system, consider

this one source. Multiple wells that are disinfected at a common treatment plant

should also be considered one source. Do not count wells that are not disinfected

or are disinfected by UV only.

I.D. Contact Person* - Enter the contact information of the person who is submitting

the form. This should be the person who will be available to answer questions

from EPA and/or state reviewers.

II. IDSE Requirements*

II.A Number of Sites - Refer to the Standard Monitoring Requirements - Attachment

sheet in Chapter 2. Copy the numbers from the “IDSE Standard Monitoring

Requirements” table that correspond to your source type and the population

served by your system. 

Note that you may need to adjust the number of each site type if you have fewer

entry points than required near entry point sites (see Step 1 in Section 7.1.1). This
IDSE Guidance Manual for the Final Stage 2 DBPR 7-26 January 2006

adjustment should be reflected in your site selection and justification in Section

IV. Your total should always be the same. 

II.B. Schedule - Enter the schedule for your system based on the letter sent to you

from 

EPA or your state. See Chapter 2 for more information on the letter.

II.C. Standard Monitoring Frequency - Refer to the Standard Monitoring

Requirements Attachment sheet in Chapter 2. Locate the monitoring frequency

from the “IDSE Standard Monitoring Requirements” table that corresponds to

your source type and the population served by your system. Put a check mark in

the box corresponding to that monitoring frequency.

III. Selecting Standard Monitoring Sites

III.A. Data Evaluated - Put a check mark in each box corresponding to the data that you

used to select each type of standard monitoring site. Water quality data may be

compliance data or operational data. 

III.B. Summary of Data* - In the space provided (or in an attached writeup), provide a

summary of the data you used to justify your site selection. See Step 8b in

Section 7.1.1 of this manual for guidance.

IV. Justification of Standard Monitoring Sites* Enter the site ID from the distribution

schematic, site type (whether it is near an entry point, average residence time, high

TTHM, or high HAA5), and justification. Justification for each standard monitoring site

should include the system characteristics that led you to choose it as a standard

monitoring site. See Step 8a in Section 7.1.1 of this manual for guidance. If you have

fewer near entry points than required near entry point monitoring locations, be sure to

replace the extra near entry point sites with high TTHM or high HAA5 sites.

Note that there is only space for 8 monitoring sites on this sheet. If you are a ground

water system serving more than 499,999 people or a subpart H system serving more than

49,999 people you are required to monitor at more than 8 sites. Therefore, you will need

to attach additional sheets.

V. Peak Historical Month and Proposed Standard Monitoring Schedule

V.A. Peak Historical Month* - Enter the month that you determined to be your peak

historical month. See Section 7.1.2 and Worksheet 7.1 for guidelines on

selecting your peak historical month.

V.B. If Multiple Sources, Source Used to Determine Peak Historical Month - If your

system has only one source, write “N/A” here. If you have more than one source,

write the name of the source you used as the basis for determining peak historical
IDSE Guidance Manual for the Final Stage 2 DBPR 7-27 January 2006

month. For example, if a system has one surface water, one ground water, and

one purchased ground water source, it is likely that they relied heavily on data

from the surface water source to select their peak historical month. This system

would write “surface water source” in the blank provided.

V.C Peak Historical Month Based On* - Put a check mark in the appropriate box to

identify the basis for determining your peak historical month. If your peak

historical month is supported by more than one parameter (e.g., peak historical

month is month of high TTHM and maximum temperature), check each box that

applies. If you used data other than TTHM, HAA5, and temperature data to

select your peak historical month (e.g., you used TOC data and/or water age

data), describe how you used additional data here. 

V. D. Proposed Standard Monitoring Schedule* - Enter the ID for each standard

monitoring site in the table (verify that these match the IDs you enter in Section

IV and on your schematic). Enter your proposed sampling schedule for the

number of monitoring periods identified in Section II.C. The entry can be a

specific date or week and can be in a number of different formats. For example:

• 7/9/07

• 2nd week in Nov ‘07

• Week of 7/9/07 

Remember that at least one monitoring period must be during the peak historical

month identified in Section V.A. Note that there is only space for 8 monitoring

sites on this sheet. If you are a ground water system serving more than 499,999

people or a subpart H system serving more than 49,999 people you are required to

monitor at more than 8 sites. Therefore, you will need to attach additional sheets.

VI. Planned Stage 1 DBPR Compliance Monitoring Schedule* Enter the projected

sampling schedule for the number of Stage 1 DBPR monitoring periods in which you will

conduct Stage 1 DBPR monitoring during your IDSE standard monitoring. Verify that

site IDs in this table match the IDs on your distribution system schematic. If you are

required to monitor at more than 8 Stage 1 DBPR locations you will need to attach

additional sheets. You may also want to attach your Stage 1 DBPR monitoring plan.

VII. Distribution System Schematic* Attach a distribution system schematic to your

monitoring plan. Your schematic must include the locations of entry points, sources,

storage facilities, standard monitoring sites, and Stage 1 compliance monitoring sites. 

IDSE standard monitoring plans will not be considered confidential business information

(CBI) and are subject to the Freedom of Information Act (FOIA). Therefore, your

distribution system schematic should not contain information that poses a security risk

to your system. EPA suggests that you consider one of the following options for

submitting distribution system schematics:
IDSE Guidance Manual for the Final Stage 2 DBPR 7-28 January 2006

• Option 1: Distribution system schematic with no landmarks or addresses

indicated. Show locations of sources, entry points, storage facilities, standard

monitoring locations, and Stage 1 compliance monitoring locations (required). 

Also include pressure zone boundaries and locations of pump stations. Provide

map scale.

• Option 2: City map without locations of pipes indicated. Show locations of

sources, entry points, storage facilities, standard monitoring locations, and Stage 1

compliance monitoring locations (required). Also include boundaries of the

distribution system, pressure zone boundaries and locations of pump stations. 

Provide map scale.

Schematics should be as clear and easy to read as possible. They should typically be

submitted on a scale of between 1:4,000 and 1:8,000; however, larger-scale drawings are

acceptable as long as systems components can still be clearly shown. All sizes from 81⁄2

inches x 11 inches to larger, plan-sized sheets are acceptable. If electronic versions are

submitted, use one of the following file types:

• Adobe PDF file (*.pdf)

• Microsoft Word (*.doc)

• WordPerfect (*.wpd)

• Image file (*.gif, *.bmp, *.jpg, *.jpeg)

VIII. Attachments Put a check mark in each of the boxes corresponding to any attachments

that you have included in your report.

A distribution system schematic is required. Refer to Section VII for details.

Note that there is only space for 8 monitoring sites in Section IV and Section VI. If you

are a ground water system serving more than 499,999 people or a subpart H system

serving more than 49,999 people, you will need to attach additional sheets for Section IV

and Section VI.

If you submit your standard monitoring plan electronically, you also have the option to

submit attachments in hard copy. Include a note in your electronic standard monitoring

plan explaining that attachments are being submitted in hard copy, and mail the hard

copy to the IPMC mailing address in your Requirements Summary Sheet. The IPMC

will match the hard copy submission with your electronic submission when it is received.

Enter the total number of pages in your monitoring plan (including attachments) in the

blank at the bottom of this section. This will allow EPA or your state to ensure that all

pages were received.
IDSE Guidance Manual for the Final Stage 2 DBPR 7-29 January 2006

Form 6: Standard Monitoring Plan Page 1 of 6

I. GENERAL INFORMATION 

A. PWS Information* B. Date Submitted* ___________

 PWSID:

 PWS Name:

PWS Address:

City: State: Zip:

Population Served:

System Type: Source Water Type: Buying / Selling Relationships:

~ CWS ~ Subpart H ~ Consecutive System 

~ NTNCWS ~ Ground ~ Wholesale System

 ~ Neither

C. PWS Operations 

Residual Disinfectant Type: ~ Chlorine ~ Chloramines ~ Other:_____________

 Number of Disinfected Sources: ___ Surface ___GWUDI ____ Ground ___ Purchased

D. Contact Person*

Name:

Title:

Phone #: Fax #:

E-mail: 

II. IDSE REQUIREMENTS*

A. Number of Sites B. Schedule C. Standard Monitoring Frequency

Total:

Near Entry Point: ~ Schedule 1 ~ During peak historical month 

 (1 monitoring period) Avg Residence Time: ~ Schedule 2

 High TTHM: ~ Schedule 3 ~ Every 90 days (4 monitoring periods)

 High HAA5: ~ Schedule 4 ~ Every 60 days (6 monitoring periods)
IDSE Guidance Manual for the Final Stage 2 DBPR 7-30 January 2006

Form 6: Standard Monitoring Plan Page 2 of 6

III. SELECTING STANDARD MONITORING SITES

A. Data Evaluated Put a “T” in each box corresponding to the data that you used to

select each type of standard monitoring site. Check all that apply.

Data Type Type of Site

Near

Entry Pt.

Avg. Residence

Time

High

TTHM

High

HAA5

System Configuration

Pipe layout, locations of storage facilities

Locations of sources and consecutive

system entry points

Pressure zones

Information on population density

Locations of large customers

Water Quality and Operational Data

Disinfectant residual data

Stage 1 DBP data

Other DBP data

Microbiological monitoring data (e.g., HPC)

Tank level data, pump run times

Customer billing records

Advanced Tools

Water distribution system model

Tracer study

B. Summary of Data* Provide a summary of data you relied on to justify standard

monitoring site selection. (attach additional sheets if needed)
IDSE Guidance Manual for the Final Stage 2 DBPR 7-31 January 2006

Form 6: Standard Monitoring Plan Page 3 of 6 

IV. JUSTIFICATION OF STANDARD MONITORING SITES*

Standard

Monitoring

Site ID 

(from map)1

Site Type Justification

~ Near Entry Pt

~ Avg. Res. Time

~ High TTHM

~ High HAA5

~ Near Entry Pt

~ Avg. Res. Time

~ High TTHM

~ High HAA5

~ Near Entry Pt

~ Avg. Res. Time

~ High TTHM

~ High HAA5

~ Near Entry Pt

~ Avg. Res. Time

~ High TTHM

~ High HAA5

~ Near Entry Pt

~ Avg. Res. Time

~ High TTHM

~ High HAA5

~ Near Entry Pt

~ Avg. Res. Time

~ High TTHM

~ High HAA5

~ Near Entry Pt

~ Avg. Res. Time

~ High TTHM

~ High HAA5

~ Near Entry Pt

~ Avg. Res. Time

~ High TTHM

~ High HAA5

1 Verify that site IDs match IDs in Section IV and on your distribution system schematic (See Section VII

of this form). Attach additional copies if you are required to select more than 8 standard monitoring

locations or need more room.
IDSE Guidance Manual for the Final Stage 2 DBPR 7-32 January 2006

Form 6: Standard Monitoring Plan Page 4 of 6

V. PEAK HISTORICAL MONTH AND PROPOSED STANDARD MONITORING SCHEDULE

A. Peak Historical Month* 

B. If Multiple Sources, Source Used to Determine Peak Historical Month 

(write “N/A” if only one source in your system)

C. Peak Historical Month Based On* (check all that apply)

~ High TTHM ~ Warmest water temperature

~ High HAA5

If you used other information to select your peak historical month, explain here 

(attach additional sheets if needed)

D. Proposed Standard Monitoring Schedule*

 Standard Monitoring

Site ID 

(from map) 1

Projected Sampling Date (date or week) 2

period 1 period 2 period 3 period 4 period 5 period 6

 

1

 Verify that site IDs match IDs in Section IV and on your distribution system schematic (See

Section VII of this form). Attach additional copies if you are required to select more than 8

standard monitoring locations.

2

 period = monitoring period. Complete for the number of periods from Section II.C. Can list exact

date or week (e.g., week of 7/9/07)
IDSE Guidance Manual for the Final Stage 2 DBPR 7-33 January 2006

Form 6: Standard Monitoring Plan Page 5 of 6

VI. PLANNED STAGE 1 DBPR COMPLIANCE MONITORING SCHEDULE*

 

Stage 1 DBPR

Monitoring Site

ID (from map) 1

Projected Sampling Date (date or week) 2

Period 1 Period 2 Period 3 Period 4

1

 Verify that site IDs match IDs on your distribution system schematic (See Section VII of

this form). Attach additional copies if you are required to monitor at more than 8 Stage 1

DBPR sites.

2

 period = monitoring period. Complete for the number of periods in which you must conduct

Stage 1 DBPR monitoring during IDSE monitoring. Can list exact date or week (e.g., week

of 7/9/07)

VII. DISTRIBUTION SYSTEM SCHEMATIC*

ATTACH a schematic of your distribution system. 

Distribution system schematics are not confidential and should not contain information

that poses a security risk to your system. EPA recommends that you use one of two

options: 

Option 1: Distribution system schematic with no landmarks or addresses

indicated. Show locations of sources, entry points, storage facilities, standard

monitoring locations, and Stage 1 compliance monitoring locations (required). Also

include pressure zone boundaries and locations of pump stations. Provide map

scale. 

Option 2: City map without locations of pipes indicated. Show locations of

sources, entry points, storage facilities, standard monitoring locations, and Stage 1

compliance monitoring locations (required). Also include boundaries of the

distribution system, pressure zone boundaries and locations of pump stations. 

Provide map scale.
IDSE Guidance Manual for the Final Stage 2 DBPR 7-34 January 2006

Form 6: Standard Monitoring Plan Page 6 of 6

VIII. ATTACHMENTS

~ Distribution System Schematic* (Section VII). 

~ Additional sheets for the summary of data or site justifications (Sections III and IV).

~ Additional copies of Page 3 for justification of Standard Monitoring Sites (Section

IV). Required if you are a subpart H system serving more than 49,999 people or

a ground water system serving more than 499,999 people.

~ Additional sheets for explaining how you used data other than TTHM, HAA5, and

temperature data to select your peak historical month (Section V).

~ Additional copies of Page 4 for proposed monitoring schedule (Section V). 

Required if you are a subpart H system serving more than 49,999 people or a

ground water system serving more than 499,999 people.

~ Additional sheets for planned Stage 1 DBPR compliance monitoring schedule

(Section VI).

Total Number of Pages in Your Plan _____

Note: Fields with an asterisk (*) are required by the Stage 2 DBPR
IDSE Guidance Manual for the Final Stage 2 DBPR 7-35 January 2006

7.2 Conducting Standard Monitoring

Conducting standard monitoring is an integral part of the IDSE. The results of standard

monitoring, along with the results of Stage 1 DBPR compliance monitoring, must be used to

select the best sites for Stage 2 DBPR compliance monitoring and must be documented in your

IDSE report.

Remember, you must submit your standard monitoring plan before you begin standard

monitoring. If EPA or your state does not approve or request modifications to your plan, or

notify you that your plan is still under review within 12 months after the deadline for plan

submission, you may consider the plan approved. You must conduct standard monitoring 

according to the approved monitoring plan.

This section presents sampling requirements and tips for sample collection for

conducting standard monitoring.

REMINDER: you must continue to collect samples and comply with the Stage 1 DBPR during

the IDSE. Results from standard monitoring should not be used for making Stage 1 compliance

determinations.

Your Requirements

You must conduct standard monitoring according to the schedule and at each of the

monitoring locations listed in your standard monitoring plan. If you deviate from the approved

plan for any reason (e.g., a site was not accessible on the planned week and you needed to

sample during the next week), you must include an explanation for the deviation in your IDSE

report.

During each sampling event, you must collect a dual sample set (i.e., two samples) at

each location. One sample must be analyzed for TTHM and the other must be analyzed for

HAA5. Two samples are required because the analytical methods used for the two groups of

contaminants require different sample preservation methods. You must use EPA-approved

methods for analysis of your TTHM and HAA5 samples. More information on EPA-approved

methods can be found in Appendix C.
IDSE Guidance Manual for the Final Stage 2 DBPR 7-36 January 2006

Tips for Sample Collection

As you conduct standard monitoring, you should keep in mind the following tips:

• Use appropriate sample bottles. You should use

sample bottles that already contain the appropriate

dechlorinating agent and preservative for sample

collection. You should contact your lab for a

recommended sampling and preservation protocol. A

typical sampling protocol can be found in Appendix C.

• Flush your sample tap. If you collect samples from a tap, you should open the cold

water tap and allow the line to flush until the water temperature has stabilized

(usually about 3-5 minutes). If you collect a sample at a hydrant or blow-off, the

flushing time only needs to be long enough to purge the connecting line to the main. 

The purpose of this step is to ensure the sample does not represent stagnant water that

has been sitting for a long time in the water line between the street and the faucet. 

The sample should represent the water flowing through the distribution system at the

chosen sampling point. 

• Collect cold water samples. If you collect indoor samples you should collect them

from a cold water line.

• Collect additional water quality data. You may wish to collect additional water

quality data, such as disinfectant residual and temperature data, at the time of DBP

sample collection. This information can be helpful as you interpret standard

monitoring results (e.g., unusually low residual at a location could mean unusually

high residence time).

• Re-sample if a sample is lost or broken. If a sample bottle is lost or broken after

sample collection, you should re-sample as soon as possible after the loss occurs. 

Only the lost sample needs to be recollected, not the entire sample set that was

collected together. Make sure to note the loss of sample and resample date as a

deviation in your IDSE report.

If you need to change an IDSE standard monitoring sampling location for reasons beyond

your control, or if you miss a required sampling period entirely, you should contact EPA or your

state so they can approve your re-sampling strategy.
IDSE Guidance Manual for the Final Stage 2 DBPR 7-37 January 2006

IDSE Tool

7.3 Selecting Stage 2 DBPR Compliance Monitoring Sites and Preparing the

IDSE Report

Every system that conducts standard monitoring must use results from Stage 1 DBPR

compliance monitoring and standard monitoring to select Stage 2 DBPR compliance monitoring

sites. You must follow a specific protocol, as laid out in the Stage 2 DBPR, to select

compliance sites unless you decide to recommend alternative Stage 2 compliance monitoring

sites to your state or EPA. 

You must include your monitoring results and recommended Stage 2 compliance

monitoring sites in an IDSE Report. You should submit your IDSE report to the Information

Processing and Management Center (IPMC) for review by EPA or your state. See Section 1.4 of

this guidance manual for information on how to submit your plan to the IPMC.

This section presents the required protocol for selecting Stage 2 DBPR compliance

monitoring sites and provides guidance for preparing an IDSE report. 

EPA has developed an IDSE Report for Standard Monitoring Form

(Form 7), presented in Section 7.3.3 and available electronically as part of the

IDSE Tool. You are not required to use this form; however, if you choose not to

use it, refer to Exhibit 7.6 for a list of the minimum elements you must include in

your IDSE report. Examples of completed reports can be found in Appendices H

and I. The IDSE Tool is available on EPA’s website at

http://www.epa.gov/safewater/disinfection/stage2.

Exhibit 7.6 Required Elements of Your IDSE Report for Standard Monitoring

• Explanation of any deviations from approved standard monitoring plan

• TTHM and HAA5 analytical results from Stage 1 DBPR monitoring and IDSE

standard monitoring

• Recommendations and justification of Stage 2 DBPR monitoring sites and

sampling dates

• If changed from the approved standard monitoring plan:

- Distribution system schematic

- Population served by the system

- System type (subpart H or ground water)
IDSE Guidance Manual for the Final Stage 2 DBPR 7-38 January 2006

7.3.1 Selecting Stage 2 DBPR Compliance Monitoring Locations

You should begin the Stage 2 site selection process by calculating the locational running

annual average (LRAA) for each standard monitoring site and Stage 1 DBPR compliance

monitoring site. Note that because the duration for IDSE standard monitoring is one year, the

LRAA for each standard monitoring site is equivalent to the average of all TTHM or HAA5 data

collected at the location (either one, four, or six data points depending on your IDSE standard

monitoring frequency). The LRAA for each Stage 1 DBPR compliance monitoring site should

be the LRAA for the year that you conducted standard monitoring (either one or four data points

depending on your Stage 1 compliance monitoring frequency). You should consider using a

spreadsheet to store your data and calculate your LRAAs. You can also use Worksheet 7.2 to

help you organize your data

You must use the site selection protocol in Exhibit 7.7 to select your Stage 2

compliance monitoring locations. The number of required Stage 2 compliance monitoring sites

for your system can be found on page 2 of the Standard Monitoring Requirements -

Attachment sheet in Chapter 2. If you complete all steps in the protocol and need additional

compliance monitoring sites for the Stage 2 DBPR, repeat the protocol until the required number

of sites has been selected. If you arrive at Step 3 or Step 7 and have no more Stage 1 DBPR sites

from which to select, continue to the next step. Example 7.4 shows how a large system uses the

protocol to select their Stage 2 compliance monitoring sites.

You may select alternate sites other than those identified using the protocol, but you

must justify the alternate locations in your IDSE report. Additional factors that may prompt you

to choose alternate sites are discussed below.

Additional Factors to Consider During Selection of Stage 2 Compliance Monitoring Sites

In general, TTHM and HAA5 LRAAs are the most important factors in site selection. 

However, the Stage 2 rule allows for some flexibility in this process. As you work through the

site selection protocol, you should consider other factors that may lead you to select a site with a

similar or slightly lower LRAA. If you do not use your highest TTHM and HAA5 LRAAs to

select your Stage 2 compliance monitoring sites, you must provide justification for your

selection in your IDSE report. The following conditions are possible reasons why you may

select a site with a slightly lower LRAA over another site:

• The site provides more complete geographic coverage of the entire distribution

system

• The site allows you to maintain a historical record

• Sampling at that site provides the opportunity to collect other water quality or

operational data (e.g., chloramine systems may want to collect nitrate or nitrite data at

that site)

EPA recognizes that a slight difference between LRAAs measured at two sites may not

be meaningful given the normal variability that may occur at a site over time. As a result, the

selection of a Stage 2 compliance monitoring site with a slightly lower LRAA may be acceptable

if other factors, such as those listed above, favor the site with the lower LRAA. Examples 7.5

and 7.6 illustrate situations in which hypothetical systems might select Stage 2 DBPR

compliance monitoring sites using criteria other than the site selection protocol.

It is possible that EPA or your state may not concur with your justification and may

require you to select different Stage 2 compliance monitoring sites.
IDSE Guidance Manual for the Final Stage 2 DBPR 7-39 January 2006

Worksheet 7.2 Stage 2 DBPR Site Selection Worksheet for Standard 

Monitoring Page 1 of 1

Instructions:

1) Enter the number of required Stage 2 DBPR compliance monitoring sites based on your

Standard Monitoring Requirements - Attachment summary sheet from Chapter 2. 

2) Enter the Site ID and LRAA for each IDSE standard monitoring and Stage 1 compliance

monitoring location. You may want to sort your entries in order by TTHM LRAA or HAA5

LRAA values. 

3) As you work through the site selection protocol in Exhibit 7.7, fill in the “Stage 2 Site

Type” column each time you select a site to indicate whether the site is a high TTHM, high

HAA5, Existing Stage 1 DBPR Compliance Monitoring Site, or selected using criteria other

than the protocol. 

No. of Stage 2 DBPR Compliance Monitoring Sites Required

 Highest TTHM Highest HAA5 Existing Stage 1 TOTAL

Site ID

LRAA

Stage 2 DBPR Site

TTHM (mg/L) HAA5 (mg/L) Type*

Example 0.075 0.045 Highest TTHM

* Enter Highest TTHM, Highest HAA5, or existing Stage 1 DBPR
IDSE Guidance Manual for the Final Stage 2 DBPR 7-40 January 2006

Exhibit 7.7 Protocol for Selecting Stage 2 DBPR (Subpart V)

Compliance Monitoring Sites

Steps1

[required by rule]

Stage 2 Compliance Monitoring

Sites Selected 2

1 Select the location with the highest TTHM LRAA 1st highest TTHM site

2 Select the remaining location with the highest HAA5

LRAA 

1st highest HAA5 site

3 For subpart H systems: Select the remaining existing

Stage 1 DBPR average residence time compliance

monitoring location with the highest HAA5 LRAA

For ground water systems: Select the remaining

existing Stage 1 DBPR maximum residence time

compliance monitoring location with the highest

HAA5 LRAA

Skip this step if you have no more Stage 1 DBPR sites

1st Stage 1 DBPR site

4 Select the remaining location with the next highest

TTHM LRAA.

2nd highest TTHM site

5 Select the remaining location with the next highest

TTHM LRAA

3rd highest TTHM site

6 Select the remaining location with the next highest

HAA5 LRAA

2nd highest HAA5 site

7 For subpart H systems: Select the remaining existing

Stage 1 DBPR average residence time compliance

monitoring location with the highest TTHM LRAA

For ground water systems: Select the remaining

existing Stage 1 DBPR maximum residence time

compliance monitoring location with the highest

TTHM LRAA

Skip this step if you have no more Stage 1 DBPR sites

2nd Stage 1 DBPR site

8 Select the remaining location with the next highest

HAA5 LRAA

3rd highest HAA5 site

If you need more Stage 2 DBPR compliance monitoring locations, Go back to Step 1 of this

protocol and repeat the steps until you have selected the required number of total sites.

1. All steps are based on your calculated LRAAs for your standard monitoring sites and Stage 1 DBPR compliance

monitoring sites. This means that your existing Stage 1 DBPR sites can be selected in steps other than 3 or 7. Stop

when you reach your required number of Stage 2 DBPR compliance monitoring sites.

2. You cannot select the same site as a highest TTHM and a highest HAA5 compliance monitoring site. 
IDSE Guidance Manual for the Final Stage 2 DBPR 7-41 January 2006

Example 7.4 Selecting Stage 2 DBPR Compliance Monitoring Sites

A consecutive system serving 15,000 people has conducted standard monitoring for

the IDSE. This system purchases disinfected ground water from a number of ground water

systems drawing from the same aquifer. Based on state determination, the system has two

Stage 1 DBPR compliance monitoring sites. According to the Standard Monitoring

Requirements Attachment sheet in Chapter 2, the system must select the following four

Stage 2 compliance monitoring sites from IDSE standard monitoring and Stage 1 DBPR sites: 

• 2 highest TTHM sites,

• 1 highest HAA5 site, and 

• 1 maximum residence time sites from the existing Stage 1 DBPR data.

The table below lists the TTHM and HAA5 LRAAs for the Stage 1 DBPR compliance

monitoring sites and standard monitoring sites during the IDSE monitoring period.

Site Number and Description TTHM LRAA (mg/L) HAA5 LRAA (mg/L)

Stage 1 DBPR Compliance Monitoring Results:

1 (Stage 1 max. residence time) 0.059 0.037

2 (Stage 1 max. residence time) 0.036 0.045

IDSE Standard Monitoring Results:

3 (high TTHM) 0.058 0.031

4 (high TTHM) 0.052 0.034

5 (high HAA5) 0.051 0.042

6 (high HAA5) 0.047 0.038

7 (ave. residence time) 0.038 0.034

8 (near entry point) 0.021 0.015
IDSE Guidance Manual for the Final Stage 2 DBPR 7-42 January 2006

Example 7.4 Selecting Stage 2 DBPR Compliance Monitoring Sites (cont.)

The system used the required protocol in Exhibit 7.7 to select their compliance monitoring

sites.

Go to Step 1: Select the Highest TTHM LRAA Site

Site 1 has the highest TTHM LRAA and is selected as the first high TTHM site.

Go to Step 2: Select the Highest HAA5 LRAA Site

Site 2 has the highest HAA5 LRAA and has not already been selected. Therefore,

Site 2 is chosen as the first high HAA5 site.

Go to Step 3: Select the Stage 1 Maximum Residence Time Site with the Highest HAA5 LRAA

There are no remaining Stage 1 sites to select from. Skip this step and go to Step 4. 

Go to Step 4: Select the Next Highest TTHM LRAA Site

Site 3 has the next highest TTHM LRAA and is therefore chosen as the next highest

TTHM site.

Go to Step 5: Select the Next Highest TTHM LRAA Site

Site 4 has the next highest TTHM LRAA and is therefore chosen as the next highest

TTHM site.

Final Inventory of Stage 2 DBPR Compliance Monitoring Sites*

Highest TTHM: Site 1, Site 3, Site 4 (3 sites)

Highest HAA5: Site 2 (1 site)

Existing Stage 1 DBPR Site (as described in Step 3): No sites

TOTAL Sites = 4

*Note that the requirements on the previous page are for 2 highest TTHM sites, 1 highest

HAA5 site, and 1 maximum residence time site from existing Stage 1 DBPR data. However,

because the two Stage 1 DBPR sample sites were the highest TTHM site and the highest

HAA5 site, these sites were selected during the first two steps of the selection protocol. As a

result, there were no remaining Stage 1 DBPR sites to choose from during Step 3. Step 3 was

skipped and the remaining two Stage 2 compliance sites were chosen using Steps 4 and 5.
IDSE Guidance Manual for the Final Stage 2 DBPR 7-43 January 2006

A

B

C

Water Treatment Plant

Example 7.6 Providing Geographic Coverage When Choosing Stage 2 Sites

In general, two representative high TTHM sites should not be located in the same

general area of the distribution system. Consider the following example:

The two highest TTHM LRAAs in the

distribution system are from adjacent historical

sample sites (sites A and B). The site with the third

highest TTHM LRAA is on the far side of the

distribution system (site C). In this case, consider

selecting sites A and C or B and C as Stage 2 sites

for a broader geographical coverage of the

distribution system.

Example 7.5 Maintaining a Historical Record

A ground water system serves 90,000 people and must select four Stage 2 compliance

sites from standard monitoring and Stage 1 DBPR data. The system has already selected one

highest TTHM site, one highest HAA5 site, and one Stage 1 maximum residence time site. 

The fourth site to be selected is a high TTHM site which must be selected from the IDSE

standard monitoring and Stage 1 DBPR sites not yet selected for Stage 2 compliance

monitoring. The table below lists three remaining high-TTHM sites among the IDSE

standard monitoring and Stage 1 DBPR sites.

Site Number and Description

LRAA

TTHM (mg/L) HAA5

(mg/L)

4 (Standard monitoring high TTHM) 0.072 0.051

8 (Standard monitoring high TTHM) 0.065 0.056

9 (Stage 1 DBPR max residence time site) 0.070 0.051

Among the three remaining high TTHM IDSE sites, standard monitoring Site 4 has

the highest TTHM LRAA. However, the Stage 1 DBPR site has only slightly lower TTHM

LRAA than standard monitoring Site 4. The system chooses the Stage 1 DBPR site over

standard monitoring site 4 for the Stage 2 high TTHM site to maintain the historical DBP
IDSE Guidance Manual for the Final Stage 2 DBPR 7-44 January 2006

IDSE Tool

7.3.2 Determining Your Stage 2 DBPR Compliance Monitoring Schedule

The first step in determining your Stage 2 DBPR compliance monitoring schedule is to

select your peak historical month. You should use the peak historical month selected in your

IDSE standard monitoring plan unless new data suggest another month. Refer to Section 7.1.2

for more information on determining peak historical month.

You must conduct Stage 2 DBPR compliance monitoring during the peak historical

month. If you are a ground water system that serves more than 9,999 people or you are a subpart

H system that serves more than 499 people, you must also conduct Stage 2 compliance sampling

at 90 day intervals before and/or after the peak historical month. 

The intent of the required time interval is to ensure that samples are representative of the

quality of water over an extended period and do not over-emphasize either high or low

concentrations of TTHM or HAA5 that might occur seasonally. For example, a system on

quarterly monitoring could sample in the third full week of every third month. It is not

necessary to sample all sites on the same day.

7.3.3 Preparing the IDSE Report for Standard Monitoring

Every system that conducts IDSE standard monitoring must prepare and submit an IDSE

Report for Standard Monitoring. You should submit the report to the Information Processing and

Management Center (IPMC) for review by EPA or your state. See Section 1.4 of this guidance

manual for information on how to submit your report to the IPMC. 

EPA has developed an IDSE Report for Standard Monitoring Form (Form 7),

presented in this section and available electronically as part of the IDSE Tool. You are not

required to use this form; however, if you choose not to use it, refer to Exhibit 7.6 for a list of the

minimum elements you must include in your IDSE report. 

The IDSE Tool creates a custom form for your system and provides links

to technical guidance from this manual. The tool is available on EPA’s website at

http://www.epa.gov/safewater/disinfection/stage2.

Before you begin Stage 2 DBPR compliance monitoring, you will also be required to

prepare a Stage 2 DBPR compliance monitoring plan. In addition, if you are a subpart H system

serving >3,300 people, you must submit a copy of your Stage 2 compliance monitoring plan to

the state. If you include compliance calculation procedures in your IDSE report, the report can

meet the requirement of the plan, and you do not have to prepare or submit a separate plan. As a

guide for specifying your compliance calculation procedures, refer to the Stage 1 DBPR,

141.133(b), and your Stage 1 compliance monitoring plan. Check with your state, as they may

have different requirements under the Stage 2 DBPR. If you are a consecutive or wholesale

system, your state may choose to use its special primacy authority to modify your Stage 2

compliance monitoring requirements. In this case, you should check with the state to see if they
IDSE Guidance Manual for the Final Stage 2 DBPR 7-45 January 2006

are going to use this authority. You should develop your IDSE report for the total number of

required Stage 2 compliance locations for your system. 

The IDSE report for standard monitoring form includes the following sections:

I. General Information

II. Stage 2 DBPR Requirements

III. Monitoring Results

IV. Justification of Stage 2 DBPR Compliance Monitoring Sites

V. Peak Historical Month and Stage 2 DBPR Compliance Monitoring Schedule

VI. Distribution System Schematic

VII. Attachments

Sections of the form with an asterisk (*) are required by the Stage 2 DBPR. Examples of

completed IDSE reports for standard monitoring using this form are provided in Appendices H

and I of this guidance manual and in the EPA manual, Initial Distribution System Evaluation

Guide for Systems Serving < 10,000 People. The rest of this section provides guidance on the

completion of this form.

I. General Information

I.A. PWS Information* - If nothing has changed since you completed your standard

monitoring plan form, copy information from your plan into this section. If your

system characteristics have changed, see Section 7.1.3 of this manual for

guidance on completing this section. 

I.B. Date Submitted* - Enter either the date that you are submitting the form

electronically, putting it in the mailbox, or dropping it off with an express

delivery service. Be sure to submit your IDSE report before the deadline found

on your requirements summary sheet.

I.C. PWS Operations - This section asks questions about your system to help inform

EPA and state personnel during the plan review process. If nothing has changed

since you completed your standard monitoring plan form, copy information from

your plan into this section. If your system characteristics have changed, see

Section 7.1.3 of this manual for guidance on completing this section.

I.D. Contact Person* - Enter the contact information of the person who is submitting

the report. This should be the person who will be available to answer questions

from EPA and/or state reviewers.

II. Stage 2 DBPR Requirements*

II.A Number of Compliance Monitoring Sites - Refer to the Standard Monitoring

Requirements - Attachment sheet in Chapter 2. Copy the numbers from the

“Stage 2 Compliance Monitoring Requirements” table that correspond to your

source type and the population served by your system. 
IDSE Guidance Manual for the Final Stage 2 DBPR 7-46 January 2006

II.B. Schedule - This should be the same schedule you entered for your standard

monitoring plan. See Section 7.1.3 of this manual for guidance. 

II.C. Compliance Monitoring Frequency - Refer to the Standard Monitoring

Requirements - Attachment in Chapter 2. Locate the monitoring frequency from

the “Stage 2 Compliance Monitoring Requirements” table that corresponds to

your source type and the population served by your system. Put a check mark in

the box corresponding to that monitoring frequency.

III. Monitoring Results*

III.A. Did you deviate in any way from your approved standard monitoring plan? - Put a

check mark in the appropriate box to identify whether your system collected any

standard monitoring samples on different dates or at different locations than

indicated in your approved standard monitoring plan. 

If you sampled on a different date or during a different week than scheduled in the

approved monitoring plan, you should write an explanation in the space provided

(or in attached sheets). You should include the standard monitoring site ID, the

scheduled sampling date or week from your monitoring plan, and the actual

sampling date. You must also explain why you sampled on a different day or

week than planned. An example explanation is shown below.

According to our standard monitoring plan, we were to collect samples at

standard monitoring sites 2 and 4 on January 14, 2009. However, a

major snowstorm created hazardous road conditions and limited our

access to sample locations. Therefore, we conducted our sampling at all

sites on January 18, 2009 after the roads were cleared.

III.B. Where were your TTHM and HAA5 samples analyzed? - Put a check mark in the

appropriate box to identify whether your system analyzed TTHM and HAA5

samples in an in-house laboratory or sent the samples to a certified laboratory for

analysis.

If you analyzed your TTHM and HAA5 samples in an in-house laboratory, check

the appropriate box to identify whether your laboratory is certified. If you sent

your TTHM and HAA5 samples to a certified laboratory, enter the name of the

laboratory in the blank. If you used more than one laboratory (e.g., if you used

different laboratories for standard monitoring samples and Stage 1 DBPR

compliance samples), list both laboratories, or check “in-house” and list the name

of the laboratory if applicable.

III.C What method(s) was used to analyze your TTHM and HAA5 samples? - Put a

check mark in the appropriate box to indicate the analytical method used to

measure the TTHM and HAA5 concentrations of your standard monitoring and

Stage 1 DBPR compliance samples. If more than one method was used (e.g., if

you used different laboratories for standard monitoring samples and Stage 1
IDSE Guidance Manual for the Final Stage 2 DBPR 7-47 January 2006

DBPR compliance samples), check more than one method. If you do not know

what method was used, contact your laboratory.

III.D. IDSE Standard Monitoring Results - TTHM - Enter your TTHM results for each

standard monitoring site for each monitoring period in which you collected data. 

For each sample result, enter the date on which sampling was conducted. If you

are a subpart H system serving more than 49,999 people or a ground water system

serving more than 499,999 people, you were required to conduct standard

monitoring at more than 8 sites. Therefore, you will need to attach additional

sheets.

III.E. IDSE Standard Monitoring Results - HAA5 - Enter your HAA5 results for each

standard monitoring site for each monitoring period in which you collected data. 

For each sample result, enter the date on which sampling was conducted. If you

are a subpart H system serving more than 49,999 people or a ground water system

serving more than 499,999 people, you were required to conduct standard

monitoring at more than 8 sites. Therefore, you will need to attach additional

sheets.

III.F. Stage 1 DBPR Compliance Monitoring Results - TTHM - Enter your TTHM

results for each Stage 1 site for each monitoring period in which you collected

data. For each sample result, enter the date on which sampling was conducted. 

Attach additional sheets if needed.

III.G. Stage 1 DBPR Compliance Monitoring Results - HAA5 - Enter your HAA5

results for each Stage 1 site for each monitoring period in which you collected

data. For each sample result, enter the date on which sampling was conducted. 

Attach additional sheets if needed.

IV. Justification of Stage 2 DBPR Compliance Monitoring Sites*

Enter the site ID from the distribution schematic and the site type (whether it is

highest TTHM, highest HAA5, Stage 1 DBPR, or a site selected using criteria other

than the site selection protocol). For example:

This site had the 2nd highest TTHM LRAA

An example of how you might justify a site that was not selected using the protocol is

below:

Among the three remaining high TTHM sites, standard monitoring Site 4 has the

highest TTHM LRAA. However, Stage 1 DBPR Site 7 has only a slightly lower

TTHM LRAA than standard monitoring Site 4. Therefore, we choose Stage 1

DBPR Site 7 over standard monitoring site 4 to maintain the historical DBP

record.
IDSE Guidance Manual for the Final Stage 2 DBPR 7-48 January 2006

V. Peak Historical Month and Proposed Stage 2 DBPR Compliance Monitoring

Schedule

V.A. Peak Historical Month* - Enter the month that you determined to be your peak

historical month.

V.B Is Your Peak Historical Month the Same as in Your IDSE Standard Monitoring

Plan? - Put a check mark in the appropriate box to identify whether your system

used the same peak historical month as in your standard monitoring plan. If your

standard monitoring results prompted you to change your peak historical month,

explain how you selected a new peak historical month.

V.C. Proposed Stage 2 DBPR Compliance Monitoring Schedule* - Enter the ID for

each Stage 2 DBPR compliance monitoring site in the table (these should match

the ID’s you enter in Section IV and on your schematic). Enter your proposed

sampling schedule for the number of monitoring periods identified in Section

II.C. The entry can be a specific date or week and can be in a number of different

formats. For example:

• 7/9/07

• 2nd week in Nov ‘07

• Week of 7/9/07 

Remember that at least one monitoring period must be during the peak historical

month identified in Section V.A. Note that there is only space for 8 monitoring

sites on this sheet. If you are a subpart H system serving more than 249,999

people you are required to monitor at more than 8 sites. Therefore, you will need

to attach additional sheets.

VI. Distribution System Schematic* - A distribution system schematic is required only if it

has changed from your approved IDSE standard monitoring plan. If it has changed,

attach the revised distribution system schematic. See Section 7.1.3 of this manual for

guidance. 

VII. Attachments - Put a check mark in each of the boxes corresponding to any attachments

that you have included in your report.

A distribution system schematic is required only if it has changed since you submitted

your IDSE standard monitoring plan. Refer to Section VI for details.

If you submit your IDSE report electronically, you also have the option to submit

attachments in hard copy. Include a note in your electronic IDSE report explaining that 

attachments are being submitted in hard copy, and mail the hard copy to the IPMC

mailing address in your Requirements Summary Sheet. The IPMC will match the hard

copy submission with your electronic submission when it is received.

If you are a subpart H system serving >3,300 people, you must submit a copy of your

Stage 2 compliance monitoring plan to the state. If you include compliance calculation
IDSE Guidance Manual for the Final Stage 2 DBPR 7-49 January 2006

procedures in your IDSE report, the report can meet the requirement of the plan, and you

do not have to prepare or submit a separate plan. As a guide for specifying your

compliance calculation procedures, refer to the Stage 1 DBPR, 141.133(b), and your

Stage 1 compliance monitoring plan. Check with your state, as they may have different

requirements under the Stage 2 DBPR. 

Enter the total number of pages in your IDSE report (including attachments) in the blank

at the bottom of this section. This will allow EPA or your state to ensure that all pages

were received.
IDSE Guidance Manual for the Final Stage 2 DBPR 7-50 January 2006

This page intentionally left blank.
IDSE Guidance Manual for the Final Stage 2 DBPR 7-51 January 2006

Form 7: IDSE Report for Standard Monitoring Page 1 of 9

I. GENERAL INFORMATION 

A. PWS Information* B. Date Submitted* _______

 PWSID:

 PWS Name:

PWS Address:

City: State: Zip:

Population Served:

System Type: Source Water Type: Buying / Selling Relationships:

~ CWS ~ Subpart H ~ Consecutive System 

~ NTNCWS ~ Ground ~ Wholesale System

 ~ Neither

C. PWS Operations 

Residual Disinfectant Type: ~ Chlorine ~ Chloramines ~ Other:_____________

 Number of Disinfected Sources: ___ Surface ___GWUDI ____ Ground ___ Purchased

D. Contact Person*

Name:

Title:

Phone #: Fax #:

E-mail: 

II. STAGE 2 DBPR REQUIREMENTS*

A. Number of

Compliance Monitoring

Sites

B. Schedule C. Compliance Monitoring Frequency

Highest TTHM: ~ Schedule 1 ~ During peak historical month 

 (1 monitoring period) Highest HAA5: ~ Schedule 2

 Existing Stage 1: ~ Schedule 3 ~ Every 90 days (4 monitoring periods)

Total: ~ Schedule 4
IDSE Guidance Manual for the Final Stage 2 DBPR 7-52 January 2006

Form 7: IDSE Report for Standard Monitoring Page 2 of 9

III. MONITORING RESULTS*

A. Did you deviate in any way from your approved standard

monitoring plan? 

~ Yes ~ No

If YES, explain (attach additional pages if necessary):

B. Where were your TTHM and HAA5 samples analyzed?

~ In-House 

Is your in-house laboratory certified? ~ Yes ~ No

~ Certified Laboratory

Name of certified laboratory:

C. What method(s) was used to analyze your TTHM and HAA5

samples?

 TTHM HAA5

~ EPA 502.2 ~ EPA 552.1

~ EPA 524.2 ~ EPA 552.2

~ EPA 551.1 ~ EPA 552.3

~ SM 6251 B
IDSE Guidance Manual for the Final Stage 2 DBPR 7-53 

Form 7: IDSE Report for Standard Monitoring III. MONITORING RESULTS (Continued)* D. IDSE Standard Monitoring Results - TTHM

Site ID1 Data Type TTHM (mg/L) 

Sample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample Result

1 Verify that site IDs for IDSE standard monitoring sites match the site IDs in your Standard Monitoring Plan.

Attach additional sheets as needed for IDSE standard monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR 7-54 

Form 7: IDSE Report for Standard Monitoring III. MONITORING RESULTS (Continued)*E. IDSE Standard Monitoring Results - HAA5

Site ID1 Data Type HAA5 (mg/L) 

Sample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample Result

1 Verify that site IDs for IDSE standard monitoring sites match the site IDs in your Standard Monitoring Plan.

Attach additional sheets as needed for IDSE standard monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR 7-55 

Form 7: IDSE Report for Standard Monitoring III. MONITORING RESULTS (Continued)*F. Stage 1 DBPR Compliance Monitoring Results - TTHM

Site ID1 Data Type TTHM (mg/L) 

Sample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample Result

1 Verify that site IDs for Stage 1 compliance monitoring sites match the site IDs in your Standard Monitoring Plan.

Attach additional sheets as needed for Stage 1 compliance monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR 7-56 

Form 7: IDSE Report for Standard Monitoring III. MONITORING RESULTS (Continued)*G. Stage 1 DBPR Compliance Monitoring Results - HAA5

Site ID1 Data Type HAA5 (mg/L) 

Sample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample Result

1 Verify that site IDs for Stage 1 compliance monitoring sites match the site IDs in your Standard Monitoring Plan.

Attach additional sheets as needed for Stage 1 compliance monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR 7-57 January 2006

Form 7: IDSE Report for Standard Monitoring Page 7 of 9

IV. JUSTIFICATION OF STAGE 2 DBPR COMPLIANCE MONITORING SITES*

Stage 2

Compliance

Monitoring

Site ID

Site Type Justification

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

Attach additional copies of this sheet if you need more room.
IDSE Guidance Manual for the Final Stage 2 DBPR 7-58 January 2006

Form 7: IDSE Report for Standard Monitoring Page 8 of 9

V. PEAK HISTORICAL MONTH AND PROPOSED STAGE 2 DBPR COMPLIANCE

MONITORING SCHEDULE

A. Peak Historical Month* 

B. Is Your Peak Historical Month the Same as in Your IDSE Standard

Monitoring Plan?

~ Yes ~ No

If no, explain how you selected your new peak historical month (attach

additional sheets if needed)

C. Proposed Stage 2 DBPR Compliance Monitoring Schedule*

Stage 2

Compliance

Monitoring

Site ID

Projected Sampling Date (date or week)1

period 1 period 2 period 3 period 4

 

1

 period = monitoring period. Complete for the number of monitoring periods from

Section II.C.

Attach additional copies of this sheet if you need more room.
IDSE Guidance Manual for the Final Stage 2 DBPR 7-59 January 2006

Form 7: IDSE Report for Standard Monitoring Page 9 of 9

VI. DISTRIBUTION SYSTEM SCHEMATIC*

ATTACH a schematic of your distribution system if it has changed since you submitted

your Standard Monitoring Plan (Form 6). 

VII. ATTACHMENTS

~ Additional sheets for explaining how and why you deviated from your standard

monitoring plan (Section III).

~ Additional sheets for Standard Monitoring Results (Section III). REQUIRED if you are

a subpart H system serving more than 49,999 people or a ground water system

serving more than 499,999 people.

~ Additional sheets for Stage 2 DBPR Compliance Monitoring Sites (Section IV). 

REQUIRED if you are a subpart H system serving more than 249,999 people.

~ Additional sheets for explaining how you selected the peak historical month (Section

V).

~ Additional sheets for proposed Stage 2 DBPR peak historical month and compliance

monitoring schedule (Section V). REQUIRED if you are a subpart H system serving

more than 249,999 people.

~ Distribution system schematic* (Section VI). REQUIRED if it has changed from

your approved IDSE standard monitoring plan.

~ Compliance calculation procedures (for Stage 2 Compliance Monitoring Plan).

Total Number of Pages in Your Report: ______

Note: Fields with an asterisk (*) are required by the Stage 2 DBPR
IDSE Guidance Manual for the Final Stage 2 DBPR 7-60 January 2006

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IDSE Guidance Manual for the Final Stage 2 DBPR 7-61 January 2006

7.4 Recordkeeping

The IDSE standard monitoring report must be kept on file for

10 years after the date it is submitted. If EPA or your state

modifies the recommendations made in your report or approves

alternative Stage 2 DBPR compliance monitoring locations, you

must also keep a copy of EPA or your state’s notification on file

for 10 years after the date of the notification. You must make

your IDSE report and any notification available for review by

your state or the public.

The standard monitoring plan, including any modifications by

EPA or your state, must also be kept on file for as long as you are

required to retain your IDSE standard monitoring report. You

must make the plan and any modifications available for review by

your state or the public.

7.5 Next Steps: Preparing the Stage 2 DBPR Compliance Monitoring Plan 

As the final step before you can begin compliance monitoring for the Stage 2 DBPR, you

must develop and implement a Stage 2 DBPR monitoring plan by the deadline provided in

your requirements summary sheet. The plan will be similar to your Stage 1 DBPR monitoring

plan in that it will identify how you intend to sample for compliance with Stage 2. You must

keep your plan on file for state and public review. If you are a subpart H system serving >

3,300 people, you must submit your plan to EPA or your state prior to when you are required to

start monitoring.

Exhibit 7.8 contains the minimum requirements for what must be included in your Stage 2

DBPR compliance monitoring plan. Because compliance monitoring plans are not addressed as

part of the IDSE provisions of the Stage 2 DBPR, EPA has not included detailed guidance for

developing Stage 2 compliance monitoring plans in this guidance manual. EPA plans to

develop other manuals and training that address the compliance monitoring provisions of the

Stage 2 DBPR.

See EPA’s website http://www.epa.gov/safewater/disinfection/stage2 for an up-to-date

inventory of Stage 2 DBPR guidance manuals and training materials, or call the Safe Drinking

Water Hotline at 1-800-426-4791.
IDSE Guidance Manual for the Final Stage 2 DBPR 7-62 January 2006

Exhibit 7.8 Required Contents of Stage 2 DBPR Compliance Monitoring Plans

All Systems Additional Requirements for Consecutive and

Wholesale Systems 1

• Monitoring locations

• Monitoring dates

• Compliance calculation

procedures

• If your state has used its special primacy

authority to modify your monitoring

requirements, you must include monitoring plans

for other systems in your combined distribution

system

1. See Appendix D of this manual for guidance specifically for consecutive and wholesale systems

References 

T.M. Walski, D.V. Chase, D.A. Savic, W. Grayman, S. Beckwith, E. Koelle. 2003. “Advanced Water 

Distribution Modeling and Management”, Haestad Methods, Waterbury CT: Haestad Press. 
Appendix A 

Formation of Disinfection Byproducts
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IDSE Guidance Manual for the Final Stage 2 DBPR A-1 January 2006

A.1 Introduction

The formation of disinfection byproducts (DBPs) is a function of many factors,

including:

• precursor concentration, 

• disinfectant dose, 

• water pH, 

• temperature, 

• contact time, and 

• bromide ion concentration. 

The purpose of this appendix is to provide a brief summary of the factors that affect DBP

formation in water treatment processes and distribution systems. More detailed information on

this subject can be found in other existing literature, including the following EPA guidance

documents:

• Enhanced Coagulation and Enhanced Precipitative Softening Guidance Manual,

available from EPA (Document #815-R-99-012)

• Controlling Disinfection By-Products and Microbial Contaminants in Drinking

Water, available from EPA (Document #600-R-01-110)

• Alternative Disinfectants and Oxidants Guidance Manual, available from EPA

(Document #815-R-99-014)

• Microbial and Disinfection Byproduct Rules: Final Simultaneous Compliance

Guidance Manual, available from EPA (Document #)

Moreover, it should be noted that the book entitled Formation and Control of

Disinfection By-Products in Drinking Water (Singer et al., 1999) contains a detailed compilation

of the chemistry of DBP formation in Chapter 3 (Krasner, 1999). The references for that chapter

represent the seminal works in the literature. Additional references are also presented in the

following discussion.

A.2 Formation of DBPs

Organic DBPs (and oxidation byproducts) are formed by the reaction between organic

substances, inorganic compounds such as bromide, and oxidizing agents that are added to water

during treatment. In most water sources, natural organic matter (NOM) is the major constituent

of organic substances and DBP precursors. Total organic carbon (TOC) is typically used as a

surrogate measure for precursor levels and is used in the Stage 1 DBPR to determine precursor

removal compliance. Dissolved organic carbon (DOC) and UV absorption at 254 nm [UV254] are

also often used as surrogate parameters for monitoring precursor levels. The following are the

major factors affecting the type and amount of DBPs formed.
IDSE Guidance Manual for the Final Stage 2 DBPR A-2 January 2006

• Type of disinfectant, dose, and residual concentration

• Concentration and characteristics of precursors

• Water temperature

• Water chemistry (including pH, bromide ion concentration, organic nitrogen

concentration, and presence of other reducing agents such as iron and manganese)

• Contact time and mixing conditions for disinfectant (oxidant), coagulant, source

water, and other treatment chemicals

A summary for each of these factors follows.

A.2.1 Impact of Disinfection Method on Organic DBP Formation

Organic DBPs can be subdivided into halogenated and non-halogenated byproducts. 

Halogenated organic disinfection byproducts are formed when organic and inorganic compounds

found in water react with free chlorine, free bromine, or free iodine. The formation reactions

may take place in the treatment plant and the distribution system. Free chlorine can be

introduced to water directly as a primary or secondary disinfectant, or as a byproduct of the use

of chlorine dioxide and chloramines. 

Reactions between precursors, bromide and iodide ions, and chlorine lead to the

formation of a variety of halogenated DBPs including THMs and HAAs. The presence of

bromide can affect both the rate and the yield of DBPs, and if the ratio of bromide to precursors

(measured as TOC) increases, the percentage of brominated DBPs also increases (Krasner, 1999

and references therein). Similarly, the presence of iodide may result in the formation of mixed

chlorobromoiodomethanes byproducts (Bichsel and Von Gunten, 2000). 

 The following is an overview of disinfectants including chlorine, chloramines, chlorine

dioxide, ultraviolet (UV) irradiation, and ozone and their potential impacts on the formation of

THMs and HAAs. Some discussion is also included of potential issues associated with the use

of these disinfectants.

Chlorine

Most water systems that disinfect use either liquid or gaseous chlorine as their

disinfectant. Halogenated byproducts are formed when free chlorine reacts with natural organic

matter. In addition, brominated byproducts are formed when source water containing bromide is

chlorinated. Chlorine reacts with natural organic matter in the water to form THMs, HAAs and

other disinfection byproducts. 
IDSE Guidance Manual for the Final Stage 2 DBPR A-3 January 2006

Water systems using chlorine can modify their treatment to reduce TTHM and HAA5

concentrations in the finished water. Treatment modifications include moving the point of

chlorination downstream in the water treatment plant, optimizing coagulation to enhance

removal of DBP precursors, and using another disinfectant or oxidant to supplement or replace

the use of free chlorine. Moving the point of chlorination downstream in the treatment train

allows the concentration of disinfection byproduct precursors to be reduced before chlorine is

added and may be implemented seasonally. Systems that are required to develop a disinfection

profile must calculate a disinfection benchmark for the treatment configuration in place before

making any changes to their disinfection practices.

Chloramines

Studies have documented that chloramines produce significantly lower THM and HAA

levels than free chlorine, and there is no clear evidence that the reaction of precursors and

chloramine leads to the formation of THMs (Singer and Reckhow, 1999; USEPA, 1999). 

Predictions of an empirical DBP formation model calibrated using ICR data indicated that under

chloraminated conditions, THMs and HAAs are formed in full-scale plants and distribution

systems at a fraction of the amount that would be expected based on observations of DBP

formation under free chlorine conditions. The amount of formation with chloramines varied

from 5% to 35% of that calculated for free chlorine, depending on the individual DBP species

(Swanson et al., 2001). When chloramination is used, it is possible that DBPs might form if

chlorine is added before ammonia. If the mixing process is inefficient, it is also possible that

DBPs might form during the mixing of chlorine and ammonia. In this case, free chlorine might

react with precursors before the complete formation of chloramines. In addition,

monochloramine slowly hydrolyzes to release free chlorine in water. This free chlorine may

contribute to the formation of small amounts of additional DBPs in the distribution system. 

Additional issues should be considered prior to switching to chloramination. For

example, systems using chloramines that have excess ammonia, warm temperatures, long

distribution system residence times, and low chloramine residuals may experience nitrification in

their distribution systems. Also, systems should be aware that switching from chlorine to

chloramines in the distribution system can also change the oxidation reduction potential of the

water. The Microbial and Disinfection Byproduct Rules: Final Simultaneous Compliance

Guidance Manual includes a detailed discussion of factors to consider prior to switching to

chloramines.

Chlorine Dioxide

The application of chlorine dioxide does not produce significant amounts of THMs and

HAAs unless chlorine is formed as an impurity in the generation process. However, THMs and

HAAs will form if excess chlorine is added to water to ensure complete reaction with sodium

chlorite during the production of chlorine dioxide. 

Chlorine dioxide can also oxidize bromide ions to bromine. The bromine can then react

with organic matter to form brominated DBPs. Systems with high bromide concentrations that

are near the Stage 2 DBPR limits for THMs or HAA5 should take this into account. 
IDSE Guidance Manual for the Final Stage 2 DBPR A-4 January 2006

When chlorine dioxide is used as a disinfectant, chlorite is formed. The MCL for chlorite

was set at 1.0 mg/L by the Stage 1 D/DBPR. Systems using chlorine dioxide must monitor daily

at the entrance to the distribution system for chlorite. They must also collect 3 chlorite samples

per month in the distribution system. As much as 70 percent of the chlorine dioxide added to

water can break down to form chlorite. This limits the dose of chlorine dioxide that can be used

and therefore the amount of inactivation that can be achieved. 

Chlorite can react with excess chlorine to reform chlorine dioxide. Some systems may

opt to boost with chlorine to maintain a residual in the distribution system. Systems that use

chlorine dioxide and then boost with chlorine in the distribution system are required by the Stage

1 D/DBPR to monitor the chlorine dioxide residual in the distribution system. If doses are high

enough, systems could exceed either the chlorine dioxide MRDL or the chlorite MCL. 

Reformed chlorine dioxide can also volatilize at consumer’s taps and react with volatile organics

to cause odor problems. 

Ultraviolet Irradiation

To date, there is no evidence to suggest that ultraviolet irradiation results in the formation

of any disinfection byproducts; however, little research has been performed in this area. Most of

the research regarding application of UV and DBP formation has focused on chlorinated DBP

formation as a result of UV application prior to the addition of chlorine or chloramines (Malley

et al., 1995). Studies comparing the effects of UV light followed by chlorination versus

chloramination suggest UV does not affect DBP formation in either of these two cases (Malley et

al., 1995). 

A main drawback with UV is the possibility of microbes passing through at times the

lamp is operating off specification. At low UV intensities, some microbes have shown the

ability to repair damage done by UV light. Because of this, even drops in lamp intensity not

enough to cause a violation of disinfection requirements may allow microbes into the

distribution system where they can repair themselves, colonize biofilms, and cause problems

with TCR compliance. Therefore any periods of the lamp operating off specification should be

minimized. 

Because UV disinfection relies on UV light interacting with the organism’s genetic

material to be effective, any substance that either absorbs or refracts the UV light can interfere

with disinfection. Compounds with the potential to do this include dissolved organic carbon

(DOC), iron, manganese, calcium, aluminum, and ozone. EPA has developed an Ultraviolet

Disinfection Guidance Manual that discusses these issues in detail.
IDSE Guidance Manual for the Final Stage 2 DBPR A-5 January 2006

Ozone

Ozone does not directly produce chlorinated DBPs. However, if chlorine is added before

or after ozonation, mixed bromo-chloro DBPs as well as chlorinated DBPs can form. Ozone can

alter the characteristics of precursors and affect the concentration and speciation of halogenated 

DBPs (THMs and HAAs) when chlorine is subsequently added downstream. In waters with 

bromide concentrations, ozonation can lead to the formation of bromate and other brominated

DBPs. Bromate, like TTHM and HAA5, is a regulated DBP. 

Ozonation of natural waters also produces aldehydes, haloketones, ketoacids, carboxylic

acids, and other types of biodegradable organic material. The biodegradable fraction of organic

material can serve as a nutrient source for microorganisms, and should be removed to prevent

microbial regrowth in the distribution system. AOC is a measure of the organic carbon readily

available as food for microorganisms. Some systems that have added ozone without biological

filtration have experienced increased AOC and microbial growth in the distribution system. 

Increased biological growth in the distribution system may result in increased corrosion, taste

and odor problems, as well as potential health risk. 

A.2.2 Disinfectant Dose

As the concentration of chlorine or chloramines increases, the production of DBPs

increases. Formation reactions continue as long as precursors and disinfectant are present

(Krasner, 1999 and references therein). 

In general, the impact of chlorine concentration is greater during primary disinfection

than during secondary disinfection. The amount of chlorine added during primary disinfection is

usually less than the long-term demand, therefore, the concentration of chlorine is often

insufficient to react with all DBP precursors in the water. On the contrary, during secondary

disinfection, DBP formation is often limited by the concentration of DBP precursors since excess

disinfectant is added to the water to maintain a residual concentration in the distribution system

(Singer and Reckhow, 1999). 

Distribution system

In distribution systems, DBP formation reactions can become limited by the disinfectant

concentration when the free chlorine residual drops to low levels. As a rule of thumb, Singer

and Reckhow (1999) suggest this event takes place when the chlorine concentration drops below

approximately 0.3 mg/L.

In many systems booster disinfection is applied to raise disinfectant residual

concentration, especially in remote areas of the distribution system or near storage tanks where

water age may be high and disinfectant residuals can be low. The additional chlorine dose

applied to the water at these booster facilities may increase THM and HAA levels. Further,

booster chlorination can maintain high HAA concentrations because the increased disinfection

residuals can prevent the biodegradation of HAAs. However, booster chlorination can also be
IDSE Guidance Manual for the Final Stage 2 DBPR A-6 January 2006

useful in decreasing DBP levels by reducing the concentration of secondary disinfectant needed

in the finished water leaving the plant. 

A.2.3 Time Dependency of DBP Formation

The longer the contact time between disinfectant/oxidant and precursors, the greater the

amount of DBPs that can be formed. Generally, DBPs continue to form in drinking water as

long as a disinfectant residual and precursors are present. After formation, THMs and HAAs are

generally chemically stable as long as a significant disinfectant residual is still present (Singer

and Reckhow, 1999). As a consequence, high concentrations of DBPs can accumulate in water

with old age. 

High THM levels usually occur where the water age is the oldest. Conversely, HAAs

cannot be consistently related to water age because HAAs are known to biodegrade over time

when the disinfectant residual is low. This might result in relatively low HAAs concentrations in

areas of the distribution system where disinfectant residuals are depleted.

A.2.4 Concentration and Characteristics of Precursors

The formation of THMs and HAAs is related to the concentration of precursors at the

point of disinfection. In general, greater DBP levels are formed in waters with higher

concentrations of precursors. Therefore, removing DBP precursors prior to disinfectant addition

is one of the most effective approaches to DBP control.

Studies conducted with different fractions of NOM have indicated the reaction between

disinfectant and NOM with high aromatic content tends to form higher DBP levels than NOM

with low aromatic content. For this reason, UV254, which is generally linked to the aromatic and

unsaturated components of NOM, is considered a good predictor of the tendency of a source

water to form THMs and HAAs (Owen et al., 1998; Singer and Reckhow, 1999). 

Specific ultraviolet light absorbance (SUVA) is also often used to characterize

aromaticity and molecular weight distribution of NOM. This parameter is defined as the ratio

between UV254 and the dissolved organic carbon (DOC) concentration of water (Letterman et al.,

1999). It should be noted that the more highly aromatic precursors in source waters,

characterized by high UV254, are more easily removed by coagulation. Thus, it is the UV254

measurement immediately upstream of the point(s) of disinfection within a treatment plant that is

more directly related to THM and HAA formation potential.
IDSE Guidance Manual for the Final Stage 2 DBPR A-7 January 2006

A.2.5 Water Temperature

The rate of formation of THMs and HAAs increases with increasing temperature.

Consequently, the highest THM and HAA levels may occur in the warm summer months. 

However, water demands are often higher during these months, resulting in lower water age

within the distribution system which helps to control DBP formation. Furthermore, high

temperature conditions in the distribution system promote the accelerated depletion of residual

chlorine, which can mitigate DBP formation and promote biodegradation of HAAs unless

chlorine dosages are increased to maintain high residuals (Singer and Reckhow, 1999). For

these reasons, depending on the specific system, the highest THM and HAA levels may be

observed during months which are warm, but not necessarily the warmest. Higher DBP

precursor levels in the fall or spring may also cause the highest THM and HAA levels to be

observed in cooler months.

Seasonal trends affect THM and HAA concentrations differently. For example, when

water is colder, microbial activity is typically lower and DBP formation reactions are slower. 

Under these conditions, the highest THM and HAA concentrations might appear in the oldest

water in the system. In warmer water, the highest HAA concentrations might appear in fresher

water, which is likely to contain higher disinfectant residuals that can prevent the biodegradation

of HAAs.

A.2.6 Water pH

In the presence of DBP precursors and chlorine, THM formation increases with

increasing pH, whereas the formation of HAAs decreases with increasing pH. The increased

THM production at high pH is likely promoted by base hydrolysis (favored at high pH). HAAs

are not sensitive to base hydrolysis but their precursors are. Consequently, pH can alter their

formation pathways, leading to decreased production with increasing pH (Singer and Reckhow,

1999).

Water pH also affects the balance of hypobromite and hypobromous acid formation

during the ozonation of waters containing significant concentrations of bromides. At low pH,

the equilibrium shifts to the less reactive hypobromous acid. Consequently, the overall

formation of bromate decrease as the pH decreases (Singer and Reckhow, 1999). However, the

hypobromous acid at low pH can react with NOM to form HAAs and THMs. This may occur if

systems using ozone operate at low pH to control bromate formation. In addition, systems may

maintain a low pH to achieve the required inactivation.
IDSE Guidance Manual for the Final Stage 2 DBPR A-8 January 2006

A.3 References

Bichsel, Y., and Von Gunten U., 2000. Environmental Science and Technology, 34 (13): 2784.

Krasner S. W., 1999. Chemistry of disinfection by-product formation. In Formation and Control

of Disinfection By-products in Drinking Water. Singer, P.C. (editor). American Water Works

Association, Denver, CO.

Letterman, R.D., A. Amirtharajah, and C.R. O’Melia. 1999. Coagulation and flocculation. In

Water quality and treatment. 5th edition. Letterman R.D. technical editor, American Water

Works Association, McGraw-Hill, New York, NY.

Malley, J.P., J.P. Shaw, and J.D. Ropp. 1995. Evaluation of by-products produced by treatment

of groundwaters with ultraviolet irradiation. AWWA Research Foundation Report No. 90685.

Denver CO.

Owen et al., 1998. Removal of DBP precursors by GAC adsorption. AWWA Research

Foundation Report No. 90744. Denver CO.

Singer, P.C., ed. 1999. Formation and Control of Disinfection By-Products in Drinking Water.

American Water Works Association, Denver, CO.

Singer, P.C. and D.A. Reckhow. 1999. Chemical oxidation. In Water quality and treatment. 5th

edition. Letterman R.D. technical editor, American Water Works Association, McGraw-Hill,

New York, NY.

R. Song et al. 1997. Bromate Minimization During Ozonation. Journal American Water Works

Association. 89(6):69.

Swanson, W.J., Z. Chowdhury, R. Summers, and G. Solarik. 2001. Predicting DBPs at full-scale:

calibration and validation of the Water Treatment Plant Model using ICR data. Conference

proceedings, 2001 AWWA Annual Conference, Washington, DC.

USEPA. 1999. Alternative disinfectants and oxidants guidance manual. EPA 815-R-99-014.
Appendix B

Stage 2 DBPR and LT2ESWTR Compliance Schedule
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IDSE Guidance Manual for the Final Stage 2 DBPR B-1 

Schedule 1Systems serving> 100,000 people1

IDSE Plan Due IDSE Report Due Begin ComplianceOctober 1, 2006 January 1, 2009 April 1, 2012

Schedule 2Systems serving 50,000 to 99,999 people1

IDSE Plan Due IDSE Report Due Begin ComplianceApril 1, 2007 July 1, 2009 October 1, 2012

Schedule 3Systems serving 10,000 to 49,999 people1

IDSE Plan Due IDSE Report Due Begin CompliaOctober 1, 2007 January 1, 2010 October 1, 201

Schedule 4Systems serving < 10,000 people1

IDSE Plan Due IDSE Report DueApril 1, 2008 July 1, 2010 Begin Complia

October 1, 201

1 Includes systems that are part of a combined distribution system in which the largest system serves this popula2 Subpart H systems serving fewer than 10,000 that must conduct Crypto monitoring can sample twice a month 

monthly for 24 months. These systems have an additional 12 months to comply with Stage 2 DBPR MCLs and 

2006 2007 2008 2009 2010 2011 2012

Crypto mon.2

Treatment Installation Pos

2013 2

Treatment Installation Possible Extension

Treatment Installation Possible Extensio

2006 2007 2008 2009 2

2010 2011 2012 2013

Treatment Installation2 Pos

LT2 Crypto monitoring

IDSE mon.

LT2 Crypto monitoring

LT2 Crypto monitoring

IDSE mon.

IDSE mon.

IDSE mon.

E. Coli mon.

Exhibit B.1 Stage 2 DBPR and LT2ESWTR Compliance Schedule
IDSE Guidance Manual for the Final Stage 2 DBPR B-2 January 2006

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Appendix C

TTHM and HAA5 Sampling Protocol
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IDSE Guidance Manual for the Final Stage 2 DBPR C-1 January 2006

C.1 Introduction

It is important that TTHM and HAA5 samples are properly collected and analyzed to

ensure accurate analytical results. For example, THMs are volatile chemicals, meaning they can

move from the liquid phase to the gas phase under ambient conditions. Therefore, care must be

taken to make sure that no air bubbles are present in the filled sample vial. This appendix

summarizes information on proper sample collection, handling, and laboratory analytical

techniques.

C.2 Analytical Methods

Exhibit C.1 lists the analytes that are included in TTHM and HAA analyses. 

Exhibit C.1 TTHM and HAA Analytes

Analyte Group Code

Analytes in Group

(Abbreviation for Analyte)

HAA5 Haloacetic acids:

 Dibromoacetic acid (DBAA)

 Dichloroacetic acid (DCAA)

 Monobromoacetic acid (MBAA)

 Monochloroacetic acid (MCAA)

 Trichloroacetic acid (TCAA)

HAA9 HAA5 plus four additional analytes

 Bromochloroacetic acid (BCAA)

 Bromodichloroacetic acid (BDCAA)

 Chlorodibromoacetic acid (CDBAA)

 Tribromoacetic acid (TBAA)

TTHM Trihalomethanes:

 Bromodichloromethane (BDCM)

 Bromoform (CHBr3) 

 Chloroform (CHCl3)

 Dibromochloromethane (DBCM)

Exhibit C.2 lists the approved laboratory analytical methods for TTHM and HAA5 along

with guidelines for sample collection and storage. These guidelines include type of sample

container, preservative and dechlorinating agents, pH, and sample collection. 
IDSE Guidance Manual for the Stage 2 DBPR C-2 

Exhibit C.2 Sampling Requirements of TTHM and HAA5 Analyses

AnalyteGroup

AnalyticalMethod1

Sample ContainerMaterial2

Preservative/Dechlorinating Agent (Recommended amount)

StorageGuidelines Samp

TTHM EPA 502.2 40 mL -120 mL screw

cap glass vials withPTFE-faced siliconeseptum

Options:(1) 3 mg Na2S2O3/40 mL sample or 

(2) 3 mg Na2S2O3/40 mL sample and immediateacidification using HCl to pH < 2 or(3) 25 mg ascorbic acid/40 mL sample andimmediate acidification using HCl to pH < 2.Option 1 may be used if THMs are the onlycompounds being determined in the sample.Options 2 & 3 require the sample to be dechlorinatedprior to the addition of acid.

Keep at 4°C.14 daysmaximumhold time3

.

Fill botdo not No air Do not Seal sspaceIf ascodechlothe saAcidificcontain

the safor VOmust bsample labora

EPA 524.2 40 mL -120 mL screw

cap glass vials withTeflon-faced siliconeseptum

EPA 551.1 60 mL screw cap glass

vials with PTFE-facedsilicone septum

1 g phosphate buffer & NH4Cl or Na2SO3 mixture per

60 mL sample (mixture consists of 1 part Na2HPO4,

99 parts KH2PO4 , and 0.6 parts NH4Cl or Na2SO3. 

1g per 60 mL results in a pH of 4.8-5.5 and 0.1 mgNH4Cl or Na2SO3 per mL of sample.)

HAA5 EPA 552.1 250 mL (approx.) amber

glass bottles fitted withTeflon-lined screw caps

0.1 mg NH4Cl per mL of sample 

EPA 552.2 50 mL (approx.) amber

glass bottles fitted withTeflon-lined screw caps

EPA 552.34 50 mL (approx.) amber

glass bottles fitted withTeflon-lined screw caps

SM 6251 B 40 mL or 60 mL screw

cap glass vials withPTFE-faced siliconeseptum

65 mg NH4Cl

1 (40 CFR 141.131 (b))2 Selection of container should be coordinated with the laboratory. 3 The holding time has been changed to 14 days for all HAA5 samples as a part of the Stage 2 DBPR. 4 EPA Method 552.3 has been added as an approved HAA5 method as part of the Stage 2 DBPR.
IDSE Guidance Manual for the Final Stage 2 DBPR C-3 January 2006

C.2.1 Sampling Procedure

It is important to follow sampling procedures provided by your certified laboratory. 

Sampling procedures may vary slightly among individual laboratories; you should contact your

laboratory to learn their procedures. The following is a common procedure for collecting

samples for TTHM and HAA5 analyses.

You will need:

1) Sample vials provided by laboratory (most laboratories will provide sample vials with

proper preservative and dechlorinating agents) 

2) Small bottle of 1:1 hydrochloric acid and eye dropper or pasteur pipette (pH

adjustment is necessary for some TTHM methods) (many laboratories will provide

ampules with acid for pH adjustment)

3) Water proof labels and permanent (indelible ink) marker

4) Ice/coolant and cooler

Procedure:

1) Label each sample vial. Use waterproof labels and indelible ink. Each label should

include:

• Unique sample ID

• System name

• Sample location

• Sample date and time

• Analysis required, if not already on label

2) Remove the aerator from the tap, if there is one present.

3) Open the water tap and allow the system to flush until the water temperature has

stabilized (usually about 3-5 minutes). The purpose of this step is to ensure the

sample does not represent stagnant water that has set for a long time in the water line

between the street and the faucet. The sample should be representative of the water

flowing through the distribution system at the chosen sampling point. 

4) Adjust the flow so that no air bubbles are visually detected in the flowing stream.
IDSE Guidance Manual for the Final Stage 2 DBPR C-4 January 2006

5) Slowly fill the sample vial almost to the top without overflowing. Use the bottle cap

to add a small amount of additional sample water while simultaneously capping the

vial to achieve a headspace-free sample. Be careful not to rinse out any of the

preservative/dechlorinating agent during this process. After the bottle is filled, invert

three or four times.

6) If collecting TTHM samples that require acidification, let the sample set for about 1

minute, allowing the dechlorinating chemical to take effect. Carefully open the vial

and adjust the pH of the TTHM sample to < 2 by adding approximately 4 drops of

hydrochloric acid for every 40 mL of sample (amount of acid needed will depend on

buffering capacity of sample). Recap the vial, and invert three or four times.

7) Invert the vial and tap it to check for air bubbles. If bubbles are detected, carefully

open the vial and add more sample water using the cap to achieve a headspace-free

sample.

8) Immediately cool the samples to 4o

C by placing them in a cooler with frozen

refrigerant packs or ice, or in a refrigerator. Samples should be maintained at this

temperature during shipment to the laboratory.

9) Complete the Sample Chain of Custody provided by the laboratory and include it

with the sample shipment.

C.2.2 Regarding Loss of Samples

Samples may be “lost” due to a number of reasons:

• Bottle broken during shipment from the water system to the laboratory

• Sample improperly collected (e.g., sample bottle not completely filled)

• Sample improperly shipped (e.g., not kept cold during shipment)

• Sample improperly preserved (e.g., not dechlorinated)

• Bottle is broken or lost at the laboratory

• Quality control doesn’t meet method specifications when sample is analyzed

You should conduct resampling for the lost sample as soon as possible after the loss is

determined. Only the lost sample needs to be recollected, not the entire sample set that was

collected together. Make sure to note the loss of sample and resample date as a deviation in your

IDSE report. 
IDSE Guidance Manual for the Final Stage 2 DBPR C-5 January 2006

C.3 Analytical Method Descriptions

The following are brief summaries of the approved TTHM and HAA5 methods.

C.3.1 EPA Method 502.2

Highly volatile compounds with low water solubility, including TTHMs, are extracted

from the water sample by bubbling an inert gas through 5 mL of the sample. The chemical

compounds that are extracted from the water sample are then trapped in a tube that contains

material to which the chemicals attach, or sorb. Once the extraction process has been completed,

the tube containing the extracted chemicals is heated and backflushed with helium, and the

mixture of helium and chemicals enters a capillary gas chromatography (GC) column. The

column is temperature programmed to separate the chemicals extracted from the water, which

are then detected with a photoionization detector (PID) and an electrolytic conductivity detector

(ELCD) placed in series. The amount of each chemical is determined using procedural standard

calibration. The PID is not required if only TTHMs are being measured. 

Chemical compounds are identified by comparing the retention times of unknown GC

peaks with retention times for chemical standards analyzed under the same conditions. 

Confirmation can be made by comparing the relative response from the two detectors. For

absolute confirmation of results, a gas chromatography/mass spectrometry (GC/MS)

determination can be made using U.S. EPA Method 524.2.

For a complete description of this method see EPA publication: EPA/600/R-95/131

Methods for the Determination of Organic Compounds in Drinking Water: Supplement III. 

C.3.2 EPA Method 524.2

Volatile organic compounds, including TTHMs, are extracted from the water sample by

bubbling an inert gas through the sample. Extracted compounds are trapped in a tube that

contains material to which the chemicals attach, or sorb. When the extraction process is

complete, the tube is heated and backflushed with helium to de-sorb the trapped chemicals into a

capillary gas chromatography (GC) column interfaced with a mass spectrometer (MS). The GC

column is temperature programmed to allow for the separation of different chemicals, which are

then detected with the MS. Compounds detected by the MS are identified by comparing their

measured mass spectra and retention times with reference mass spectra and retention times in a

database. Reference mass spectra and retention times for different compounds are obtained by

measuring calibration standards under the same conditions that are used for the water samples. 

The concentration of each compound is measured by comparing the MS response of the

compound with the MS response of another compound used as an internal standard. Surrogate

chemicals, whose concentrations are known in every sample, are measured using the same

internal standard calibration procedure.
IDSE Guidance Manual for the Final Stage 2 DBPR C-6 January 2006

 For a complete description of this method see EPA publication: EPA/600/R-95/131

Methods for the Determination of Organic Compounds in Drinking Water: Supplement III. 

C.3.3 EPA Method 551.1

A 50 mL volume of the sample is extracted using either 3 mL of methyl-tert-butyl ether

(MTBE) or 5 mL of pentane. A small sub-sample of the extract (2 μL) is then injected into a GC

equipped with a fused silica capillary column for separation, and a linearized electron capture

detector for analysis. Concentrations of different chemical compounds are determined by

comparing their measured amounts to procedural standard calibration curves.

A typical sample can be extracted and analyzed using this method in 50 minutes for

chlorination byproducts (e.g., TTHM) and chlorinated solvents, and in two hours for all of the

compounds analyzed by this method. Results can be confirmed by using a dissimilar GC column

or by the use of GC/MS.

For a complete description of this method see EPA publication: EPA/600/R-95/131

Methods for the Determination of Organic Compounds in Drinking Water: Supplement III. 

C.3.4 EPA Method 552.1

A 100 mL volume of the sample is adjusted to pH 5.0 and extracted using a preconditioned miniature anion exchange column. The chemical compounds to be analyzed are first

eluted using small amounts of acidic methanol, and are then esterified directly in this medium

after adding a small volume of methyl-tert-butyl ether (MTBE) as a co-solvent. The methyl

esters are partitioned into the MTBE phase, and are identified and measured using capillary

column gas chromatography with an electron capture detector (GC/ECD).

For a complete description of this method see EPA publication: EPA/600/R-92/129

Methods for the Determination of Organic Compounds in Drinking Water: Supplement II. 

C.3.5 EPA Method 552.2

The pH of a 40 mL volume of sample is adjusted to less than 0.5, and the sample is

extracted using 4 mL of methyl-tert-butyl ether (MTBE). The haloacetic acids that have been

partitioned are then converted to their methyl esters by adding acidic methanol and heating them

slightly. The acidic extract is then returned to neutral pH using a saturated solution of sodium

bicarbonate. The chemical compounds of interest are identified and measured using capillary

column gas chromatography with an electron capture detector (GC/ECD). Chemical

concentrations are determined using standard calibration procedures.
IDSE Guidance Manual for the Final Stage 2 DBPR C-7 January 2006

For a complete description of this method see EPA publication: EPA/600/R-95/131

Methods for the Determination of Organic Compounds in Drinking Water: Supplement III. 

C.3.6 EPA Method 552.3

The pH of a 40 mL sample is adjusted to 0.5 or less using concentrated sulfuric acid. The

sample is then extracted with either methyl tert-butyl ether (MTBE) or tert-amyl methyl ether

(TAME) containing an internal standard. The haloacetic acids that have been partitioned are

converted to their methyl esters by adding acidic methanol followed by heating for two hours.

Sodium sulfate is added to separate the partitioned methylated haloacetic acids from the acidic

methanol and the aqueous layer is discarded. The extract is neutralized with a saturated solution

of sodium bicarbonate and the solvent layer is removed for analysis. A gas chromatograph

equipped with a capillary column and an electron capture detector (GC/ECD) is used for

analysis. Chemical concentrations are determined using procedural standard calibration.

For a complete description of this method see Method 552.3 Determination of Haloacetic

Acids and Dalapon in Drinking Water by Liquid-Liquid Microextraction, Derivatization, and

Gas Chromatography with Electron Capture Detection Revision 1.0 (EPA 815-B-03-002),

available from EPA’s website at http://www.epa.gov/safewater/methods/sourcalt.html.

C.3.7 Standard Method 6251 B

The sample is extracted using methyl-tert-butyl ether (MTBE) at an acidic pH. A salting

agent is added during the extraction process to increase the extraction’s efficiency. Once

extracted, compounds are methylated using diazomethane solution to produce methyl ester or

other ether derivatives that can be separated in a gas chromatograph. A gas chromatograph

equipped with a fused silica capillary column and an electron capture detector (GC/ECD) is used

for analysis. Alternative detectors can be used if quality control criteria are met. Calibration

standards are extracted, methylated, and analyzed in the same manner as the water samples to

compensate for less than 100% recoveries during sample preparation.

For a complete description of this method see Standard Methods for the Examination of

Water and Wastewater: 19th or 20th Edition published jointly by the APHA, AWWA, and WEF

or Standard Methods Online version 6251 B-94 available at http://www.standardmethods.org.
IDSE Guidance Manual for the Final Stage 2 DBPR C-8 January 2006

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Appendix D 

Consecutive and Wholesale System Issues
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IDSE Guidance Manual for the Final Stage 2 DBPR D-1 January 2006

D.1 Introduction

If your system is part of a combined distribution system, your compliance schedule for

the IDSE is based on the population served by the largest system in your combined distribution

system. It is important that all systems in a combined distribution system conduct an IDSE at the

same time so that all systems in that combined distribution system know their relative DBP

concentrations and can make the necessary treatment and/or operational changes before Stage 2

compliance begins. 

The following questions and answers are provided to help you determine if you are in a

combined distribution system and what this means with respect to your IDSE schedule.

What is a combined distribution system?

The Stage 2 DBPR rule defines combined distribution system, wholesale system, and

consecutive system as follows: 

• A 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.

• A 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.

• A 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.

In Example D.1, where system C buys water from system B who buys water from

systems A and D, all four systems are considered to be in the same combined distribution

system. Even if systems A and D never exchange water, they are still considered to be part of

the same combined system. 
IDSE Guidance Manual for the Final Stage 2 DBPR D-2 January 2006

Combined Distribution

System

System A System B System C

Treatment

Plant

River

Wholesale System Consecutive System Consecutive System

System D

Wholesale System

Treatment

Plant

Lake

Example D.1 Example of a Combined Distribution System

If you receive water from a wholesale system only on an emergency basis or receive only

a small percentage and small volume of water from a wholesale system, your state may have

excluded you from the combined distribution system. If you deliver water to a consecutive

system only on an emergency basis or deliver only a small percentage and small volume of water

to a consecutive system, your state may also have excluded you from the combined distribution

system. You should receive a letter from EPA or your state that tells you the schedule that was

determined for your system by your state. See Section 2.2 for more information.

How do I know if I am a subpart H or a ground water system?

If you treat or deliver surface water or ground water under the direct influence of surface

water (GWUDI) as any part of your supply, you are considered a subpart H system. If you treat

or deliver only ground water, you are considered a ground water system. If you treat or deliver a

combination of the two, you are considered a subpart H system. If you do not treat your own

water and you do not know whether you receive surface water, GWUDI, or ground water, you

should consult with your state to determine what your IDSE and Stage 2 compliance monitoring

requirements are.

If I’m in a combined distribution system, which of my IDSE requirements are based on the

population of the largest system in my combined distribution system?

If you are part of a combined distribution system, only your compliance schedule is based

on the population of the largest system in your combined distribution system. Other

requirements are based on your retail population and source water type. The largest system may

be a wholesale system or a consecutive system.
IDSE Guidance Manual for the Final Stage 2 DBPR D-3 January 2006

If I’m in a combined distribution system, which of my IDSE requirements are based on my

individual system’s population?

If you are in a combined distribution system, the number of samples that you must collect

and the frequency at which you must monitor for both the IDSE and Stage 2 DBPR monitoring

are based on your individual system’s population.

If I’m in a combined distribution system, when do I submit my 40/30 Certification?

If you are part of combined distribution system and want to submit a 40/30 certification,

submit your request based on the schedule of the largest system in your combined distribution

system using the information in the table below. 

Population Served by the Largest System

in the Combined Distribution System 40/30 Certification Deadline

Systems serving $ 100,000 people October 1, 2006

Systems serving 50,000-99,999 people April 1, 2007

Systems serving 10,000-49,999 people October 1, 2007

Systems serving < 10,000 people April 1, 2008

How does my standard monitoring or system specific study schedule change if I’m in a

combined distribution system?

If you are part of a combined distribution system and plan to conduct standard

monitoring or an SSS, your schedule for conducting activities associated with these IDSE

options is based on the population of the largest system within your combined distribution

system. You can use the table below to help identify the appropriate schedule for your system

for submitting your monitoring plan, performing IDSE monitoring, and submitting your report.
IDSE Guidance Manual for the Final Stage 2 DBPR D-4 January 2006

Population Served by

the Largest System in

the Combined

Distribution System

You Must Submit Your

Standard Monitoring or

SSS Plan to the State

By 1

You Should Complete

Any Monitoring By

You Must Complete

Your IDSE Report

By 2

$ 100,000 people October 1, 2006 September 30, 2008 January 1, 2009

50,000-99,999 people April 1, 2007 March 31, 2009 July 1, 2009

10,000-49,999 people October 1, 2007 September 30, 2009 January 1, 2010

< 10,000 people April 1, 2008 March 31, 2010 July 1, 2010

1

 If the state does not approve or modify your plan within 12 months after the date identified in this column, you may

consider the plan that you submitted as approved and must implement that plan so that you complete standard

monitoring no later than the date identified in the third column. 2

 If the state does not approve or modify your report within three months after the date identified in this column (six

months after the date identified in this column if you must comply on the schedule of systems serving 10,000 to

49,999), you may consider the report that you submitted as approved and must implement the recommended Stage 2

compliance monitoring.

What else should I do if I’m in a combined distribution system?

It is very important that you start communicating with the other systems within your

combined distribution system to share data and information. You should copy other systems

within your combined distribution system on correspondence you submit to the EPA or your

state as part of the IDSE process. If you are unsure of what other systems are within your

combined distribution system and how to contact these systems, your state drinking water

program may be able to provide contact information.

Can my combined distribution system be considered one system for the purposes of the IDSE?

No, each individual system must conduct its own IDSE. The schedule for your IDSE

must be based on the population of the largest system in the combined distribution system. The

rest of your IDSE requirements are based on your individual system’s population. You cannot

conduct one IDSE for the entire combined distribution system. 

Can my combined distribution system be considered one system for the purposes of Stage 2

compliance monitoring?

If your state chooses to use its authority to treat your combined distribution system as one

system for Stage 2 DBPR compliance monitoring, the minimum number of Stage 2 DBPR

monitoring sites and monitoring frequency for the combined distribution system will be based on

the total population and nature of the interconnection of the combined distribution system. Each

consecutive or wholesale system must have at least one Stage 2 compliance monitoring location. 

Remember this will only happen if the state allows this option. Consequently, you should

develop your IDSE report for the total number of required Stage 2 compliance locations for your

system unless you hear otherwise from your state.
IDSE Guidance Manual for the Final Stage 2 DBPR D-5 January 2006

D.2 Communication Between Wholesale and Consecutive Systems

As discussed in Section D.1, the Stage 2 DBPR requires consecutive and wholesale

systems to conduct an IDSE at the same time as the largest system in the combined distribution

system. Note that in some cases, this may not be the wholesale provider. This section discusses

recommended approaches for communication between consecutive and wholesale systems when

completing an IDSE.

Consecutive systems are encouraged to contact their wholesale provider as soon as is

reasonably possible after promulgation of the Stage 2 DBPR to determine what plans, if any, the

wholesale system has already made regarding the IDSE. Keep in mind that, while it is

recommended, it is not the responsibility of the wholesale system to contact the consecutive 

system regarding the IDSE. Consecutive systems are encouraged to reach out to the wholesale

systems to make the initial contact regarding the IDSE. When a consecutive system receives

water from another consecutive system, communication should involve all three parties, i.e., both

consecutive systems and the wholesale system. At a minimum, you should discuss the following

questions during this initial contact:

1. When are our (both the wholesale and consecutive system) IDSE plans due?

2. When are our IDSE reports due?

3. What type of IDSE does the wholesale system intend to complete (Standard

Monitoring Program or System Specific Study)? Note: Systems are not required to

choose the same IDSE option

4. At what stage in IDSE planning is the wholesale system?

5. During what month(s) does the wholesale system intend to conduct DBP monitoring?

6. Does the wholesale system have water quality data (e.g., temperature, DBP data,

source water quality data, operational data, which wholesale sources serve which

consecutive systems and when) that might help the consecutive system prepare their

IDSE plan?

7. Would the wholesale system be willing to exchange copies of draft IDSE plans with

the consecutive system?

Consecutive systems can consider but are not required to select the same peak historical

month as the wholesale system. The peak historical month for a consecutive system that has

another source(s) may actually be in a different month than the month selected by the wholesale

system. If a consecutive system that has no other sources and that has limited data from which to

make a decision, they could reasonably assume that its peak historical month is the same as the

month selected by the wholesale system. 

Consecutive systems that may have limited data can take advantage of water quality data

that may be more readily available to wholesale systems, such as water temperature, source

water quality, disinfectant residual, TTHM, and HAA5 data. This will provide them some of the

data needed to work through the recommended steps presented in Chapter 7 for selecting

standard monitoring sites, thus improving the IDSE plan they are able to develop and leading to

better selection of Stage 2 compliance monitoring sites.
IDSE Guidance Manual for the Final Stage 2 DBPR D-6 January 2006

Consecutive systems should attempt to coordinate their IDSE monitoring with that of the

wholesale system. Coordinating IDSE monitoring schedules will allow the two (or more)

systems to better utilize data from the IDSE monitoring period to formulate a Stage 2 DBPR

compliance strategy, if necessary. Additionally, there may be some benefit in trying to better

understand how DBP formation occurs throughout the combined distribution system, especially

if DBP levels are relatively high. 

Where it is not possible to coordinate IDSE monitoring, consecutive systems are still

encouraged to work with their wholesale system to coordinate their proposed Stage 2 DBPR

compliance monitoring schedules that must be included in the final IDSE report. Draft and final

copies of the IDSE plans for the consecutive system and the wholesale system should be shared

between the systems. Where a consecutive system receives water through another consecutive

system, all three (or more) systems should share their IDSE plans. This information can be used

to verify that water quality and water age throughout the combined distribution system is

represented through the monitoring plans. For example, if you have multiple entry points from

the same wholesaler, they may have a storage tank prior to one entry point to your system but no

storage tank prior to another entry point. In this case, you would want to select the site after the

tank that is more likely to have high water age as a monitoring location for your standard

monitoring plan. 

As IDSE monitoring progresses, consecutive and wholesale systems are encouraged to

share monitoring results. When such an approach is utilized, results can be compared for

consistency and to help identify potential compliance issues related to the Stage 2 DBPR. 

A copy of each system’s IDSE report should be shared with the other system(s). It is not

necessary for multiple consecutive systems within a combined distribution system to share their

reports, unless one of those systems provides water to another consecutive system, but it is

recommended that the wholesaler provide a copy of its report to each consecutive system, and

each consecutive system provide a copy of its report to the wholesale system. This will help

consecutive systems to determine which compliance strategies, if necessary, are feasible for

them. It will also help the wholesale system to understand DBP formation in the finished water.

Upon completion of the IDSE, it is recommended that consecutive and wholesale systems

work together to discuss their Stage 2 DBPR compliance monitoring schedules for the IDSE

report. As with IDSE monitoring, there may be some benefit in coordinating Stage 2

monitoring. Consecutive systems may want to contract with their wholesale system, or contract

together with the same laboratory to coordinate Stage 2 compliance monitoring. If consecutive

and wholesale systems have the same peak historical month, they may wish to take their samples

at approximately the same time during the peak month. Observing DBP formation throughout

the combined distribution system using Stage 2 compliance monitoring data can help to identify

possible solutions to compliance-related issues. 

More information on communication between consecutive and wholesale systems can be

found in EPA’s Stage 2 DBPR Consecutive Systems Guidance Manual.
IDSE Guidance Manual for the Final Stage 2 DBPR D-7 January 2006

D.3 Understanding DBP Formation in Combined Distribution Systems

The IDSE will help consecutive and wholesale systems to better understand DBP

formation in their systems. Since the Stage 1 DBPR did not explicitly address consecutive

systems, the IDSE may provide the first opportunity for some consecutive systems to acquire

comprehensive information about DBP levels in their distribution system. As discussed above,

consecutive and wholesale systems should consider coordinating their IDSE sampling schedules

to facilitate a better understanding of DBP formation across the combined distribution system. 

Wholesale and consecutive systems should also consider exchanging any existing monitoring

data, particularly any DBP data collected by the wholesale system in the consecutive system. 

This data may be helpful to both systems in understanding DBP formation in the combined

distribution system and may help the consecutive system in choosing monitoring locations for

the IDSE.

DBP formation typically increases with water age. Wholesale and consecutive systems

can make a relative estimate of water age by looking at the extent of their wholesale and

consecutive distribution systems, and the distribution of customers. DBP sampling at the entry

point as part of the IDSE can help consecutive systems understand whether DBP formation is

occurring primarily in the wholesale system or the consecutive system. This can help systems to

focus control strategies on the wholesale system, the consecutive system, or a combination of the

two. Information on reducing DBP levels in consecutive systems and discussing compliance

strategies with wholesale systems can be found in EPA’s Stage 2 DBPR Consecutive Systems

Guidance Manual. 
IDSE Guidance Manual for the Final Stage 2 DBPR D-8 January 2006

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Appendix E

Example IDSE Existing Monitoring Results System Specific Study

Plan and Report for a Surface Water System Serving 40,000 People

This appendix is provided as an example IDSE study plan and report for a Subpart H

system serving 40,000 people and opting to complete a System Specific Study (SSS) using

existing monitoring results. The system in this example has a surface water intake with a

treatment plant and two additional wells that are each disinfected at the well locations. In all,

the system has three treatment plants. Because the water blends in the distribution system, the

entire system is categorized as a Subpart H system.

Since the system has three treatment plants, it is required to collect four samples per

treatment plant each quarter for Stage 1 DBPR compliance. The system therefore satisfies the

minimum number of sampling locations required for an Existing Monitoring Results SSS. If the

system submits two years of its Stage 1 DBPR compliance data, it also satisfies the requirement

for minimum number of TTHM and HAA5 samples. The Stage 1 DBPR sampling locations are

representative of the distribution system, so the system is not proposing to do any additional

monitoring and is submitting both their IDSE Plan and their IDSE Report by their plan deadline.

Chapter 5 presents detailed guidance on the requirements for performing an existing

monitoring results SSS; selection of Stage 2 compliance monitoring locations; and preparing the

existing monitoring results IDSE report. The application of the basic guidance on the use of

existing monitoring results to select locations meeting the standard monitoring location criteria

and the use of the data to select Stage 2 compliance monitoring locations is shown in this

example.
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IDSE Guidance Manual for the Final Stage 2 DBPR E-1 January 2006

Form 2: Existing Monitoring Results SSS Plan Page 1 of 16 

I. GENERAL INFORMATION

A. PWS Information* B. Date Submitted* 

 PWSID: US0000000 Sept. 1, 2007

PWS Name: City of Magnolia

PWS Address: PO Box 1234

City: Magnolia City State: US Zip: 11111

Population Served: 40,000

System Type: Source Water Type: Buying / Selling Relationships:

: CWS : Subpart H ~ Consecutive System 

~ NTNCWS ~ Ground ~ Wholesale System 

 : Neither 

C. PWS Operations

Residual Disinfectant Type: : Chlorine ~ Chloramines ~ Other_____________

Number of Disinfected Sources: __1__Surface ____GWUDI __2__Ground ____Purchased

D. Contact Person*

Name: Ms. Mary Flower, P.E.

Title: City Engineer

Phone #: 234-555-1111 Fax #: 234-555-2222

E-mail: MFlower@ci.magnolia.us

II. SSS REQUIREMENTS*

A. Minimum Number of Monitoring Locations 12 

B. Minimum Number of Required Samples

 72 TTHM 72 HAA5

C. IDSE Schedule

 ~ Schedule 1 ~ Schedule 2 : Schedule 3 ~ Schedule 4
IDSE Guidance Manual for the Final Stage 2 DBPR E-2 January 2006

Form 2: Existing Monitoring Results SSS Plan Page 2 of 16

III. PEAK HISTORICAL MONTH

A. Peak Historical Month* July 

B. If Multiple Sources, Source Used to Determine Peak Historical Month

(write “N/A” if only one source in your system)

_______Surface water source_________________________________

C. Peak Historical Month Based On (check as many as needed)

: High TTHM ~ High HAA5 : Warmest water temperature

If you used other information to select your peak historical month, explain here 

(attach additional sheets if needed):

IV. PREVIOUSLY COLLECTED MONITORING RESULTS*

A. Where were your TTHM and HAA5 samples analyzed?

~ In-House 

Is your in-house laboratory certified? ~ Yes ~ No

: Certified Laboratory

Name of certified laboratory: ACME Analytical Services

B. What method(s) was used to analyze your TTHM and HAA5 samples?

 TTHM HAA5

~ EPA 502.2 : EPA 552.1

~ EPA 524.2 ~ EPA 552.2

: EPA 551.1 ~ EPA 552.3

~ SM 6251 B
IDSE Guidance Manual for the Final Stage 2 DBPR E-3 

Form 2: Existing Monitoring Results SSS Plan 

IV. PREVIOUSLY COLLECTED MONITORING RESULTS (Continued)*C. TTHM Results

Site ID1

12-

monthperiod

Data

Qualifies

(yes/no) 

Data Type TTHM (mg/L)

#1 - Stage 1 SWPlant AverageResidence Time

Jan 05-Jan 06

Yes Sample Date 1/13/05 4/13/05 7/13/05 10/12/05

Sample Result 0.028 0.034 0.035 0.030 

#1 - Stage 1 SWPlant AverageResidence Time

Jan 06-Jan 07

Yes Sample Date 1/11/06 4/12/06 7/12/06 10/11/06

Sample Result 0.024 0.033 0.037 0.031 

#1 - Stage 1 SWPlant AverageResidence Time

Jan 07-July 07

Yes Sample Date 1/10/07 4/11/07 7/11/07

Sample Result 0.029 0.034 0.036 

#2 -Stage 1 SW AverageResidence Time

Jan 05-Jan 06

Yes Sample Date 1/13/05 4/13/05 7/13/05 10/12/05

Sample Result 0.049 0.056 0.063 0.057 

#2 - Stage 1 SWAverageResidence Time

Jan 06-Jan 07

Yes Sample Date 1/11/06 4/12/06 7/12/06 10/11/06

Sample Result 0.045 0.052 0.060 0.054 

#2 - Stage 1 SWAverageResidence Time

Jan 07-July 07

Yes Sample Date 1/10/07 4/11/07 7/11/07

Sample Result 0.046 0.055 0.063 

1 Verify that site IDs match the site IDs on your distribution system schematic.

Attach additional sheets as needed for previously collected compliance operational and monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR E-4 

Form 2: Existing Monitoring Results SSS Plan 

IV. PREVIOUSLY COLLECTED MONITORING RESULTS (Continued)*C. TTHM Results

Site ID1

12-

monthperiod

Data

Qualifies

(yes/no)

Data Type TTHM (mg/L)

#3 - Stage 1 SWAverageResidence Time

Jan 05-Jan 06

Yes Sample Date 1/13/05 4/13/05 7/13/05 10/12/05

Sample Result 0.038 0.047 0.065 0.052 

#3 - Stage 1 SWAverageResidence Time

Jan 06-Jan 07

Yes Sample Date 1/11/06 4/12/06 7/12/06 10/11/06

Sample Result 0.040 0.046 0.068 0.037 

#3 - Stage 1 SWAverageResidence Time

Jan 07-July 07

Yes Sample Date 1/10/07 4/11/07 7/11/07

Sample Result 0.036 0.042 0.070 

#4 -Stage 1 SWMaximumResidence Time

Jan 05-Jan 06

Yes Sample Date 1/13/05 4/13/05 7/13/05 10/12/05

Sample Result 0.032 0.060 0.074 0.062 

#4 - Stage 1 SWMaximumResidence Time

Jan 06-Jan 07

Yes Sample Date 1/11/06 4/12/06 7/12/06 10/11/06

Sample Result 0.042 0.069 0.082 0.071 

#4 - Stage 1 SWMaximumResidence Time

Jan 07-July 07

Yes Sample Date 1/10/07 4/11/07 7/11/07

Sample Result 0.044 0.059 0.081 

1 Verify that site IDs match the site IDs on your distribution system schematic.

Attach additional sheets as needed for previously collected compliance operational and monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR E-5 

Form 2: Existing Monitoring Results SSS Plan 

IV. PREVIOUSLY COLLECTED MONITORING RESULTS (Continued)*C. TTHM Results

Site ID1

12-

monthperiod

Data

Qualifies

(yes/no)

Data Type TTHM (mg/L) 

#5 - Stage 1Well 1 AverageResidence Time

Jan 05-Jan 06

Yes Sample Date 1/13/05 4/13/05 7/13/05 10/12/05

Sample Result 0.038 0.025 0.030 0.032 

#5 - Stage 1Well 1 AverageResidence Time

Jan 06-Jan 07

Yes Sample Date 1/11/06 4/12/06 7/12/06 10/11/06

Sample Result 0.026 0.031 0.030 0.024 

#5 - Stage 1Well 1 AverageResidence Time

Jan 07-July 07

Yes Sample Date 1/10/07 4/11/07 7/11/07

Sample Result 0.011 0.027 0.032 

#6 - Stage 1Well 1 AverageResidence Time

Jan 05-Jan 06

Yes Sample Date 1/13/05 4/13/05 7/13/05 10/12/05

Sample Result 0.032 0.051 0.058 0.042 

#6 - Stage 1Well 1 AverageResidence Time

Jan 06-Jan 07

Yes Sample Date 1/11/06 4/12/06 7/12/06 10/11/06

Sample Result 0.024 0.046 0.050 0.049 

#6 - Stage 1Well 1 AverageResidence Time

Jan 07-July 07

Yes Sample Date 1/10/07 4/11/07 7/11/07

Sample Result 0.030 0.041 0.051 

1 Verify that site IDs match the site IDs on your distribution system schematic.

Attach additional sheets as needed for previously collected compliance operational and monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR E-6 

Form 2: Existing Monitoring Results SSS Plan 

IV. PREVIOUSLY COLLECTED MONITORING RESULTS (Continued)*C. TTHM Results

Site ID1

12-

monthperiod

Data

Qualifies

(yes/no)

Data Type TTHM (mg/L)

#7 -Stage 1 Well1 AverageResidence Time

Jan 05-Jan 06

Yes Sample Date 1/13/05 4/13/05 7/13/05 10/12/05

Sample Result 0.031 0.037 0.045 0.033 

#7 - Stage 1Well 1 AverageResidence Time

Jan 06-Jan 07

Yes Sample Date 1/11/06 4/12/06 7/12/06 10/11/06

Sample Result 0.019 0.028 0.038 0.051 

#7 Stage 1 Well1 AverageResidence Time

Jan 07-July 07

Yes Sample Date 1/10/07 4/11/07 7/11/07

Sample Result 0.022 0.035 0.046 

#8 - Stage 1Well 1 MaximumResidence Time

Jan 05-Jan 06

Yes Sample Date 1/13/05 4/13/05 7/13/05 10/12/05

Sample Result 0.038 0.051 0.075 0.073 

#8 - Stage 1Well 1 MaximumResidence Time

Jan 06-Jan 07

Yes Sample Date 1/11/06 4/12/06 7/12/06 10/11/06

Sample Result 0.049 0.064 0.075 0.072 

#8 - Stage 1Well 1 MaximumResidence Time

Jan 07-July 07

Yes Sample Date 1/10/07 4/11/07 7/11/07

Sample Result 0.036 0.060 0.080 

1 Verify that site IDs match the site IDs on your distribution system schematic.

Attach additional sheets as needed for previously collected compliance operational and monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR E-7 

Form 2: Existing Monitoring Results SSS Plan IV. PREVIOUSLY COLLECTED MONITORING RESULTS (Continued)*C. TTHM Results

Site ID1

12-

monthperiod

Data

Qualifies

(yes/no)

Data Type TTHM (mg/L)

#9 - Stage 1Well 2 AverageResidence Time

Jan 05-Jan 06

Yes Sample Date 1/14/05 4/14/05 7/14/05 10/13/05

Sample Result 0.022 0.029 0.026 0.033 

#9 - Stage 1Well 2 AverageResidence Time

Jan 06-Jan 07

Yes Sample Date 1/12/06 4/13/06 7/13/06 10/12/06

Sample Result 0.024 0.022 0.031 0.026 

#9 - Stage 1Well 2 AverageResidence Time

Jan 07-July 07

Yes Sample Date 1/11/07 4/12/07 7/12/07

Sample Result 0.010 0.021 0.023 

#10 - Stage 1Well 2 AverageResidence Time

Jan 05-Jan 06

Yes Sample Date 1/14/05 4/14/05 7/14/05 10/13/05

Sample Result 0.024 0.035 0.045 0.042 

#10 - Stage 1Well 2 AverageResidence Time

Jan 06-Jan 07

Yes Sample Date 1/12/06 4/13/06 7/13/06 10/12/06

Sample Result 0.016 0.043 0.060 0.051 

#10 - Stage 1Well 2 AverageResidence Time

Jan 07-July 07

Yes Sample Date 1/11/07 4/12/07 7/12/07

Sample Result 0.011 0.052 0.083 

1 Verify that site IDs match the site IDs on your distribution system schematic.

Attach additional sheets as needed for previously collected compliance operational and monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR E-8 

Form 2: Existing Monitoring Results SSS Plan 

IV. PREVIOUSLY COLLECTED MONITORING RESULTS (Continued)*C. TTHM Results

Site ID1

12-

monthperiod

Data

Qualifies

(yes/no)

Data Type TTHM (mg/L)

#11 - Stage 1Well 2 AverageResidence Time

Jan 05-Jan 06

Yes Sample Date 1/14/05 4/14/05 7/14/05 10/13/05

Sample Result 0.027 0.032 0.068 0.059 

#11 - Stage 1Well 2 AverageResidence Time

Jan 06-Jan 07

Yes Sample Date 1/12/06 4/13/06 7/13/06 10/12/06

Sample Result 0.021 0.047 0.060 0.045 

#11 - Stage 1Well 2 AverageResidence Time

Jan 07-July 07

Yes Sample Date 1/11/07 4/12/07 7/12/07

Sample Result 0.018 0.025 0.065 

#12 - Stage 1Well 2 MaximumResidence Time

Jan 05-Jan 06

Yes Sample Date 1/14/05 4/14/05 7/14/05 10/13/05

Sample Result 0.068 0.073 0.085 0.074 

#12 - Stage 1Well 2 MaximumResidence Time

Jan 06-Jan 07

Yes Sample Date 1/12/06 4/13/06 7/13/06 10/12/06

Sample Result 0.069 0.077 0.089 0.078 

#12 - Stage 1Well 2 MaximumResidence Time

Jan 07-July 07

Yes Sample Date 1/11/07 4/12/07 7/12/07

Sample Result 0.067 0.075 0.086 

1 Verify that site IDs match the site IDs on your distribution system schematic.

Attach additional sheets as needed for previously collected compliance operational and monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR E-9 

Form 2: Existing Monitoring Results SSS Plan 

IV. PREVIOUSLY COLLECTED MONITORING RESULTS (Continued)*D. HAA5 Results

Site ID1

12-

monthperiod

Data

Qualifies

(yes/no)

Data Type HAA5 (mg/L)

#1 - Stage 1 SWPlant AverageResidence Time

Jan 05-Jan 06

Yes Sample Date 1/13/05 4/13/05 7/13/05 10/12/05

Sample Result 0.028 0.034 0.035 0.030 

#1 - Stage 1 SWPlant AverageResidence Time

Jan 06-Jan 07

Yes Sample Date 1/11/06 4/12/06 7/12/06 10/11/06

Sample Result 0.024 0.033 0.037 0.031 

#1 - Stage 1 SWPlant AverageResidence Time

Jan 07-July 07

Yes Sample Date 1/10/07 4/11/07 7/11/07

Sample Result 0.029 0.034 0.036 

#2 -Stage 1 SW AverageResidence Time

Jan 05-Jan 06

Yes Sample Date 1/13/05 4/13/05 7/13/05 10/12/05

Sample Result 0.049 0.059 0.063 0.057 

#2 - Stage 1 SWAverageResidence Time

Jan 06-Jan 07

Yes Sample Date 1/11/06 4/12/06 7/12/06 10/11/06

Sample Result 0.045 0.052 0.060 0.054 

#2 - Stage 1 SWAverageResidence Time

Jan 07-July 07

Yes Sample Date 1/10/07 4/11/07 7/11/07

Sample Result 0.046 0.055 0.063 

1 Verify that site IDs match the site IDs on your distribution system schematic.

Attach additional sheets as needed for previously collected compliance operational and monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR E-10 

Form 2: Existing Monitoring Results SSS Plan IV. PREVIOUSLY COLLECTED MONITORING RESULTS (Continued)*D. HAA5 Results

Site ID1

12-

monthperiod

Data

Qualifies

(yes/no)

Data Type HAA5 (mg/L)

#3 -Stage 1 SW AverageResidence Time

Jan 05-Jan 06

Yes Sample Date 1/13/05 4/13/05 7/13/05 10/12/05

Sample Result 0.022 0.035 0.052 0.031 

#3 - Stage 1 SWAverageResidence Time

Jan 06-Jan 07

Yes Sample Date 1/11/06 4/12/06 7/12/06 10/11/06

Sample Result 0.024 0.041 0.059 0.037 

#3 -Stage 1 SW AverageResidence Time

Jan 07-July 07

Yes Sample Date 1/10/07 4/11/07 7/11/07

Sample Result 0.017 0.045 0.065 

#4 -Stage 1 SWMaximumResidence Time

Jan 05-Jan 06

Yes Sample Date 1/13/05 4/13/05 7/13/05 10/12/05

Sample Result 0.039 0.049 0.058 0.041 

#4 - Stage 1 SWMaximumResidence Time

Jan 06-Jan 07

Yes Sample Date 1/11/06 4/12/06 7/12/06 10/11/06

Sample Result 0.023 0.044 0.052 0.039 

#4 - Stage 1 SWMaximumResidence Time

Jan 07-July 07

Yes Sample Date 1/10/07 4/11/07 7/11/07

Sample Result 0.027 0.051 0.060 

1 Verify that site IDs match the site IDs on your distribution system schematic.

Attach additional sheets as needed for previously collected compliance operational and monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR E-11 

Form 2: Existing Monitoring Results SSS Plan IV. PREVIOUSLY COLLECTED MONITORING RESULTS (Continued)*D. HAA5 Results

Site ID1

12-

monthperiod

Data

Qualifies

(yes/no)

Data Type HAA5 (mg/L)

#5 - Stage 1Well 1 AverageResidence Time

Jan 05-Jan 06

Yes Sample Date 1/13/05 4/13/05 7/13/05 10/12/05

Sample Result 0.029 0.036 0.043 0.033 

#5 - Stage 1Well 1 AverageResidence Time

Jan 06-Jan 07

Yes Sample Date 1/11/06 4/12/06 7/12/06 10/11/06

Sample Result 0.026 0.034 0.046 0.037 

#5 - Stage 1Well 1 AverageResidence Time

Jan 07-July 07

Yes Sample Date 1/10/07 4/11/07 7/11/07

Sample Result 0.025 0.035 0.049 

#6 - Stage 1Well 1 AverageResidence Time

Jan 05-Jan 06

Yes Sample Date 1/13/05 4/13/05 7/13/05 10/12/05

Sample Result 0.040 0.045 0.051 0.044 

#6 - Stage 1Well 1 AverageResidence Time

Jan 06-Jan 07

Yes Sample Date 1/11/06 4/12/06 7/12/06 10/11/06

Sample Result 0.037 0.043 0.050 0.044 

#6 - Stage 1Well 1 AverageResidence Time

Jan 07-July 07

Yes Sample Date 1/10/07 4/11/07 7/11/07

Sample Result 0.042 0.048 0.053 

1 Verify that site IDs match the site IDs on your distribution system schematic.

Attach additional sheets as needed for previously collected compliance operational and monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR E-12 

Form 2: Existing Monitoring Results SSS Plan IV. PREVIOUSLY COLLECTED MONITORING RESULTS (Continued)*D. HAA5 Results

Site ID1

12-

monthperiod

Data

Qualifies

(yes/no)

Data Type HAA5 (mg/L)

#7 -Stage 1 Well1 AverageResidence Time

Jan 05-Jan 06

Yes Sample Date 1/13/05 4/13/05 7/13/05 10/12/05

Sample Result 0.049 0.055 0.064 0.056 

#7 - Stage 1Well 1 AverageResidence Time

Jan 06-Jan 07

Yes Sample Date 1/11/06 4/12/06 7/12/06 10/11/06

Sample Result 0.045 0.052 0.061 0.054 

#7 Stage 1 Well1 AverageResidence Time

Jan 07-July 07

Yes Sample Date 1/10/07 4/11/07 7/11/07

Sample Result 0.048 0.057 0.065 

#8 - Stage 1Well 1 MaximumResidence Time

Jan 05-Jan 06

Yes Sample Date 1/13/05 4/13/05 7/13/05 10/12/05

Sample Result 0.030 0.057 0.066 0.053 

#8 - Stage 1Well 1 MaximumResidence Time

Jan 06-Jan 07

Yes Sample Date 1/11/06 4/12/06 7/12/06 10/11/06

Sample Result 0.026 0.042 0.053 0.054 

#8 - Stage 1Well 1 MaximumResidence Time

Jan 07-July 07

Yes Sample Date 1/10/07 4/11/07 7/11/07

Sample Result 0.028 0.045 0.064 

1 Verify that site IDs match the site IDs on your distribution system schematic.

Attach additional sheets as needed for previously collected compliance operational and monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR E-13 

Form 2: Existing Monitoring Results SSS Plan IV. PREVIOUSLY COLLECTED MONITORING RESULTS (Continued)*D. HAA5 Results

Site ID1

12-

monthperiod

Data

Qualifies

(yes/no)

Data Type HAA5 (mg/L)

#9 - Stage 1Well 2 AverageResidence Time

Jan 05-Jan 06

Yes Sample Date 1/14/05 4/14/05 7/14/05 10/13/05

Sample Result 0.032 0.038 0.046 0.035 

#9 - Stage 1Well 2 AverageResidence Time

Jan 06-Jan 07

Yes Sample Date 1/12/06 4/13/06 7/13/06 10/12/06

Sample Result 0.030 0.041 0.048 0.039 

#9 - Stage 1Well 2 AverageResidence Time

Jan 07-July 07

Yes Sample Date 1/11/07 4/12/07 7/12/07

Sample Result 0.031 0.036 0.045 

#10 - Stage 1Well 2 AverageResidence Time

Jan 05-Jan 06

Yes Sample Date 1/14/05 4/14/05 7/14/05 10/13/05

Sample Result 0.031 0.037 0.056 0.044 

#10 - Stage 1Well 2 AverageResidence Time

Jan 06-Jan 07

Yes Sample Date 1/12/06 4/13/06 7/13/06 10/12/06

Sample Result 0.037 0.044 0.053 0.042 

#10 - Stage 1Well 2 AverageResidence Time

Jan 07-July 07

Yes Sample Date 1/11/07 4/12/07 7/12/07

Sample Result 0.038 0.043 0.051 

1 Verify that site IDs match the site IDs on your distribution system schematic.

Attach additional sheets as needed for previously collected compliance and operational monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR E-14 

Form 2: Existing Monitoring Results SSS Plan IV. PREVIOUSLY COLLECTED MONITORING RESULTS (Continued)*D. HAA5 Results

Site ID1

12-

monthperiod

Data

Qualifies

(yes/no)

Data Type HAA5 (mg/L)

#11 - Stage 1Well 2 AverageResidence Time

Jan 05-Jan 06

Yes Sample Date 1/14/05 4/14/05 7/14/05 10/13/05

Sample Result 0.038 0.043 0.050 0.044 

#11 - Stage 1Well 2 AverageResidence Time

Jan 06-Jan 07

Yes Sample Date 1/12/06 4/13/06 7/13/06 10/12/06

Sample Result 0.042 0.046 0.053 0.045 

#11 - Stage 1Well 2 AverageResidence Time

Jan 07-July 07

Yes Sample Date 1/11/07 4/12/07 7/12/07

Sample Result 0.037 0.042 0.051 

#12 - Stage 1Well 2 MaximumResidence Time

Jan 05-Jan 06

Yes Sample Date 1/14/05 4/14/05 7/14/05 10/13/05

Sample Result 0.040 0.045 0.048 0.043 

#12 - Stage 1Well 2 MaximumResidence Time

Jan 06-Jan 07

Yes Sample Date 1/12/06 4/13/06 7/13/06 10/12/06

Sample Result 0.043 0.047 0.052 0.046 

#12 - Stage 1Well 2 MaximumResidence Time

Jan 07-July 07

Yes Sample Date 1/11/07 4/12/07 7/12/07

Sample Result 0.040 0.048 0.056 

1 Verify that site IDs match the site IDs on your distribution system schematic.

Attach additional sheets as needed for previously collected compliance and operational monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR E-15 January 2006

Form 2: Existing Monitoring Results SSS PlanPage 15 of 16

V. CERTIFICATION OF DATA*

I hereby 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 Stage 1 DBPR results.

• The samples are representative of the entire distribution system.

• Treatment and the distribution system have not changed significantly since the

samples were collected.

Signature:

Date: May 30, 2007

VI. PROPOSED SSS MONITORING SCHEDULE*

Skip if you are submitting your IDSE Report at the same time as your plan

SSS Site ID

(from map)1

Projected Sampling Date (date or week)2

period 1 period 2 period 3 period 4 period 5 period 6

1

 Verify that site IDs match IDs on your distribution system schematic (See Section VII of this

form). Attach additional copies of this sheet if necessary.

2

 period = monitoring period. Can list exact date or week (e.g., week of 7/9/07)
IDSE Guidance Manual for the Final Stage 2 DBPR E-16 January 2006

Form 2: Existing Monitoring Results SSS PlanPage 16 of 16

VII. DISTRIBUTION SYSTEM SCHEMATIC*

ATTACH a schematic of your distribution system. 

Distribution system schematics are not confidential and should not contain information that

poses a security risk to your system. EPA recommends that you use one of two options: 

Option 1: Distribution system schematic with no landmarks or

addresses indicated. Show locations of sources, entry points, storage

facilities, operational monitoring locations, and Stage 1 compliance

monitoring locations (required). Also include pressure zone boundaries

and locations of pump stations. Provide map scale. 

Option 2: City map without locations of pipes indicated. Show

locations of sources, entry points, storage facilities, operational monitoring

locations, and Stage 1 compliance monitoring locations (required). Also

include boundaries of the distribution system, pressure zone boundaries

and locations of pump stations. Provide map scale.

VIII. ATTACHMENTS

~ Additional sheets for explaining how you selected the peak historical month

 (Section III).

 ~ Additional sheets for previously collected monitoring results (Section IV).

~ Additional sheets for proposed monitoring dates (Section VI).

: Distribution system schematic* (Section VII).

Total Number of Pages in Your Plan: 17 

Note: Fields with an asterisk (*) are required by the Stage 2 DBPR.
IDSE Guidance Manual for the Final Stage 2 DBPR E-17 January 2006

Friendship Heights Well

Field and Pumping

Station

12

Flower Village

9

11

10

6

4 7

5

P

PS1

2

1

3

River

River Run WTP

Columbus Well

Field and Pumping

Station

8

P

Stage 1 DBPR site

Well Field and

Pumping Station

Pump Station

Ground StorageTank

Elevated Storage Tank

Magnolia City Distribution System Schematic Attachment #9
IDSE Guidance Manual for the Final Stage 2 DBPR E-18 January 2006

This page intentionally left blank.
IDSE Guidance Manual for the Final Stage 2 DBPR E-19 January 2006

Form 3: IDSE Report for an Existing Monitoring

Results SSS Page 1 of 5

I. GENERAL INFORMATION

(Skip this section if you are submitting the plan and report at the same time)

A. PWS Information* B. Date Submitted*

 PWSID:

PWS Name:

PWS Address:

City: State: Zip:

Population Served:

System Type: Source Water Type: Buying / Selling Relationships:

~ CWS ~ Subpart H ~ Consecutive System 

~ NTNCWS ~ Ground ~ Wholesale System 

 ~ Neither 

C. PWS Operations

Residual Disinfectant Type: ~ Chlorine ~ Chloramines ~ Other_____________

Number of Disinfected Sources: _____Surface____GWUDI_____Ground____Purchased

D. Contact Person*

Name:

Title:

Phone #: Fax #:

E-mail: 

II. STAGE 2 DBPR REQUIREMENTS*

A. Number of required Stage 2 DBPR Compliance Monitoring Sites 4 TOTAL

 2 Highest TTHM 1 Stage 1 DBPR 1 Highest HAA5
IDSE Guidance Manual for the Final Stage 2 DBPR E-20 January 2006

Form 3: IDSE Report for an Existing Monitoring

Results SSS Page 2 of 5

II. STAGE 2 DBPR REQUIREMENTS (continued)*

B. IDSE Schedule C. Required Stage 2 DBPR Compliance Monitoring

Frequency

 ~ Schedule 1 ~ During peak historical month (1 monitoring period)

 ~ Schedule 2 : Every 90 days (4 monitoring periods)

 : Schedule 3

 ~ Schedule 4

III. ADDITIONAL SSS AND STAGE 1 COMPLIANCE MONITORING RESULTS*

(Skip this section if you are submitting the plan and report at the same time)

A. Where were your TTHM and HAA5 samples analyzed?

~ In-House

Is your in-house laboratory certified? ~ Yes ~ No

~ Certified Laboratory

Name of certified laboratory:

B. What method(s) was used to analyze your TTHM and HAA5 samples?

 TTHM HAA5

~ EPA 502.2 ~ EPA 552.1

~ EPA 524.2 ~ EPA 552.2

~ EPA 551.1 ~ EPA 552.3

~ SM 6251 B
IDSE Guidance Manual for the Final Stage 2 DBPR E-21 January 2006

Form 3: IDSE Report for an Existing Monitoring

Results SSS Page 3 of 5

IV. JUSTIFICATION OF STAGE 2 DBPR COMPLIANCE MONITORING SITES*

Stage 2

Compliance

Monitoring

Site ID

Site Type Justification

#12 - Stage 1

Well 2 Max

Residence

Time

: Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

1st highest TTHM LRAA. 

Sampled quarterly at all sites, so compared LRAAs for

all sites instead of comparing individual sample results

from peak historical month. This is true for the selection

of all Stage 2 compliance monitoring sites.

#2 - Stage 1

SW Plant Ave

Residence

Time Site

~ Highest TTHM

: Highest HAA5

~ Stage 1 DBPR

1st highest HAA5; site #7 had the same LRAA result. 

Site #7 is selected for the Stage 1 site.

#7 - Stage 1

Well 1 Av

Residence

Time

~ Highest TTHM

~ Highest HAA5

: Stage 1 DBPR

Stage 1 site with highest HAA5 LRAA

# 4 - Stage 1

SW plant max

residence time 

: Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

2nd highest TTHM LRAA

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

Attach additional copies of this sheet if you need more room.
IDSE Guidance Manual for the Final Stage 2 DBPR E-22 January 2006

Form 3: IDSE Report for an Existing Monitoring

Results SSS Page 4 of 5

V. PEAK HISTORICAL MONTH

A. Peak Historical Month* July 

B. Is Your Peak Historical Month the Same as In Your SSS Plan?

: Yes ~ No

If no, explain how you selected your new peak historical month (attach

additional sheets if needed):

VI. PROPOSED STAGE 2 DBPR COMPLIANCE MONITORING SCHEDULE*

Stage 2

Compliance

Monitoring

Site ID

Projected Sampling Date (date or week) 1

period 1 period 2 period 3 period 4

#12 7/15/2013 10/15/2013 1/15/2014 4/15/2014

#2 7/15/2013 10/15/2013 1/15/2014 4/15/2014

#7 7/15/2013 10/15/2013 1/15/2014 4/15/2014

#4 7/15/2013 10/15/2013 1/15/2014 4/15/2014

1

 period = monitoring period. Complete for the number of monitoring periods from

Section II.C.

Attach additional copies of this sheet if you need more room.
IDSE Guidance Manual for the Final Stage 2 DBPR E-23 January 2006

Form 3: IDSE Report for an Existing Monitoring

Results SSS Page 5 of 5

VII. DISTRIBUTION SYSTEM SCHEMATIC*

(Skip this section if you are submitting the plan and report at the same time)

ATTACH a schematic of your distribution system if it has changed since you submitted

your Existing Monitoring Results SSS Plan (Form 2). 

VIII. ATTACHMENTS

~ Additional sheets for Additional SSS Monitoring Results (Section III).

~ Additional sheets for Stage 2 DBPR Monitoring Sites (Section IV). REQUIRED if you 

 are a subpart H system serving more than 249,999 people.

~ Additional sheets for explaining how you selected the peak historical month (Section 

 V).

~ Additional sheets for proposed compliance monitoring dates (Section VI). REQUIRED if 

 you are a subpart H system serving more than 249,999 people.

~ Explanation of deviations from approved study plan.

~ Distribution system schematic* (Section VII). REQUIRED if it has changed from your 

 approved SSS plan.

~ Compliance calculation procedures (for Stage 2 Compliance Monitoring Plan).

Total Number of Pages in Your Report: 5 

Note: Fields with an asterisk (*) are required by the Stage 2 DBPR.
IDSE Guidance Manual for the Final Stage 2 DBPR E-24 January 2006

This page intentionally left blank.
Appendix F

Example IDSE System Specific Study Using a Hydraulic Model for 

a Surface Water System Serving 57,000 People

This appendix is provided as an example IDSE plan and report for a surface water

system serving 57,000 people and opting to complete a System Specific Study (SSS) using a

water distribution system model. For this example, the state did not require any modifications to

the study plan and the system did not deviate from the approved study plan.

Chapter 6 presents detailed guidance on the requirements for performing a modeling

SSS, selecting Stage 2 DBPR compliance monitoring locations using modeling SSS data, and

preparing a modeling SSS report. The application of the basic guidance on preliminary location

selection and Stage 2 DBPR compliance monitoring location selection is shown in this example,

along with several instances of the use of best professional judgement being applied.
This page intentionally left blank.
IDSE Guidance Manual for the Final Stage 2 DBPR F-1 January 2006

Form 4: Modeling Study Plan Page 1 of 6

I. GENERAL INFORMATION 

A. PWS Information* B. Date Submitted* 3/8/07 

 PWSID: US1111111

 PWS Name: Big City Water System

PWS Address: 1234 Main Street

City: Big City State: US Zip: 99999

Population Served: 57,000

System Type: Source Water Type: Buying / Selling Relationships:

: CWS : Subpart H ~ Consecutive System 

~ NTNCWS ~ Ground ~ Wholesale System

 : Neither

C. PWS Operations 

Residual Disinfectant Type: : Chlorine ~ Chloramines ~ Other:_____________

 Number of Disinfected Sources: 1 Surface ___GWUDI ____ Ground ___ Purchased

D. Contact Person*

Name: Mr. John Smith, P.E.

Title: Water System Manager

Phone #: 123-555-0000 Fax #: 123-555-0001

E-mail: jsmith@ci.bigcity.us

II. IDSE REQUIREMENTS*

A. SSS Monitoring B. Schedule C. SSS Monitoring Frequency

Number of Samples

per Monitoring Period:

: During peak month of TTHM formation

(1 monitoring period) 16 ~ Schedule 1

Number of Monitoring

Periods:

: Schedule 2 ~ Additional (describe) 

 

 _ 1 ~ Schedule 3

 Total: 16 ~ Schedule 4
IDSE Guidance Manual for the Final Stage 2 DBPR F-2 January 2006

Form 4: Modeling Study Plan Page 2 of 6

III. MODEL DESCRIPTION

A. Answer Yes or No to the following questions* 

(provide documentation in attached sheets)

1. Is your model an Extended Period Simulation model? Y / N

2. Does your model meet the minimum requirements described

below? Attach tables or spreadsheets to demonstrate that your

model meets these requirements.

Include 75% of pipe volume Y / N

Include 50% of pipe length Y / N

Include all pressure zones Y / N

Include all pipes 12" and larger Y / N

Include all 8" 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

Y / N

Include all 6" and larger pipes that connect remote areas

of a distribution system to the main portion of the system

Y / N

Include all storage facilities with standard operations

represented in the model

Y / N

Include all active pump stations with realistic controls Y / N

Include all active control valves Y / N

3. Is your model (or will it be) calibrated to simulate actual water

levels at all storage facilities and represent the current distribution

system configuration during the period of high TTHM formation?

Y / N

4. If calibration is complete, does the model simulate 24 hour

variation in demand and show a consistently repeating 24 hour

pattern of residence time?

 Y / N

B. Provide a history of your model development and calibration*, including

dates (attach additional sheets if needed)

See attached sheet. 
IDSE Guidance Manual for the Final Stage 2 DBPR F-3 January 2006

Form 4: Modeling Study Plan Page 3 of 6

III. MODEL DESCRIPTION (Continued)

C. How was demand data assigned to the model? (attach additional sheets if

needed)

1. What method was used to assign

demands throughout the system?

Customer accounts were geocoded and 

assigned to each node using Thiessen

polygons.

2. How did you estimate diurnal demand

variation? How did you determine

total system demand?

Diurnal demand patterns were calculated using a

mass balance into/out of each pressure zone using

the calibration data. Total system demand was

calculated based on water production records from

the WTP.

3. How many demand categories did

you use?

6 different demand categories were used:

residential (based on calculation described above),

industrial, school, golf course, swimming pool, and

one for a specific industry.

4. How did you address large water

users?

Large water users were asked about their demand

patterns. One industry had a usage pattern that

was much different than the others so it was

assigned an individual pattern.

D. Describe all calibration activities* If your model is not currently calibrated,

describe how calibration will be completed within 12 months of plan

submission using the questions 1-8 as guidance (attach additional sheets if

needed)

1. When was the model last calibrated? The model was calibrated in 2003 to conditions in

July 2002.

2. What types of data were used in the

calibration?

SCADA readings for tank levels, pump flows, and

pump discharge pressures were collected on 5

minute intervals. 6 pressure recorders with

dataloggers were installed in system for 1 week.

3. When was the calibration data

collected?

July 12 to July 19, 2002

4. What field tests have been performed

to collect calibration data?

No field tests were performed.
IDSE Guidance Manual for the Final Stage 2 DBPR F-4 January 2006

Form 4: Modeling Study Plan Page 4 of 6 

III. MODEL DESCRIPTION (Continued)

D. (Continued)

5.

How did you determine friction factors

(C-factors)?

C-factors were determined through trial and error

simulations to fit the calibration data as closely as

possible. Pipe material and pipe diameter were

also considered when determining C-factors.

6. Was the calibration completed for the

peak month for TTHM formation? If

not, was the model performance

verified for the peak month for TTHM

formation?

The peak month is August. The model calibration

was verified using SCADA data for tank levels in

August 2006. 

7.

How well do actual tank levels

correlate with predicted tank levels

during the peak month for TTHM

formation? 

See Attachments (Section VIII) for

additional submission

requirements.

The August 2006 actual tank levels are predicted

well (within 2 feet) by the model. See attached

graphs.

8.

If you are using a water quality model,

what parameters are modeled? How

was the model calibrated?

n/a

IV. PEAK MONTH FOR TTHM FORMATION

A. Peak Month For TTHM Formation* August 

B. Justification of Peak Month for TTHM Formation

Describe how your system determined which month is the peak month for TTHM

formation (attach additional sheets if needed):

High temperature and high source water TOC, based on past 5 years of data
IDSE Guidance Manual for the Final Stage 2 DBPR F-5 January 2006

Form 4: Modeling Study Plan Page 5 of 6 

V. MODELING INFORMATION *

How was the SSS modeling performed? (attach additional sheets as needed)

1. Was modeling done for the operating

conditions during the peak month for

TTHM formation?

Yes, modeling was done for August 2006 conditions.

2. How were operational controls

represented in the model?

Logical controls for all pump stations were set using tank

level set points for summer operation.

3. How was water age simulated during

the peak month for TTHM formation

(time steps, length of simulation,

etc.)? If not yet done, indicate how

this will be addressed in the IDSE

report.

The water age simulation was run for 960 hours to

ensure full turnover of all tanks. Tank #2 had the high

average water age. 

4. What are the average water age

results for your distribution system? 

See Attachments (Section VIII) for

additional submission

requirements.

The average water age (for the final 24 hours of the 960

hour simulation) is given in the attached table. Nodes

with zero demand have a water age approximately equal

to 960 hours and were not considered in the analysis for

site selection.

Table is attached.

VI. PLANNED STAGE 1 DBPR COMPLIANCE MONITORING SCHEDULE*

 

Stage 1 DBPR

Monitoring Site

ID (from map) 1

Projected Sampling Date (date or week) 2

Period 1 Period 2 Period 3 Period 4

Stage 1 #1 3/12/2008 6/7/2008 8/22/2008 10/1/2008

Stage 1 #2 3/12/2008 6/7/2008 8/22/2008 10/1/2008

Stage 1 #3 3/12/2008 6/7/2008 8/22/2008 10/1/2008

Stage 1 #4 3/12/2008 6/7/2008 8/22/2008 10/1/2008

1 Verify that site IDs match IDs on your distribution system schematic (See Section VII of

this form). Attach additional copies if you are required to monitor at more than 8 Stage 1

DBPR sites.

2 period = monitoring period. Complete for the number of periods in which you must conduct

Stage 1 DBPR monitoring during IDSE monitoring. Can list exact date or week (e.g., week

of 7/9/07)
IDSE Guidance Manual for the Final Stage 2 DBPR F-6 January 2006

Form 4: Modeling Study Plan Page 6 of 6

VII. DISTRIBUTION SYSTEM SCHEMATIC*

ATTACH a schematic of your distribution system. 

Distribution system schematics are not confidential and should not contain information that

poses a security risk to your system. EPA recommends that you submit the following:

Distribution system schematic with no landmarks or addresses indicated. Show

locations of sources, entry points, storage facilities, locations of completed monitoring,

and Stage 1 compliance monitoring locations (required). Also include pressure zone

boundaries and locations of pump stations. Provide map scale.

VIII. ATTACHMENTS

: Distribution System Schematic* (Section VII).

: Tabular or spreadsheet documentation that your model meets minimum

requirements* (Section III.A).

: Additional sheets for explaining your model (Section III.B).

: Graph of predicted tank levels vs. measured tank levels for the storage facility with

the high residence time in each pressure zone* (Section III.D). Required if

calibration is complete.

: Time series graph of water age at the longest residence time storage facility in the 

 distribution system showing the predictions for the entire EPS simulation period* 

 (Section V). Required if calibration is complete

~ Additional sheets for explaining how you selected the peak historic month for TTHM

formation (Section V).

: Model output showing preliminary 24 hour water age predictions for all nodes 

throughout the distribution system* (Required for all submissions. If your model is

calibrated, this should be your final water age predictions)(Section V).

~ Additional sheets describing the planned Stage 1 DBPR Compliance Monitoring 

Schedule (Section VI).

Total Number of Pages in Your Plan: 19 

Note: All items marked with an asterisk (*) are required by the rule.
IDSE Guidance Manual for the Final Stage 2 DBPR F-7 January 2006

Scale 1:8,000
IDSE Guidance Manual for the Final Stage 2 DBPR F-8 January 2006

MINIMUM MODEL REQUIREMENTS

No GIS system for the water mains exists. Using information from the paper water atlas sheets

for the City and the model input data, the following characteristics were estimated. There are no

active control valves in the distribution system.

Length (ft) Volume (cf)

Pipe

Diameter

(in)

Total Not In

Model

In Model % in

Model

Total Not In

Model

In

Model

% in

Model

4 15,142 10,400 4,472 31.3 1,321 908 414 31.3

6 234,996 4,000 230,996 98.3 46,141 785 45,356 98.3

8 156,720 0 156,720 100.0 54,706 0 54,706 100.0

10 15,505 0 15,505 100.0 8,457 0 8,457 100.0

12 136,404 0 136,404 100.0 107,131 0 107,131 100.0

16 26,815 0 26,815 100.0 37,441 0 37,441 100.0

20 12,832 0 12,832 100.0 27,995 0 27,995 100.0

24 1,761 0 1,761 100.0 5,532 0 5,532 100.0

Total 600,175 14,400 585,775 97.6 288,725 1,693 287,032 99.4
IDSE Guidance Manual for the Final Stage 2 DBPR F-9 January 2006

HISTORY OF MODEL DEVELOPMENT AND CALIBRATION

Model was developed in 2003 and calibrated to conditions in July 2002 (maximum demand day). 

No new major facilities have been constructed in the system since 2003. The model was used to

determine new pipe sizes for future construction, to adjust operation of the pumps, to examine

water age, and to identify fire flow improvements. New mains that were constructed since 2003

have been added to the model.

ADDITIONAL MODEL INFORMATION

Pump Station Controls

Pump Station Controlling

Tank

Pump Number Pump ON

Level (ft)

Pump OFF

Level (ft)

WTP High

Service

Tank #1 1 (Lead) 27.0 28.5

2 (Lag 1) 26.0 28.5

3 (Lag 2) 24.0 28.0

4 (Lag 3) 20.0 26.5

PS #1 Tank #3 1 (Lead) 25.0 29.0

2 (Lag 1) 24.0 28.0

3 (Lag 2) 23.5 27.0

PS #2 Tank #4 1 (Lag 1) 28.0 33.0

2 (Lead) 30.0 35.0

3 (Lag 2/Fire) 20.0 30.0

Tank Information

Tank Pressure Zone Average Water Age (hrs)

1 Central 120.08

2 East 134.19

3 East 77.33

4 West 60.89
IDSE Guidance Manual for the Final Stage 2 DBPR F-10 

CALIBRATION RESULTS

Tank #1, Central Pressure Zone

Calibration Verification Results - August 2006 Data

889890891892893894895896897898899

8/24/2006 0:00 8/24/2006 12:00 8/25/2006 0:00 8/25/2006 12:00 8/26/2006 0:00 8/26/2006 12:00 8/27/2006 0:0

Date/Time

Level (ft) 
IDSE Guidance Manual for the Final Stage 2 DBPR F-11 

CALIBRATION RESULTS (CONTINUED)

Tank #2, East Pressure Zone

Calibration Verification Results - August 2006 Data

102410251026102710281029103010311032

8/24/2006 0:00 8/24/2006 12:00 8/25/2006 0:00 8/25/2006 12:00 8/26/2006 0:00 8/26/2006 12:00 8/27/2006 0:0

Date/Time

Level (ft) 
IDSE Guidance Manual for the Final Stage 2 DBPR F-12 

CALIBRATION RESULTS (CONTINUED)

Tank #4, West Pressure Zone

Calibration Verification Results - August 2006 Data

100510061007100810091010101110121013

8/24/2006 0:00 8/24/2006 12:00 8/25/2006 0:00 8/25/2006 12:00 8/26/2006 0:00 8/26/2006 12:00 8/27/2006 0:0

Date/Time

Level (ft) 
IDSE Guidance Manual for the Final Stage 2 DBPR F-13 

Water Age for Tank 2

0

20406080

100120140

0 100 200 300 400 500 600 700 800 900 

Time (hours)

Age (hours)

MODELING ANALYSIS RESULTS
IDSE Guidance Manual for the Final Stage 2 DBPR F-14 January 2006

MODELING ANALYSIS RESULTS

Average Water Age for All Nodes (Hour 936 to Hour 960 of Simulation)

ID

Average

(hrs) ID

Average

(hrs) ID Average (hrs) ID Average (hrs)

10 263.32 96 0.76 182 1.47 268 6.57

12 3.05 98 0.83 184 18.37 270 13.57

14 21.28 100 0.95 186 16.35 272 79.19

16 4.68 102 947.88 188 9.42 274 172.01

18 581.18 104 947.88 190 48.29 276 280.49

20 5 106 333.21 192 34.8 278 35.64

22 947.93 108 264.09 194 58.32 280 947.93

24 947.81 110 270.36 196 52.38 282 27.33

26 246.72 112 33.79 198 44.4 284 947.93

28 16.64 114 947.93 200 46.24 286 27.3

30 947.76 116 947.93 202 44.64 288 947.93

32 947.76 118 419.19 204 40.19 292 26.54

34 32.95 120 331.35 206 46.77 294 947.93

36 18.67 122 288.94 208 947.93 296 25.95

38 0.04 124 65.68 210 47.64 298 54.63

40 0.38 126 174.07 212 48.59 300 76.66

42 183.79 128 40.42 214 45.22 302 23.47

44 2.96 130 0.05 216 41.58 304 28.74

46 0.09 132 847.23 218 49.83 306 22.85

48 0.16 134 947.93 220 43.94 308 8.04

50 0.25 136 290.74 222 8.77 310 21.75

52 0.33 138 1.12 224 947.93 312 27.97

54 0.16 140 20.57 226 947.93 314 23.31

56 0.31 142 1.36 228 34.13 316 22.94

58 0.15 144 497.02 230 39.62 318 4.14

60 894.92 146 21.59 232 42.32 320 6.65

62 2.84 148 0.12 234 35.18 322 4.5

64 886.42 150 751.59 236 36.64 324 947.93

66 0.15 152 947.93 238 11.73 326 3.71

68 0.24 154 947.93 240 947.93 328 1.98

70 0 156 355.98 242 11.4 330 3.43

72 894.96 158 18.04 244 947.93 332 3.19

74 934.2 160 0.08 246 9.9 334 947.93

76 889.41 162 491.68 248 46 336 947.93

78 0.81 164 947.93 250 947.93 338 2.9

80 0.68 166 947.93 252 17.1 340 2.5

82 0.63 168 230.29 254 15.64 342 3.12

84 947.93 170 24.57 256 25.88 344 947.93

86 579.20 172 549.5 258 947.93 346 3.64

88 0.4 174 587.53 260 4.89 348 34.98

90 93.09 176 947.93 262 5.02 350 947.93

92 14.19 178 947.93 264 947.93 352 99.19

94 19.75 180 1.45 266 947.93 354 947.93
IDSE Guidance Manual for the Final Stage 2 DBPR F-15 January 2006

MODELING ANALYSIS RESULTS (CONTINUED)

Average Water Age for All Nodes (Hour 936 to Hour 960 of Simulation)

ID Average

(hrs) ID Average (hrs) ID Average (hrs) ID Average (hrs)

356 17.38 446 5.61 1028 8.26 1071 0.24

358 947.93 448 2.07 1029 6.64 1072 14.53

360 947.93 450 8.73 1030 6.57 1073 3.55

362 947.93 452 12.94 1031 9.37 1074 9.89

364 83.58 454 2.38 1032 9.09 1075 947.93

366 947.93 470 0.49 1033 8.06 1076 4.37

368 947.93 472 0.49 1034 9.44 1077 1.99

370 7.49 474 0.41 1035 7.56 1078 3.36

372 12.99 476 0.55 1036 5.78 1079 5.48

374 29.83 480 947.93 1037 7.12 1080 10.56

376 6.76 482 130.78 1038 10.42 1081 3.82

378 919.41 484 0.11 1039 9.59 1082 3.6

380 223.06 486 588.10 1040 10.82 1083 947.93

384 20.56 488 947.93 1041 8.56 1084 3.54

388 12.38 490 18.14 1042 7.71 1085 947.93

390 13.03 1000 62.06 1043 10.54 1086 15.45

392 1.53 1001 0.16 1044 12.2 1087 28.45

394 45.29 1002 7.11 1045 11.08 1088 3.18

396 45.07 1003 95.1 1046 6.31 1089 2.68

398 2.91 1004 108.24 1047 0.78 1090 13.68

400 16.09 1005 947.93 1048 8.91 1091 4

402 7.69 1006 93.84 1049 5.99 1092 40.09

404 8.21 1007 947.93 1050 5.54 1093 12.76

406 11.3 1008 7.58 1051 5.67 1094 0.32

408 15.69 1009 947.93 1052 4.38 1095 15.78

410 11.36 1010 947.93 1053 4.94 1096 0.86

412 33.78 1011 8.11 1054 4.86 1097 23.18

414 34.6 1012 13.93 1055 11.25 1098 5.46

416 35.59 1013 5.64 1056 947.93 1099 2.26

418 38.42 1014 12 1057 4.74 1100 947.93

420 36.09 1015 0 1058 10.28 1101 9.96

422 77.88 1016 6.17 1059 9.12 1102 9.65

424 70.07 1017 155.01 1060 5.08 1103 2.62

426 66.5 1018 7.2 1061 6.25 1104 2.84

428 59.04 1019 20.33 1062 4.38 1105 2.87

430 34.85 1020 23.77 1063 7.17 1106 3.17

432 39.89 1021 16.59 1064 3.98 1107 2.49

434 37.1 1022 5.61 1065 5.3 1108 947.93

436 29.81 1023 6.3 1066 4.24 1109 2.58

438 11.31 1024 0.63 1067 6.25 1110 947.93

440 4.39 1025 7.06 1068 62.36 1111 13.53

442 8.26 1026 11.19 1069 9.19 1112 0.55

444 6.1 1027 6.53 1070 5.27 1113 19.15
IDSE Guidance Manual for the Final Stage 2 DBPR F-16 January 2006

MODELING ANALYSIS RESULTS (CONTINUED)

Average Water Age for All Nodes (Hour 936 to Hour 960 of Simulation)

ID Average

(hrs) ID Average (hrs) ID Average (hrs) ID Average (hrs)

1114 7.76 1157 11.18 1200 16.11 1243 947.93

1115 3.33 1158 11.08 1201 22.86 1244 44.19

1116 947.93 1159 12.28 1202 24.73 1245 28.38

1117 3.39 1160 12.71 1203 7.42 1246 20.8

1118 2.96 1161 9.74 1204 17.71 1247 13.59

1119 3.54 1162 6.69 1205 4.75 1248 17.77

1120 3.11 1163 16.61 1206 21.63 1249 15.55

1121 12.42 1164 7.23 1207 8.88 1250 15.21

1122 11.1 1165 21.24 1208 947.93 1251 93.45

1123 947.93 1166 55.84 1209 30.85 1252 334.45

1124 91.17 1167 4.14 1210 20.75 1253 47.35

1125 3.9 1168 4.01 1211 24.67 1254 44.01

1126 4.03 1169 26.65 1212 19.74 1255 73.19

1127 947.93 1170 11.46 1213 19.27 1256 180.69

1128 5.77 1171 13.53 1214 16.71 1257 14.57

1129 33.29 1172 10.92 1215 21.05 1258 13.66

1130 4.15 1173 15.57 1216 947.93 1259 128.65

1131 3.66 1174 30.07 1217 18.78 1260 5.87

1132 4.33 1175 9 1218 17.59 1261 5.25

1133 4.38 1176 12.33 1219 37.14 1262 3.38

1134 9.14 1177 0.55 1220 10.53 1263 55.17

1135 0.55 1178 947.93 1221 15.7 1264 947.93

1136 35.4 1179 30.74 1222 25.96 1265 57.91

1137 4.25 1180 13.37 1223 28.42 1266 16.04

1138 4.85 1181 34.46 1224 28.09 1267 15.39

1139 4.42 1182 21.7 1225 16.94 1268 9.4

1140 62.47 1183 13.97 1226 15.21 1269 5.49

1141 4.6 1184 29.7 1227 21.73 1270 10.51

1142 947.93 1185 23.94 1228 43.29 1271 13.76

1143 947.93 1186 9.61 1229 11.98 1272 9.59

1144 4.28 1187 8.47 1230 17.13 1273 28.08

1145 4.93 1188 23.68 1231 9.13 1274 173.08

1146 6.34 1189 21.97 1232 17.52 1275 15.82

1147 6.08 1190 21.6 1233 16.95 1276 183.99

1148 16.55 1191 21.85 1234 17.2 1277 154.62

1149 8.71 1192 22 1235 16.81 1278 172.86

1150 4.67 1193 18 1236 20.4 1279 35.13

1151 7.07 1194 22.54 1237 947.93 1280 155.92

1152 7.82 1195 20.72 1238 947.93 1281 29.41

1153 7.42 1196 947.93 1239 14.17 1282 8.24

1154 19.91 1197 33.84 1240 14.04 1283 25.69

1155 9.08 1198 37.03 1241 62.71 1284 947.93

1156 0.4 1199 23.58 1242 13.92 1285 947.93
IDSE Guidance Manual for the Final Stage 2 DBPR F-17 January 2006

MODELING ANALYSIS RESULTS (CONTINUED)

Average Water Age for All Nodes (Hour 936 to Hour 960 of Simulation)

ID Average

(hrs) ID Average (hrs) ID Average (hrs) ID Average (hrs)

1286 15.41 1329 947.93 1372 36.44 1415 30.44

1287 13.2 1330 27.25 1373 947.93 1416 15.56

1288 947.93 1331 12.31 1374 38.16 1417 36.91

1289 13.18 1332 64.6 1375 47.25 1418 947.93

1290 947.93 1333 10.2 1376 32.22 1419 20.34

1291 44.01 1334 35.3 1377 38.87 1420 1.71

1292 30.5 1335 107.16 1378 31.36 1421 947.93

1293 10.47 1336 30.62 1379 15.1 1422 21.62

1294 39.4 1337 947.93 1380 31.67 1423 22.44

1295 64.59 1338 46.6 1381 32.44 1424 27.88

1296 90.1 1339 26.67 1382 28.03 1425 27.93

1297 66.63 1340 6.72 1383 28.28 1426 22.1

1298 22.13 1341 25.72 1384 31.44 1427 33.81

1299 69.96 1342 26.8 1385 28.46 1428 1.71

1300 67.85 1343 9.95 1386 21.36 1429 5.35

1301 80.4 1344 26.07 1387 28.67 1430 18.02

1302 61.48 1345 25.99 1388 54.41 1431 5.3

1303 4.7 1346 25.39 1389 27.44 1432 8.3

1304 67.69 1347 23.62 1390 13.34 1433 9.92

1305 64.22 1348 947.93 1391 13.05 1434 18.12

1306 73.64 1349 947.93 1392 12.04 1435 57.1

1307 68.43 1350 25.09 1393 947.93 1436 15.31

1308 28.44 1351 22.99 1394 14.01 1437 18.75

1309 28.17 1352 23.95 1395 15.85 1438 58.41

1310 28.4 1353 9.39 1396 31.76 1439 81.12

1311 30.9 1354 22.1 1397 14.79 1440 65.54

1312 61.1 1355 947.93 1398 56.36 1441 26.22

1313 11.5 1356 106.7 1399 16.5 1442 24.87

1314 14.01 1357 45.02 1400 34.68 1443 26.12

1315 28.05 1358 947.93 1401 947.93 1444 27.32

1316 27.83 1359 51.76 1402 20.62 1445 947.93

1317 43.49 1360 54.77 1403 30.51 1446 2.98

1318 35.48 1361 48.44 1404 30.37 1447 26.42

1319 26.95 1362 30.27 1405 947.93 1448 22.2

1320 27.3 1363 947.93 1406 947.93 1449 10.38

1321 20.57 1364 27.34 1407 29.74 1450 4.93

1322 9.35 1365 32.52 1408 30.68 1451 20.56

1323 60.46 1366 67.84 1409 28.82 1452 20.09

1324 36.99 1367 38.08 1410 39.05 1453 2.8

1325 13.44 1368 32.98 1411 1.69 1454 3.84

1326 67.16 1369 947.93 1412 28.82 1455 6.55

1327 48.75 1370 34.52 1413 4.52 1456 21.22

1328 947.93 1371 30.84 1414 28.66 1457 2.15
IDSE Guidance Manual for the Final Stage 2 DBPR F-18 January 2006

MODELING ANALYSIS RESULTS (CONTINUED)

Average Water Age for All Nodes (Hour 936 to Hour 960 of Simulation)

ID Average (hrs) ID Average (hrs) ID Average (hrs) ID Average (hrs)

1458 12.74 1501 27.28 1544 2.94 1587 17.62

1459 1.94 1502 21.53 1545 947.93 1588 54.87

1460 1.83 1503 15.63 1546 1.49 1589 45.46

1461 1.63 1504 16.98 1547 1.62 1590 11.65

1462 1.91 1505 24.66 1548 947.93 1591 947.93

1463 33.73 1506 947.93 1549 9.1 1592 62.9

1464 29.76 1507 11.1 1550 7.02 1593 44.65

1465 947.93 1508 12.54 1551 5.53 1594 32.05

1466 4.96 1509 26.33 1552 8.93 1595 43.9

1467 4.86 1510 947.93 1553 5.51 1596 3.47

1468 5.17 1511 23.21 1554 947.93 1597 947.93

1469 5.39 1512 947.93 1555 29.7 1598 4.1

1470 28.36 1513 18.48 1556 7.21 1599 229.18

1471 7.62 1514 17.66 1557 8.33 1600 4.68

1472 947.93 1515 17.77 1558 16.13 1601 121.33

1473 6.88 1516 8.21 1559 21.2 1602 28.19

1474 9.07 1517 8.07 1560 4.41 1603 124.75

1475 14.69 1518 6.18 1561 35.53 1604 24.75

1476 7.97 1519 4.67 1562 18.2 1605 17.01

1477 14.39 1520 4.39 1563 53.95 1606 16.78

1478 17.08 1521 4.33 1564 21.74 1607 9.42

1479 16.1 1522 5.45 1565 18.58 1608 74.9

1480 11.46 1523 4.6 1566 17.41 1609 6.61

1481 947.93 1524 4.82 1567 17.39 1610 9.45

1482 12.63 1525 947.93 1568 20.31 1611 9.54

1483 35.05 1526 947.93 1569 24.61 1612 10.05

1484 8.09 1527 6.23 1570 18.49 1613 12.7

1485 6.71 1528 31.31 1571 33.57 1614 10.52

1486 34.93 1529 75.19 1572 21.88 1615 9.56

1487 5.47 1530 1.51 1573 22.31 1616 6.49

1488 13.62 1531 3.88 1574 27.95 1617 51.88

1489 26.17 1532 19.37 1575 15.85 1618 11.17

1490 947.93 1533 324.34 1576 947.93 1619 11

1491 26.13 1534 39.59 1577 18.55 1620 12.65

1492 26.9 1535 10.21 1578 18.16 1621 23.87

1493 26.12 1536 947.93 1579 17.63 1622 30.62

1494 21.46 1537 28.04 1580 21 1623 26.81

1495 29.26 1538 26.12 1581 52.83 1624 6.86

1496 109.84 1539 947.93 1582 947.93 1625 6.32

1497 31.54 1540 947.93 1583 19.81 1626 7.54

1498 90.57 1541 32.43 1584 26.65 1627 63.75

1499 24.39 1542 318.95 1585 26.24 1628 11.24

1500 16.31 1543 947.93 1586 947.93 1629 947.93
IDSE Guidance Manual for the Final Stage 2 DBPR F-19 January 2006

MODELING ANALYSIS RESULTS (CONTINUED)

Average Water Age for All Nodes (Hour 936 to Hour 960 of Simulation)

ID Average (hrs) ID Average (hrs) ID Average

(hrs)

1630 14.57 1673 4.33 1716 2.6

1631 11.29 1674 4.37 1717 2.43

1632 11.45 1675 4.2 1718 2.5

1633 12.1 1676 5.36 1719 113.62

1634 11.92 1677 6.02 1720 1.79

1635 12.35 1678 5.67 1721 20.44

1636 233.36 1679 29.71 1722 1.47

1637 947.93 1680 5.57 1723 1.15

1638 13.44 1681 5.95 1724 5.27

1639 30.77 1682 6.27 1725 947.93

1640 30.78 1683 6.75 1726 1.07

1641 3.38 1684 6.19 1727 2.37

1642 35.68 1685 6.48 1728 42.65

1643 14.93 1686 14.02 1729 112.12

1644 50.93 1687 14.57 1730 947.93

1645 32.32 1688 18.25 1731 33.5

1646 33.81 1689 15.42 1732 42.95

1647 25.23 1690 5.34 1733 116.37

1648 26.59 1691 6.78 1734 123.36

1649 25.16 1692 4.34 1735 9.67

1650 29.32 1693 6.02 1736 117.02

1651 21.69 1694 8.44 1737 5.31

1652 41.66 1695 23.73 1738 8.1

1653 9.53 1696 5.29 1739 947.93

1654 5.65 1697 5.87 1740 125.05

1655 19.64 1698 4.97 1741 166.46

1656 14.9 1699 4.23 1742 100.57

1657 5.55 1700 5.17 1743 112.85

1658 5.71 1701 4.52 1744 176.36

1659 5.14 1702 3.83 1745 169.74

1660 4.96 1703 5.99 1746 947.93

1661 947.93 1704 3.09 1747 947.93

1662 8.48 1705 3.6

1663 5.4 1706 3.33

1664 4.46 1707 5.83

1665 6.13 1708 3.46

1666 6.32 1709 3.19

1667 5.25 1710 3.93

1668 7.75 1711 18.99

1669 103.99 1712 5.16

1670 4.93 1713 947.93

1671 4.64 1714 2.68

1672 6.97 1715 2.37
IDSE Guidance Manual for the Final Stage 2 DBPR F-20 January 2006

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IDSE Guidance Manual for the Final Stage 2 DBPR F-21 January 2006

Form 5: IDSE Report for a Modeling SSS Page 1 of 11

I. GENERAL INFORMATION

(Skip this section if you are submitting the plan and report at the same time)

A. PWS Information* B. Date Submitted* 

 PWSID: US1111111 2/17/09

PWS Name: Big City Water System

PWS Address: 1234 Main Street

City: Big City State: US Zip: 99999

Population Served: 57,000

System Type: Source Water Type: Buying / Selling Relationships:

: CWS : Subpart H ~ Consecutive System 

~ NTNCWS ~ Ground ~ Wholesale System 

 : Neither

C. PWS Operations 

Residual Disinfectant Type: : Chlorine ~ Chloramines ~ Other:__________

Number of Disinfected Sources: 1 Surface ___GWUDI ____ Ground ___ Purchased

D. Contact Person*

Name: Mr. John Smith, P.E.

Title: Water System Manager

Phone Number: 123-555-0000 Fax: 123-555-0001

E-mail: jsmith@ci.bigcity.us

II. SSS AND STAGE 2 DBPR REQUIREMENTS*

A. Number of Required Stage 2 DBPR Compliance Monitoring Sites 8 TOTAL

 3 Highest TTHM 2 Stage 1 DBPR

 3 Highest HAA5

B. IDSE Schedule C. Required Stage 2 DBPR Monitoring Frequency

 ~ Schedule 1 ~ Once during peak historical month

 : Schedule 2 : Every 90 days (4 monitoring periods)

 ~ Schedule 3 D. Number of Required SSS Samples

 ~ Schedule 4 16 TOTAL
IDSE Guidance Manual for the Final Stage 2 DBPR F-22 January 2006

Form 5: IDSE Report for a Modeling SSS Page 2 of 11

III. MODELING INFORMATION

(Skip this section if you submitted a modeling study plan with an approved model calibration

and your information has not changed, or if you are submitting your plan and report at the

same time)

A. How was demand data assigned to the model? (attach additional sheets if

needed)

1. What method was used to assign

demands throughout the system?

2. How did you estimate diurnal demand

variation? How did you determine

total system demand?

3. How many demand categories did

you use?

4. How did you address large water

users?

B. Describe all calibration activities undertaken* (attach additional sheets if

needed)

1. When was the model last calibrated?

2. What types of data were used in the

calibration?

3. When was the calibration data

collected?

4. What field tests have been performed

to collect calibration data?
IDSE Guidance Manual for the Final Stage 2 DBPR F-23 January 2006

Form 5: IDSE Report for a Modeling SSS Page 3 of 11

III. MODELING INFORMATION (Continued)

5. How did you determine friction factors

(C-factors)?

6. Was the calibration completed for the

peak month for TTHM formation? If

not, was the model performance

verified for the peak month for TTHM

formation?

7. How well do actual tank levels

correlate with predicted tank levels

during the peak month for TTHM

formation? 

Submit a graph of predicted tank

levels vs. measured tank levels for

the storage facility with the highest

water age in each pressure zone*.

8. If you are using a water quality model,

what parameters are modeled? How

was the model calibrated?
IDSE Guidance Manual for the Final Stage 2 DBPR F-24 January 2006

Form 5: IDSE Report for a Modeling SSS Page 4 of 11 

III. MODELING INFORMATION (Continued)

C. How was the SSS modeling performed?* (attach additional sheets as needed)

1. Was modeling done for the operating

conditions during the peak month for

TTHM formation*?

2. How were operational controls

represented in the model?

3. How was water age simulated during

the peak month for TTHM formation

(time steps, length of simulation,

etc.)? 

4.

What are the average water age

results for your distribution system? 

Submit final model output showing 

24-hour average residence time 

throughout the distribution

system*.

Submit graph of water age at the

longest residence time storage

facility in the distribution system

showing the predictions for the

entire EPS simulation period*.
IDSE Guidance Manual for the Final Stage 2 DBPR F-25 January 2006

Form 5: IDSE Report for a Modeling SSS Page 5 of 11 

IV. SSS MONITORING LOCATION SELECTION 

How were the SSS monitoring locations selected? (attach additional sheets as needed)

1.

What model results were used as the

basis for selection?

The average water age results from the last 24

hours of the 960 hour simulation were analyzed. 

Nodes were ranked by age and a histogram of

water age ranges was created.

2.

What criteria were used in selecting

average residence time, high TTHM,

and high HAA5 sites?

The high TTHM and high HAA5 sites were selected

with water ages in the range of 300 - 500 hours. 

These were the high results from the modeling

(excluding zero demand nodes). The average

water age was determined to be 20 hours based on

the most frequently occurring age in the histogram.

3. What additional data was used in the

analysis, and how was it used?

TCR data for chlorine residual was examined for

each potential sampling site. High water age

locations with measurable residual were selected

for high HAA5 sites. High water age locations with

low residual chlorine were selected for high TTHM

sites.

4. How did you look at practical

considerations like accessibility of

sampling locations?

Once model nodes were identified, the proposed

location was found on the paper water atlas sheets

and an accessible sampling point was determined

in the vicinity of the original node. Accessible

locations served by the same water main as the

model node were targeted. If the targeted water

main was not accessible, an alternate location on a

water main of the same diameter was found in the 

vicinity.

5. How did you verify that your selected

sampling locations corresponded to

the selected node in your model?

Using the paper water atlas sheets and comparing

the locations to the information in the hydraulic

model, locations were verified.
IDSE Guidance Manual for the Final Stage 2 DBPR F-26 January 2006

Form 5: IDSE Report for a Modeling SSS Page 6 of 11

V. SSS AND STAGE 1 DBPR MONITORING RESULTS*

A. TTHM Results

Site ID &

Category

Data Type TTHM (mg/L) LRAA

Stage 1 Site 1 Sample Date 3/12/08 6/7/08 8/22/08 10/1/08

Sample Result 0.041 0.048 0.062 0.050 0.050

Stage 1 Site 2 Sample Date 3/12/08 6/7/08 8/22/08 10/1/08

Sample Result 0.045 0.046 0.058 0.053 0.051

Stage 1 Site 3 Sample Date 3/12/08 6/7/08 8/22/08 10/1/08

Sample Result 0.051 0.055 0.075 0.059 0.060

Stage 1 Site 4 Sample Date 3/12/08 6/7/08 8/22/08 10/1/08

Sample Result 0.048 0.052 0.068 0.053 0.055

SSS-1

Entry

Sample Date 8/5/08

Sample Result 0.028 0.028

SSS-2

Average

Sample Date 8/5/08

Sample Result 0.048 0.048

SSS-3

Average

Sample Date 8/5/08

Sample Result 0.058 0.058

SSS-4

Average

Sample Date 8/5/08

Sample Result 0.067 0.067

SSS-5

Average

Sample Date 8/5/08

Sample Result 0.033 0.033

SSS-6

High TTHM

Sample Date 8/5/08

Sample Result 0.056 0.056

SSS-7

High TTHM

Sample Date 8/5/08

Sample Result 0.059 0.059

SSS-8

High TTHM

Sample Date 8/5/08

Sample Result 0.055 0.055

Attach additional sheets as needed for SSS and Stage 1 DBPR results.
IDSE Guidance Manual for the Final Stage 2 DBPR F-27 January 2006

Form 5: IDSE Report for a Modeling SSS Page 7 of 11

V. SSS AND STAGE 1 DBPR MONITORING RESULTS* (Continued)

B. HAA5 Results

Site ID &

Category

Data Type HAA5 (mg/L) LRAA

Stage 1 Site 1 Sample Date 3/12/08 6/7/08 8/22/08 10/1/08

Sample Result 0.034 0.046 0.006 0.042 0.032

Stage 1 Site 2 Sample Date 3/12/08 6/7/08 8/22/08 10/1/08

Sample Result 0.030 0.045 0.044 0.042 0.040

Stage 1 Site 3 Sample Date 3/12/08 6/7/08 8/22/08 10/1/08

Sample Result 0.032 0.038 0.037 0.040 0.037

Stage 1 Site 4 Sample Date 3/12/08 6/7/08 8/22/08 10/1/08

Sample Result 0.040 0.004 0.012 0.044 0.025

SSS-1

Entry

Sample Date 8/5/08

Sample Result 0.018 0.018

SSS-2

Average

Sample Date 8/5/08

Sample Result 0.020 0.020

SSS-3

Average

Sample Date 8/5/08

Sample Result 0.019 0.019

SSS-4

Average

Sample Date 8/5/08

Sample Result 0.026 0.026

SSS-5

Average

Sample Date 8/5/08

Sample Result 0.033 0.033

SSS-6

High TTHM

Sample Date 8/5/08

Sample Result 0.048 0.048

SSS-7

High TTHM

Sample Date 8/5/08

Sample Result 0.057 0.055

SSS-8

High TTHM

Sample Date 8/5/08

Sample Result 0.046 0.046

Attach additional sheets as needed for SSS and Stage 1 DBPR results.
IDSE Guidance Manual for the Final Stage 2 DBPR F-28 January 2006

Form 5: IDSE Report for a Modeling SSS Page 8 of 11

V. SSS AND STAGE 1 DBPR MONITORING RESULTS* (Continued)

C. Where were your TTHM and HAA5 samples analyzed?

: In-House

Is your in-house laboratory certified? : Yes ~ No

~ Certified Laboratory

Name of certified laboratory: 

D. What method(s) was used to analyze your TTHM and HAA5 samples?

 TTHM HAA5

: EPA 502.2 : EPA 552.1 ~ EPA 552.2

~ EPA 524.2 ~ EPA 552.3 ~ SM 6251 B

~ EPA 551.1

VI. SELECTION OF STAGE 2 DBPR COMPLIANCE MONITORING LOCATIONS

Describe the comparison of sampling and modeling results (attach additional sheets as

needed):

1. How well did the sampling results

correspond to the modeling results?

For most SSS monitoring sites, the results were in

accordance with the modeling results. 

Discrepancies were found at 2 sites: SSS-4 and

SSS-11. SSS-4 was an average residence time

site with TTHM results that were more typical of a

high TTHM site. SSS-11 was a high TTHM site

with TTHM results that were more typical of an

average site.

2. For samples that did not match well

with model results, what follow-up

investigations were performed?

At sites SSS-4 and SSS-11, data for chlorine

residual was reviewed from TCR sampling. The

time of sample collection was compared to the

water age graph. The model results for water age

at SSS-11 are highly variable and therefore that

site was eliminated from further consideration. The

discrepancy at SSS-4 could have been related to

variation over time, although the model results are

less conclusive at that site. SSS-4 was also

eliminated from further consideration.

3. Were additional samples collected?

(Include data on table in section IV)

No

4. Submit a graph of water age 

versus time for each selected

sampling location*.

Graphs are attached.
IDSE Guidance Manual for the Final Stage 2 DBPR F-29 January 2006

Form 5: IDSE Report for a Modeling SSS Page 9 of 11

VII. JUSTIFICATION OF STAGE 2 DBPR COMPLIANCE MONITORING SITES*

 Compliance

Monitoring

Site ID

Site Type Justification

Stage 2 Site 1 : Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

SSS-12

High average water age, high TTHM results during

monitoring, located in East Pressure Zone

Stage 2 Site 2 ~ Highest TTHM

: Highest HAA5

~ Stage 1 DBPR

SSS-14

High average water age, high HAA5 results during

monitoring, measurable residual in historical TCR

data, located in East Pressure Zone

Stage 2 Site 3 ~ Highest TTHM

~ Highest HAA5

: Stage 1 DBPR

Stage 1 Site 2

Average residence time Stage 1 DBPR site with

high HAA5 LRAA, relatively high water age, located

in East Pressure Zone

Stage 2 Site 4 : Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

SSS-9

High average water age, high TTHM results during

monitoring, located in East Pressure Zone

Stage 2 Site 5 : Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

SSS-15

High average water age, high TTHM results during

monitoring, located in East Pressure Zone

Stage 2 Site 6 ~ Highest TTHM

: Highest HAA5

~ Stage 1 DBPR

SSS-10

High average water age, high HAA5 results during

monitoring, measurable residual in historical TCR

data, located in Central Pressure Zone

Stage 2 Site 7 ~ Highest TTHM

~ Highest HAA5

: Stage 1 DBPR

Stage 1 Site 4

High average water age, high TTHM historical data,

located in West Pressure Zone

Stage 2 Site 8 ~ Highest TTHM

: Highest HAA5

~ Stage 1 DBPR

SSS-13

High average water age, high HAA5 results during

monitoring, measurable residual in historical TCR

data, located in East Pressure Zone

Attach additional copies of this sheet if you need more room.
IDSE Guidance Manual for the Final Stage 2 DBPR F-30 January 2006

Form 5: IDSE Report for a Modeling SSS Page 10 of 11

VIII. PEAK HISTORICAL MONTH

A. Peak Historical Month* August 

B. Is Your Peak Historical Month the Same as your Peak Month for TTHM

Formation in your Model Study Plan?

: Yes ~ No

If no, explain how you selected your new peak month for TTHM formation

(attach additional sheets if needed):

IX. PROPOSED STAGE 2 COMPLIANCE MONITORING SCHEDULE*

Stage 2

Compliance

Monitoring

Site ID

Projected Sampling Date (date or week)1

period 1 period 2 period 3 period 4

Stage 2 Site 1 11/2012, wk 1 2/2013, wk 1 5/2013, wk 1 8/2013, wk 1

Stage 2 Site 2 11/2012, wk 1 2/2013, wk 1 5/2013, wk 1 8/2013, wk 1

Stage 2 Site 3 11/2012, wk 1 2/2013, wk 1 5/2013, wk 1 8/2013, wk 1

Stage 2 Site 4 11/2012, wk 1 2/2013, wk 1 5/2013, wk 1 8/2013, wk 1

Stage 2 Site 5 11/2012, wk 1 2/2013, wk 1 5/2013, wk 1 8/2013, wk 1

Stage 2 Site 6 11/2012, wk 1 2/2013, wk 1 5/2013, wk 1 8/2013, wk 1

Stage 2 Site 7 11/2012, wk 1 2/2013, wk 1 5/2013, wk 1 8/2013, wk 1

Stage 2 Site 8 11/2012, wk 1 2/2013, wk 1 5/2013, wk 1 8/2013, wk 1

1

 period = monitoring period. Complete for the number of monitoring periods from

Section II.C.

Attach additional copies of this sheet if you need more room.
IDSE Guidance Manual for the Final Stage 2 DBPR F-31 January 2006

Form 5: IDSE Report for a Modeling SSS Page 11 of 11

X. DISTRIBUTION SYSTEM SCHEMATIC*

(Skip this section if you submitted a modeling study plan and your distribution system

schematic was complete and has not changed from your approved modeling study plan, or if

you are submitting the plan and report at the same time)

ATTACH a schematic of your distribution system. If your schematic has changed or if

you did not show your SSS monitoring locations on the distribution system schematic

you submitted with your model study plan (Form 4), you must submit a revised

distribution system schematic. 

XI. ATTACHMENTS

~ Tabular or spreadsheet documentation that your model meets minimum calibration

requirements if updated since approved modeling study plan* (Section III).

~ Additional sheets for explaining model information/results, including required graphs if

not submitted as part of an approved modeling study plan* (Section III).

: Additional sheets for sampling results, if needed (Section V).

: Additional sheets for selection of Stage 2 DBPR compliance monitoring sites (Section

VI).

: Graph of water age versus time for all Stage 2 DBPR sites selected* (Section VI).

~ Additional sheets for justification of Stage 2 DBPR Monitoring Sites, if needed

(Section VII). REQUIRED if you are a subpart H system serving more than

249,999 people.

~ Additional sheets for explaining how you selected the peak historical month (Section

VIII).

~ Additional sheets for proposed compliance monitoring schedule (Section IX). 

REQUIRED if you are a subpart H system serving more than 249,999 people.

~ Explanation of deviations from approved study plan.

: Distribution system schematic* (Section X). REQUIRED if it has changed from

your approved model study plan or if monitoring locations were not shown.

~ Compliance calculation procedures (for Stage 2 Compliance Monitoring Plan). 

Total Number of Pages in Your Report: 25 

Note: All items marked with an asterisk (*) are required by the rule.
IDSE Guidance Manual for the Final Stage 2 DBPR F-32 January 2006

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IDSE Guidance Manual for the Final Stage 2 DBPR F-33 January 2006

Scale 1:8,000
IDSE Guidance Manual for the Final Stage 2 DBPR F-34 January 2006

Percentage of nodes

0

10

20

30

40

50

60

0

20406080

100120140160180200220240260280300320340360380400420440460480500520540560580600620640660680700

More

Time (hours)

% of nodes

SSS MONITORING LOCATION SELECTION

Histogram of Water Age Results 

Average Age = midpoint of most frequently occurring range

 = midpoint of 20 - 40 hour range = 30 hours
IDSE Guidance Manual for the Final Stage 2 DBPR F-35 January 2006

SSS MONITORING LOCATION SELECTION (CONTINUED)

Average Water Age Results for SSS monitoring locations

 (Hour 936 to Hour 960 of Simulation)

Node Average Water Age (hrs) Preliminary Category ID

1411 1.69 Entry SSS-1

1362 30.27 Average SSS-2

1336 30.62 Average SSS-3

1639 30.77 Average SSS-4

1640 30.78 Average SSS-5

276 280.49 High TTHM SSS-6

1533 324.34 High TTHM SSS-7

144 497.02 High TTHM SSS-8

18 581.18 High TTHM SSS-9

174 587.53 High TTHM SSS-10

486 588.10 High TTHM SSS-11

122 288.94 High HAA5 SSS-12

120 331.35 High HAA5 SSS-13

106 333.21 High HAA5 SSS-14

162 491.68 High HAA5 SSS-15

86 579.20 High HAA5 SSS-16
IDSE Guidance Manual for the Final Stage 2 DBPR F-36 

SSS MONITORING LOCATION SELECTION (CONTINUED)

Selection of Stage 2 DBPR Compliance Monitoring Sites

SSS Sites TTHM

LRAA

Results

TTHM

Rank*

HAA5

LRAA

Results

HAA5

Rank*

Preliminary

Category

Water

Age

Zone Stage 2

DBPR

Selected

Sites

Stage 2 DBPR 

SSS-1 0.028 20 0.018 20 Entry 1.69 CentralSSS-2 0.048 17 0.020 18 Average 30.27 CentralSSS-3 0.058 10 0.019 19 Average 30.62 CentralSSS-4 0.067 4 0.026 16 Average 30.77 Central RejectedSSS-5 0.033 19 0.033 12 Average 30.78 WestSSS-6 0.056 11 0.048 7 High TTHM 280.49 EastSSS-7 0.059 9 0.055 3 High TTHM 324.34 EastSSS-8 0.055 12 0.046 8 High TTHM 497.02 EastSSS-9 0.068 3 0.029 15 High TTHM 581.18 East Site 4 TTHM

SSS-10 0.064 6 0.057 4 High TTHM 587.53 Central Site 6 HAASSS-11 0.043 18 0.030 14 High TTHM 588.10 East RejectedSSS-12 0.073 1 0.050 6 High HAA5 288.94 East Site 1 TTHMSSS-13 0.061 7 0.052 5 High HAA5 331.35 East Site 8 HAASSS-14 0.069 2 0.060 1 High HAA5 333.21 East Site 2 HAASSS-15 0.064 5 0.058 2 High HAA5 491.68 East Site 5 TTHMSSS-16 0.048 16 0.046 9 High HAA5 579.20 East

Stage 1,

Site 1

0.050 15 0.032 13 Stage 1 203.22 East

Stage 1,

Site 2

0.051 14 0.040 10 Stage 1 31.05 East Site 3 Stage 

Stage 1,

Site 3

0.060 8 0.037 11 Stage 1 423.44 East

Stage 1,

Site 4

0.055 13 0.025 17 Stage 1 496.81 West Site 7 Stage 1 - Not highest b

high site and locate

*Ranked from highest(1) to lowest (20)
IDSE Guidance Manual for the Final Stage 2 DBPR F-37 January 2006

SSS MONITORING LOCATION SELECTION (CONTINUED)

WATER AGE RESULTS GRAPHS

Site A

0

100

200

300

400

500

600

700

800

900

0 6 12 18 24

Time (hrs)

Water Age (hrs)

Water Age Average Water Age
IDSE Guidance Manual for the Final Stage 2 DBPR F-38 January 2006

STAGE 2 DBPR MONITORING LOCATIONS

WATER AGE RESULTS

Site B

0

100

200

300

400

500

600

700

800

900

0 6 12 18 24

Time (hrs)

Water Age (hrs)

Water Age Average Water Age
IDSE Guidance Manual for the Final Stage 2 DBPR F-39 January 2006

STAGE 2 DBPR MONITORING LOCATIONS

WATER AGE RESULTS (CONTINUED)

Site C

0

100

200

300

400

500

600

700

800

900

0 6 12 18 24

Time (hrs)

Water Age (hrs)

Water Age Average Water Age
IDSE Guidance Manual for the Final Stage 2 DBPR F-40 January 2006

STAGE 2 DBPR MONITORING LOCATIONS

WATER AGE RESULTS (CONTINUED)

Site D

0

50

100

150

200

250

300

350

400

450

500

0 6 12 18 24

Time (hrs)

Water Age (hrs)

Water Age Average Water Age
IDSE Guidance Manual for the Final Stage 2 DBPR F-41 January 2006

STAGE 2 DBPR MONITORING LOCATIONS

WATER AGE RESULTS (CONTINUED)

Site E

0

100

200

300

400

500

600

700

800

900

0 6 12 18 24

Time (hrs)

Water Age (hrs)

Water Age Average Water Age
IDSE Guidance Manual for the Final Stage 2 DBPR F-42 January 2006

STAGE 2 DBPR MONITORING LOCATIONS

WATER AGE RESULTS (CONTINUED)

Site F

0

100

200

300

400

500

600

700

800

900

0 6 12 18 24

Time (hrs)

Water Age (hrs)

Water Age Average Water Age
IDSE Guidance Manual for the Final Stage 2 DBPR F-43 January 2006

STAGE 2 DBPR MONITORING LOCATIONS

WATER AGE RESULTS (CONTINUED)

Site G

0

100

200

300

400

500

600

700

800

900

0 6 12 18 24

Time (hrs)

Water Age (hrs)

Water Age Average Water Age
IDSE Guidance Manual for the Final Stage 2 DBPR F-44 January 2006

STAGE 2 DBPR MONITORING LOCATIONS

WATER AGE RESULTS (CONTINUED)

Site H

0

100

200

300

400

500

600

700

800

900

0 6 12 18 24

Time (hrs)

Water Age (hrs)

Water Age Average Water Age
IDSE Guidance Manual for the Final Stage 2 DBPR F-45 January 2006

MONITORING RESULTS - ADDITIONAL SHEETS

Form 5: IDSE Report for a Modeling SSS 

V. SSS AND STAGE 1 DBPR COMPLIANCE MONITORING RESULTS

A. TTHM Results*

Site ID Data Type TTHM (mg/L) LRAA

SSS-9

High TTHM

Sample Date 8/6/08

Sample Result 0.068 0.068

SSS-10

High TTHM

Sample Date 8/6/08

Sample Result 0.064 0.064

SSS-11

High TTHM

Sample Date 8/6/08

Sample Result 0.043 0.043

SSS-12

High HAA5

Sample Date 8/6/08

Sample Result 0.073 0.073

SSS-13

High HAA5

Sample Date 8/6/08

Sample Result 0.061 0.061

SSS-14

High HAA5

Sample Date 8/6/08

Sample Result 0.069 0.069

SSS-15

High HAA5

Sample Date 8/6/08

Sample Result 0.064 0.064

SSS-16

High HAA5

Sample Date 8/6/08

Sample Result 0.048 0.048

Sample Result

Sample Date

Sample Result

Sample Date

Sample Result

Sample Date

Sample Result

Sample Date

Attach additional sheets as needed for SSS and Stage 1 DBPR results.
IDSE Guidance Manual for the Final Stage 2 DBPR F-46 January 2006

MONITORING RESULTS - ADDITIONAL SHEETS

Form 5: IDSE Report for a Modeling SSS 

V. SSS AND STAGE 1 DBPR COMPLIANCE MONITORING RESULTS

A. HAA5 Results*

Site ID Data Type HAA5 (mg/L) LRAA

SSS-9

High TTHM

Sample Date 8/6/08

Sample Result 0.029 0.029

SSS-10

High TTHM

Sample Date 8/6/08

Sample Result 0.057 0.057

SSS-11

High TTHM

Sample Date 8/6/08

Sample Result 0.030 0.030

SSS-12

High HAA5

Sample Date 8/6/08

Sample Result 0.050 0.050

SSS-13

High HAA5

Sample Date 8/6/08

Sample Result 0.052 0.052

SSS-14

High HAA5

Sample Date 8/6/08

Sample Result 0.060 0.060

SSS-15

High HAA5

Sample Date 8/6/08

Sample Result 0.058 0.058

SSS-16

High HAA5

Sample Date 8/6/08

Sample Result 0.046 0.046

Sample Date

Sample Result

Sample Date

Sample Result

Sample Date

Sample Result

Sample Date

Sample Result

Attach additional sheets as needed for SSS and Stage 1 DBPR results.
Appendix G

Complex Modeling Analysis Example for a System 

with Multiple Sources
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IDSE Guidance Manual for the Final Stage 2 DBPR G-1 January 2006

Complex Modeling Analysis Example for a System with Multiple Sources

Chapter 6 discussed modeling in general terms and the example included in Section 6.2.2

is applicable to systems with a single water source or multiple sources with similar water quality

in terms of initial DBP concentrations and DBP formation potentials. However, some systems

may have multiple sources with very different water quality characteristics. For example, a

system may be served by both a groundwater source with low DBP precursor concentrations and

a surface water source with high DBP precursor concentrations. For these special cases, a

simple water age simulation will not capture the true variation in DBP concentrations because it

does not distinguish between the different quality source waters. A high water age for the low

DBP source may not result in a high DBP concentration. For example, in this case study the low

DBP precursor source has a TTHM formation potential of 0.022 mg/L and the high DBP

precursor source has a TTHM formation potential of 0.122 mg/L. Very old water from the low

DBP precursor source may have a TTHM concentration on the order of 0.020 mg/L while

relatively fresh water from the high DBP precursor source could have a TTHM concentration

greater than 0.100 mg/L. Similar situations arise in consecutive systems where the water age

entering the distribution system is different at different entry points.

Most modeling software that is currently available cannot apply a source-specific

formation rate coefficient. The formation rate coefficient is currently specified as a single,

globally-applied parameter. Special provisions should be made when using models to analyze

systems with multiple sources of varying water quality. A source-adjusted water age can be

calculated or an estimate of maximum possible DBP concentration can be developed. These are

illustrated in the following example.

Systems in this category should submit additional documentation that describes their

modeling procedures and analysis for selection of SSS monitoring sites.

Source-Adjusted Water Age Analysis

The system schematic is shown in Exhibit G.1. If the two sources in this example have

very different DBP formation rates and ultimate formation potentials, then a simple water age

analysis as performed in Section 6.2.2 will not necessarily identify the locations with highest

DBP levels. For example, if the water in Tank 3 comes mostly from the RIVER source and this

source has a much lower DBP formation potential than the LAKE source, then this tank may no

longer contain water with the highest DBP concentration, even though it has the oldest water in

the system.

Ideally, one would like to account for both the individual DBP formation potential and

kinetics for each source water as well as the blending of these waters together in an integrated

fashion when simulating the system. Unfortunately, the current generation of network water

quality models is not capable of directly performing this kind of analysis. However, one can

perform a series of simulations and calculations to approximately account for significant

differences in DBP production between different source waters. 
IDSE Guidance Manual for the Final Stage 2 DBPR G-2 January 2006

Exhibit G.1 Schematic of the Case Study Distribution System 

Calculating a source-adjusted water age for this case study requires a source trace

analysis and data on the ultimate DBP formation potential (maximum concentration) for each

source. The first step is to calculate the percentage of water from each source for all nodes in the

system. These values can be obtained by changing the type of water quality analysis from AGE

to TRACE, selecting the LAKE source as the source to be traced, and re-running the simulation. 

Exhibit G.2 displays the average percentage of water from the LAKE source reaching each node.

The percentage from the RIVER source at any node would simply be 100 minus the LAKE

percentage. Note how the nodes on the left side of the network receive mainly LAKE water

while the nodes in the upper right, which had the oldest water in the example in Section 6.2.2,

receive the least amount of LAKE water.

LAKE Source Tank 3 

Tank 1 

RIVER Source 

Tank 2 
IDSE Guidance Manual for the Final Stage 2 DBPR G-3 January 2006

Exhibit G.2 Average Percentage of Water From the LAKE Source

The adjusted water age for each node of the system can be calculated as a weighted

average by using the following equation:

Adjusted Age = Age * (PLAKE + PRIVER / R) / 100

where Age = the original age estimate, 

PLAKE = percentage of LAKE water, 

PRIVER = percentage of RIVER water, and 

R = ratio of LAKE DBP formation potential to RIVER DBP formation potential.

A similar version of this equation can be used with more than two sources by including

all sources in the weighted average.

In this case, a review of historical data showed that R was equal to 5.5, i.e. the LAKE

source has the potential to form 5.5 times greater DBP concentrations than the RIVER source. 

Exporting both the age results and the source tracing results from the model into a spreadsheet

and applying the formula shown above gives the resulting source-adjusted water age throughout

the network, as shown in Exhibit G.3. Comparing these results with the unadjusted ages in

Section 6.2.2 shows a similar pattern in terms of which nodes have the highest ages but a much
IDSE Guidance Manual for the Final Stage 2 DBPR G-4 January 2006

lower adjusted water age overall. This demonstrates that the RIVER water remains in the system

the longest but has much lower potential to form DBPs than the LAKE water. The results of the

adjusted water age analysis demonstrate the importance of considering different sources. For

example, node 131, which was predicted to have the second highest water age in the simple

water age analysis, has an adjusted water age of only 22.5 hours.

Exhibit G.3 Source-Adjusted Water Age Throughout the Study Area

Rather than using water age as the basis for selecting sampling sites, another option

would be to model DBP formation and thereby directly identify locations with high levels of

DBPs. The required input data for each DBP of interest (i.e., each chemical species) and for

each water source must be available:

1. the DBP concentration leaving the treatment plant

2. a first-order rate constant based on laboratory tests

3. an ultimate formation potential (maximum concentration) of the DBP

Exhibit G.4 lists the values of these parameters for TTHM for the case study. Note the

large difference in the formation potential and formation rate coefficient between the two

sources.
IDSE Guidance Manual for the Final Stage 2 DBPR G-5 January 2006

Exhibit G.4 Total THM Growth Parameters for the Case Study Example

RIVER

Source

LAKE Source

Total THM at Distribution System

Entry Point (mg/L)

0.012 0.108

Total THM Formation Potential, F

(mg/L)

0.022 0.122

First-Order Growth Constant, k

(1/days)

2.3 15.1

These parameters are normally used in the following THM growth expression that is

applied system-wide:

C = Co + (F – Co)(1 – exp(-kt))

where C = TTHM concentration (mg/L), 

Co = initial TTHM concentration leaving the source (mg/L), 

F = ultimate TTHM formation (mg/L), 

k = growth constant (1/days), and 

t = time in days

exp = natural log, e. 

Because there are two distinctly different THM sources in this example, the above

equation cannot be applied directly. Instead, as was done for the adjusted water age analysis, a

separate THM growth simulation should be made for each individual source with the results of

each combined outside of the model according to the percent of water from each source. Or, to

simulate a worst case scenario, a DBP simulation could be made using the appropriate source

concentrations for each source but using the highest values for F and k for the global formation

equation. The results from this worst-case simulation are given in Exhibit G.5. The results for

the DBP modeling are quite different from the results for the water age analysis at certain nodes,

as shown in Exhibit G.6. 

The results for this case study depend greatly on the system configuration and the

operational conditions. This is a simple representation of a distribution system and does not

reflect the level of complexity that is present in real systems. However, this example does

illustrate the difficulty in predicting water age or DBP concentrations for systems with multiple

sources with varying water quality characteristics.
IDSE Guidance Manual for the Final Stage 2 DBPR G-6 January 2006

Exhibit G.5 Maximum Possible TTHM Simulation Results
IDSE Guidance Manual for the Final Stage 2 DBPR G-7 January 2006

Exhibit G.6 Summary of Results from Different Analyses

Average Source Adjusted Max. THM 

Water Age Water Age formation

Node ID hours hours ug/l

10 0.03 0.03 108.00

15 72.89 12.67 12.79

20 114.22 19 11.91

35 14.9 4.53 27.86

40 31.35 17.63 57.59

50 46.22 20.49 43.86

60 0.08 0.01 12.00

601 0.8 0.13 12.00

61 0.21 0.04 12.00

101 8.33 5.85 73.77

103 6.28 5.21 88.52

105 9.06 6.15 71.02

107 9.91 7.7 82.53

109 9.86 7.29 78.01

111 8.69 6.11 73.90

113 9.68 6.49 70.14

115 9.47 6.03 66.19

117 9.16 5.88 66.86

119 11.56 2.41 16.86

120 10.69 5.91 56.55

121 10.93 1.83 12.08

123 3.39 0.57 12.00

125 67.79 11.3 11.99

127 108.72 18.09 11.92

129 113.89 18.95 11.91

131 135.44 22.53 11.90

139 108.63 18.07 11.92

141 97.77 16.46 12.16

143 76.02 13.18 12.76

145 32.38 5.92 13.87

147 24.66 4.67 14.65

149 30.58 5.88 14.96

151 39.84 7.4 14.19

153 70.11 11.7 12.02

157 10.68 2.23 16.84

159 10.54 2.19 16.73

161 10.75 2.31 17.60

163 10.75 2.31 17.59

164 20.74 4.28 16.57

166 42.97 8.85 16.51

167 11.3 2.53 18.64

169 11.16 2.5 18.66

171 11.39 2.56 18.67

173 11.38 2.55 18.64

177 22.1 13.43 62.77

179 25.41 16.16 66.04
IDSE Guidance Manual for the Final Stage 2 DBPR G-8 January 2006

181 14.87 4.52 27.83

183 19.29 12.76 68.97

184 15.85 10.53 69.40

185 15.68 10.45 69.55

187 10.59 7.12 70.29

189 11.59 7.37 66.08

191 10.09 6.67 68.98

193 9.58 6.03 65.33

195 10.06 6.26 64.62

197 12.26 8.72 74.89

199 11.34 2.54 18.56

201 11.32 2.58 19.02

203 11.38 2.58 18.98

204 10.3 6.95 70.65

205 15.51 10.46 70.47

206 15.29 9.2 62.13

207 15.17 9.14 62.24

208 15.62 9.39 62.07

209 14.98 9.27 64.12

211 14.7 9.47 66.99

213 15.32 9.56 64.75

215 22.64 13.76 62.86

217 24.55 14.76 62.10

219 33.48 19.68 60.53

225 34.01 20.14 61.03

229 19.75 12.01 62.84

231 31.31 18.81 62.02

237 19.98 12.13 62.75

239 25.77 14.89 59.38

241 28.85 16.34 58.05

243 78.49 44.19 57.66

247 30.62 17.24 57.66

249 28.14 16.17 59.02

251 41.28 20.12 48.96

253 46.92 22.56 48.17

255 43.68 21.09 48.41

257 9.85 5.99 62.94

259 9.6 6.06 65.60

261 9.09 5.87 67.24

263 9.14 5.94 67.76

265 10.82 2.42 18.58

267 10.36 6.44 64.48

269 11.13 4.19 36.21

271 11.14 2.7 20.71

273 10.74 3.42 29.46

275 10.39 3.55 32.22

River Source 0 0 12.00

Lake Source 0 0 108.00

Tank 1 75.35 25.63 31.97

Tank 2 122.41 35.84 26.50

Tank 3 189.26 31.48 11.85
Appendix H

Example IDSE Standard Monitoring Plan and Report for

a Surface Water System Serving 160,000 People

This appendix provides an example IDSE standard monitoring plan and report for a

surface water system serving 160,000 people. For this example, the state did not require any

modifications to the standard monitoring plan. 

Chapter 7 discusses the standard monitoring plan, conducting standard monitoring,

selection of Stage 2 DBPR sites, and preparing the IDSE report. The application of the basic

guidance on standard monitoring location selection and Stage 2 DBPR compliance monitoring

location selection is shown in this example.
This page intentionally left blank.
IDSE Guidance Manual for the Final Stage 2 DBPR H-1 January 2006

Form 6: Standard Monitoring Plan Page 1 of 6

I. GENERAL INFORMATION 

A. PWS Information* B. Date Submitted* Sept 15, 2006

 PWSID: US1111111

 PWS Name: Elm City

PWS Address: 1234 Main Street

City: Elm City State: US Zip: 99999

Population Served: 160,000

System Type: Source Water Type: Buying / Selling Relationships:

: CWS : Subpart H ~ Consecutive System 

~ NTNCWS ~ Ground ~ Wholesale System

 : Neither

C. PWS Operations 

Residual Disinfectant Type: : Chlorine ~ Chloramines ~ Other:_____________

 Number of Disinfected Sources: 2 Surface ___GWUDI ____ Ground ___ Purchased

D. Contact Person*

Name: Mr. Ronald Doe, P.E.

Title: Water System Superintendent

Phone #: 123-555-0000 Fax #: 123-555-0001

E-mail: Rdoe@ci.elmcity.us

II. IDSE REQUIREMENTS*

A. Number of Sites B. Schedule C. Standard Monitoring Frequency

Total: 16

Near Entry Point: 3 : Schedule 1 ~ During peak historical month 

 (1 monitoring period) Avg Residence Time: 4 ~ Schedule 2

 High TTHM: 5 ~ Schedule 3 ~ Every 90 days (4 monitoring periods)

 High HAA5: 4 ~ Schedule 4 : Every 60 days (6 monitoring periods)
IDSE Guidance Manual for the Final Stage 2 DBPR H-2 January 2006

Form 6: Standard Monitoring Plan Page 2 of 6

III. SELECTING STANDARD MONITORING SITES

A. Data Evaluated Put a “T” in each box corresponding to the data that you used to select

each type of standard monitoring site. Check all that apply.

Data Type Type of Site

Near

Entry Pt.

Avg. Residence

Time

High

TTHM

High

HAA5

System Configuration

Pipe layout, locations of storage facilities T TT

Locations of sources and consecutive

system entry points

T

Pressure zones T TT

Information on population density T

Locations of large customers T

Water Quality and Operational Data

Disinfectant residual data T TT

Stage 1 DBP data T T

Other DBP data

Microbiological monitoring data (e.g., HPC) T T

Tank level data, pump run times T TT

Customer billing records T TT

Advanced Tools

Water distribution system model

Tracer study

B. Summary of Data* Provide a summary of data you relied on to justify standard

monitoring site selection. (attach additional sheets if needed)

Both plants operate year round. We used residual and HPC data from Total Coliform sites collected

from 2003 through 2005 with our current system map to select sites. We evaluated chlorine residual

data from June and July (range from 0.2 - 2.3 mg/L), and calculated our system average (1-1.2

mg/L). We looked for sites with levels close to this average for average residence time sites,

although we used HPC data, water age estimates, and pipe data to determine the cause of low

residuals. We have estimated our high water age in the distribution system to be near 5 days. We

relied on tank and residual data to select high TTHM sites. For high HAA5 sites, we also evaluated

HPC data to eliminate areas of suspected biological activity, and Stage 1 sites as a reference point. 

We plotted all of our candidate sites on our map to ensure that they are geographically and

hydraulically diverse. 
IDSE Guidance Manual for the Final Stage 2 DBPR H-3 January 2006

Form 6: Standard Monitoring Plan Page 3 of 6 

IV. JUSTIFICATION OF STANDARD MONITORING SITES*

Standard

Monitoring

Site ID 

(from map)1

Site Type Justification

Standard

Monitoring #1

: Near Entry Pt

~ Avg. Res. Time

~ High TTHM

~ High HAA5

See attached sheets.

Standard

Monitoring #2

: Near Entry Pt

~ Avg. Res. Time

~ High TTHM

~ High HAA5

See attached sheets.

Standard

Monitoring #3

~ Near Entry Pt

: Avg. Res. Time

~ High TTHM

~ High HAA5

See attached sheets.

Standard

Monitoring #4

~ Near Entry Pt

: Avg. Res. Time

~ High TTHM

~ High HAA5

See attached sheets.

Standard

Monitoring #5

~ Near Entry Pt

: Avg. Res. Time

~ High TTHM

~ High HAA5

See attached sheets.

Standard

Monitoring #6

~ Near Entry Pt

: Avg. Res. Time

~ High TTHM

~ High HAA5

See attached sheets.

Standard

Monitoring #7

~ Near Entry Pt

~ Avg. Res. Time

~ High TTHM

: High HAA5

See attached sheets.

Standard

Monitoring #8

~ Near Entry Pt

~ Avg. Res. Time

~ High TTHM

: High HAA5

See attached sheets.

1 Verify that site IDs match IDs in Section IV and on your distribution system schematic (See

Section VII of this form). Attach additional copies if you are required to select more than 8

standard monitoring locations or need more room.
IDSE Guidance Manual for the Final Stage 2 DBPR H-4 January 2006

Form 6: Standard Monitoring Plan Page 4 of 6

V. PEAK HISTORICAL MONTH AND PROPOSED STANDARD MONITORING SCHEDULE

A. Peak Historical Month* July 

B. If Multiple Sources, Source Used to Determine Peak Historical Month 

(write “N/A” if only one source in your system)

Both Hardwood WTP and Softwood WTP had same peak historical month based on Stage 1 TTHM data.

C. Peak Historical Month Based On* (check all that apply)

: High TTHM ~ Warmest water temperature

~ High HAA5

If you used other information to select your peak historical month, explain here 

(attach additional sheets if needed)

D. Proposed Standard Monitoring Schedule*

 Standard Monitoring

Site ID 

(from map) 1

Projected Sampling Date (date or week) 2

period 1 period 2 period 3 period 4 period 5 period 6

SM #1 11/2007, wk 2 1/2008, wk 2 3/2008, wk 2 5/2008, wk 2 7/2008, wk 2 9/2008, wk 2

SM #2 11/2007, wk 2 1/2008, wk 2 3/2008, wk 2 5/2008, wk 2 7/2008, wk 2 9/2008, wk 2

SM #3 11/2007, wk 2 1/2008, wk 2 3/2008, wk 2 5/2008, wk 2 7/2008, wk 2 9/2008, wk 2

SM #4 11/2007, wk 2 1/2008, wk 2 3/2008, wk 2 5/2008, wk 2 7/2008, wk 2 9/2008, wk 2

SM #5 11/2007, wk 2 1/2008, wk 2 3/2008, wk 2 5/2008, wk 2 7/2008, wk 2 9/2008, wk 2

SM #6 11/2007, wk 2 1/2008, wk 2 3/2008, wk 2 5/2008, wk 2 7/2008, wk 2 9/2008, wk 2

SM #7 11/2007, wk 2 1/2008, wk 2 3/2008, wk 2 5/2008, wk 2 7/2008, wk 2 9/2008, wk 2

SM #8 11/2007, wk 2 1/2008, wk 2 3/2008, wk 2 5/2008, wk 2 7/2008, wk 2 9/2008, wk 2

1

 Verify that site IDs match IDs in Section IV and on your distribution system schematic (See

Section VII of this form). Attach additional copies if you are required to select more than 8

standard monitoring locations.

2

 period = monitoring period. Complete for the number of periods from Section II.C. Can list exact

date or week (e.g., week of 7/9/07)
IDSE Guidance Manual for the Final Stage 2 DBPR H-5 January 2006

Form 6: Standard Monitoring Plan Page 5 of 6

VI. PLANNED STAGE 1 DBPR COMPLIANCE MONITORING SCHEDULE*

Stage 1 DBPR

Monitoring Site

ID (from map) 1

Projected Sampling Date (date or week) 2

Period 1 Period 2 Period 3 Period 4

Stage 1 #1 10/2007, wk 2 1/2008, wk 2 4/2008, wk2 7/2008, wk 2

Stage 1 #2 10/2007, wk 2 1/2008, wk 2 4/2008, wk2 7/2008, wk 2

Stage 1 #3 10/2007, wk 2 1/2008, wk 2 4/2008, wk2 7/2008, wk 2

Stage 1 #4 10/2007, wk 2 1/2008, wk 2 4/2008, wk2 7/2008, wk 2

Stage 1 #5 10/2007, wk 2 1/2008, wk 2 4/2008, wk2 7/2008, wk 2

Stage 1 #6 10/2007, wk 2 1/2008, wk 2 4/2008, wk2 7/2008, wk 2

Stage 1 #7 10/2007, wk 2 1/2008, wk 2 4/2008, wk2 7/2008, wk 2

Stage 1 #8 10/2007, wk 2 1/2008, wk 2 4/2008, wk2 7/2008, wk 2

1

 Verify that site IDs match IDs on your distribution system schematic (See Section VII of

this form). Attach additional copies if you are required to monitor at more than 8 Stage 1

DBPR sites.

2

 period = monitoring period. Complete for the number of periods in which you must conduct

Stage 1 DBPR monitoring during IDSE monitoring. Can list exact date or week (e.g., week

of 7/9/07)

VII. DISTRIBUTION SYSTEM SCHEMATIC*

ATTACH a schematic of your distribution system. 

Distribution system schematics are not confidential and should not contain information

that poses a security risk to your system. EPA recommends that you use one of two

options: 

Option 1: Distribution system schematic with no landmarks or addresses

indicated. Show locations of sources, entry points, storage facilities, standard

monitoring locations, and Stage 1 compliance monitoring locations (required). Also

include pressure zone boundaries and locations of pump stations. Provide map

scale. 

Option 2: City map without locations of pipes indicated. Show locations of

sources, entry points, storage facilities, standard monitoring locations, and Stage 1

compliance monitoring locations (required). Also include boundaries of the

distribution system, pressure zone boundaries and locations of pump stations. 

Provide map scale.
IDSE Guidance Manual for the Final Stage 2 DBPR H-6 January 2006

Form 6: Standard Monitoring Plan Page 6 of 6

VIII. ATTACHMENTS

: Distribution System Schematic* (Section VII).

: Additional sheets for the summary of data or site justifications (Sections III and IV).

: Additional copies of Page 3 for justification of Standard Monitoring Sites (Section

IV). Required if you are a subpart H system serving more than 49,999 people or

a ground water system serving more than 499,999 people.

~ Additional sheets for explaining how you used data other than TTHM, HAA5, and

temperature data to select your peak historical month (Section V).

: Additional copies of Page 4 for proposed monitoring schedule (Section V). 

Required if you are a subpart H system serving more than 49,999 people or a

ground water system serving more than 499,999 people.

~ Additional sheets for planned Stage 1 DBPR compliance monitoring schedule

(Section VI).

Total Number of Pages in Your Plan 11___

Note: Fields with an asterisk (*) are required by the Stage 2 DBPR
IDSE Guidance Manual for the Final Stage 2 DBPR H-7 January 2006

Form 6: Standard Monitoring Plan Attachment #1 

IV. JUSTIFICATION OF STANDARD MONITORING SITES* 

Standard

Monitoring

Site ID 

(from map)1

Site Type Justification

Standard

Monitoring #9

9 Near Entry Pt

~ Avg. Res. Time

~ High TTHM

: High HAA5

See attached sheets.

Standard

Monitoring

#10

9 Near Entry Pt

~ Avg. Res. Time

~ High TTHM

: High HAA5

See attached sheets.

Standard

Monitoring

#11

~ Near Entry Pt

9 Avg. Res. Time

: High TTHM

~ High HAA5

See attached sheets.

Standard

Monitoring

#12

~ Near Entry Pt

9 Avg. Res. Time

: High TTHM

~ High HAA5

See attached sheets.

Standard

Monitoring

#13

~ Near Entry Pt

9 Avg. Res. Time

: High TTHM

~ High HAA5

See attached sheets.

Standard

Monitoring

#14

~ Near Entry Pt

9 Avg. Res. Time

: High TTHM

~ High HAA5

See attached sheets.

Standard

Monitoring

#15

~ Near Entry Pt

~ Avg. Res. Time

: High TTHM

9 High HAA5

See attached sheets.

Standard

Monitoring

#16

~ Near Entry Pt

~ Avg. Res. Time

: High TTHM

9 High HAA5

See attached sheets.

1 Site IDs should match IDs in Section IV and on your distribution system schematic (See

Section VII of this form). Attach additional copies of this sheet if you are required to select

more than 8 standard monitoring locations or need more room.
IDSE Guidance Manual for the Final Stage 2 DBPR H-8 January 2006

Justification of Standard Monitoring Sites Attachment #2

Standard Monitoring #1

Entry point to the distribution system for the southern part of the system (Hardwood Water Treatment

Plant). This is where the first group of customers receives water.

Standard Monitoring #2

Entry point to the distribution system for the Softwood River Water Treatment Plant. This location is just

after the high service pumps at the Water Treatment Plant.

Standard Monitoring #3

Represents average residence time of water in the southern section of the system. In the summer

months, this TCR site typically has chlorine residuals that are close to our calculated system-wide average

for the area served by the Hardwood WTP (1.2 mg/L). There are no storage facilities between the

treatment plant and this location. The site is on an 8 inch water main.

Standard Monitoring #4

Represents average residence time of water in the southern part of the system. There are no storage

facilities between the treatment plant and this location. Although this site is physically close to standard

monitoring site #3, site #3 and site #4 are at the edges of different pressure zones. The chlorine residual

concentration at this location is typically 30 percent less than the system-wide average (0.8 mg/L) in the

summer months. However, we attribute this additional loss of chlorine to the fact that the transmission

and distribution lines serving this area are older unlined cast iron and have been observed to show

significant build-up of corrosion by-products. The site is on a 12 inch transmission main.

Standard Monitoring #5

Represents average residence time of water in northern part of the system. In the summer months, this

TCR site typically has chlorine residuals that are close to our calculated system-wide average for the area

served by the Softwood WTP (1.0 mg/L). There are no storage facilities between the treatment plant and

this location. The site is in a residential area with predominantly 8 and 10 inch water mains.

Standard Monitoring #6

Represents average residence time in the northern part of the system. Although chlorine residual in the

summer months is on the low end of the system-wide average (1.0 mg/L), we think this can be attributed

to some older cast iron water mains in the area. Even though it is close in proximity to standard

monitoring site #5, it is at the edge of a different pressure zone from Standard Monitoring Site #5. The site

is on a 12 inch main.

Standard Monitoring #7

Represents high HAA5 levels. Sample location is in an area approaching the perimeter of the system in

the western pressure zone. Chlorine residual at this location ranges between 0.3 and 0.6 mg/L in the

summer months, and the HPCs are consistently below 100 cfu/mL year round. The site is on a 6 inch

main and is not downstream of any storage facilities.

Standard Monitoring #8

Represents high HAA5 levels in the southern part of the system and is hydraulically downstream of the

Oakville Ground Storage Facility, which has a residence time of about 1 1⁄2 days in the summer months. 

This is a TCR site with residual concentrations ranging from 0.4 to 0.7 mg/L in the summer months and

HPCs are usually less than 200 cfu/mL. The site is on an 8 inch water main.

Standard Monitoring #9

Represents high HAA5 levels in the mixing zone. This site is sometimes served by water that is

hydraulically downstream of the Weeping Willow Tank. The chlorine residual varies. It is consistently less

than 1.0 mg/L but never below 0.4 mg/L and the HPCs are usually low (below 100 cfu/mL). The site is in a

commercial area served by 8 and 10 inch water mains.
IDSE Guidance Manual for the Final Stage 2 DBPR H-9 January 2006

Justification of Standard Monitoring Sites (Continued) Attachment #3

Standard Monitoring #10

Represents high HAA5 levels in the northern part of the system. The site is not served by any storage

facilities, but the location is near the north-western perimeter of the system where we have not historically

monitored for TTHM or HAA5. It is in a business district served mainly by 8 inch water mains. The

chlorine residual levels at this location range from 0.5 to 0.8 mg/L in the summer, and HPC levels are

generally < 100 cfu/mL. 

Standard Monitoring #11

Represents high TTHM levels. This site is in the central portion of the system and is served by the

Hardwood WTP. It is in a sparsely populated area with larger service lines (10 and 12 inches). Chlorine

residuals near this location are on the low side (0.3 - 0.5) in the summer. We are concerned that this area

has high water age because of the relatively large pipe size and low demand. We have not historically

monitored for TTHM or HAA5 in this area.

Standard Monitoring #12

Represents high TTHM levels. This site is at a location on the northern edge of the central pressure zone,

geographically distant from the Hardwood WTP. It is at the entrance to a small subdivision (approx 15

houses) in the Oakville community and is on a 6 inch water line. It is not served by any storage facilities,

but residuals in this area are very low in the summer months (< 0.2 mg/L). Also, our operations staff

noted that this is a historic problem area in terms of customer complaints of stale or discolored water and

chlorine residual maintenance. 

Standard Monitoring #13

Represents high TTHM levels in the south-eastern portion of this system on a 4-inch water line. This

location has been problematic in the past due to positive total coliform test results, non-detectable chlorine

residuals, high heterotrophic plate count results, and odor complaints. A 4-inch blow-off was installed

downstream of this location, but it continues to have periodic poor water quality. Although close in

proximity, it is at the edge of a different pressure zone from our Stage 1 compliance monitoring site # 8.

Standard Monitoring #14

Represents high TTHM levels. This site is in the mixing zone and is influenced by both the Softwood and

Hardwood WTPs. During high demand periods, it receives water from the Appleville Storage Tank, which

has a residence time of 2 days in the summer. Chlorine residuals at this location are generally very low,

indicating this may be a hydraulic dead end. 

Standard Monitoring #15

Represents high TTHM levels in the northwestern corner of the system. This location is downstream from

the Cypressville Storage Tank, which has a residence time of 1 to 2 days in the summer. The site is on a

6 inch water main leading into several sparsely populated residential areas. There are often low chlorine

residuals in the areas downstream of this tank. 

Standard Monitoring #16

Represents high TTHM levels at the edge of the mixing zone. This sampling location is in the mixed zone

before the last group of connections near the end of the distribution system. It is on a 6 inch line and

receives water from the Cypressville Storage Tank. We have limited chlorine residual data for this area,

but operators suspect that it is low in the summer due to the high water age in this area.
IDSE Guidance Manual for the Final Stage 2 DBPR H-10 January 2006

Form 6: Standard Monitoring Plan Attachment #4

V. PEAK HISTORICAL MONTH AND PROPOSED STANDARD MONITORING DATES

A. Peak Historical Month* 

B. If Multiple Sources, Source Used to Determine Peak Historical Month 

(write “N/A” if only one source in your system)

C. Peak Historical Month Based On* (check all that apply)

~ High TTHM ~ Warmest water temperature

~ High HAA5

If you used other information to select your peak historical month, explain here 

(attach additional sheets if needed)

D. Proposed Standard Monitoring Schedule*

 Standard Monitoring

Site ID 

(from map) 1

Projected Sampling Date (date or week) 2

period 1 period 2 period 3 period 4 period 5 period 6

SM #9 11/2007, wk 2 1/2008, wk 2 3/2008, wk 2 5/2008, wk 2 7/2008, wk 2 9/2008, wk 2

SM #10 11/2007, wk 2 1/2008, wk 2 3/2008, wk 2 5/2008, wk 2 7/2008, wk 2 9/2008, wk 2

SM #11 11/2007, wk 2 1/2008, wk 2 3/2008, wk 2 5/2008, wk 2 7/2008, wk 2 9/2008, wk 2

SM #12 11/2007, wk 2 1/2008, wk 2 3/2008, wk 2 5/2008, wk 2 7/2008, wk 2 9/2008, wk 2

SM #13 11/2007, wk 2 1/2008, wk 2 3/2008, wk 2 5/2008, wk 2 7/2008, wk 2 9/2008, wk 2

SM #14 11/2007, wk 2 1/2008, wk 2 3/2008, wk 2 5/2008, wk 2 7/2008, wk 2 9/2008, wk 2

SM #15 11/2007, wk 2 1/2008, wk 2 3/2008, wk 2 5/2008, wk 2 7/2008, wk 2 9/2008, wk 2

SM #16 11/2007, wk 2 1/2008, wk 2 3/2008, wk 2 5/2008, wk 2 7/2008, wk 2 9/2008, wk 2

1

 Verify that site IDs match IDs in Section IV and on your distribution system schematic (See

Section VII of this form). Attach additional copies if you are required to select more than 8

standard monitoring locations.

2

 period = monitoring period. Complete for the number of periods from Section II.C. Can list exact

date or week (e.g., week of 7/9/07)
IDSE Guidance Manual for the Final Stage 2 DBPR H-11 January 2006

Hardwood WTP

Stage 1 DBPR site

Elevated storage tank

Ground storage tank

P Pump station

P

1

2

3

4

5

6

7

8

9

10

11

12

Softwood WTP

River

Dow ntow n

Reservoir

Standard Monitoring Site

Chlorine booster station

Cedarville

Poplarville

Weeping Willow

Industrial Park Oakville

Pineville

Appleville

P

P

13

14

15

16

1

2

3

4

5

6

7

8

MIXING ZONE

PS1

CB2

PS2

PS3

CB1

Elm City Distribution System Schematic Attachment #5

 Scale: 1:5000'
IDSE Guidance Manual for the Final Stage 2 DBPR H-12 January 2006

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IDSE Guidance Manual for the Final Stage 2 DBPR H-13 January 2006

Form 7: IDSE Report for Standard Monitoring Page 1 of 9

I. GENERAL INFORMATION 

A. PWS Information* B. Date Submitted* Dec 1, 2008

 PWSID: US1111111

 PWS Name: Elm City

PWS Address: 1234 Main Street

City: Elm City State: US Zip: 99999

Population Served 160,000

System Type: Source Water Type: Buying / Selling Relationships:

: CWS : Subpart H ~ Consecutive System 

~ NTNCWS ~ Ground ~ Wholesale System

 : Neither

C. PWS Operations 

Residual Disinfectant Type: : Chlorine ~ Chloramines ~ Other:_____________

 Number of Disinfected Sources: 2__ Surface ___GWUDI ____ Ground ___ Purchased

D. Contact Person*

Name: Mr. Ronald Doe, P.E.

Title: Water Superintendent

Phone #: 123-555-0000 Fax #: 123-555-0001

E-mail: Rdoe@ci.elmcity.us

II. STAGE 2 DBPR REQUIREMENTS*

A. Number of

Compliance Monitoring

Sites

B. Schedule C. Compliance Monitoring Frequency

Highest TTHM: 3 : Schedule 1 ~ During peak historical month 

 (1 monitoring period) Highest HAA5: 3 ~ Schedule 2

 Existing Stage 1: 2 ~ Schedule 3 : Every 90 days (4 monitoring periods)

Total: 8 ~ Schedule 4
IDSE Guidance Manual for the Final Stage 2 DBPR H-14 January 2006

Form 7: IDSE Report for Standard Monitoring Page 2 of 9

III. MONITORING RESULTS*

A. Did you deviate in any way from your approved standard

monitoring plan? 

: Yes ~ No

If YES, explain (attach additional pages if necessary):

The IDSE Monitoring Plan indicated samples should be taken during the second

week of March, 2008. Our sampler was very ill this week and could not collect all of

the standard monitoring samples. He collected all remaining samples on Monday

and Tuesday of the next week. 

B. Where were your TTHM and HAA5 samples analyzed?

: In-House 

Is your in-house laboratory certified? : Yes ~ No

~ Certified Laboratory

Name of certified laboratory:

C. What method(s) was used to analyze your TTHM and HAA5

samples?

 TTHM HAA5

~ EPA 502.2 ~ EPA 552.1

~ EPA 524.2 ~ EPA 552.2

: EPA 551.1 : EPA 552.3

~ SM 6251 B
IDSE Guidance Manual for the Final Stage 2 DBPR H-15 

Form 7: IDSE Report for Standard Monitoring III. MONITORING RESULTS (Continued)* D. IDSE Standard Monitoring Results - TTHM

Site ID1 Data Type TTHM (mg/L) 

StandardMonitoring #1

Sample Date 11/13/07 1/9/08 3/14/08 5/13/08 7/10/08 9/9/08Sample Result 0.022 0.016 0.028 0.036 0.037 0.030 

StandardMonitoring #2

Sample Date 11/13/07 1/9/08 3/14/08 5/13/08 7/10/08 9/9/08Sample Result 0.031 0.027 0.035 0.031 0.039 0.030 

StandardMonitoring #3

Sample Date 11/13/07 1/9/08 3/14/08 5/13/08 7/10/08 9/9/08Sample Result 0.042 0.033 0.039 0.040 0.048 0.045 

StandardMonitoring #4

Sample Date 11/13/07 1/9/08 3/14/08 5/13/08 7/10/08 9/9/08Sample Result 0.048 0.041 0.047 0.055 0.056 0.043 

StandardMonitoring #5

Sample Date 11/13/07 1/9/08 3/14/08 5/13/08 7/10/08 9/9/08Sample Result 0.025 0.023 0.042 0.048 0.049 0.035 

StandardMonitoring #6

Sample Date 11/13/07 1/9/08 3/14/08 5/13/08 7/10/08 9/9/08Sample Result 0.033 0.017 0.041 0.050 0.058 0.045 

StandardMonitoring #7

Sample Date 11/13/07 1/9/08 3/17/08 5/13/08 7/10/08 9/9/08Sample Result 0.044 0.026 0.056 0.052 0.070 0.042 

StandardMonitoring #8

Sample Date 11/13/07 1/9/08 3/17/08 5/13/08 7/10/08 9/9/08Sample Result 0.040 0.035 0.050 0.064 0.064 0.052 

1 Verify that site IDs for IDSE standard monitoring sites match the site IDs in your Standard Monitoring Plan.

Attach additional sheets as needed for IDSE standard monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR H-16 

Form 7: IDSE Report for Standard Monitoring III. MONITORING RESULTS (Continued)*E. IDSE Standard Monitoring Results - HAA5

Site ID1 Data Type HAA5 (mg/L) 

StandardMonitoring #1

Sample Date 11/13/07 1/9/08 3/14/08 5/13/08 7/10/08 9/9/08Sample Result 0.030 0.028 0.032 0.027 0.033 0.02

StandardMonitoring #2

Sample Date 11/13/07 1/9/08 3/14/08 5/13/08 7/10/08 9/9/08Sample Result 0.025 0.026 0.022 0.034 0.030 0.02

StandardMonitoring #3

Sample Date 11/13/07 1/9/08 3/14/08 5/13/08 7/10/08 9/9/08Sample Result 0.041 0.030 0.022 0.029 0.036 0.04

StandardMonitoring #4

Sample Date 11/13/07 1/9/08 3/14/08 5/13/08 7/10/08 9/9/08Sample Result 0.027 0.019 0.020 0.025 0.025 0.02

StandardMonitoring #5

Sample Date 11/13/07 1/9/08 3/14/08 5/13/08 7/10/08 9/9/08Sample Result 0.040 0.028 0.023 0.056 0.040 0.05

StandardMonitoring #6

Sample Date 11/13/07 1/9/08 3/14/08 5/13/08 7/10/08 9/9/08Sample Result 0.029 0.019 0.014 0.020 0.021 0.02

StandardMonitoring #7

Sample Date 11/13/07 1/9/08 3/17/08 5/13/08 7/10/08 9/9/08Sample Result 0.062 0.035 0.055 0.052 0.052 0.06

StandardMonitoring #8

Sample Date 11/13/07 1/9/08 3/17/08 5/13/08 7/10/08 9/9/08Sample Result 0.049 0.047 0.050 0.059 0.058 0.05

1 Verify that site IDs for IDSE standard monitoring sites match the site IDs in your Standard Monitoring Plan.

Attach additional sheets as needed for IDSE standard monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR H-17 

Form 7: IDSE Report for Standard Monitoring III. MONITORING RESULTS (Continued)*F. Stage 1 DBPR Compliance Monitoring Results - TTHM

Site ID1 Data Type TTHM (mg/L) 

Stage 1 #1(avg. res. time)

Sample Date 10/10/07 1/7/08 4/7/08 7/8/08Sample Result 0.062 0.045 0.034 0.056 

Stage 1 #2(avg. res. time)

Sample Date 10/10/07 1/7/08 4/7/08 7/8/08Sample Result 0.045 0.036 0.042 0.045 

Stage 1 #3(avg. res. time)

Sample Date 10/10/07 1/7/08 4/7/08 7/8/08Sample Result 0.048 0.032 0.034 0.067 

Stage 1 #4(max. res. time)

Sample Date 10/10/07 1/7/08 4/7/08 7/8/08Sample Result 0.056 0.042 0.057 0.076 

Stage 1 #5(avg. res. time)

Sample Date 10/10/07 1/7/08 4/7/08 7/8/08Sample Result 0.042 0.044 0.020 0.062 

Stage 1 #6(avg. res. time)

Sample Date 10/10/07 1/7/08 4/7/08 7/8/08Sample Result 0.039 0.046 0.049 0.050 

Stage 1 #7(avg. res. time)

Sample Date 10/10/07 1/7/08 4/7/08 7/8/08Sample Result 0.050 0.041 0.022 0.059 

Stage 1 #8(max. res. time)

Sample Date 10/10/07 1/7/08 4/7/08 7/8/08Sample Result 0.060 0.065 0.050 0.073 

1 Verify that site IDs for Stage 1 compliance monitoring sites match the site IDs in your Standard Monitoring Plan.

Attach additional sheets as needed for Stage 1 compliance monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR H-18 

Form 7: IDSE Report for Standard Monitoring III. MONITORING RESULTS (Continued)*G. Stage 1 DBPR Compliance Monitoring Results - HAA5

Site ID1 Data Type HAA5 (mg/L) 

Stage 1 #1(avg. res. time)

Sample Date 10/10/07 1/7/08 4/7/08 7/8/08Sample Result 0.045 0.024 0.032 0.043 

Stage 1 #2(avg. res. time)

Sample Date 10/10/07 1/7/08 4/7/08 7/8/08Sample Result 0.056 0.047 0.050 0.055 

Stage 1 #3(avg. res. time)

Sample Date 10/10/07 1/7/08 4/7/08 7/8/08Sample Result 0.049 0.032 0.062 0.045 

Stage 1 #4(max. res. time)

Sample Date 10/10/07 1/7/08 4/7/08 7/8/08Sample Result 0.028 0.021 0.025 0.026 

Stage 1 #5(avg. res. time)

Sample Date 10/10/07 1/7/08 4/7/08 7/8/08Sample Result 0.041 0.034 0.045 0.033 

Stage 1 #6(avg. res. time)

Sample Date 10/10/07 1/7/08 4/7/08 7/8/08Sample Result 0.041 0.022 0.030 0.039 

Stage 1 #7(avg. res. time)

Sample Date 10/10/07 1/7/08 4/7/08 7/8/08Sample Result 0.058 0.048 0.046 0.064 

Stage 1 #8(max. res. time)

Sample Date 10/10/07 1/7/08 4/7/08 7/8/08Sample Result 0.030 0.019 0.022 0.037 

1 Verify that site IDs for Stage 1 compliance monitoring sites match the site IDs in your Standard Monitoring Plan.

Attach additional sheets as needed for Stage 1 compliance monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR H-19 January 2006

Form 7: IDSE Report for Standard Monitoring Page 7 of 9

IV. JUSTIFICATION OF STAGE 2 DBPR COMPLIANCE MONITORING SITES*

Stage 2

Compliance

Monitoring

Site ID

Site Type Justification

Standard

Monitoring

#13

: Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

This site had the highest TTHM LRAA among all the

sites. 

Standard

Monitoring

#10

~ Highest TTHM

: Highest HAA5

~ Stage 1 DBPR

This site had the highest HAA5 LRAA (and was not

selected as the highest TTHM site)

Stage 1 #7 ~ Highest TTHM

~ Highest HAA5

: Stage 1 DBPR

Among the Stage 1 DBPR compliance monitoring

locations with average water residence time, this site

had the highest HAA5 LRAA

Stage 1 #8 : Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

This site had the second highest TTHM LRAA

Standard

Monitoring

#14

: Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

This site had the third highest TTHM LRAA

Standard

Monitoring # 7

~ Highest TTHM

: Highest HAA5

~ Stage 1 DBPR

This site had the second highest HAA5 LRAA

Stage 1 #1 ~ Highest TTHM

~ Highest HAA5

: Stage 1 DBPR

Among the Stage 1 DBPR compliance monitoring

locations with average water residence time, this site

had the highest TTHM LRAA. Stage 1 DBPR site #4

had higher TTHM LRAAs but is maximum residence

time site, therefore, it was not chosen.

Stage 1 # 2 ~ Highest TTHM

: Highest HAA5

~ Stage 1 DBPR

This site had the third highest HAA5 LRAA. Standard

Monitoring Site #8 had the same LRAA, but we chose

to use Stage 1 site #2 to maintain a historical record.

Attach additional copies of this sheet if you need more room.
IDSE Guidance Manual for the Final Stage 2 DBPR H-20 January 2006

Form 7: IDSE Report for Standard Monitoring Page 8 of 9

V. PEAK HISTORICAL MONTH AND PROPOSED STAGE 2 DBPR COMPLIANCE

MONITORING SCHEDULE

A. Peak Historical Month* July 

B. Is Your Peak Historical Month the Same as in Your IDSE Standard

Monitoring Plan?

: Yes ~ No

If no, explain how you selected your new peak historical month (attach

additional sheets if needed)

C. Proposed Stage 2 DBPR Compliance Monitoring Schedule*

Stage 2

Compliance

Monitoring

Site ID

Projected Sampling Date (date or week)1 

period 1 period 2 period 3 period 4

SM # 13 4/2012 wk 2 7/2012 wk 2 10/2012 wk 2 1/2013 wk 2

SM # 10 4/2012 wk 2 7/2012 wk 2 10/2012 wk 2 1/2013 wk 2

Stage 1 # 7 4/2012 wk 2 7/2012 wk 2 10/2012 wk 2 1/2013 wk 2

Stage 1 # 8 4/2012 wk 2 7/2012 wk 2 10/2012 wk 2 1/2013 wk 2

SM #14 4/2012 wk 2 7/2012 wk 2 10/2012 wk 2 1/2013 wk 2

SM # 7 4/2012 wk 2 7/2012 wk 2 10/2012 wk 2 1/2013 wk 2

Stage 1 # 1 4/2012 wk 2 7/2012 wk 2 10/2012 wk 2 1/2013 wk 2

Stage 1 # 2 4/2012 wk 2 7/2012 wk 2 10/2012 wk 2 1/2013 wk 2

1 period = monitoring period. Complete for the number of monitoring periods from Section

II.C.

Attach additional copies of this sheet if you need more room.
IDSE Guidance Manual for the Final Stage 2 DBPR H-21 January 2006

Form 7: IDSE Report for Standard Monitoring Page 9 of 9

VI. DISTRIBUTION SYSTEM SCHEMATIC*

ATTACH a schematic of your distribution system if it has changed since you submitted

your Standard Monitoring Plan (Form 6).

VII. ATTACHMENTS

~ Additional sheets for explaining how and why you deviated from your standard

monitoring plan (Section III).

: Additional sheets for Standard Monitoring Results (Section III). REQUIRED if you are

a subpart H system serving more than 49,999 people or a ground water system

serving more than 499,999 people.

~ Additional sheets for Stage 2 DBPR Compliance Monitoring Sites (Section IV). 

REQUIRED if you are a subpart H system serving more than 249,999 people.

~ Additional sheets for explaining how you selected the peak historical month (Section

V).

~ Additional sheets for proposed Stage 2 DBPR peak historical month and compliance

monitoring schedule (Section V). REQUIRED if you are a subpart H system serving

more than 249,999 people.

~ Distribution system schematic* (Section VI). REQUIRED if it has changed from 

your approved IDSE standard monitoring plan.

~ Compliance calculation procedures (for Stage 2 Compliance Monitoring Plan).

Total Number of Pages in Your Report: _11_____

Note: Fields with an asterisk (*) are required by the Stage 2 DBPR
IDSE Guidance Manual for the Final Stage 2 DBPR H-22 

Form 7: IDSE Report for Standard Monitoring III. MONITORING RESULTS (Continued)* D. IDSE Standard Monitoring Results - TTHM

Site ID1 Data Type TTHM (mg/L) 

StandardMonitoring #9

Sample Date 11/14/07 1/10/08 3/17/08 5/14/08 7/9/08 9/10/08Sample Result 0.047 0.033 0.049 0.052 0.062 0.037 

StandardMonitoring #10

Sample Date 11/14/07 1/10/08 3/17/08 5/14/08 7/9/08 9/10/08Sample Result 0.022 0.020 0.051 0.050 0.052 0.042 

StandardMonitoring #11

Sample Date 11/14/07 1/10/08 3/18/08 5/14/08 7/9/08 9/10/08Sample Result 0.045 0.025 0.062 0.060 0.060 0.064 

StandardMonitoring #12

Sample Date 11/14/07 1/10/08 3/18/08 5/14/08 7/9/08 9/10/08Sample Result 0.061 0.042 0.056 0.050 0.068 0.051 

StandardMonitoring #13

Sample Date 11/14/07 1/10/08 3/18/08 5/14/08 7/9/08 9/10/08Sample Result 0.072 0.032 0.065 0.070 0.085 0.071 

StandardMonitoring #14

Sample Date 11/14/07 1/10/08 3/18/08 5/14/08 7/9/08 9/10/08Sample Result 0.055 0.033 0.068 0.062 0.080 0.062 

StandardMonitoring #15

Sample Date 11/14/07 1/10/08 3/18/08 5/14/08 7/9/08 9/10/08Sample Result 0.052 0.036 0.048 0.056 0.070 0.065 

StandardMonitoring #16

Sample Date 11/14/07 1/10/08 3/18/08 5/14/08 7/9/08 9/10/08Sample Result 0.055 0.031 0.072 0.049 0.068 0.069 

1 Verify that site IDs for IDSE standard monitoring sites match the site IDs in your Standard Monitoring Plan.

Attach additional sheets as needed for IDSE standard monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR H-23 

Form 7: IDSE Report for Standard Monitoring III. MONITORING RESULTS (Continued)*E. IDSE Standard Monitoring Results - HAA5

Site ID1 Data Type HAA5 (mg/L) 

StandardMonitoring #9

Sample Date 11/14/07 1/10/08 3/17/08 5/14/08 7/9/08 9/10/08Sample Result 0.040 0.034 0.045 0.058 0.065 0.048 

StandardMonitoring #10

Sample Date 11/14/07 1/10/08 3/17/08 5/14/08 7/9/08 9/10/08Sample Result 0.067 0.058 0.056 0.044 0.065 0.050 

StandardMonitoring #11

Sample Date 11/14/07 1/10/08 3/18/08 5/14/08 7/9/08 9/10/08Sample Result 0.033 0.030 0.042 0.040 0.046 0.038 

StandardMonitoring #12

Sample Date 11/14/07 1/10/08 3/18/08 5/14/08 7/9/08 9/10/08Sample Result 0.028 0.028 0.039 0.045 0.040 0.033 

StandardMonitoring #13

Sample Date 11/14/07 1/10/08 3/18/08 5/14/08 7/9/08 9/10/08Sample Result 0.039 0.033 0.041 0.039 0.062 0.045 

StandardMonitoring #14

Sample Date 11/14/07 1/10/08 3/18/08 5/14/08 7/9/08 9/10/08Sample Result 0.034 0.031 0.042 0.030 0.058 0.038 

StandardMonitoring #15

Sample Date 11/14/07 1/10/08 3/18/08 5/14/08 7/9/08 9/10/08Sample Result 0.034 0.028 0.028 0.040 0.054 0.038 

StandardMonitoring #16

Sample Date 11/14/07 1/10/08 3/18/08 5/14/08 7/9/08 9/10/08Sample Result 0.034 0.025 0.046 0.048 0.038 0.028 

1 Verify that site IDs for IDSE standard monitoring sites match the site IDs in your Standard Monitoring Plan.

Attach additional sheets as needed for IDSE standard monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR H-24 January 2006

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Appendix I

Example IDSE Standard Monitoring Plan and Report for

a Ground Water System Serving 200,000 People

This appendix is provided as an example IDSE standard monitoring plan and report for a

ground water system serving 200,000 people and choosing to complete standard monitoring. 

For this example, the state did not require any modifications to the study plan.

Chapter 7 discusses the standard monitoring plan, conducting standard monitoring,

selection of Stage 2 DBPR sites, and preparing the standard monitoring report. The application

of the basic guidance on standard monitoring location selection and Stage 2 DBPR compliance

monitoring location selection is shown in this example, along with several instances of the use of

best professional judgement being applied.
This page intentionally left blank.
IDSE Guidance Manual for the Final Stage 2 DBPR I-1 January 2006

Form 6: Standard Monitoring Plan Page 1 of 6

I. GENERAL INFORMATION 

A. PWS Information* B. Date Submitted* Sept 25, 2006

 PWSID: US5555555

 PWS Name: Oak City

PWS Address: 124 Oak Drive

City: Oak City State: US Zip: 11111-1234

Population Served: 200,000

System Type: Source Water Type: Buying / Selling Relationships:

: CWS ~ Subpart H ~ Consecutive System 

~ NTNCWS : Ground ~ Wholesale System

 : Neither

C. PWS Operations 

Residual Disinfectant Type: : Chlorine ~ Chloramines ~ Other:_____________

 Number of Disinfected Sources: ___ Surface ___GWUDI __2_ Ground ___ Purchased

D. Contact Person*

Name: Mr. Joseph Smith, P.E.

Title: Superintendent of Water

Phone #: 123-555-1111 Fax #: 123-555-2222

E-mail: JSmith@ci.oakcity.us

II. IDSE REQUIREMENTS*

A. Number of Sites B. Schedule C. Standard Monitoring Frequency

Total: 8

Near Entry Point: 1 : Schedule 1 ~ During peak historical month 

 (1 monitoring period) Avg Residence Time: 1 ~ Schedule 2

 High TTHM: 3 ~ Schedule 3 : Every 90 days (4 monitoring periods)

 High HAA5: 3 ~ Schedule 4 9 Every 60 days (6 monitoring periods)
IDSE Guidance Manual for the Final Stage 2 DBPR I-2 January 2006

Form 6: Standard Monitoring Plan Page 2 of 6

III. SELECTING STANDARD MONITORING SITES

A. Data Evaluated Put a “T” in each box corresponding to the data that you used to select

each type of standard monitoring site. Check all that apply.

Data Type Type of Site

Near

Entry Pt.

Avg. Residence

Time

High

TTHM

High

HAA5

System Configuration

Pipe layout, locations of storage facilities T TT

Locations of sources and consecutive

system entry points

T

Pressure zones T T

Information on population density

Locations of large customers

Water Quality and Operational Data

Disinfectant residual data T TT

Stage 1 DBP data T T

Other DBP data

Microbiological monitoring data (e.g., HPC) T T

Tank level data, pump run times T

Customer billing records

Advanced Tools

Water distribution system model

Tracer study

B. Summary of Data* Provide a summary of data you relied on to justify standard

monitoring site selection. (attach additional sheets if needed)

The Blue Springs Well field is only in operation during high demand in the summer months, so we

focused most sites in the influence zone of the Silver Springs Well field which operates year round. 

We used residual and HPC data from Total Coliform sites collected in 2005 and 2006 along with

Stage 1 DBPR data and our system map to select sites. We evaluated chlorine residual data from

June, July, and August which ranged from 2.0 mg/L at the Silver Springs disinfection station to no

detect in the distribution system. The system average during the summer is typically around 1.1 mg/L. 

Sites with residuals close to this were considered for average residence time sites. Residuals along

with data on storage tanks, booster stations, and operator notes were used to locate areas of high

residence time for high TTHM and HAA5 sites. Areas of biological activity were identified using

disinfectant residual data because we do not have a lot of HPC data. Sites were plotted on our system

map to ensure adequate coverage of the different geographic and operational areas. 
IDSE Guidance Manual for the Final Stage 2 DBPR I-3 January 2006

Form 6: Standard Monitoring Plan Page 3 of 6 

IV. JUSTIFICATION OF STANDARD MONITORING SITES*

Standard

Monitoring

Site ID 

(from map)1

Site Type Justification

Standard

Monitoring #1

: Near Entry Pt

~ Avg. Res. Time

~ High TTHM

~ High HAA5

See attached sheets.

Standard

Monitoring #2

~ Near Entry Pt

: Avg. Res. Time

~ High TTHM

~ High HAA5

See attached sheets.

Standard

Monitoring #3

~ Near Entry Pt

~ Avg. Res. Time

: High TTHM

~ High HAA5

See attached sheets.

Standard

Monitoring #4

~ Near Entry Pt

~ Avg. Res. Time

: High TTHM

~ High HAA5

See attached sheets.

Standard

Monitoring #5

~ Near Entry Pt

~ Avg. Res. Time

: High TTHM

~ High HAA5

See attached sheets.

Standard

Monitoring #6

~ Near Entry Pt

~ Avg. Res. Time

~ High TTHM

: High HAA5

See attached sheets.

Standard

Monitoring #7

~ Near Entry Pt

~ Avg. Res. Time

~ High TTHM

: High HAA5

See attached sheets.

Standard

Monitoring #8

~ Near Entry Pt

~ Avg. Res. Time

~ High TTHM

: High HAA5

See attached sheets.

1 Verify that site IDs match IDs in Section IV and on your distribution system schematic (See

Section VII of this form). Attach additional copies if you are required to select more than 8

standard monitoring locations or need more room.
IDSE Guidance Manual for the Final Stage 2 DBPR I-4 January 2006

Form 6: Standard Monitoring Plan Page 4 of 6

V. PEAK HISTORICAL MONTH AND PROPOSED STANDARD MONITORING SCHEDULE

A. Peak Historical Month* August 

B. If Multiple Sources, Source Used to Determine Peak Historical Month 

(write “N/A” if only one source in your system)

Silver Springs Well field

C. Peak Historical Month Based On* (check all that apply)

: High TTHM : Warmest water temperature

: High HAA5

If you used other information to select your peak historical month, explain here 

(attach additional sheets if needed)

D. Proposed Standard Monitoring Schedule*

 Standard

Monitoring Site

ID 

(from map) 1

Projected Sampling Date (date or week) 2

period 1 period 2 period 3 period 4 period 5 period 6

SM #1 2nd week 11/2007 2nd week 2/2008 2nd week 5/2008 2nd week 8/2008

SM #2 2nd week 11/2007 2nd week 2/2008 2nd week 5/2008 2nd week 8/2008

SM #3 2nd week 11/2007 2nd week 2/2008 2nd week 5/2008 2nd week 8/2008

SM #4 2nd week 11/2007 2nd week 2/2008 2nd week 5/2008 2nd week 8/2008

SM #5 2nd week 11/2007 2nd week 2/2008 2nd week 5/2008 2nd week 8/2008

SM #6 2nd week 11/2007 2nd week 2/2008 2nd week 5/2008 2nd week 8/2008

SM #7 2nd week 11/2007 2nd week 2/2008 2nd week 5/2008 2nd week 8/2008

SM #8 2nd week 11/2007 2nd week 2/2008 2nd week 5/2008 2nd week 8/2008

1

 Verify that site IDs match IDs in Section IV and on your distribution system schematic

(See Section VII of this form). Attach additional copies if you are required to select more

than 8 standard monitoring locations.

2

 period = monitoring period. Complete for the number of periods from Section II.C. Can

list exact date or week (e.g., week of 7/9/07)
IDSE Guidance Manual for the Final Stage 2 DBPR I-5 January 2006

Form 6: Standard Monitoring Plan Page 5 of 6

VI. PLANNED STAGE 1 DBPR COMPLIANCE MONITORING SCHEDULE*

 

Stage 1 DBPR

Monitoring Site

ID (from map) 1

Projected Sampling Date (date or week) 2

Period 1 Period 2 Period 3 Period 4

Stage 1 #1

max. residence

time site

2nd week of

11/2007

2nd week of 

2/2008

2nd week of

5/2008

2nd week of 

8/2008

Stage 1 #2

max. residence

time site

2nd week of

11/2007

2nd week of 

2/2008

2nd week of

5/2008

2nd week of 

8/2008

1

 Verify that site IDs match IDs on your distribution system schematic (See Section VII of

this form). Attach additional copies if you are required to monitor at more than 8 Stage 1

DBPR sites.

2

 period = monitoring period. Complete for the number of periods in which you must conduct

Stage 1 DBPR monitoring during IDSE monitoring. Can list exact date or week (e.g., week

of 7/9/07)

VII. DISTRIBUTION SYSTEM SCHEMATIC*

ATTACH a schematic of your distribution system. 

Distribution system schematics are not confidential and should not contain information

that poses a security risk to your system. EPA recommends that you use one of two

options: 

Option 1: Distribution system schematic with no landmarks or addresses

indicated. Show locations of sources, entry points, storage facilities, standard

monitoring locations, and Stage 1 compliance monitoring locations (required). Also

include pressure zone boundaries and locations of pump stations. Provide map

scale. 

Option 2: City map without locations of pipes indicated. Show locations of

sources, entry points, storage facilities, standard monitoring locations, and Stage 1

compliance monitoring locations (required). Also include boundaries of the

distribution system, pressure zone boundaries and locations of pump stations. 

Provide map scale.
IDSE Guidance Manual for the Final Stage 2 DBPR I-6 January 2006

Form 6: Standard Monitoring Plan Page 6 of 6

VIII. ATTACHMENTS

: Distribution System Schematic* (Section VII).

: Additional sheets for the summary of data or site justifications (Sections III and IV).

~ Additional copies of Page 3 for justification of Standard Monitoring Sites (Section

IV). Required if you are a subpart H system serving more than 49,999 people or

a ground water system serving more than 499,999 people.

~ Additional sheets for explaining how you used data other than TTHM, HAA5, and

temperature data to select your peak historical month (Section V).

~ Additional copies of Page 4 for proposed monitoring schedule (Section V). 

Required if you are a subpart H system serving more than 49,999 people or a

ground water system serving more than 499,999 people.

~ Additional sheets for planned Stage 1 DBPR compliance monitoring schedule

(Section VI).

Total Number of Pages in Your Plan __10___

Note: Fields with an asterisk (*) are required by the Stage 2 DBPR
IDSE Guidance Manual for the Final Stage 2 DBPR I-7 January 2006

P

1

1

Elevated Storage

Tank

Ground StorageTank

Pump Station

Chlorine Booster Station

Stage 1 DBPR site

Standard Monitoring site

Silver Springs

Wellfield

Blue Springs

Wellfield

Silver Springs

Disinfection Station

Blue Disinfection

Station (Seasonal

Source)

Downtown

Cedarton

Mapleville

Cherrydale

P

P

P

2

2

3

4

5

6

7

8

Mixing Zone

Oak City Distribution System Schematic Attachment #1

Scale = 1:6,000'
IDSE Guidance Manual for the Final Stage 2 DBPR I-8 January 2006

This page left intentionally blank
IDSE Guidance Manual for the Final Stage 2 DBPR I-9 January 2006

Justification of IDSE Monitoring Sites Attachment #2

Standard Monitoring #1

Chosen to represent the entry point to the distribution system from the Silver Spring disinfection

station. The Silver Spring disinfection station has a much higher annual flow than the Blue

disinfection station, which uses a seasonal source. The site is located on a 16 inch water main.

Standard Monitoring #2

Chosen to represent average residence time in the system. Chlorine residual concentrations in

the surrounding area are close to system average (1.1 mg/L). There are no storage facilities or

booster stations between the entry point and this site located at the edge of the mixing zone in the

Silver Spring disinfection station Service area. The site is located in a residential zone on a 6

inch main.

Standard Monitoring #3

Chosen to represent high TTHM levels in the Silver Spring disinfection station influence zone

and the mixing zone. This monitoring location is located before the last group of connections on

a 6 inch pipe in proximity to the end of the distribution system in the mixing zone. It is also

downstream of a booster station. At this location, water demand tends to be low, total chlorine

levels are always low (ranging between 0.3 and 0.9 mg/L) and HPCs are often greater than 200

cfu/mL. Operations staff indicate this site has a lot of customers complaints. 

Standard Monitoring #4

Chosen to represent high TTHM levels in the Silver Spring disinfection station influence zone. 

This monitoring location is located near the TCR #4 sample site, and before the last group of

connections before the end of the distribution system. This site is in a 12 inch main in the

extremities of the system and is likely to have high water age during periods of low demand.

Standard Monitoring #5

Chosen to represent high TTHM levels in both influence zones. This monitoring location is after

the first group of connections (approximately 0.5 miles) downstream of a 1.5 MG elevated

storage facility in the influence zone of the Blue disinfection station. Operations data indicate

this reservoir may have high water age during the summer months. DBP data at the nearby

Stage 1 DBPR sampling site indicate high TTHM and HAA5 levels for this area.

Standard Monitoring #6

Chosen to represent high HAA5 levels in the Silver Spring disinfection station influence zone. 

Sample tap is a hose bib at an elementary school located in a zone of the distribution system with

water age greater than average near a storage tank. Total chlorine levels at this location range

between 0.9 and 1.2 mg/L. The site is located on an 8 inch main.
IDSE Guidance Manual for the Final Stage 2 DBPR I-10 January 2006

Justification of IDSE Monitoring Sites (Continued) Attachment #2

Standard Monitoring #7

Chosen to represent high HAA5 levels in the Silver Spring disinfection station influence zone

and the mixing zone. This location is a dedicated sampling location on an 8 inch main routinely

used for monitoring water quality in downtown Oak City. It is located near an elevated storage

tank. In this area, the water age is greater than the average, but the total chlorine is never below

0.7 mg/L. 

Standard Monitoring #8

Chosen to represent high HAA5 levels in the Blue disinfection station influence zone. Total

chlorine levels at this location range between 0.8 and 1.4 mg/L. The site is on the extremities of

the system, in an area where DBP monitoring has not traditionally been performed. It is on a 6

inch main. 
IDSE Guidance Manual for the Final Stage 2 DBPR I-11 January 2006

Form 7: IDSE Report for Standard Monitoring Page 1 of 9

I. GENERAL INFORMATION 

A. PWS Information* B. Date Submitted* Nov 30, 2008

 PWSID: US5555555

 PWS Name: Oak City

PWS Address: 124 Oak Drive

City: Oak City State: US Zip: 11111-1234

Population Served: 200,000

System Type: Source Water Type: Buying / Selling Relationships:

: CWS ~ Subpart H ~ Consecutive System 

~ NTNCWS : Ground ~ Wholesale System

 : Neither

C. PWS Operations 

Residual Disinfectant Type: : Chlorine ~ Chloramines ~ Other:_____________

 Number of Disinfected Sources: ___ Surface ___GWUDI __2_ Ground ___ Purchased

D. Contact Person*

Name: Mr. Joseph Smith, P.E.

Title: Superintendent of Water

Phone #: 123-555-1111 Fax #: 123-555-2222

E-mail: JSmith@ci.oakcity.us

II. STAGE 2 DBPR REQUIREMENTS*

A. Number of

Compliance Monitoring

Sites

B. Schedule C. Compliance Monitoring Frequency

Highest TTHM: 3 : Schedule 1 ~ During peak historical month 

 (1 monitoring period) Highest HAA5: 2 ~ Schedule 2

 Existing Stage 1: 1 ~ Schedule 3 : Every 90 days (4 monitoring periods)

Total: 6 ~ Schedule 4
IDSE Guidance Manual for the Final Stage 2 DBPR I-12 January 2006

Form 7: IDSE Report for Standard Monitoring Page 2 of 9

III. MONITORING RESULTS*

A. Did you deviate in any way from your approved standard

monitoring plan? 

: Yes ~ No

If YES, explain (attach additional pages if necessary):

Sampling was planned for August 13, 2007 but system maintenance was planned in 

the area of Standard monitoring location #1 for that day. The maintenance required 

extensive system flushing so the samples were taken on the previous Friday.

B. Where were your TTHM and HAA5 samples analyzed?

~ In-House 

Is your in-house laboratory certified? ~ Yes ~ No

: Certified Laboratory

Name of certified laboratory: Oak City Laboratories

C. What method(s) was used to analyze your TTHM and HAA5

samples?

 TTHM HAA5

~ EPA 502.2 ~ EPA 552.1

: EPA 524.2 ~ EPA 552.2

~ EPA 551.1 ~ EPA 552.3

: SM 6251 B
IDSE Guidance Manual for the Final Stage 2 DBPR I-13 

Form 7: IDSE Report for Standard Monitoring III. MONITORING RESULTS (Continued)* D. IDSE Standard Monitoring Results - TTHM

Site ID1 Data Type TTHM (mg/L) 

Standard Monitoring #1 Sample Date 11/19/07 2/18/08 5/19/08 8/17/08

Sample Result 0.026 0.022 0.030 0.035 

Standard Monitoring #2 Sample Date 11/19/07 2/18/08 5/19/08 8/17/08

Sample Result 0.054 0.039 0.042 0.056 

Standard Monitoring #3 Sample Date 11/19/07 2/18/08 5/19/08 8/17/08

Sample Result 0.062 0.061 0.072 0.075 

Standard Monitoring #4 Sample Date 11/19/07 2/18/08 5/19/08 8/17/08

Sample Result 0.049 0.058 0.072 0.069 

Standard Monitoring #5 Sample Date 11/19/07 2/18/08 5/19/08 8/17/08

Sample Result 0.038 0.068 0.075 0.071 

Standard Monitoring #6 Sample Date 11/19/07 2/18/08 5/19/08 8/17/08

Sample Result 0.033 0.029 0.041 0.042 

Standard Monitoring #7 Sample Date 11/19/07 2/18/08 5/19/08 8/17/08

Sample Result 0.035 0.029 0.037 0.047 

Standard Monitoring #8 Sample Date 11/19/07 2/18/08 5/19/08 8/17/08

Sample Result 0.031 0.033 0.038 0.041 

1 Verify that site IDs for IDSE standard monitoring sites match the site IDs in your Standard Monitoring Plan.

Attach additional sheets as needed for IDSE standard monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR I-14 

Form 7: IDSE Report for Standard Monitoring III. MONITORING RESULTS (Continued)*E. IDSE Standard Monitoring Results - HAA5

Site ID1 Data Type HAA5 (mg/L) 

Standard Monitoring #1 Sample Date 11/19/07 2/18/08 5/19/08 8/17/08

Sample Result 0.020 0.024 0.033 0.037 

Standard Monitoring #2 Sample Date 11/19/07 2/18/08 5/19/08 8/17/08

Sample Result 0.022 0.029 0.036 0.040 

Standard Monitoring #3 Sample Date 11/19/07 2/18/08 5/19/08 8/17/08

Sample Result 0.021 0.025 0.026 0.028 

Standard Monitoring #4 Sample Date 11/19/07 2/18/08 5/19/08 8/17/08

Sample Result 0.020 0.021 0.038 0.028 

Standard Monitoring #5 Sample Date 11/19/07 2/18/08 5/19/08 8/17/08

Sample Result 0.024 0.028 0.042 0.045 

Standard Monitoring #6 Sample Date 11/19/07 2/18/08 5/19/08 8/17/08

Sample Result 0.043 0.038 0.048 0.052 

Standard Monitoring #7 Sample Date 11/19/07 2/18/08 5/19/08 8/17/08

Sample Result 0.036 0.040 0.046 0.040 

Standard Monitoring #8 Sample Date 11/19/07 2/18/08 5/19/08 8/17/08

Sample Result 0.033 0.042 0.043 0.040 

1 Verify that site IDs for IDSE standard monitoring sites match the site IDs in your Standard Monitoring Plan.

Attach additional sheets as needed for IDSE standard monitoring results.
IDSE Guidance Manual for the final Stage 2 DBPR I-15 

Form 7: IDSE Report for Standard Monitoring III. MONITORING RESULTS (Continued)*F. Stage 1 DBPR Compliance Monitoring Results - TTHM

Site ID1 Data Type TTHM (mg/L) 

Stage 1 #1max. residence time site

Sample Date 11/19/07 2/18/08 5/19/08 8/17/08Sample Result 0.055 0.044 0.066 0.072 

Stage 1 #2max. residence time site

Sample Date 11/19/07 2/18/08 5/19/08 8/17/08Sample Result 0.060 0.068 0.068 0.098 Sample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample Result

1 Verify that site IDs for Stage 1 compliance monitoring sites match the site IDs in your Standard Monitoring Plan.

Attach additional sheets as needed for Stage 1 compliance monitoring results.
IDSE Guidance Manual for the final Stage 2 DBPR I-16 

Form 7: IDSE Report for Standard Monitoring III. MONITORING RESULTS (Continued)*G. Stage 1 DBPR Compliance Monitoring Results - HAA5

Site ID1 Data Type HAA5 (mg/L) 

Stage 1 #1max. residence time site

Sample Date 11/19/07 2/18/08 5/19/08 8/17/08Sample Result 0.024 0.032 0.043 0.045 

Stage 1 #2max. residence time site

Sample Date 11/19/07 2/18/08 5/19/08 8/17/08Sample Result 0.042 0.033 0.030 0.038 Sample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample ResultSample DateSample Result

1 Verify that site IDs for Stage 1 compliance monitoring sites match the site IDs in your Standard Monitoring Plan.

Attach additional sheets as needed for Stage 1 compliance monitoring results.
IDSE Guidance Manual for the Final Stage 2 DBPR I-17 January 2006

Form 7: IDSE Report for Standard Monitoring Page 7 of 9

IV. JUSTIFICATION OF STAGE 2 DBPR COMPLIANCE MONITORING SITES*

Stage 2

Compliance

Monitoring

Site ID

Site Type Justification

Stage 1 #2 : Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

Stage 1 DBPR location #2 had the highest TTHM

LRAA. 

Standard

Monitoring #6

~ Highest TTHM

: Highest HAA5

~ Stage 1 DBPR

Standard Monitoring location #6 had the highest

HAA5 LRAA.

Stage 1 #1 ~ Highest TTHM

~ Highest HAA5

: Stage 1 DBPR

As one of the two Stage 1 DBPR maximum

residence time sites was already selected as a

Stage 2 DBPR location #1 was chosen as the

third Stage 2 DBPR compliance monitoring

location.

Standard

Monitoring #3

: Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

Standard monitoring location #3 had the next

highest TTHM LRAA among the locations not

previously selected. 

Standard

Monitoring #5

: Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

Standard monitoring location #5 had the next

highest TTHM LRAA among the locations not

previously selected. 

Standard

Monitoring #8

~ Highest TTHM

: Highest HAA5

~ Stage 1 DBPR

Standard monitoring locations #7 and #8 had

similar HAA5 LRAAs among locations not

previously selected. Standard monitoring

location #8 was chosen for geographic

representation as this quadrant of the distribution

has no sample sites.

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

~ Highest TTHM

~ Highest HAA5

~ Stage 1 DBPR

Attach additional copies of this sheet if you need more room.
IDSE Guidance Manual for the Final Stage 2 DBPR I-18 January 2006

Form 7: IDSE Report for Standard Monitoring Page 8 of 9

V. PEAK HISTORICAL MONTH AND PROPOSED STAGE 2 DBPR COMPLIANCE

MONITORING SCHEDULE

A. Peak Historical Month* August 

B. Is Your Peak Historical Month the Same as in Your IDSE Standard Monitoring

Plan?

: Yes ~ No

If no, explain how you selected your new peak historical month (attach

additional sheets if needed)

C. Proposed Stage 2 DBPR Compliance Monitoring Schedule*

Stage 2

Compliance

Monitoring

Site ID

Projected Sampling Date (date or week)1

period 1 period 2 period 3 period 4

Stage 1 #2 5/2012 3rd week 8/2012 3rd week 11/2012 3rd week 2/2013 3rd week

SM #6 5/2012 3rd week 8/2012 3rd week 11/2012 3rd week 2/2013 3rd week

Stage 1 #1 5/2012 3rd week 8/2012 3rd week 11/2012 3rd week 2/2013 3rd week

SM #3 5/2012 3rd week 8/2012 3rd week 11/2012 3rd week 2/2013 3rd week

SM #5 5/2012 3rd week 8/2012 3rd week 11/2012 3rd week 2/2013 3rd week

SM #8 5/2012 3rd week 8/2012 3rd week 11/2012 3rd week 2/2013 3rd week

1

 period = monitoring period. Complete for the number of monitoring periods from Section

II.C.

Attach additional copies of this sheet if you need more room.
IDSE Guidance Manual for the Final Stage 2 DBPR I-19 January 2006

Form 7: IDSE Report for Standard Monitoring Page 9 of 9

VI. DISTRIBUTION SYSTEM SCHEMATIC*

ATTACH a schematic of your distribution system if it has changed since you submitted

your Standard Monitoring Plan (Form 6). 

VII. ATTACHMENTS

~ Additional sheets for explaining how and why you deviated from your standard

monitoring plan (Section III).

~ Additional sheets for Standard Monitoring Results (Section III). REQUIRED if you are

a subpart H system serving more than 49,999 people or a ground water system

serving more than 499,999 people.

~ Additional sheets for Stage 2 DBPR Compliance Monitoring Sites (Section IV). 

REQUIRED if you are a subpart H system serving more than 249,999 people.

~ Additional sheets for explaining how you selected the peak historical month (Section

V).

~ Additional sheets for proposed Stage 2 DBPR peak historical month and compliance

monitoring schedule (Section V). REQUIRED if you are a subpart H system serving

more than 249,999 people.

9 Distribution system schematic* (Section VI). REQUIRED if it has changed from

your approved IDSE standard monitoring plan.

~ Compliance calculation procedures (for Stage 2 Compliance Monitoring Plan)

Total Number of Pages in Your Report: ___9___

Note: Fields with an asterisk (*) are required by the Stage 2 DBPR
IDSE Guidance Manual for the Final Stage 2 DBPR I-20 January 2006

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