Revised Total Coliform Rule

Assessments and Corrective Actions

Guidance Manual

Interim Final
Office of Water (4606M) 

EPA 815-R-14-006 

September 2014 
RTCR ACAGM - Interim Final i 

DISCLAIMER

This manual is intended to provide information to assist public water systems in 

complying with the Level 1 and Level 2 assessment and corrective action requirements under the 

Revised Total Coliform Rule (RTCR). 

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. While EPA has made every effort to ensure the accuracy of the 

discussion in this guidance, the obligations of the regulated community are determined by 

statutes, regulations or other legally binding requirements. In the event of a conflict between the 

discussion in this document and any statute or regulation, this document would not be 

controlling. 

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 suggestions 

for complying with the RTCR requirements, the guidance presented here may not be appropriate 

for all situations and alternative approaches may provide satisfactory performance.

Mention of trade names or commercial products does not constitute an EPA endorsement 

or recommendation for use. 

EPA may decide to revise this guidance without public notice and comment period to 

reflect the changes to EPA’s approach to implementing the Revised Total Coliform Rule or to 

clarify or update text.

Copies of this guidance can be downloaded from 

http://water.epa.gov/lawsregs/rulesregs/sdwa/tcr/regulation_revisions.cfm. 
RTCR ACAGM - Interim Final ii 

ACKNOWLEDGMENTS

• American Water Works Association

• Association of State Drinking Water Administrators

• Association of Metropolitan Water Agencies

• California Department of Public Health

• New Hampshire Department of Environmental Services

• Nevada Division of Environmental Protection

• Park Water Company

• RTCR Regional and State Implementation Workgroup
RTCR ACAGM - Interim Final iii 

CONTENTS

List of Figures .............................................................................................................................. vii

List of Acronyms ........................................................................................................................ viii

1. Overview of this Manual ....................................................................................................... 1-1

1.1. What is the purpose of this manual? ................................................................................... 1-1

1.2. What is the Revised Total Coliform Rule (RTCR)? ........................................................... 1-1

1.3. Who needs to comply with the RTCR? ............................................................................... 1-2

1.4. How is this document organized? ....................................................................................... 1-2

2. Assessment and Corrective Actions under the Revised Total Coliform Rule .................. 2-1

2.1. Why does the RTCR require assessment and corrective action? ........................................ 2-1

2.2. What causes a contamination to occur? .............................................................................. 2-1

2.3. What are examples of sanitary defects? .............................................................................. 2-5

2.4. What types of assessments are PWSs required to conduct? ................................................ 2-7

2.5. What happens if a sanitary defect is identified during an assessment? ............................... 2-8

2.6. What if no sanitary defect is identified? .............................................................................. 2-8

3. Level 1 Assessments ............................................................................................................... 3-1

3.1. What is a Level 1 assessment? ............................................................................................ 3-1

3.2. Why do systems need to conduct a Level 1 assessment? .................................................... 3-1

3.3. Who is responsible for conducting a Level 1 assessment? ................................................. 3-2

3.4. How do PWSs document a Level 1 assessment? ................................................................ 3-3

3.5. How do PWSs conduct a Level 1 assessment? ................................................................... 3-4

3.5.1. Assessing samples, sampling sites and sampling protocols......................................... 3-6

3.5.2. Assessing the distribution system area near the positive samples ............................... 3-7

3.5.2.1. Operational data .................................................................................................. 3-8

3.5.2.2. Water quality data ............................................................................................... 3-9

3.5.2.3. Operational activities and unusual events ......................................................... 3-12

3.5.2.4. Assessing distribution system components ....................................................... 3-12

3.5.2.5. Assessing storage facilities ............................................................................... 3-14

3.5.3. Assessing the treatment facilities ............................................................................... 3-15

3.5.4. Assessing the source water ........................................................................................ 3-17

3.5.4.1. Wells ................................................................................................................. 3-17

3.5.4.2. Springs .............................................................................................................. 3-18

3.5.4.3. Surface water .................................................................................................... 3-18

3.5.5. Additional considerations .......................................................................................... 3-19
RTCR ACAGM - Interim Final iv 

3.5.5.1. Systems with limited or no distribution system ................................................ 3-19

3.5.5.2. Large systems.................................................................................................... 3-20

3.5.5.3. Wholesale and consecutive systems ................................................................. 3-20

3.6. What is the timeline for completing the Level 1 assessment? .......................................... 3-21

4. Level 2 Assessments............................................................................................................... 4-1

4.1. What is a Level 2 assessment? ............................................................................................ 4-1

4.2. Why do PWSs need to conduct a Level 2 assessment? ....................................................... 4-2

4.3. Who is responsible for conducting a Level 2 assessment? ................................................. 4-2

4.4. How do PWSs document a Level 2 assessment? ................................................................ 4-4

4.5. How do PWSs conduct a Level 2 assessment? ................................................................... 4-5

4.5.1. Assessing samples, sampling sites and sampling protocols....................................... 4-10

4.5.2. Assessing the distribution system area near the positive samples ............................. 4-11

4.5.2.1. Operational data ................................................................................................ 4-11

4.5.2.2. Water quality data ............................................................................................. 4-13

4.5.2.3. Operational activities and unusual events ......................................................... 4-17

4.5.2.4. Assessing distribution system components ....................................................... 4-18

4.5.2.5. Assessing storage facilities ............................................................................... 4-19

4.5.3. Assessing the treatment facilities ............................................................................... 4-21

4.5.4. Assessing the source water ........................................................................................ 4-22

4.5.4.1. Wells ................................................................................................................. 4-22

4.5.4.2. Springs .............................................................................................................. 4-23

4.5.4.3. Surface water .................................................................................................... 4-24

4.5.5. Additional considerations .......................................................................................... 4-24

4.5.5.1. Systems with limited or no distribution system ................................................ 4-24

4.5.5.2. Large systems.................................................................................................... 4-25

4.5.5.3. Wholesale and consecutive systems ................................................................. 4-25

4.6. What is the timeline for completing the Level 2 assessment? .......................................... 4-26

5. Corrective Action ................................................................................................................... 5-1

5.1. What is the RTCR’s requirement regarding corrective action? .......................................... 5-1

5.2. What corrective actions can PWSs take? ............................................................................ 5-1

5.2.1. Disinfection ................................................................................................................ 5-12

5.2.2. Flushing...................................................................................................................... 5-13

5.2.3. Replacement / Repair of distribution system components ......................................... 5-14

5.2.3.1. Water mains ...................................................................................................... 5-14
RTCR ACAGM - Interim Final v 

5.2.3.2. Valves ............................................................................................................... 5-15

5.2.3.3. Fittings .............................................................................................................. 5-15

5.2.3.4. Hydrants ............................................................................................................ 5-15

5.2.3.5. Meters ............................................................................................................... 5-15

5.2.3.6. Dedicated sample taps ....................................................................................... 5-15

5.2.4. Maintenance of adequate pressure ............................................................................. 5-16

5.2.4.1. Booster pumping stations .................................................................................. 5-17

5.2.4.2. Variable frequency drive (VFD) ....................................................................... 5-17

5.2.4.3. Elevated storage facilities ................................................................................. 5-17

5.2.4.4. Surge relief valves ............................................................................................. 5-17

5.2.4.5. Surge tanks ........................................................................................................ 5-18

5.2.5. Maintenance of appropriate water age, hydraulic residence time and mixing .......... 5-18

5.2.5.1. Looping dead-ends ............................................................................................ 5-19

5.2.5.2. Installing appropriate main sizes ...................................................................... 5-19

5.2.5.3. Installing automated flushing devices ............................................................... 5-19

5.2.5.4. Storage facility modifications ........................................................................... 5-20

5.2.6. Maintenance of storage facility .................................................................................. 5-21

5.2.6.1. Inspection / cleaning of tanks ........................................................................... 5-22

5.2.6.2. Lining of storage tanks...................................................................................... 5-22

5.2.6.3. Vent / hatch repair ............................................................................................. 5-22

5.2.6.4. Tank repair ........................................................................................................ 5-23

5.2.7. Implementation or upgrade of a Cross-connection Control and Backflow 

Prevention Program ................................................................................................... 5-23

5.2.8. Sampler training ......................................................................................................... 5-23

5.2.9. Addition or upgrade of on-line monitoring and control............................................. 5-23

5.2.9.1. Water quality monitoring and control ............................................................... 5-24

5.2.9.2. Pressure monitoring and control ....................................................................... 5-24

5.2.10. Addition of security measures ................................................................................. 5-25

5.2.11. Development and implementation of an operations plan ........................................ 5-25

5.2.11.1. Standard operating procedures ........................................................................ 5-25

5.2.11.2. Sample siting plans ......................................................................................... 5-26

5.2.11.3. Routine inspections ......................................................................................... 5-26

5.2.11.4. Emergency response plan ............................................................................... 5-26

5.2.11.5. Appropriately qualified operators ................................................................... 5-26

5.3 What are some of the best practices PWSs can take? ....................................................... 5-27
RTCR ACAGM - Interim Final vi 

6. Simultaneous Compliance with the RTCR and with the Requirements of Other

Drinking Water Rules ........................................................................................................... 6-1

6.1. Using sanitary surveys to meet the requirements of the RTCR .......................................... 6-1

6.1.1. Sanitary surveys and assessments ................................................................................ 6-1

6.1.1.1. What is a sanitary survey? .................................................................................. 6-1

6.1.1.2. What are the differences and overlaps between a sanitary survey and a 

Level 1 or Level 2 assessment? .......................................................................... 6-2

6.1.2. Sanitary surveys and monitoring ................................................................................. 6-4

6.1.3. Sanitary surveys and annual site visits......................................................................... 6-5

6.2. Changing treatment practices to comply with the corrective action requirements of the 

RTCR .................................................................................................................................. 6-5

7. References ............................................................................................................................... 7-1

APPENDIX A. Summary of the RTCR Requirements ......................................................... A-1

APPENDIX B. Example Assessment Forms .......................................................................... B-1

APPENDIX C. Examples of Completed Assessments ........................................................... C-1

APPENDIX D. Industry Standards for Operating a Public Water System ........................ D-1
LIST OF FIGURES

Chapter 2. Assessment and Corrective Actions under the Revised Total Coliform Rule

Figure 2-1: Example of How Contamination Can Get Into a Water Pipe When All Three 

Conditions Are Present ............................................................................................. 2-4

Figure 2-2: Examples of Sanitary Defects ................................................................................... 2-7

Chapter 3. Level 1 Assessments

Figure 3-1: General Progression of Conducting a Level 1 Assessment ...................................... 3-6

Figure 3-2: Example Time Series Graph for Distribution System Chlorine Results ................. 3-11

Chapter 4. Level 2 Assessments

Figure 4-1: General Progression of Conducting a Level 2 Assessment ...................................... 4-7

Figure 4-2: Example Time Series Graph for Distribution System Chlorine Results ................. 4-14

Figure 4-3: Example of Spatial Analysis of Disinfectant Residual and Customer Complaint 

Data ........................................................................................................................ 4-16

LIST OF TABLES

Chapter 3. Level 1 Assessments 

Table 3-1: Typical Water Quality Data to Be Evaluated During an Assessment ...................... 3-10

Table 3-2: Typical Items to Evaluate in Distribution System Assessment ................................ 3-13

Table 3-3: Typical Items to Evaluate at Storage Facilities ........................................................ 3-15

Table 3-4: Typical Treatment Facility Elements to Evaluate .................................................... 3-16

Table 3-5: Typical Items to Evaluate at Wells ........................................................................... 3-18

Chapter 4. Level 2 Assessments 

Table 4-1: Examples of Possible Differences in the Level of Effort Between a Level 1 and 

a Level 2 Assessment ................................................................................................. 4-8

Table 4-2: Typical Water Quality Data to Be Evaluated During an Assessment ...................... 4-13

Table 4-3: Typical Items to Evaluate in Distribution System Assessment ................................ 4-19

Table 4-4: Typical Items to Evaluate at Storage Facilities ........................................................ 4-20

Table 4-5: Typical Treatment Facility Elements to Evaluate .................................................... 4-22

Table 4-6: Typical Items to Evaluate at Wells ........................................................................... 4-23

Chapter 5. Corrective Action

Table 5-1: Common Causes of Total Coliforms and E. coli in the Distribution System and 

Possible Corrective Actions to Address Them .......................................................... 5-4

Table 5-2: List of Common Corrective Actions ........................................................................ 5-11

RTCR ACAGM - Interim Final vii 
RTCR ACAGM - Interim Final viii 

LIST OF ACRONYMS

AGI Acute gastrointestinal illness

AMWA Association of Metropolitan Water Agencies

ANSI American National Standards Institute

ASDWA Association of State Drinking Water Agencies

AWWA American Water Works Association 

BAT Best available technology

DBPs Disinfection by-products 

CCCBFP Cross-connection Control and Backflow Prevention 

CFR Code of Federal Regulations

CSIS Customer service information system

CWS Community water system

EPA Environmental Protection Agency 

GIS Geographic information systems

GWR Ground Water Rule 

GWUDI Ground water under the direct influence of surface water

HAA5 Haloacetic acids

HPC Heterotrophic plate count 

HRT Hydraulic residence time

IESWTR Interim Enhanced Surface Water Treatment Rule 

LCR Lead and Copper Rule 

LIMS Laboratory information management system

MCL Maximum contaminant level

MCLG Maximum contaminant level goal

MMIS Maintenance management information system

MRDL Maximum residual disinfectant level

NOM Natural organic matter

NCWS Non-community water system

NSF National Science Foundation 

NTNCWS Non-transient non-community water system

O&M Operations and maintenance 
RTCR ACAGM - Interim Final ix 

PN Public notification

PWS Public water system

RTCR Revised Total Coliform Rule

SCADA Supervisory control and data acquisition

SDWA Safe Drinking Water Act

SOPs Standard operating procedures

SWTR Surface Water Treatment Rule

TCR Total Coliform Rule

TTHM Total trihalomethanes

VFD Variable frequency drive
RTCR ACAGM - Interim Final 1-1

1. Overview of this Manual

1.1. What is the purpose of this manual? 

Under the Revised Total Coliform Rule (RTCR) (USEPA 2013 and USEPA 2014) (40 

CFR1 part 141 subpart Y), a public water system (PWS2) that is vulnerable to microbial

contamination (as indicated by its monitoring results) is required to conduct assessment and 

corrective action of the system to identify and correct any sanitary defects3 in the distribution 

system or treatment processes (40 CFR 141.859). This document provides PWSs with guidance 

on implementing the assessment and corrective action requirements of the RTCR. 

The guidance is intended for use by PWS owners and operators. States,4 other primacy 

agencies and technical assistance providers may also benefit from reading this guidance. 

1.2. What is the Revised Total Coliform Rule (RTCR)? 

The RTCR is a revision of the Total Coliform Rule (TCR), which was promulgated in 

1989. The RTCR retains the objectives and the basic monitoring requirements of the TCR but 

offers greater public health protection by the addition of new requirements. The changes include 

the following: 

• The health goal and legal limits5

 for the presence of total coliforms in drinking water

have been replaced with a treatment technique that requires PWSs to conduct an

assessment of their system if monitoring results indicate that they might be vulnerable

to contamination and to correct for any problems identified during the assessment.

1

 CFR – Code of Federal Regulations

2 PWS and system are used interchangeably throughout this document.

3 Sanitary defect as defined at 40 CFR 141.2 – A defect that could provide a pathway of entry for microbial contamination into 

the distribution system or that is indicative of a failure or imminent failure in a barrier that is already in place. See 40 CFR

141.851. See Chapter 2 of this document for a more detailed discussion of sanitary defects.

4 In this document, “state” is used to generally refer to the primacy agency, whether it be the state agency, the Tribal government 

or the Environmental Protection Agency (EPA) (40 CFR 141.2). A primacy agency is the entity that has the primary 

responsibility for administering and enforcing regulations under the Safe Drinking Water Act (SDWA) in a given jurisdiction. In 

many cases, the state agency is the primacy agency. For Tribes and states or territories that have not been granted primacy 

enforcement authority, EPA is the primacy agency for administration and enforcement of the RTCR.

5 These are the maximum contaminant level goal (MCLG) and maximum contaminant level (MCL), respectively. 

The MCLG is 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. The MCL is the maximum permissible level of a 

contaminant in water which is delivered to any user of a public water system. (40 CFR 141.2)
RTCR ACAGM - Interim Final 1-2

• Small ground water systems need to meet specific criteria to remain on a reduced

monitoring schedule.

• High risk small systems with unacceptable compliance history are required to

increase their monitoring.

• Seasonal systems, which do not serve water to the public all year round, such as some

campgrounds and state and national parks, are required to comply with new

requirements to address the additional vulnerability to microbial contamination in

these systems due to their operating characteristics.

For more information on the other requirements of the RTCR, go to Appendix A of this 

document. 

1.3. Who needs to comply with the RTCR? 

All PWSs (community or non-community) regardless of the type of source water use (i.e., 

surface water, ground water or ground water under the direct influence of surface water 

(GWUDI)) are required to comply with the RTCR (40 CFR 141.851(b)). 

1.4. How is this document organized? 

The document is organized as follows: 

• Chapter 1 – Overview of this Manual. This chapter introduces the guidance manual and

summarizes each section of the document.

• Chapter 2 – Assessment and Corrective Action under the Revised Total Coliform Rule.

This chapter provides an overview of the assessment and corrective action requirements of

the RTCR (including the schedule for and who must conduct assessments), discusses how a

contamination can occur in the distribution system, discusses what a sanitary defect is and

gives examples of sanitary defects.

• Chapter 3 – Level 1 Assessment. This chapter discusses what a Level 1 assessment is, when

is it required, why it needs to be conducted, who can conduct it, how to document it, what

steps can be followed to conduct one and what the timeline is for completing it.
RTCR ACAGM - Interim Final 1-3

• Chapter 4 – Level 2 Assessment. This chapter discusses what a Level 2 assessment is, when

is it required, why it needs to be conducted, who can conduct it, how to document it, what

steps can be followed to conduct one and what the timeline is for completing it. It also

discusses the differences between a Level 1 and Level 2 assessment.

• Chapter 5 – Corrective Action. This chapter discusses requirements and provides guidance

related to the identification and correction of sanitary defects, particularly those in the

distribution system. It also provides guidance related to actions that systems could take

regardless of the outcome of the assessments.

• Chapter 6 – Simultaneous Compliance with the RTCR with the Requirements of Other

Drinking Water Rules. This chapter discusses the considerations systems should take into

account when complying with the RTCR and how those could affect their compliance with

other drinking water rules.

• Chapter 7 – References

• Appendix A – Summary of the RTCR Requirements. This appendix provides a summary

of the requirements of the RTCR in a tabular format.

• Appendix B – Example Assessment Forms. This appendix provides concept examples of

Level 1 and Level 2 assessment forms. State primacy agencies may develop their own forms

for use by PWSs under their jurisdiction.

• Appendix C –Examples of Completed Assessments. This appendix goes through some

examples of systems being triggered into conducting an assessment and shows how the

assessment forms are filled out.

• Appendix D – Industry Standards for Operating a Public Water System. This appendix

provides a list of standards that may help systems complete a corrective action.
RTCR ACAGM - Interim Final 2-1

2. Assessment and Corrective Actions under the Revised Total

Coliform Rule

2.1. Why does the RTCR require assessment and corrective action? 

The RTCR aims to increase public health protection through the reduction of defects that 

could either provide pathways that allow fecal contamination and/or waterborne pathogens to 

enter into the distribution system, or could indicate a failure or imminent failure in a barrier that 

is already in place. The RTCR uses the term sanitary defects to refer to these deficiencies. 

The RTCR requires all PWSs to monitor for total coliforms and E. coli in their 

distribution system on a regular basis. Total coliforms are used as indicators of the integrity of 

the distribution system and E. coli as an indicator of the presence of fecal contamination. Refer 

to Section III.B of the preamble to the final RTCR for more discussion on the use of total 

coliforms and E. coli in the RTCR (USEPA 2013 and USEPA 2014). 

If the monitoring results indicate that the 

system may be vulnerable to fecal contamination 

(e.g., multiple positive results for total coliforms 

or E. coli), the system must conduct an assessment 

to determine if there are sanitary defects that 

could be causing the contamination. If there are 

no sanitary defects found, there may be problems

in the sampling practices. Refer to Section 3.1 and Section 4.1 of this document to find out when 

a PWS must conduct an assessment. Any sanitary defects identified during the assessment must 

be corrected to prevent future occurrence of contamination. 

Fecal contamination and waterborne pathogens (such as bacteria, viruses and parasitic 

protozoa) can cause a variety of illnesses, including acute gastrointestinal illness (AGI) with 

diarrhea, abdominal discomfort, nausea, vomiting and other symptoms. In general, reduction of 

the pathways and conditions that allow the entry of contaminants into the distribution system 

should lead to reduced exposure and associated risk from these contaminants. 

2.2. What causes a contamination to occur? 

There are numerous factors that can contribute to the presence of coliforms and E. coli in 

the distribution system. Coliform bacteria may be present in the distribution system if three 

conditions simultaneously occur (see Figure 2-1): 

Conducting an assessment and correcting 

for identified sanitary defect(s) should 

lead to a reduction of the pathways and 

the conditions that may allow the entry 

of contaminants into the distribution 

system.
RTCR ACAGM - Interim Final 2-2

1. A source of coliform bacteria;

2. A pathway into the distribution system or a breach in the system’s physical integrity;

and

3. A mechanism that allows coliform bacteria to be carried on this pathway into the

distribution system or that allows bacteria within biofilms, corrosion tubercles or

sediment to break free and enter the water.

Sources of coliform bacteria can include:

• Soil and Water Surrounding the Pipes – Coliform bacteria are common in the soil and

water surrounding pipes, valves and other distribution system infrastructure.

• Biofilms and Microbial Growth - Coliforms may attach to or become enmeshed in

biofilms on pipe walls in distribution systems, where they are protected from

disinfectants. Over time, these coliforms (including their associated pathogens) may

detach or slough from biofilms, causing persistent detections and possibly waterborne

disease.

• Corrosion Tubercles - A number of cases have been documented showing the

presence of coliform bacteria present within corrosion tubercles (i.e., deposits of

corrosion products on the interior of the pipes).

• Customer Connections - Customer connections and premise plumbing, such as the

service line connections to schools, hospitals, public and private housing and other

buildings, can be the source of coliform bacteria when a backflow event has occurred

and water and contamination from the building pipes are drawn back into the public

water distribution system, due to a change in pressure.

• Materials Used in the Distribution System - In some instances, materials used in the

distribution system can result in the presence of total coliforms through

contamination of the materials prior to installation (e.g., instances of well

contamination by not disinfecting the pump prior to installation). Some materials may

also support the growth of coliforms by providing nutrients for microbial growth

(e.g., pipe gaskets and elastic sealants containing polyamide and silicone can be a

source of nutrients for bacterial proliferation (NRC 2006)).

• Sediments - Sediment accumulation can provide a habitat for microbial growth in a

distribution system. Furthermore, the sediments can protect the microbes from

disinfectants.
RTCR ACAGM - Interim Final 2-3

Pathways through which total coliform bacteria can enter the distribution system can be: 

• Finished Water Storage Facility Deficiencies - Storage tank deficiencies, such as

vents without screens, inadequate hatches, access hatches that are not locked, physical

openings in storage tank roofs and lack of a cover, can result in the entry of

contaminants. Microorganisms can also be introduced into underground storage

facilities from surface water or ground water infiltration or runoff.

• Unprotected Cross Connections - A cross connection is a pathway whereby a

connection exists between a non-potable water source and a potable source (e.g., the

PWS). If not protected by an adequate backflow prevention device, the cross

connection can be a pathway for bacteria to enter the potable water distribution

system.

• Intrusion - Leaks or small holes in the pipe can provide a pathway for contaminants

outside of a pipe to enter the distribution system during low and negative pressure

events (termed intrusion). Points through which intrusions can occur also include pipe

fracture cracks, leaking joints, submerged air-vacuum/air-release valves and

deteriorating seals.

• Improper Main Installation, Repair or Replacement - Main installation, repair or

replacement can result in a loss of pressure and exposure of the pipe interior to

contaminated soil and runoff. If sanitary procedures are not followed, contaminants

can be introduced into the pipes during the main break repair process.

Mechanisms that allow coliform bacteria to enter the distribution system (assuming a 

source of contaminants and a pathway are present) or that allow bacteria to proliferate in the 

distribution system include the following:

• Weather-Related Events - A range of different weather-related events can contribute

to the increase of total coliforms and sometimes fecal indicators in source waters. In

other cases, coliforms may enter the distribution system more directly. Types of

weather-related events that have been attributed to indicator-positive samples include

significant rainfall events, droughts and excessively warm or cold weather.

• Treatment Breakthrough - Failure of the treatment barrier can lead to the presence of

coliforms in the distribution system.

• Backflow – An unprotected cross connection that allows the backflow of non-potable

water to enter the potable system because of reduced pressure in the distribution

system (termed backsiphonage) or the presence of increased pressure in the nonpotable system (termed backpressure).
RTCR ACAGM - Interim Final 2-4

• Hydraulic Conditions - Contaminant intrusion may occur if a very low or negative

pressure occurs within the pipe. Low pressure conditions in the distribution system

can also allow a flow reversal or backflow of non-potable water to enter the system

from a cross connection or other source such as intrusion.

• Operations - Sudden velocity or flow direction changes during operational activities

within a distribution system can result in the release of biofilms, scales or sediments

with microbial contamination. These velocity and flow changes are sometimes related

to firefighting, valve exercising and changing from one source to another.

• Maintenance Practices – Maintenance practices such as flushing and line cleaning can

affect the distribution system water quality in a negative manner if not conducted

properly and improper flushing can result in moving a contaminant further into the

distribution system.

• Retention Times - Long retention time in the distribution system, including storage

facilities, can reduce the levels of disinfectant residual and allow for the deposition

and accumulation of sediment.

• Presence of Nutrients - Some materials or system operations can introduce nutrients

such as carbon, nitrogen and phosphorus into the distribution system that may support

growth of total coliform bacteria.

Figure 2-1: Example of How Contamination Can Get Into a Water Pipe When All 

Three Conditions Are Present
RTCR ACAGM - Interim Final 2-5

Additional information on the causes of coliforms and E. coli in the distribution system 

can be found in a series of issue papers and white papers located at 

http://water.epa.gov/lawsregs/rulesregs/sdwa/tcr/regulation_revisions.cfm#issuepapers

2.3. What are examples of sanitary defects? 

Proper operation and maintenance of the distribution system is the last protective barrier 

to microbial contamination of drinking water. If the distribution system is breached via sanitary 

defects, microbial contamination can enter the treated water and be transported to customers, 

potentially resulting in adverse health outcomes. That is why it is so important to prevent 

sanitary defects and eliminate them when they occur. 

Examples of sanitary defects can include:

Cross connection and backflow issues 

• Required cross connection control devices not in place or not operating properly

• Unprotected cross connection (e.g., hoses connected from the hydrant to the raw

sewage masher spray bar in a wastewater facility; potable water plumbed directly to

the raw waste system in a recreational vehicle)

• Unauthorized connections to water mains

Operational issues

• Failure to follow Standard Operating Procedures (SOPs) that protect distribution

system integrity and sanitary condition

• Inadequate disinfection during and after pipe repair/replacement activities

• Failure to monitor and replace chlorine supply

• Improper chlorine residual measurements

• Sample collection and transportation problems

• Failure to follow sample siting plan

• Use of unapproved or untested source of water

• Untrained sample collector

Distribution system issues

• Inadequate inspection and maintenance of distribution system

• Loss of distribution system integrity (e.g., main breaks)

• Failure to maintain adequate pressure or low pressure event

• Pump failure
RTCR ACAGM - Interim Final 2-6

• Supervisory control and data acquisition (SCADA) and control issues

• Improper or lack of flushing operations

• Improper construction of new, replaced or renovated lines or service connections

Storage issues 

• Overflow, vents, hatches and other penetrations not configured, screened or sealed

properly

• Holes in tanks that could allow entry of insects or small animals

• Leaks in tanks that could be harboring growth

• Bladder pressure tanks that can become waterlogged

• Inadequate inspection and maintenance of storage facilities

• Inadequate disinfection during and after pipe repair/replacement activities

Source water issues 

• Cracks or holes in well seals or casings

• Leaking sewer lines or septic tanks

• Sewage overflow upstream of the source

• Lack of wellhead protection

• Unsanitary conditions at the wellhead

• Contamination during pump or motor repair or replacement

• Watertight seal at wellhead not present

Disinfection issues 

• Inability to maintain required residual throughout the distribution system

• Failure of chlorination equipment

• Improper settings on chemical feed

• Failure in redundant disinfection

• Loss of power

This is not an exhaustive or binding list. Systems should check with their states as they 

may have an additional or different list of conditions that they consider “sanitary defects.” 
RTCR ACAGM - Interim Final 2-7

Figure 2-2: Examples of Sanitary Defects

Photos courtesy of Nevada Division of Environmental Protection

2.4. What types of assessments are PWSs required to conduct? 

Systems are required to conduct either a Level 1 or Level 2 assessment depending on the 

condition that triggered the assessment. A Level 2 assessment is triggered by conditions that 

pose a more immediate and/or more severe public health risk compared to conditions that trigger 

a Level 1 assessment. Therefore, the Level 2 is a more detailed assessment than a Level 1 

assessment and may involve more effort and resources. The two levels of assessment recognize 
RTCR ACAGM - Interim Final 2-8

the difference in the severity of the situation and the varying level of effort required for the 

assessment.

Whether it is a Level 1 or Level 2 assessment, systems must complete the assessment and 

the assessment form required by the state and must submit the form to the state within 30 days of 

triggering the assessment.

For more information on how to conduct a Level 1 assessment and a Level 2 assessment, 

go to Chapter 3 and Chapter 4, respectively, of this guidance manual. 

2.5. What happens if a sanitary defect is identified during an assessment? 

If a sanitary defect is identified during the assessment, the system is required to take 

corrective actions to address the defect. If there are multiple sanitary defects identified, the 

system is required to correct all those sanitary defects. Chapter 5 of this guidance manual 

discusses some of actions that can be taken depending on the type of sanitary defect that has 

been identified. 

Sanitary defects detected, corrective actions completed and a proposed timetable for any 

corrective actions not already completed must be included in the assessment form that is due to 

the state within 30 days of triggering the assessment. Systems must comply with the required 

time period in conducting the assessment and taking the corrective action.

2.6. What if no sanitary defect is identified? 

It is possible that even after conducting an assessment, the positive sample cannot be 

conclusively linked to a given sanitary defect due to the complexity of the distribution system 

configuration and/or transport of contaminants throughout the system. In this case, this 

conclusion must be documented in the assessment form. The state may require the system to 

provide supporting documents to back up its conclusion. Even though a sanitary defect might not 

be identified, the Environmental Protection Agency (EPA) recommends some best practices that 

systems might consider performing after they have been triggered to conduct an assessment but 

did not find any sanitary defect. Section 5.3 of this document lists some of these best practices 

that can be taken. 
RTCR ACAGM - Interim Final 3-1

3. Level 1 Assessments

3.1. What is a Level 1 assessment?

A Level 1 assessment6 is a basic examination of the source water, treatment, distribution 

system (including storage facilities) and relevant operational practices. It is intended as a selfassessment and will be performed by a responsible party of the system in most cases (40 CFR 

141.859(b)(3)). 

A Level 1 assessment is triggered if sampling results in any one of the following scenarios

(40 CFR 141.859(a)(1)): 

1. For systems collecting 40 or more samples per month, the number of total coliformpositive samples exceed 5.0% of the total coliform samples collected for the month

(including routine and repeat samples); or

2. For systems collecting fewer than 40 samples per month, there are two or more total

coliform-positive samples in the same month (either routine or repeat); or

3. For any system, the system fails to take every required repeat sample after any single

routine total coliform-positive sample.

3.2. Why do systems need to conduct a Level 1 assessment? 

The purpose of performing a Level 1 assessment is to enhance public health protection by 

identifying the presence of sanitary defects and correcting all such defects identified. 

Performing assessments will also help identify if there are deficiencies or problems in the 

sampling practices (40 CFR 141.859(b)(1)). 

Sanitary defects are defined as: defects that could provide a pathway of entry for microbial 

contamination into the distribution system or that are indicative of a failure or imminent failure 

in a barrier that is already in place (40 CFR 141.2). 

6 Level 1 assessment is defined at 40 CFR 141.2 as “an evaluation to identify the possible presence of sanitary defects, defects in 

distribution system coliform monitoring practices, and (when possible) the likely reason that the system triggered the assessment. 

It is conducted by the system operator or owner. Minimum elements include review and identification of atypical events that 

could affect distributed water quality or indicate that distributed water quality was impaired; changes in distribution system 

maintenance and operation that could affect distributed water quality (including water storage); source and treatment 

considerations that bear on distributed water quality, where appropriate (e.g., whether a ground water system is disinfected); 

existing water quality monitoring data; and inadequacies in sample sites, sampling protocol, and sample processing. The system 

must conduct the assessment consistent with any State directives that tailor specific assessment elements with respect to the size 

and type of the system and the size, type, and characteristics of the distribution system.”
RTCR ACAGM - Interim Final 3-2

Identifying and correcting sanitary defects early will provide some assurance that 

issues have been addressed that may compromise public health. While the Level 1 assessment 

is intended to be a basic and relatively simple assessment, it should be conducted thoroughly 

enough to capture the possibility that there may be multiple sanitary defects. In some cases, 

however, a sanitary defect may not be found despite conducting a thorough assessment.

Ideally, a well-performed Level 1 assessment will prevent most systems from developing 

conditions that lead to fecal contamination or a Level 2 assessment. For guidance on Level 2 

assessments, see Chapter 4 of this document. 

For systems eligible to monitor at a reduced frequency (i.e., less than monthly; see 40 

CFR 141.854 and 141.855), it is also important that they conduct a Level 1 assessment within the 

specified timeframe (see Section 3.6 of this document regarding the timeframes associated with 

the Level 1 assessment) as failing to do so might 

result in them being placed into more frequent 

monitoring. Also keep in mind that if a system’s 

monitoring frequency has been increased to monthly, 

the system needs to have a clean compliance history 

(i.e., no history of RTCR violations within the last 12 

months) to be able to return to a reduced monitoring 

frequency. Failure to conduct a Level 1 assessment within the required timeframe and according 

to the state requirements is a treatment technique violation, which disqualifies a system from 

having a clean compliance history. Also, keep in mind that a treatment technique violation under 

the RTCR has an accompanying requirement to notify the public. Appendix A of this document 

presents a summary of the RTCR requirements. 

3.3. Who is responsible for conducting a Level 1 assessment? 

A Level 1 assessment is a PWS self-assessment that should be conducted or managed 

by a responsible party of the PWS (40 CFR 141.859(b)(3)). This should be someone familiar 

enough with the system to answer the questions in the Level 1 assessment form or to gather 

correct information from others who work for the system. Systems may also seek assistance from 

external parties, if desired. External assistance may be provided by state personnel, a certified 

operator from a similar system, a circuit rider, consultant or other utility expert.

If a system has qualified for reduced 

monitoring, it can remain on the reduced 

monitoring schedule if it does not have 

more than one Level 1 assessment 

triggered per rolling 12-month period.
RTCR ACAGM - Interim Final 3-3

Remember that the assessment must be consistent with state requirements so systems 

should check with their states to make sure that they have the appropriate person conducting the 

Level 1 assessment.

3.4. How do PWSs document a Level 1 assessment? 

The Level 1 assessment must be documented using an assessment form, which 

systems must complete and submit to their states within 30 days after they have learned 

that they have exceeded a trigger (40 CFR 141.859(b)(3)).

Appendix B of this document contains an example of a Level 1 assessment form. The 

sample form is intended as a conceptual example to describe practical expectations for the level 

of resources committed to undertaking a Level 1 assessment. States can use the example form 

presented in this document or develop their own forms. It is possible that states have different 

forms that are specific to different system types. Systems should contact their states to make 

sure that they are using the right form. 

The example assessment form is designed to Systems must submit a Level 1 

assessment form to their states within 30 

days after learning that they have 

exceeded a trigger. The assessment form 

must describe sanitary defects detected, 

corrective actions completed, and a 

proposed timetable for any corrective 

actions not completed. If no sanitary 

defects were detected, systems may note 

in their form that no sanitary defects 

were identified (see Section 2.6 of this 

document). See 40 CFR 141.859(b)(3).

cover the typical elements found within a PWS. For 

each element, the assessment form provides 

suggestions on items to evaluate that are related to 

the pathways and mechanisms for microbial 

contamination. Since an assessment is an 

examination of a particular PWS, it will therefore 

have different components for each system 

depending on the system’s source water, 

configuration and the number and type of 

distribution system facilities present. The form 

cannot cover all possible situations or distribution system configurations. Systems should use 

professional judgment in the application of the form to their situation and provide additional 

information to support conclusions, if warranted. 

The state makes the final determination on the adequacy and completeness of 

information provided in the assessment (40 CFR 141.859(b)(3)). The state will review the 

assessment form and if it determines that the assessment is insufficient, it will consult with the 

system on follow-up efforts that may be required. Systems should be familiar with the forms and 

required submittals so that they are prepared for an assessment in advance, should one be 

required. For example, systems may wish to create a standard operating procedure (SOP) for 

what to do when coliform results trigger an assessment. When developing the SOP, systems 
RTCR ACAGM - Interim Final 3-4

should verify with their states whether there is a specific version of the assessment form that 

needs to be used, and understand which data source(s) can be used to fill out the various sections. 

3.5. How do PWSs conduct a Level 1 assessment? 

At a minimum, a Level 1 assessment must include a review and identification of the 

following elements (40 CFR 141.859(b)(2)): 

• Atypical events that may have affected distributed water quality or indicate that

distributed water quality was impaired (see Section 3.5.2 of this document).

• Changes in distribution system maintenance and operation that may have affected or

are affecting distributed water quality including water storage (see Section 3.5.2 of

this document).

• An evaluation of source water quality and treatment changes or conditions that may

affect distributed water quality, where appropriate (see Sections 3.5.3 and 3.5.4 of

this document).

• Existing water quality monitoring data (see Section 3.5.2 of this document).

• Inadequacies in sample sites, sampling protocol and sample processing (see Section

3.5.1 of this document).

The Level 1 assessment form example found in Appendix B of this document lays 

out the elements of the system that need to be looked at during an assessment and gives an idea 

of the depth and level of detail that is expected of the assessment. States may also tailor specific 

assessment elements to the size and type of system. 

Systems may tailor their assessment activities based 

on the specific characteristics of their distribution 

system, in accordance with state requirements. As 

stated previously, the form is provided as an example 

only. Systems should contact their states to obtain 

the specific forms for their situation. 

For the Level 1 assessment, the assessor

should look at conditions that could have occurred 

prior to the collection of the total coliform-positive 

sample(s). A Level 1 assessment can often be 

completed using data on hand at the PWS, with 

the assessor conducting limited inspections, and not necessarily conducting extensive new 

field investigations. Interviews of appropriate PWS employees can also be a valuable means of 

obtaining important information. 

If the state allows it, systems may 

conduct a Level 1 assessment while they 

consult with the state by phone. It is

possible that the state may fill out the 

assessment form for the system while the 

consultation is happening. If not, the 

system would still need to fill out the 

assessment form and submit it to its 

state. Systems should check with their 

state to see if there are alternative 

methods they can use to submit the form, 

e.g., via an online submission or email.
RTCR ACAGM - Interim Final 3-5

The assessor should begin the assessment by evaluating the sample site itself. The 

assessor should review the sampling procedures, 

laboratory procedures and conditions of the sampling 

tap and note any errors and unsanitary conditions. The 

In general, in performing a Level 1 

assessment systems should follow a 

progression starting with the (1) 

location of the initial coliform positive 

samples and working through the (2) 

distribution system to the (3) treatment 

plant and (4) source. See Figure 3-1.

Depending on the system’s 

configuration, not all these components 

may be present.

area immediately surrounding the positive sample 

site(s) should be evaluated next. Historical water 

quality data should be examined along with a list of 

events that may have occurred in the vicinity of the 

positive sample sites to determine a possible cause for 

a loss of distribution system integrity. The assessment 

of the distribution system area could include 

additional sampling to try to identify the extent of the 

contamination, being sure to consider that the 

contamination may have migrated within the system. Next, the assessor should evaluate the 

impact of treatment plant issues or other system-wide events based on historical performance 

data, environmental factors, operational activities and other external events. Customer complaint 

data, main break reports and other system data may be helpful in the assessment of system-wide 

events that could have contributed to degraded water quality. The assessor should evaluate 

changes in the source water, along with weather events or other occurrences that could influence 

source water quality. 

The subsequent sections will go into detail on how the assessor can assess the different 

parts of the water system using the progression outlined above. 

The assessor should go over and complete the entire assessment form, even if the 

apparent cause is understood, to ensure that he/she has a complete picture of the overall integrity 

of the system and does not inadvertently overlook a potential sanitary defect. It is also possible 

that the coliform positive samples resulted from multiple causes.

Once an assessment has been triggered, system personnel may become busy performing 

the investigation, answering questions and responding to the public, on top of their normal daily 

responsibilities. Therefore, systems should prepare for a possible assessment by developing 

some standard datasets based on operational data for items such as disinfectant residuals, 

treatment process variables and field sampling results. Much of this data can typically be 

found in monthly operating reports and other summaries that are submitted to the states. These 

datasets should be continuously updated so that they are ready to be used immediately upon 

triggering an assessment. For further discussion on operational data, see Section 3.5.2.1 of this 

document. 
RTCR ACAGM - Interim Final 3-6

Figure 3-1: General Progression of Conducting a Level 1 Assessment

Location of 

the Positive 

Sample

• Samples, sampling sites, sampling procedure

Distribution 

Area Near 

Positive 

Sample(s)

•Review operational data and water quality data

•Review operational activities and unusual activities

• Assess distribution system components (e.g., pipes, valves, pumps, etc.)

• Assess storage facilities

Treatment 

Facilities

• Assess treatment facility closest to the location of the positive sample

Source Water

• Assess wells, springs or surface water

3.5.1. Assessing samples, sampling sites and sampling protocols

This section of the assessment is designed to help the assessor determine whether water 

samples could have been contaminated during the sample collection or processing, resulting in 

total coliform- or E. coli-positive samples. In that 

case, the positive results may not indicate a 

distribution system problem but rather a sampling 

problem. Several references are available to provide 

detailed guidance on sampling (AWWA 2008; APHA 

et al. 2005; USEPA 2001a; USEPA 2006c; USEPA 

2006d). 

The evaluation of the sample site(s) with the positive sample(s) and the sampling 

protocol would be performed in a similar manner for systems of all sizes and types. The sample 

site(s) is/are a key indicator of whether the problem is system-wide or localized. This part of the 

Systems should be careful not to jump to 

the conclusion that the sampling process 

caused the coliform detection before the 

other elements have also been assessed 

and ruled out as a possible source of 

contamination.
RTCR ACAGM - Interim Final 3-7

assessment should include a field visit to inspect the sample location(s) or a detailed discussion 

with the sample collector to determine the conditions at the sample site(s).

Some of the common items that should be evaluated at the sample site(s) include: 

• Cleanliness and suitability of the sample tap and sink,

• Potential for hot water to enter the sample through the tap, and

• Conditions that may have changed at the sample site since the last sample collection,

such as new uses for the sink as janitorial cleanup area, dirt accumulation near the

faucet or installation of a point-of-use device on the faucet.

In addition to sample tap contamination, it is possible that elements of the sampling 

protocol that were not followed closely could result in contamination of the sample. Elements of 

the sampling protocol that systems should follow may include:

• Removal of the tap aerator,

• Adequate flushing of the tap prior to sample collection,

• Proper storage and preparation of the sampling container,

• Correct sample collection technique, including elimination of splashing water from

sink and the sampler touching the inside of the sample bottle,

• Correct storage, preservation and handling of sample(s) during transport to

laboratory, including items such as cleanliness of coolers and use of watertight bottles

during transport (to prevent leakage), and

• Compliance with holding time and temperature requirements, including items such as

maintenance of ice packs.

Finally, this evaluation should include a discussion with the laboratory to determine if all 

laboratory quality checks were performed with satisfactory results. 

3.5.2. Assessing the distribution system area near the positive samples

Once the evaluation of the sample site(s) has been completed, the assessor should 

proceed to evaluate the area of the distribution system near the positive samples. This part of the 

assessment is designed to help determine if there is a sanitary defect causing the contamination, 

understand the potential movement of contamination and proactively prevent future coliform 

positive samples. 

A Level 1 assessment of the distribution system should include the collection and review 

of available data. The data to be reviewed includes operational data (e.g., pressures, flows),
RTCR ACAGM - Interim Final 3-8

water quality (e.g., pH, turbidity, etc.) and information on the physical condition of 

distribution system components (see Sections 3.5.2.1 to 3.5.2.5 of this document). 

The area of the distribution system that should be evaluated depends on the system 

configuration along with the extent of coliform positive samples. Smaller systems would be 

expected to have fewer distribution system components and therefore a lesser level of effort in 

completing the assessment. Larger systems may focus their evaluation on areas of the system 

that have been shown to be more greatly affected, particularly if the data review confirms that 

the spread of contamination has been limited.

3.5.2.1. Operational data

The operational data review includes collection, compilation and analysis of the system 

data from a variety of sources to get a more complete understanding of the system conditions and 

events that may have occurred prior to triggering an assessment. The data collected should 

include recent data as well as historical trends to provide a basis for comparison to determine if 

atypical events such as main breaks or system component failures have occurred. 

The operational data elements should be reviewed by all systems, regardless of size or 

type. The available data and accessibility of electronic data may vary by system size and type. 

Larger systems may have electronic databases from which to extract pertinent 

information including: 

• Distribution system and treatment plant process data from SCADA systems for

pumping, storage and pressure data,

• Water quality measurements from laboratory information management systems

(LIMS) or external laboratory reporting systems,

• Customer complaint and water usage data from customer service information systems

(CSIS),

• Data on operations and repairs in the distribution system from maintenance

management information systems (MMIS),

• Recent and historical information from main break databases,

• Pipe material and condition information from asset management databases,

• Hydrant testing and fire-fighting from fire department information, and

• Activities performed from operations logs.

For smaller systems, much of the data sources listed above may not be electronic and 

would thus involve additional effort by the system to compile the data as part of the assessment. 
RTCR ACAGM - Interim Final 3-9

EPA encourages these types of systems to maintain records of the above-mentioned data 

elements to help them quickly conduct an assessment, should they be triggered to do one. 

The operational data review may provide an indication of the elements of the assessment 

on which to focus the assessor’s efforts. For example, if the SCADA data or other available 

information indicates some low-pressure readings in a particular area of the distribution system, 

follow-up investigations could focus on that area. However, the assessor should not ignore other 

areas of the distribution system as microbial contamination can be a result of multiple causes.

Tables and graphs summarizing the data and findings could be helpful supplemental 

items to prepare and submit to the state, if a system is asked or required to do so. Although 

systems, under the federal regulations, are not required to submit the collected data and 

supplemental analysis with the assessment form, EPA recommends that these items be kept on 

file for future reference in case the system gets triggered for another assessment. States may also

require the system to submit such data and analysis or may want to look at this information

during their review of the assessment forms or during a sanitary survey. 

3.5.2.2. Water quality data

As part of any assessment, the assessor should compile and evaluate water quality data. 

This data would include parameters collected in the distribution system and at the source or 

treatment plant (discussed further in Section 3.5.3 of this document). The parameters to be 

evaluated will likely vary by system type, treatment process used and other operational practices 

but may include the items outlined in Table 3-1. Systems that do not currently collect water 

quality data at one of the locations suggested in Table 3-1 might consider doing so in order to 

create a baseline for comparison should another assessment be triggered in the future. 

The assessor may find it appropriate to collect special purpose samples of total coliforms 

(and potential subsequent E. coli) analysis and monitor for additional water quality parameters 

such as disinfectant residual. An example of a special purpose sample is one taken to determine 

whether disinfection practices are sufficient following pipe placement, replacement or repair.

Records of any special purpose samples taken should be kept for comparison should another 

assessment be triggered in the future. Take note that special purpose samples, such as those taken

during an assessment, must not be counted towards compliance (i.e., they should not be included 

in determining whether an assessment has been triggered). 
Table 3-1: Typical Water Quality Data to Be Evaluated During an Assessment

Water Quality Parameter Location of Sample Collection 

Disinfectant residual concentration

Throughout the distribution system, including 

total coliform sampling sites as specified in the 

sample siting plan

At storage tanks throughout the distribution 

system

At the entrance to the distribution system at 

each source

Disinfection by-products (DBPs)

At approved monitoring locations 

distribution system

in the 

Total coliforms and E. coli

All distribution system sampling sites, 

including those for repeat, additional routine

and special purpose samples (like those 

associated with recent main installation or 

repair)

Entrance to the distribution system at each 

source 

Heterotrophic plate count (HTP) All distribution 

coliforms

system sampling sites for total 

Nitrite and nitrate (systems using chloramine) Distribution system sites with low 

residual

disinfectant 

Once the water quality and operational data have been collected, they should be evaluated 

to determine if any atypical events or measured values have occurred. Depending on the data that 

are available, there may be several ways to examine the data. One good method is to develop a 

historical trend for monitoring results and individual parameters at each sampling location. 

Spreadsheet and graphing software can be helpful in developing and reviewing historic trends. 

The historical time series can be evaluated visually to determine if there are differences between 

current results (under assessment) and historical trends. See Figure 3-2. 

A spatial analysis of data can also help identify problem areas. Mapping of water 

quality results can be done using a paper map or geographic information system (GIS) software. 

The correlation between different water quality variables (e.g., disinfectant residual and total 

coliform) can be more apparent when the data is viewed in a spatial analysis. The results of a 

spatial data analysis can be used to focus the Level 1 assessment activities on the appropriate 

areas and components of the distribution system. 

Consideration of flow pathways or use of a hydraulic model can also help in 

determining if a specific activity could be related to the coliform-positive samples at a given 

RTCR ACAGM - Interim Final 3-10
RTCR ACAGM - Interim Final 3-11

location. This type of analysis can be useful in finding the source of contamination, particularly 

if several positive samples fall within the influence zone of a specific distribution system pump 

station or tank. In this instance, the assessor can focus his/her attention on specific locations at 

the distribution system in determining the cause of the positive samples. However, as mentioned 

previously, other areas of the distribution system should not be ignored, as the contamination 

may be a result of multiple causes.

The assessor could also consider supplemental data sources beyond water quality 

measurements in the assessment. For example, customer complaints might show an increase in a 

particular area of the distribution system that could be correlated to distribution system problems. 

Figure 3-2: Example Time Series Graph for Distribution System Chlorine Results

Figure 3-2 provides an example of a historical time series graph of total chlorine 

measurements from distribution system samples using Microsoft Excel software. The average 

total chlorine concentration for each month is plotted for multiple years. This type of graph can 

help to identify if measured values are within normal ranges or might represent an atypical 

condition within the distribution system. Similar graphs could be constructed for minimum and 

maximum residual disinfectant measurements, total coliform-positive samples and related water 

quality sampling data.
RTCR ACAGM - Interim Final 3-12

3.5.2.3. Operational activities and unusual events

Along with water quality measurements, it is important to understand the extent of 

activities occurring in the water system that may have resulted in total coliform-positive samples. 

Compilation of operational activity data may require consultation with different departments 

within the water system and with external agencies. The types of activities and events to be noted 

would include those that might result in distribution system contamination, including:

• Pipe breaks and associated repairs,

• Events resulting in a loss of pressure (e.g., power failures),

• Flushing and hydrant testing,

• Construction activity that impacts water pipes,

• Unusually high (or low) demands that might alter typical flow patterns, including

temporary connections for construction and firefighting,

• Break-ins and vandalism at system facilities,

• Treatment process upsets,

• Weather events, and

• Source water changes.

Once a list of distribution system activities and events has been compiled, this list can be 

compared to historical records to determine if any activities or events could have led to the 

distribution system contamination. Any suspect operational activities or events should be further 

investigated and documented on the assessment form. 

3.5.2.4. Assessing distribution system components

The objective of this evaluation is to help determine if a particular distribution system 

component has a sanitary defect that would require correction or if distribution system events 

could have contributed to the positive coliform samples. 

From the operational data review, data should have been compiled to indicate what 

activities had been occurring in the distribution system near the location of the total coliformpositive samples, including operational changes, maintenance and atypical events. For a Level 1 

assessment for distribution system components, the focus should primarily be on available data 

that indicates the condition of the component at its last inspection date, observations from recent 

visits by operations staff and other related data such as disinfectant residual that might assist in 

focusing the assessment efforts. This would include any previously noted sanitary defects or 

significant deficiencies and records on how these were addressed. Under this step of the 

assessment, further detail should be obtained for any location or event that might be significant. 
Additional data could be collected to help define the extent of the contamination and to 

determine whether the contamination has spread. An on-site inspection of components could be 

considered if it has been a year or more since the last inspection or sanitary survey or if the 

evaluation of the available data indicates that an on-site inspection is needed. 

The assessor should focus first on the area of the distribution system closest to the 

positive coliform samples. Operator knowledge or the results of a flow path analysis or hydraulic 

model can be used to determine the area(s) likely to be associated with a given sample site. For 

example, if the positive sample is located within a defined pressure zone, the entry point to the 

zone and related facilities should be assessed before moving the assessment to other more remote 

zones. Once the immediate area has been examined, the assessor can continue to evaluate the 

areas of the distribution system farther from the positive coliform samples. 

The assessor should evaluate distribution system facilities to determine whether

infrastructure and equipment are operational and in good repair. The evaluation should include 

elements such as those presented in Table 3-2. The items in Table 3-2 are not intended to be an 

exhaustive or binding list but rather a summary of typical distribution system components to help 

assessors think about the system configuration. Depending on system configuration, not all 

elements would be present in all systems. 

Table 3-2: Typical Items to Evaluate in Distribution System Assessment

Component Typical Items to Evaluate

Pump stations Proper operation of pumps and valves 

Recent losses of power

Recent losses of pressure

Proper operation of surge control appurtenances 

Distribution system pressure Maintenance of adequate pressure

Air-relief / Air-vacuum valves Proper operation of valves 

Valve vault free of standing water and debris 

Fire hydrants Proper operation of shut-off valves

Leaks at connection to lateral piping 

Flushing assemblies / Blow-offs Proper operation of valves 

Leaks at connection to piping 

Pipes Recent main breaks

Recent leaks

Recent installation of new mains or construction activity

Distribution system isolation 

valves Recent operation resulting in breakage 

RTCR ACAGM - Interim Final 3-13
RTCR ACAGM - Interim Final 3-14

Appendix C of this document includes an example of an assessment where distribution 

system problems were found. In this example, the assessment of the distribution system revealed 

an air release valve submerged in a flooded valve vault. To correct the problem, a permanent 

sump pump was installed and portions of the system were shock chlorinated. 

3.5.2.5. Assessing storage facilities

Storage facilities, or tanks, have been linked to microbial contamination events and 

therefore are an important component to assess when responding to positive coliform samples

(Clark et al. 1996). Microbial contamination can enter storage facilities either through system 

water or external tank breaches. If contamination is introduced through system water (i.e., 

transported to the storage facility or tank from a different contamination site), microbes can 

remain viable and possibly multiply within the tank water and sediments. 

Table 3-3 outlines some of the typical items that should be evaluated for storage facilities

or tanks. The items in Table 3-3 are not intended to be an exhaustive or binding list but rather a 

summary of typical storage facility or tank components to help assessors think about the system 

configuration. Depending on system configuration, not all items would be present in all systems. 

Review of the most recent tank inspection reports, review of operation and maintenance 

records and operator interviews should provide valuable information for the assessment. If a 

thorough inspection of the storage facility or tank has not been completed in the recommended 

timeframe for that facility (usually every three to five years), the system should consider whether 

a professional cleaning and inspection is appropriate as part of the Level 1 assessment. For 

systems that use hydropneumatic tanks and/or bladder tanks, these tanks should be maintained 

and inspected according to manufacturer recommendations. A Level 1 assessment should include 

review and inspection of maintenance records for these types of tanks. 

If warranted, the assessor could also examine historical disinfectant residual data for the 

tank and its vicinity and collect additional samples for disinfectant residual and/or total 

coliforms. Depending on the record review and results of additional monitoring, an on-site 

inspection may be appropriate. 

The assessment should initially be focused on the storage facilities that supply the area 

near the total coliform-positive sample, with evaluation of other more remote facilities as a next 

step.
Table 3-3: Typical Items to Evaluate at Storage Facilities

Storage Tank Element Typical Items to Evaluate

Access hatches Signs of vandalism or forced entry 

Ability of hatch to seal tightly when closed

Rust, holes or other breaches 

Vents Signs of vandalism or forced entry 

Absence of screen; 

screens

holes or other breaches in 

Rust, holes or other breaches in vent piping and 

penetration through tank wall 

Overflow piping Rust, holes or other breaches in piping and 

penetration through tank wall 

Absence of 

screens

screens; holes or other breaches in 

Control valves Correct operation of level control valves, altitude 

valves and related appurtenances

Tank exterior Signs of deterioration, rust or other breaches 

Tank interior Integrity of lining material

Presence and extent of floating material and 

sediment within tank; existence of microbes within 

sediment

Presence of dead animals

Disinfectant residual Level of disinfectant in 

tank levels

tank, ideally at different 

3.5.3. Assessing the treatment facilities

For a PWS operating a treatment plant, even if the only treatment is a chlorinator at a 

well, assessment of the proper operation of the treatment process is important to determine if a 

plant upset could be the source of the microbial contamination resulting in positive coliform

samples. For most treatment facilities, regulatory data collected for compliance with related 

treatment requirements (e.g., Surface Water Treatment Rule (SWTR), Ground Water Rule 

(GWR)) should be available. A review of this data may indicate a potential treatment plant 

problem that could have allowed microbial contaminants to enter the distribution system. 

As part of a Level 1 assessment, the assessor should review the treatment process data 

and records. When reviewing the treatment data and records, particular attention should be paid 

to disinfection processes and turbidity removal, as these processes are responsible for the 

majority of microbial inactivation (Letterman et al. 1999). For disinfection processes, data and 

RTCR ACAGM - Interim Final 3-15
records regarding the disinfectant feed systems and resulting disinfectant concentration should be 

evaluated to ensure that proper dosing has taken place and desired residuals are maintained. For 

turbidity removal, data and records regarding coagulation/sedimentation and filtration processes 

should be evaluated to ensure that microbial contaminants could not have entered the distribution 

system along with a spike in turbidity. Power outages and other events that disrupt normal 

operations should also be considered. Depending on the results of the data and records reviews, 

additional monitoring or site visits may be appropriate.

Table 3-4 provides an overview of the types of data elements that could be reviewed as 

part of a Level 1 assessment. The items in Table 3-4 are not intended to be an exhaustive list but 

rather a summary of typical treatment facility components to help assessors think about the 

system configuration. Depending on system configuration, not all elements would be present in 

all systems.

Table 3-4: Typical Treatment Facility Elements to Evaluate

Treatment Facility Element Typical Items to Evaluate

Equipment 

(pumps, mixing units, settling 

units, pipes, valves, chemical feed 

units, filters) 

Status of equipment – operational and maintained in 

accordance with the treatment plant Operation and 

Maintenance procedures

Recent installations or repairs

Treatment Process Introduction of new sources or changes in the 

water

source 

Recent changes in the treatment process

Interruptions in treatment 

or proper mixing 

– lapses in chemical feed

Turbidity measurements at all appropriate locations 

in the treatment process (source, settled water, preand post-filtration, finished water, etc.) 

Disinfectant residual measurements and C x 

(concentration x time) calculations

T 

Flow rates at each plant process

Appendix C of this document includes an example of an assessment where a treatment 

system was determined to be the cause of positive coliform samples. In this case, pressure was 

lost during regular maintenance of a treatment system and the system may not have been 

properly disinfected prior to resuming service. 

RTCR ACAGM - Interim Final 3-16
RTCR ACAGM - Interim Final 3-17

3.5.4. Assessing the source water

To wrap up a Level 1 assessment that began with the sample site and worked backward 

through the distribution system to the treatment plant, the final component for evaluation would 

be the source water. The source water can include wells, springs and surface water bodies (see 

Sections 3.5.4.1 to 3.5.4.3 of this document). Changes in source water, extreme weather events 

and introduction of new sources can all be possible causes of microbial contamination. The 

source water should be evaluated using historical data and system records to determine if the 

source water has contributed to the coliform positive samples. Additional monitoring and site 

visits may be appropriate based on the results of the evaluation of the data and records.

3.5.4.1. Wells

For systems served by a well (or wells), the integrity of the well and proper operation of 

the well system should be verified to ensure that contamination could not have entered the 

distribution system from the well. The assessor should pay particular attention to potential 

pathways that would allow the entrance of surface water, soil, animals or other foreign matter 

into the well. Well inspection records and operation and maintenance records should be reviewed 

and weather events should be considered if runoff could have affected the well. The well should 

be constructed to prevent the accumulation of surface water around the well head and prevent 

inundation during periods of flooding or increased runoff. Table 3-5 outlines some typical items

that should be evaluated for wells. The items in Table 3-5 are not intended to be an exhaustive or 

binding list but rather a summary of typical well components to help assessors think about the 

system configuration. Some elements may not be present depending on the design/configuration 

of the well and the type of pump in the well. 
Table 3-5: Typical Items to Evaluate at Wells

Well Element Typical Items to Evaluate

Well house / enclosure Signs of vandalism or forced entry 

Unsanitary conditions like the presence of rodents or other animals

Well cap / Well seal Tightness of well cap and seals, presence of gaps or openings

Well vent Vent properly screened, 

height above ground 

angled to be self-draining and has sufficient 

Well casing Holes, breaks, corrosion or deformation in casing and welds 

Annular grout seal Missing, sunken, bridged or channeled grout surrounding the well 

casing 

Pump and pump assembly Attached to casing with no unprotected openings and has watertight 

seal

Pitless adapter Integrity of pitless adapter connection

Inundation Signs of inundation by floodwater or 

wellhead

runoff; depressions around 

3.5.4.2. Springs

For systems served by a spring (or springs), the assessment should verify the sanitary 

condition and proper operation of the spring and associated piping. Typical items the assessor 

should evaluate for a spring source include: 

• Condition of the spring development,

• Impacts from surface water runoff and weather conditions,

• The physical condition of the spring box,

• Impacts from vandalism or forced entry to determine if holes or other breaches

could have occurred that would allow for the introduction of microbial

contaminants,

• Signs of inundation, including deposits of soil or soil erosion, and

• Signs of small animals, slugs, bugs, etc., in the spring box.

Appendix C of this document includes an example of an assessment where a spring 

source was contaminated through a broken pipe. In this case, the pipe was replaced to correct the 

defect.

3.5.4.3. Surface water 

Surface water sources can be impacted by extreme weather events that can influence the 

influent water quality to the treatment plant. Atypical events may impede the ability of the 

RTCR ACAGM - Interim Final 3-18
RTCR ACAGM - Interim Final 3-19

treatment process to perform as desired and may allow for the introduction of microbial 

contaminants into the distribution system. Heavy rainfall and rapid snowmelt can carry large soil 

loads into surface water sources, thereby increasing turbidity and baseline microbial contaminant 

concentrations. Similarly, flooding can alter the raw water quality and require treatment changes 

to achieve good finished water quality. 

For systems that have multiple surface water sources, a change from one source to another 

could trigger a treatment upset that might result in microbial contamination entering the 

distribution system. In performing the Level 1 assessment, the assessor should obtain and review 

the source water data to determine if atypical surface water quality could have impacted the 

treatment process.

3.5.5. Additional considerations

EPA recognizes that the process of conducting a Level 1 assessment presented in the 

preceding sections may not necessarily apply to all types of systems. Because of the complexity 

and the diversity of the different configurations of PWSs, a one-size-fits-all approach will not be 

appropriate for all systems. Larger systems will more than likely have all the elements mentioned 

in the preceding sections while smaller systems may only have some of them. For example, some 

small ground water systems may only have a well, provide no treatment and have a limited 

distribution system consisting only of premise plumbing. The process of performing a Level 1

assessment will therefore vary from system to system. This section presents additional 

considerations systems may want to incorporate in their assessment protocol depending on their

system type. 

3.5.5.1. Systems with limited or no distribution system

For small systems, it might be the case that they do not have any treatment process or an 

extensive distribution system. In this case, the Level 1 assessment will only focus on those 

elements that are present in the system such as the source water (e.g., wells) and the limited 

distribution system.

For non-community water systems (NCWSs) that have their own source water and do not 

supply water beyond their premises (typical examples are schools and churches), then an 

assessment of the pipes inside the building (what is typically considered premise plumbing) is 

required. Typically in a community water system (CWS), premise plumbing is beyond the 

control of the PWS. However, in the case of NCWSs, the premise plumbing may be part of the

system and if so, must also be included as part of the assessment. One thing the assessor might 

look for is the presence of cross connections. The majority of backflow events resulting from 

unprotected cross connections occur in premise plumbing (USEPA 2001b). 
RTCR ACAGM - Interim Final 3-20

In cases where the results of total coliform monitoring also triggered GWR requirements 

in addition to triggering an assessment under the RTCR, it might be possible to combine the 

assessments required under both rules into one assessment, as long as the combined assessment 

complies with the requirements of both rules. Systems should check with their states before 

performing such a combined assessment. See also Chapter 6 of this document regarding the 

overlap between an assessment under the RTCR and a sanitary survey.

3.5.5.2. Large systems

Large systems may want to determine whether the contamination is widespread or 

localized in the distribution system. If the total coliform-positive samples that triggered the 

assessment are clustered in one part of the system, the assessor may want to target the 

assessment to specific sections of the distribution system or facilities. It may not be practical or 

necessary to conduct an assessment of the entire distribution system. Looking at historical data 

may also help determine if the problem is episodic or chronic. Knowing so would help determine 

the type of corrective action the system has to take to address the problem. 

3.5.5.3. Wholesale and consecutive systems

For PWSs that purchase water from another system, also known as consecutive systems, 

the source water can be considered to be the connection(s) from the wholesale (seller) system. 

During a Level 1 assessment, a review of the records related to the connection (e.g., flows, 

pressures, water quality parameters if measured) should be performed. 

It is also recommended that the consecutive PWS contact the wholesale system to 

coordinate assessment efforts. The possibility exists that a contamination event occurred in the 

wholesale system upstream of the connection and that the contamination has migrated to the 

consecutive system. While the wholesale system would not be required to perform a Level 1 

assessment in this case (unless it also exceeded the trigger level for total coliforms), it may be 

required to conduct source water monitoring under the GWR and may want to voluntarily 

investigate its system along with the assessment being performed by the consecutive system. 

Water quality data from the wholesale system at or near the connection point for the consecutive 

system may also prove to be valuable in the Level 1 assessment.

Similarly, if a wholesale system experiences a total coliform trigger, it should notify its 

consecutive system(s) if the contamination could have spread to the consecutive system area. 

Additional samples and data from the consecutive system may help to define the extent of 

contamination and identify potential problems and sanitary defects. 
RTCR ACAGM - Interim Final 3-21

Consecutive systems may or may not have additional sources and treatment facilities, 

such as their own wells with treatment or booster chlorination of purchased water. These 

complicating factors should be considered during the assessment as needed. If additional sources 

are present, they should be evaluated as described in Section 3.5.4 of this document, depending 

on the location of the positive distribution system samples and what areas of the distribution 

system are fed by which source. If treatment facilities are present, they should be evaluated as 

described in Section 3.5.3 of this document. Furthermore, the samples, sampling sites, sampling 

protocols and distribution system area should be evaluated as described in Sections 3.5.1 and 

3.5.2 of this document. 

3.6. What is the timeline for completing the Level 1 assessment?

The Level 1 assessment must be completed as soon as practical after the system learns 

that a trigger has been exceeded. The system must submit the completed assessment form to the 

state for review within 30 days after it has determined that a trigger had been exceeded. See 40 

CFR 141.859(b)(3). The 30-day timeframe allows for 

sufficient time for problem identification and 

potential remediation of the problem in conjunction 

with the follow-up assessment, in most cases. 

If the state determines that the assessment is 

insufficient, it must consult with the system. 

Assessments may be considered insufficient if they 

are not fully executed (e.g., the conditions at the well 

were not fully assessed) or if the assessment was 

incomplete (e.g., not all of the required elements were 

examined). If necessary after consultation, the system

must submit a revised assessment form to the state on an agreed-upon schedule not to exceed 30 

days from the date of the consultation. See 40 CFR 141.859(b)(3) and 141.859(d). 

For corrective actions not completed by the time of submission of the assessment 

form (e.g., in the case where parts need to be ordered and may take longer than 30 days to be 

delivered and installed), the system must complete the corrective action(s) in compliance with a 

schedule determined by the state in consultation with the system. To facilitate the discussion 

during the consultation, the system may propose a schedule for the corrective action(s). The 

system must notify the state when each scheduled corrective action is completed. See 40 CFR 

141.859(c) and 141.859(d). 

Systems must conduct the assessment as 

soon as practical after learning that they 

have triggered an assessment. The 

system has 30 days from the time it 

learns of the trigger to complete the 

assessment (and necessary corrective 

actions, if possible) and submit the 

assessment form to the State (with the 

timetable to complete any remaining 

necessary corrective actions).
RTCR ACAGM - Interim Final 4-1

4. Level 2 Assessments

4.1. What is a Level 2 assessment?

A Level 2 assessment7 is a more detailed examination of the system, its operational 

practices and its monitoring program and results. The elements of a Level 2 assessment are the 

same as those of a Level 1 assessment, but each element is investigated in greater detail

because the incidents that trigger a Level 2 assessment are of a more critical nature and are more 

likely to result in direct public health impact, as described in Section 4.2 below. A Level 2 

assessment will likely include field investigations, additional sampling and additional inspections 

of facilities beyond those performed in a Level 1 assessment. The level of effort and resources 

required to implement the Level 2 assessments will be commensurate with a more 

comprehensive investigation and a higher-level review of available information and it may 

involve the engagement of additional parties and 

expertise (40 CFR 141.859(b)(4)). 

A Level 2 assessment is triggered if sampling 

results in any one of the following scenarios (40 CFR 

141.859(a)(2)): 

1. An E. coli maximum contaminant level (MCL) violation; or

2. Triggering of a second Level 1 assessment within a rolling 12-month period, unless the

state has determined a likely cause for the situation that resulted in the initial Level 1

treatment technique trigger and establishes that the system has fully corrected the

problem; or

3. A system with approved reduced annual monitoring has a Level 1 treatment technique

trigger in each of two consecutive years.

7 A Level 2 assessment is defined at 40 CFR 141.2 as an “evaluation to identify the possible presence of sanitary defects, defects 

in distribution system coliform monitoring practices, and (when possible) the likely reason that the system triggered the 

assessment. A Level 2 assessment provides a more detailed examination of the system (including the system’s monitoring and 

operational practices) than does a Level 1 assessment through the use of more comprehensive investigation and review of 

available information, additional internal and external resources, and other relevant practices. It is conducted by an individual 

approved by the State, which may include the system operator. Minimum elements include review and identification of atypical 

events that could affect distributed water quality or indicate that distributed water quality was impaired; changes in distribution 

system maintenance and operation that could affect distributed water quality (including water storage); source and treatment 

considerations that bear on distributed water quality, where appropriate (e.g., whether a ground water system is disinfected); 

existing water quality monitoring data; and inadequacies in sample sites, sampling protocol, and sample processing. The system 

must conduct the assessment consistent with any State directives that tailor specific assessment elements with respect to the size 

and type of the system and the size, type, and characteristics of the distribution system. The system must comply with any 

expedited actions or additional actions required by the State in the case of an E. coli MCL violation.”

The system must ensure that a Level 

2 assessment is completed as soon 

as practical after it is triggered.
RTCR ACAGM - Interim Final 4-2

Conducting a Level 2 assessment is 

important to protecting public health. 

Failure to conduct it will result in a 

treatment technique violation that for some 

small systems will also trigger them to 

conduct more frequent monitoring.

4.2. Why do PWSs need to conduct a Level 2 assessment? 

As discussed in Section 3.2 of this document, the purpose of performing assessments, 

either a Level 1 or Level 2 assessment, is to enhance public health protection by identifying the 

presence of sanitary defects or to identify defects in the sampling practices (40 CFR 

141.859(b)(1)). In the case of a Level 2 assessment, it is even more important to conduct them, 

given that they are triggered by events that either (a) pose a potential immediate acute public 

health threat (i.e., trigger associated with the presence of E. coli) or (b) may pose a potential 

serious health impact because of the persistence of the contamination (i.e., a second Level 1 

trigger). EPA anticipates that Level 2 assessments following triggers associated with the 

presence of E. coli may be more involved than the Level 2 assessments following triggers in 

which there is no E. coli present, given the differing potential of public health concern. 

For systems eligible to monitor at a reduced 

frequency (i.e., less than monthly; see 40 CFR 

141.854 and 141.855), it is also important to conduct 

a Level 2 assessment within the specified timeframe 

(see Section 4.6 of this document regarding the 

timeframes associated with the Level 2 assessment) 

as failing to do so might result in the system being 

placed into more frequent monitoring. Also keep in 

mind that for a system’s monitoring frequency has been increased to monthly, the system needs 

to have a clean compliance history (i.e., no history of violations within the last 12 months) to be 

able to return to a reduced monitoring frequency. Failure to conduct a Level 2 assessment within 

the required timeframe and according to state requirements is a treatment technique violation, 

which disqualifies a system from having a clean compliance history. Also, keep in mind that a 

treatment technique violation under the RTCR has an accompanying requirement to notify the 

public. Appendix A of this document presents a summary of the RTCR requirements. 

4.3. Who is responsible for conducting a Level 2 assessment? 

Since a Level 2 assessment is triggered by a more significant event, a more 

comprehensive assessment is therefore needed compared to a Level 1 assessment. The level of 

effort and resources committed to undertaking a Level 2 assessment, relative to a Level 1 

assessment, will be commensurate with the more 

comprehensive investigation and review of available 

information and the engagement of additional parties 

and expertise. With a Level 2 assessment, the party 

conducting the assessment will likely conduct field 

investigations, additional sampling and additional inspections of facilities beyond those to be 

The Level 2 assessment must be 

conducted by a party approved by the 

state.
RTCR ACAGM - Interim Final 4-3

performed for a Level 1 assessment. For these reasons, a Level 2 assessment must be 

conducted by a party approved by the state due to the higher level of complexity (40 CFR 

141.859(b)(4)(i) and (ii)). The party conducting the assessment could be the state itself, a third 

party or, if approved, one of the staff or management of the system with the required certification 

or qualifications specified by the state. 

Examples of such approved parties may include: 

• State personnel,

• An operator certified by the state to operate a system of similar size, type and

complexity,

• Technical assistance provider such as a circuit rider,

• A supervisor or manager from the water system, supported by other experts or

employees of the system, and

• A consultant/consulting engineer.

The state will determine its criteria, policies and processes for approval of Level 2 

assessors and will determine which of the above parties are appropriate to conduct the 

assessment given the complexity of the system. Whoever conducts the assessment, whether the 

system or a third party, must follow the state requirements for conducting the Level 2 

assessment. Systems should be aware of who may be the appropriate assessors for their systems 

so that if the Level 2 assessment is ever triggered, the system does not lose time in identifying 

who will conduct this assessment. When a Level 2 assessment is triggered, the system should 

resolve uncertainties about the assessor by consulting with the state as soon as possible.

Qualities of a Level 2 assessor may include: 

• An understanding of the objectives and structure of the RTCR,

• An understanding of the nature of the coliform group and E. coli, including its

sources, control and public health significance,

• A familiarity with bacteriological sampling practices,

• A working knowledge in how to interpret distribution system water quality data,

• A working knowledge in how to interpret distribution system operational data,

• A working knowledge in how to interpret data regarding the source of supply,

• An understanding of disinfection practices and the potential implications of changes

in disinfection practices, and

• Familiarity with the water system treatment plant and distribution system.

In general, the assessor needs “working knowledge” to oversee all elements covered by 

the Level 2 assessment. The depth of the understanding and knowledge required will depend on 
RTCR ACAGM - Interim Final 4-4

the complexity of the system being assessed. For example, a small system with only a well, 

storage tank and limited distribution system will require a different level of expertise than a large 

metropolitan water system. While both have operational data, in one case the assessor may be 

interpreting information manually recorded from a pressure gauge while in the other case the 

assessor may need a working familiarity with SCADA.

It is important to recognize that in some cases, one individual may not have all the 

expertise and a team approach may be warranted. It is also worth noting that systems may gain 

value from having someone outside their system provide a “fresh set of eyes.” The state may 

wish to consider allowing certified operators with the appropriate qualifications to conduct Level 

2 assessments at other equivalent systems. 

Although, the Level 2 assessment must be performed by someone approved by the state, 

note that the system is ultimately responsible for making sure that the assessment is 

conducted properly and completely. In all likelihood, the system and the approved assessor 

will have to work closely together to compile and review all of the information relevant to the 

successful completion of the assessment at the water system.

4.4. How do PWSs document a Level 2 assessment? 

The Level 2 assessment must be documented using an assessment form, which 

systems must complete and submit to their states within 30 days after they have learned

that they have exceeded the trigger (40 CFR 

141.859(b)(4)). 

Appendix B of this document contains an 

Systems must submit a Level 2 assessment 

form to their states within 30 days after 

learning that they have exceeded a trigger. 

The assessment form must describe 

sanitary defects detected, corrective 

actions completed, and a proposed 

timetable for any corrective actions not 

completed. If no sanitary defects were 

identified, systems may also note in their 

form that no sanitary defects were 

identified (see Section 2.6 of this 

document). See 40 CFR 141.859(b)(4).

example of a Level 2 assessment form. The 

sample form is intended as a conceptual example to 

describe practical expectations for the level of 

resources committed to undertaking a Level 2 

assessment. States can use the example form 

presented in this document or develop their own 

forms. It is possible that states have different forms 

that are specific to different system types. Systems 

should contact their states to make sure that they 

are using the right form. 

The example assessment form is designed to cover the typical elements found within a 

PWS. For each element, the assessment form provides suggestions on items to evaluate that are 

related to the pathways and mechanisms for microbial contamination. Since an assessment is an 
RTCR ACAGM - Interim Final 4-5

examination of a particular PWS, it should therefore have different components for each system 

depending on the system’s source water, configuration and the number and type of distribution 

system facilities present. The form most likely cannot cover all possible situations or distribution 

system configurations. Systems should use professional judgment in the application of the form 

to their situation and provide additional information to support conclusions, if warranted. 

The state makes the final determination on the adequacy and completeness of 

information provided in the assessment (40 CFR 141.859(b)(4)). The state may request a 

consultation with the system if the state deems the assessment as inadequate or incomplete. The 

state may also direct the system to perform an expedited action or additional actions in cases 

with significant potential for public health impact, such as in the case of an E. coli MCL 

violation.8 For example, the state may direct the system to apply temporary disinfection while 

the assessment is ongoing and before the cause and source of the contamination is determined.

Systems should be familiar with the forms and required submittals so that they are 

prepared for an assessment in advance, should one be required. For example, systems may wish 

to create a standard operating procedure (SOP) for what to do when coliform results trigger an 

assessment. When developing the SOP, systems should verify with their states whether there is a 

specific version of the assessment form that needs to be used and understand which data 

source(s) can be used to fill out the various sections. 

4.5. How do PWSs conduct a Level 2 assessment? 

As with a Level 1 assessment, at a minimum, the Level 2 assessment must include review 

and identification of the following elements (40 CFR 141.859(b)(2)): 

• Atypical events that may have affected distributed water quality or indicate that

distributed water quality was impaired (see Section 4.5.2 of this document).

• Changes in distribution system maintenance and operation that may have affected or

are affecting distributed water quality including water storage (see Section 4.5.2 of

this document).

• An evaluation of source water quality and treatment changes or conditions that may

affect distributed water quality, where appropriate (see Sections 4.5.3 and 4.5.4 of

this document).

• Existing water quality monitoring data (see Section 4.5.2 of this document).

• Inadequacies in sample sites, sampling protocol and sample processing (see Section

4.5.1 of this document).

8 In the case of an E. coli MCL violation, the system is also required to issue a Tier 1 public notification (PN). For the 

requirements of a Tier 1 PN, see 40 CFR 141.202.
RTCR ACAGM - Interim Final 4-6

The Level 2 assessment form example found in Appendix B of this document lays out 

the elements of the system that need to be looked at during an assessment and gives an idea of 

the depth and level of detail that is expected of each assessment. States may also tailor specific 

assessment elements to the size and type of the system. Systems may tailor their assessment 

activities based on the specific characteristics of their distribution system, in accordance with 

state requirements. As stated previously, the form is provided as an example only. Systems

should contact their states to obtain the specific forms for their situation. 

The assessor should begin the assessment by 

evaluating the sample site itself. The assessor should 

review the sampling procedures, laboratory 

procedures and conditions of the sampling tap and 

note any errors and unsanitary conditions. The area 

immediately surrounding the positive sample site(s) 

should be evaluated next. Historical water quality 

data should be examined along with a list of events 

that may have occurred in the vicinity of the positive 

sample sites to determine a possible cause for a loss 

of distribution system integrity. The assessment of 

the distribution system area could include additional 

sampling to try to identify the extent of the contamination, being sure to consider that the 

contamination may have migrated within the system. Next, the assessor should evaluate the 

impact of treatment plant issues or other system-wide events based on historical performance 

data, environmental factors, operational activities and other external events. Customer complaint 

data, main break reports and other system data may be helpful in the assessment of system-wide 

events that could have contributed to degraded water quality. Finally, the assessor should 

evaluate changes in the source water, along with weather events or other occurrences that could 

influence source water quality.

In general, in performing a Level 2 

assessment PWSs should follow a 

progression starting with the (1) location 

of the initial coliform positive samples and 

working through the (2) distribution 

system to the (3) treatment plant and (4) 

source. See Figure 4-1 below.

Depending on the system’s configuration, 

not all these components may be present.
RTCR ACAGM - Interim Final 4-7

Figure 4-1: General Progression of Conducting a Level 2 Assessment

Location of 

the Positive 

Sample

• Samples, sampling sites, sampling procedure

Distribution 

Area Near 

Positive 

Sample(s)

•Review operational data and water quality data

•Review operational activities and unusual activities

• Assess distribution system components (e.g., pipes, valves, pumps, etc.)

• Assess storage facilities

Treatment 

Facilities

• Assess treatment facility closest to the location of the positive sample

Source Water

• Assess wells, springs or surface water

The subsequent sections go into detail on how the different parts of the system should be 

assessed using the progression outlined above. 

Even though both the Level 1 and Level 2 assessments look at the same elements, the 

Level 2 assessment will require a more comprehensive investigation and the engagement of 

additional parties and expertise compared to a Level 1 assessment as discussed in Section 4.3 of 

this document. Table 4-1 presents examples of possible differences in the level of effort between 

a Level 1 and Level 2 assessment.
Table 4-1: Examples of Possible Differences in the Level of Effort Between 

a Level 1 and a Level 2 Assessment

Level 1 Effort Level 2 Effort

• Review all monitoring results from appropriate

areas of the distribution system for the previous

12 months

• Review all monitoring results from appropriate

areas of the distribution system for the previous

12 months

• Conduct additional investigatory monitoring

• Review cross connection control records for • Review cross connection control records for

medium- and high-risk facilities in the area of

the positive samples

•

medium- and high-risk facilities in the area of

the positive samples

Inspect backflow prevention devices in the

medium- and high-risk facilities in the area of

the positive samples

• Review records of storage tank inspections •

•

Review records of storage tank inspections

Inspect storage tanks that feed the area of the 

positive samples

• Review records of inspections of wells and

surface water source and weather events

• Review records of inspections of wells and

surface water source and weather events

• Inspect wells and surface water sources

• Interview sample collectors, distribution system

managers, other appropriate employees

•

•

•

Interview sample collectors, distribution system 

managers, other appropriate employees

Consult with outside experts, professional 

engineers

Interview residents and businesses in the area of 

the positive samples 

• Review records of entry point and distribution

system disinfectant levels

•

•

Review records of entry point and distribution 

system disinfectant levels, including historical 

seasonal changes if any

Conduct additional residual testing at the entry 

point and appropriate locations in the 

distribution system

• Review records of distribution system

maintenance, especially in the area of the

positive samples

•

•

Review records of distribution system 

maintenance, especially in the area of the 

positive samples

Inspect on-going maintenance activities

• Notify the state of results 

state as needed

and discuss with the •

•

Consult with the state about assessment plans 

and approach, especially if the assessment is 

triggered by detection of E. coli.

Notify the state of results and discuss with the 

state 

RTCR ACAGM - Interim Final 4-8
Level 1 Effort Level 2 Effort

• Conduct on-site inspections as indicated by • Conduct on-site inspections as indicated above

record reviews and interviews above

In a Level 2 assessment, the conditions that could have occurred prior to the total 

coliform-positive sample(s), as well as the current condition of water system facilities and 

system operation and maintenance, should be examined in detail, and the assessor should 

conduct a physical inspection of suspected facilities. During this examination, the assessor 

should note any atypical conditions, even if those conditions do not appear to definitively 

correlate with the total coliform- or E. coli-positive samples, and should review past Level 1 and 

Level 2 assessments and sanitary survey results. 

The assessor should also consult with others involved in operation or management of the 

system to gather additional observations and insight as to possible causes for the trigger. This 

consultation would also help to identify whether there are multiple causes for the trigger and/or 

sources of contamination. Gathering information on all elements would also be useful in setting a 

baseline if another assessment is triggered in the future. This baseline information provides a 

good indication of where additional follow-up may be needed.

The Level 2 assessment should be conducted thoroughly to capture the possibility 

that there may be multiple causes for the coliform positive samples. Level 2 assessments 

should be conducted as quickly as possible after the system learns that it has triggered a Level 2 

assessment (e.g., soon after notification of E. coli positive sample results). The assessor should 

go over and complete the entire assessment form, even if the apparent cause of the contamination 

has been identified and is understood, to ensure that he/she has a complete picture of the overall 

integrity of the system and does not inadvertently overlook a potential sanitary defect. 

Once an assessment has been triggered, system personnel may become very busy 

performing the investigation, answering questions and responding to the public. Therefore, 

systems should prepare for a possible assessment by developing some standard datasets 

based on operational data for items such as disinfectant residuals, treatment process 

variables and field sampling results. Much of this data can typically be found in monthly 

operating reports and other summaries that are submitted to the state. These datasets should be 

continuously updated so that they are ready to be used immediately upon triggering an 

assessment. For further discussion on operational data, see Section 4.5.2.1 of this document. 

RTCR ACAGM - Interim Final 4-9
RTCR ACAGM - Interim Final 4-10

4.5.1. Assessing samples, sampling sites and sampling protocols

This section of the assessment is designed to determine whether water samples could 

have been contaminated during the sample collection or processing, resulting in total coliformor E. coli-positive samples. In that case, the positive results may not indicate a distribution 

system problem but rather a sampling problem. Several references are available to provide 

detailed guidance on sampling (AWWA 2008; APHA et al. 2005; USEPA 2001a; USEPA 

2006c; USEPA 2006d). 

The evaluation of the sample site(s) with the 

positive sample(s) and the sampling protocol would 

be performed in a similar manner for systems of all 

sizes and types. The sample site(s) is/are a key 

indicator of whether the problem is system-wide or 

localized. This part of the assessment should include a 

field visit to inspect the sample location(s) or a 

detailed discussion with the sample collector to determine the conditions at the sample site(s).

Some of the common items the assessor should evaluate at the sample site(s) include: 

• Cleanliness and suitability of the sample tap and sink,

• Potential for hot water to enter the sample through the tap, and

• Conditions that may have changed at the sample site since the last sample collection,

such as new uses for the sink as janitorial cleanup area, dirt accumulation near the

faucet or installation of a point-of-use device on the faucet.

In addition to sample tap contamination, it is possible that elements of the sampling 

protocol that were not followed closely could result in contamination of the sample. Elements of 

the sampling protocol that systems should follow may include:

• Removal of the tap aerator,

• Adequate flushing of the tap prior to sample collection,

• Proper storage and preparation of the sampling container,

• Correct sample collection technique, including items such as elimination of splashing

water from sink and the sampler touching the inside of the sample bottle,

• Correct storage, preservation and handling of sample(s) during transport to

laboratory, including items such as cleanliness of coolers and use of watertight bottles

during transport (to prevent leakage), and

• Compliance with holding time and temperature requirements, including items such as

maintenance of ice packs.

Systems should be careful not to jump to 

the conclusion that the sampling process 

caused the coliform detection before the 

other elements have also been assessed 

and ruled out as a possible source of 

contamination.
RTCR ACAGM - Interim Final 4-11

Finally, this evaluation should include a discussion with the laboratory to determine if all 

laboratory quality checks were performed with satisfactory results. 

4.5.2. Assessing the distribution system area near the positive samples

Once the evaluation of the sample site(s) has been completed, the assessor should 

proceed to evaluate the area of the distribution system near the positive samples. This part of the 

assessment is designed to help determine if there is a sanitary defect causing the contamination, 

understand the potential movement of contamination and proactively prevent future coliform 

positive samples. 

A Level 2 assessment of the distribution system should include the collection and review 

of available data. The data to be reviewed should include operational data (e.g., pressures, 

flows), water quality (e.g., pH, turbidity, etc.) and information on the physical condition of 

distribution system components (see Sections 4.5.2.1 to 4.5.2.5 of this document). A Level 2 

assessment would warrant a detailed investigation of the components, particularly those near a 

cluster of positive sample locations. This detailed investigation would warrant site visits and 

possibly hiring expert assistance for inspections, particularly for storage tanks that might require 

specialty equipment and confined space entry safety measures. The Level 2 assessment form (see 

an example form in Appendix B of this document) provides a list of questions that should be 

answered as part of a Level 2 assessment. The questions in the form provide an indication of the 

level of detail that should be included for each component evaluation. 

The area of the distribution system that the assessor should evaluate depends on the

system configuration along with the extent of coliform positive samples. Smaller systems

will likely have fewer distribution system components and therefore a lesser level of effort in 

completing the assessment. For larger systems, the assessor may focus the evaluation on areas of 

the system that have been shown to be more greatly affected, particularly if the data review 

confirms that the spread of contamination has been limited. 

4.5.2.1. Operational data

The operational data review should include collection, compilation and analysis of the 

system data from a variety of sources to get a more complete understanding of the system 

conditions and events that may have occurred prior to triggering an assessment. The data 

collected should include recent data as well as historical trends to provide a basis for comparison 

to determine if atypical events such as main breaks or system component failures have occurred. 
RTCR ACAGM - Interim Final 4-12

The operational data elements should be reviewed during all Level 2 assessments, 

although the available data and accessibility of electronic data may vary by water system size 

and type. 

Larger systems may have electronic databases from which to extract pertinent 

information including: 

• Distribution system and treatment plant process data from SCADA systems for

pumping, storage and pressure data,

• Water quality measurements from LIMS or external laboratory reporting systems,

• Customer complaint and water usage data from CSIS,

• Data on operations and repairs in the distribution system from MMIS,

• Recent and historical information from main break databases,

• Pipe material and condition information from asset management databases,

• Hydrant testing and fire-fighting from fire department information, and

• Activities performed from operations logs.

For smaller systems, much of the data sources listed above may not be electronic and 

would thus involve additional effort by the system to compile the data as part of the assessment. 

EPA therefore encourages these types of systems to maintain records of the above-mentioned 

data elements to help the assessor quickly conduct an assessment, should they be triggered to do 

one. 

The operational data review can provide an indication of the elements of the assessment 

on which to focus efforts. For example, if the SCADA data indicates some low-pressure readings 

in a particular area of the distribution system, follow-up investigations could focus on that area. 

However, the assessor should not ignore other areas of the distribution system, as microbial 

contamination can be a result of multiple causes.

Tables and graphs summarizing the data and findings could be helpful supplemental 

items to prepare and submit to the state, if systems are asked or required to do so. Although 

systems, under the federal regulations, are not required to submit the collected data and 

supplemental analysis with the assessment form, EPA recommends that these items be kept on 

file for future reference in case another assessment is triggered. States may also require the 

system to submit such data and analysis or may want to look at this information during their 

review of the assessment forms or during a sanitary survey. 
4.5.2.2. Water quality data

As part of any assessment, water quality data should be compiled and evaluated. This 

data would include parameters collected in the distribution system and at the source or treatment 

plant (discussed further in Section 4.5.3 of this document). The parameters to be evaluated will 

likely vary by system type, treatment process used and other operational practices but may 

include the items outlined in Table 4-2. Systems that do not currently collect water quality data 

at one of the locations suggested in Table 4-2, might consider doing so in order to create a 

baseline for comparison should another assessment be triggered in the future. 

The assessor may find it appropriate to collect special purpose samples of total coliforms 

(and potential subsequent E. coli) analysis and monitor additional water quality parameters such 

as disinfectant residual. An example of a special purpose sample is one taken to determine 

whether disinfection practices are sufficient following pipe placement, replacement or repair. 

Records of any special purpose samples taken should be kept for comparison should another 

assessment be triggered in the future. Take note that special purpose samples, such as those 

taken during an assessment, must not be counted towards compliance (i.e., they should not be 

included in determining whether an assessment has been triggered). 

Table 4-2: Typical Water Quality Data to Be Evaluated During an Assessment

Water Quality Parameter Location of Sample Collection 

Disinfectant residual concentration Throughout the distribution system, including total 

coliform sampling sites

At storage tanks throughout the distribution system

At the entrance to the distribution system at each 

source 

DBPs At approved monitoring locations 

system

in the distribution 

Total coliforms and E. coli

All distribution system sampling sites, including those 

for repeat, additional routine and special purpose 

samples (like those associated with recent main 

installation or repair)

Entrance to the distribution system at each source

HPC All distribution 

coliforms

system sampling sites for total 

Nitrite and nitrate (systems using 

chloramine) Distribution system sites with low disinfectant residual 

Once the water quality and operational data have been collected, they should be analyzed 

to determine if any atypical events or measured values have occurred. Depending on the data that 

RTCR ACAGM - Interim Final 4-13
RTCR ACAGM - Interim Final 4-14

are available, there may be several ways to examine the data. One good method is to develop a 

historical trend for monitoring results and individual parameters at each sampling location. 

Spreadsheet and graphing software can be helpful in developing and reviewing historic trends. 

The historical time series can be evaluated visually to determine if there are differences between 

current results (under assessment) and historical trends. 

Figure 4-2 provides an example of a historical time series graph of total chlorine 

measurements from distribution system samples using Microsoft Excel software. The average 

total chlorine concentration for each month is plotted for multiple years. This type of graph can 

help to identify if measured values are within normal ranges or might represent an atypical 

condition within the distribution system. Similar graphs could be constructed for minimum and 

maximum residual disinfectant measurements, total coliform-positive samples and related water 

quality sampling data.

Figure 4-2: Example Time Series Graph for Distribution System Chlorine Results
RTCR ACAGM - Interim Final 4-15

A spatial analysis of data can also help to identify problem areas. Mapping of water 

quality results can be done using a paper map or GIS software (see example in Figure 4-3). The

correlation between different water quality variables (e.g., disinfectant residual and total 

coliforms) can be more apparent when the data is viewed in a spatial analysis. The results of a 

spatial data analysis can be used to focus the Level 2 assessment activities on the appropriate 

areas and components of the distribution system. 
RTCR ACAGM - Interim Final 4-16

Figure 4-3: Example of Spatial Analysis of Disinfectant Residual and Customer 

Complaint Data
RTCR ACAGM - Interim Final 4-17

Consideration of flow pathways or use of a hydraulic model can also help determine if 

a specific activity could be related to the coliform-positive samples at a given location. This type 

of analysis can be useful in finding the source of contamination, particularly if several positive 

samples fall within the influence zone of a specific distribution system pump station or tank. In 

this instance, the assessor can focus attention on specific locations at the distribution system in 

determining the cause of the positive samples. However, as mentioned previously, other areas of 

the distribution system should not be ignored, because the contamination can be a result of 

multiple causes.

The assessor might also want to review and consider supplemental data sources beyond 

water quality measurements in the assessment. For example, customer complaints might show an 

increase in a particular area of the distribution system that could be correlated to distribution 

system problems as shown in Figure 4-3 where the correlation between the level of disinfectant 

residual and the location of customer complaints are plotted. 

4.5.2.3. Operational activities and unusual events

Along with water quality measurements, it is important to understand the extent of 

activities occurring in the water system that may have resulted in total coliform-positive samples. 

Compilation of operational activity data may require the assessor to consult with different 

departments within the water system and with external agencies. The types of activities and 

events to compile and review would include those that might result in distribution system 

contamination, including: 

• Pipe breaks and associated repairs,

• Events resulting in a loss of pressure (e.g., power failures),

• Flushing and hydrant testing,

• Construction activity that impacts water pipes,

• Unusually high (or low) demands that might alter typical flow patterns, including

temporary connections for construction and firefighting,

• Break-ins and vandalism at system facilities,

• Treatment process upsets,

• Weather events, and

• Source water changes.

Once a list of distribution system activities and events has been compiled, the assessor 

can compare this list to historical records to determine if any activities or events could have led 

to the distribution system contamination. Any suspect operational activities or events should be 

further investigated and documented on the assessment form. 
RTCR ACAGM - Interim Final 4-18

Public health officials also track reported illnesses, doctor visits and purchase of overthe-counter medicines. These public health data sources might be helpful to the assessor in 

understanding the potential source and extent of contamination. Systems should work to develop 

relationships with their local public health officials so that if an assessment needs to be 

conducted, health information can be more readily accessible. 

Appendix C of this document includes an example of an assessment where the suspected 

cause of the contamination was inadequate chlorination of an in-line conditioner after repair 

work was done on the pump and the plumbing around it. The in-line conditioner was chlorinated 

afterwards and put back into service.

4.5.2.4. Assessing distribution system components

The objective of this evaluation is to help determine if a particular distribution system 

component has a sanitary defect that would require correction or if distribution system events 

could have contributed to the positive coliform samples. From the operational data review, the 

assessor should have compiled data to indicate what activities had been occurring in the 

distribution system near the location of the total coliform-positive samples, including operational 

changes, maintenance and atypical events. Under this step of the assessment, the assessor might 

ask that the system obtain further detail for any location or event that might be significant. The 

system could collect additional data to help define the extent of the contamination and to 

determine whether the contamination has spread. 

The assessor should focus first on the area of the distribution system closest to the 

positive coliform samples. Operator knowledge or the results of a flow path analysis or hydraulic 

model can be used to determine the area(s) likely to be associated with a given sample site. For 

example, if the positive sample is located within a defined pressure zone, the entry point to the 

zone and related facilities in the immediate area should be assessed first before continuing the 

assessment in other areas of the distribution system, progressing from closer areas to areas 

farther from the positive coliform samples. 

The assessor should evaluate distribution system facilities to determine whether the

infrastructure and equipment are operational and in good repair. The evaluation should include 

elements such as those presented in Table 4-3. The items in Table 4-3 are not intended to be an 

exhaustive or binding list but rather a summary of typical distribution system components to help 

focus the assessment on the existing water system configuration. Depending on the system 

configuration, not all elements would be present in all systems. 

A Level 2 assessment of water system components should include a review of data and 

information that indicates the latest observed condition of the component, its condition at its last 
inspection date, observations from recent visits by operations staff and other related data such as 

disinfectant residual that might assist in focusing the assessment efforts. This would include any 

previously noted sanitary defects or significant deficiencies and records on how these were 

addressed. An on-site inspection of the component by the assessor should be completed to verify 

its current condition. 

Table 4-3: Typical Items to Evaluate in Distribution System Assessment

Component Typical Items to Evaluate

Pump stations Proper operation of pumps and valves 

Recent losses of power

Recent losses of pressure

Proper operation of surge control appurtenances 

Distribution system pressure Maintenance of adequate pressure

Air-relief / Air-vacuum valves Proper operation of valves 

Valve vault free of standing water and debris 

Fire hydrants Proper operation of shut-off valves

Leaks at connection to lateral piping

Flushing assemblies / Blow-offs Proper operation of valves 

Leaks at connection to piping 

Pipes Recent main breaks

Recent leaks

Recent installation of new mains or construction activity

Distribution system isolation Recent operation resulting in breakage valves

4.5.2.5. Assessing storage facilities

Storage facilities, or tanks, have been linked to microbial contamination events and 

therefore are an important component to assess when responding to positive coliform samples

(Clark et al. 1996). Microbial contamination can enter storage facilities either through system 

water or external tank breaches. If contamination is introduced through system water (i.e., 

transported to the storage facility from a different contamination site), microbes can remain 

viable and possibly multiply within the tank water and sediments. 

Table 4-4 outlines some of the typical storage facility items that should be evaluated 

during an assessment. The items in Table 4-4 are not intended to be an exhaustive or binding list 

but rather a summary of typical storage facility components to help focus the assessment on the 

existing water system configuration. Depending on system configuration, not all items would be 

present in all systems.

RTCR ACAGM - Interim Final 4-19
The assessment should initially focus on the storage facilities that supply the area near the 

total coliform-positive samples, with evaluation of other more remote facilities as a next step. 

Review of recent tank inspection reports, operator interviews and examination of historical 

disinfectant residual data for the tank and its vicinity may also provide the assessor with valuable 

information for the assessment. The assessor might ask the system to collect additional samples

for residual and/or total coliform analysis or suggest a more complete inspection of the storage 

facility by a qualified party such as a professional cleaning and inspection company. 

 For systems with hydropneumatic tanks and/or bladder tanks, these tanks should be 

maintained and inspected according to manufacturer recommendations. A Level 2 assessment 

should include review and inspection of maintenance records for these types of tanks. 

Table 4-4: Typical Items to Evaluate at Storage Facilities

Storage Tank Element Typical Items to Evaluate

Access hatches Signs of vandalism or forced entry 

Ability of hatch to seal tightly when closed

Rust, holes or other breaches 

Vents Signs of vandalism or forced entry 

Absence of screen; holes or other breaches in 

screens

Rust, holes or other breaches in vent piping and 

penetration through tank wall 

Rust, holes or other breaches in piping and Overflow piping penetration through tank wall 

Absence of screen; holes or other breaches in 

screens

Correct operation of level control valves, altitude Control valves valves and related appurtenances

Tank exterior Signs of deterioration, rust or other breaches 

Tank interior Integrity of lining material

Presence and extent of floating material and 

sediment within tank; existence of microbes within 

sediment

Presence of dead animals

Level of disinfectant in tank, ideally at different 

Disinfectant residual tank levels

RTCR ACAGM - Interim Final 4-20
RTCR ACAGM - Interim Final 4-21

4.5.3. Assessing the treatment facilities

For a PWS operating a treatment plant, even if the only treatment is a chlorinator at a 

well, assessment of the proper operation of the treatment process is important to determine if a 

plant upset could be the source of the microbial contamination resulting in positive coliform

samples. For most treatment facilities, regulatory data collected for compliance with related 

treatment requirements (e.g., SWTR, GWR) should be available. A review of this data may 

indicate a potential treatment plant problem that could have allowed microbial contaminants to 

enter the distribution system. 

As part of a Level 2 assessment, the assessor should review the treatment process data. 

When reviewing the treatment data, he/she should pay particular attention to disinfection 

processes and turbidity removal, as these processes are responsible for the majority of microbial 

inactivation (Letterman et al. 1999). For disinfection processes, the disinfectant feed systems and 

resulting disinfectant concentration should be evaluated to ensure that proper dosing has taken 

place and desired residuals are maintained. For turbidity removal, the coagulation/sedimentation 

and filtration processes should be evaluated to ensure that microbial contaminants could not have 

entered the distribution system along with a spike in turbidity. Power outages and other events 

that disrupt normal operations should also be considered if review of operational data shows that 

they have occurred. 

Table 4-5 provides an overview of the types of data elements that should be reviewed as 

part of a Level 2 assessment. The items in Table 4-5 are not intended to be an exhaustive or 

binding list but rather a summary of typical treatment facility components to help assessors think 

about the system configuration. Depending on system configuration, not all elements would be 

present in all systems.
Table 4-5: Typical Treatment Facility Elements to Evaluate

Treatment Facility 

Element Typical Items to Evaluate

Equipment 

(pumps, mixing units, 

settling units, pipes, 

valves, chemical feed 

units, filters) 

Status of equipment – operational and maintained in accordance with the 

treatment plant Operation and Maintenance procedures 

Recent installations or repairs

Treatment Process

Introduction of new sources or changes in the source water

Recent changes in the treatment process

Interruptions in treatment – lapses in chemical feed or proper mixing 

Turbidity measurements at all appropriate locations in the treatment 

(source, settled water, pre- and post-filtration, finished water, etc.) 

process 

Disinfectant residual measurements and C x T (concentration x time) calculations

Flow rates at each plant process

4.5.4. Assessing the source water

To wrap up a Level 2 assessment that began with the sample site and worked backward 

through the distribution system to the treatment plant, the final component for evaluation would 

be the source water. The source water can include wells, springs and surface water bodies (see 

Sections 4.5.4.1 to 4.5.4.3 of this document). Changes in source water, extreme weather events 

and introduction of new sources can all be possible causes of microbial contamination. The 

source water should be evaluated using historical data and system records to determine if the 

source water has contributed to the coliform positive samples. For a Level 2 assessment, site 

visits and additional source water monitoring would likely be appropriate. 

4.5.4.1. Wells

For systems served by a well (or wells), the assessment should verify the integrity of the 

well and proper operation of the well system to ensure that contamination could not have entered 

the distribution system from the well. The assessor should pay particular attention to potential 

pathways that would allow the entrance of surface water, soil, animals or other foreign matter 

into the well. The well should also be constructed to prevent the accumulation of surface water 

around the wellhead and prevent inundation during periods of flooding or increased runoff. Well 

inspection records and operation and maintenance records should be reviewed and weather 

RTCR ACAGM - Interim Final 4-22
events should be considered if runoff could have affected the well. Table 4-6 outlines some 

typical items to evaluate for wells. The items in Table 4-6 are not intended to be an exhaustive 

or binding list but rather a summary of typical well components to help systems and the assessor

think about the system configuration. Some elements may not be present depending on the 

design/configuration of the well and the type of pump in the well.

Table 4-6: Typical Items to Evaluate at Wells

Well Element Typical Items to Evaluate

Well house / enclosure Signs of vandalism or forced entry 

Unsanitary conditions like the presence of rodents or other animals 

Well cap / Well seal Tightness of well cap and seals, presence of gaps or openings

Well vent Vent properly screened, 

height above ground 

angled to be self-draining and has sufficient 

Well casing Holes, breaks, corrosion or deformation in casing and welds

Annular grout seal Missing, sunken, bridged or channeled grout surrounding the well 

casing

Pump and pump assembly Attached to casing with no unprotected openings and has watertight 

seal

Pitless adapter Integrity of pitless adapter connection

Inundation Signs of inundation by floodwater or 

wellhead

runoff; depressions around 

Appendix C of this document provides an example of an assessment where well 

contamination was the likely cause of positive coliform samples. In this case, the well was found 

to have unsanitary conditions, possibly due to recent flooding and a corroded casing. 

4.5.4.2. Springs

For systems served by a spring (or springs), the assessment should verify the sanitary 

condition and proper operation of the spring and associated piping. Typical items the assessor 

should evaluate for a spring source include: 

• Condition of the spring development,

• Impacts from surface water runoff and weather conditions,

• The physical condition of the spring box,

• Impacts from vandalism or forced entry to determine if holes or other breaches

could have occurred that would allow for the introduction of microbial

contaminants,

RTCR ACAGM - Interim Final 4-23
RTCR ACAGM - Interim Final 4-24

• Signs of inundation, including deposits of soil or soil erosion, and

• Signs of small animals, slugs, bugs, etc., in the spring box.

4.5.4.3. Surface water 

Surface water sources can be impacted by extreme weather events that can influence the 

influent water quality to the treatment plant. Atypical events may impede the ability of the 

treatment process to perform as desired and may allow for the introduction of microbial 

contaminants into the distribution system. Heavy rainfall and rapid snowmelt can carry large soil 

loads into surface water sources, thereby increasing turbidity and baseline microbial contaminant 

concentrations. Similarly, flooding can alter the raw water quality and require treatment changes 

to achieve good finished water quality. 

For systems that have multiple surface water sources, a change from one source to another 

could trigger a treatment upset that might result in microbial contamination entering the 

distribution system. In performing the Level 2 assessment, systems should obtain source water 

data and review it with the assessor to determine if atypical surface water quality could have 

impacted the treatment process.

4.5.5. Additional considerations

EPA recognizes that the process of conducting a Level 2 assessment presented in the 

preceding sections may not necessarily apply to all types of systems. Because of the complexity 

and the diversity of the different configurations of PWSs, a one-size-fits-all approach will not be 

appropriate for all systems. Larger systems will more than likely have all the elements mentioned 

in the preceding sections while smaller systems may only have some of them. For example, some 

small ground water systems may only have a well, provide no treatment and have a limited 

distribution system consisting only of premise plumbing. The process of performing a Level 2

assessment will therefore vary from system to system. This section presents additional 

considerations systems may want to incorporate in their assessment protocol depending on their 

system type.

4.5.5.1. Systems with limited or no distribution system

For small systems, it might be the case that they do not have any treatment process or an 

extensive distribution system. In this case, the Level 2 assessment will only focus on those 

elements that are present in the system such as the source water (e.g., wells) and the limited 

distribution system.
RTCR ACAGM - Interim Final 4-25

For NCWSs that have their own source water and do not supply water beyond their 

premises (typical examples are schools and churches), then an assessment of the pipes inside the 

building (what is typically considered premise plumbing) is required. Typically in a CWS, 

premise plumbing is beyond the control of the PWS. However, in the case of NCWSs, the 

premise plumbing may be part of the system and if so, must also be included as part of the 

assessment. One thing the assessor will look for is the presence of cross connections. The 

majority of backflow events resulting from unprotected cross connection occur in premise 

plumbing (USEPA 2001b). 

In cases where the results of total coliform monitoring also triggered the GWR 

requirements in addition to triggering an assessment under the RTCR, it might be possible to 

combine the assessments required under both rules into one assessment, as long as the combined 

assessment complies with the requirements of both rules. Systems should check with their states 

before performing such assessment. See also Chapter 6 of this document regarding the overlap 

between an assessment under the RTCR and a sanitary survey.

4.5.5.2. Large systems

Large systems may want to determine whether the contamination is widespread or 

localized in the distribution system. If the total coliform-positive samples that triggered the 

assessment are clustered in one part of the system, the assessment could be targeted to specific 

sections of the distribution system or facilities if appropriate. It may not be practical or necessary 

to conduct an assessment of the entire distribution system. Looking at historical data may also 

help determine if the problem is episodic or chronic. Knowing so would help determine the type 

of corrective action to take to address the problem. 

4.5.5.3. Wholesale and consecutive systems

For PWSs that purchase water from another system, also known as consecutive systems, 

the source water can be considered to be the connection(s) from the wholesale (seller) system. 

During a Level 2 assessment, a review of the records related to the connection (e.g., flows, 

pressures, water quality parameters if measured) should be performed. 

It is also recommended that the consecutive PWS contact the wholesale system to 

coordinate assessment efforts. The possibility exists that a contamination event occurred in the 

wholesale system upstream of the connection and that the contamination has migrated to the 

consecutive system. While the wholesale system would not be required to perform a Level 2 

assessment in this case (unless it also exceeded the trigger level), it may be required to conduct 

source water monitoring under the GWR and may want to voluntarily investigate its system 

along with the assessment being performed on the consecutive system. Water quality data from 
RTCR ACAGM - Interim Final 4-26

the wholesale system at or near the connection point for the consecutive system may also prove 

to be valuable in the Level 2 assessment.

Similarly, if a wholesale system experiences a total coliform trigger, it should notify its 

consecutive system(s) if the contamination could have spread to the consecutive system area. 

Additional samples and data from the consecutive system may help define the extent of 

contamination in the wholesale system and identify potential problems and sanitary defects. 

Consecutive systems may or may not have additional sources and treatment facilities, 

such as their own wells with treatment or booster chlorination of purchased water. These 

complicating factors should be considered during the assessment as needed. If additional sources 

are present, they should be evaluated as described in Section 4.5.4 of this document, depending 

on the location of the positive distribution system samples and what areas of the distribution 

system are fed by which source. If treatment facilities are present, they should be evaluated as 

described in Section 4.5.3 of this document. Furthermore, the samples, sampling sites, sampling 

protocols and distribution system area should be evaluated as described in Sections 4.5.1 and 

4.5.2 of this document. 

4.6. What is the timeline for completing the Level 2 assessment?

A Level 2 assessment must be completed as soon as practical after the determination that 

a trigger has been exceeded. Systems must then submit the completed assessment form to their 

states for review within 30 days after learning that 

they trigger an assessment. See 40 CFR 

141.859(b)(4). The 30-day timeframe allows for 

sufficient time for problem identification and 

potential remediation of the problem in conjunction 

with the follow-up assessment, in most cases. 

If the state determines that the assessment is 

insufficient, the state must consult with the system. 

Assessments may be considered insufficient if they 

are not fully executed (e.g., the conditions at the 

well were not fully assessed) or if the assessment 

was incomplete (e.g., not all of the required elements were examined). If necessary after 

consultation, the system must submit a revised assessment form to the state on an agreed-upon 

schedule not to exceed 30 days from the date of the consultation. See 40 CFR 141.859(b)(4) and 

141.859(d). 

Systems must conduct the assessment as 

soon as practical after learning that they 

have triggered an assessment. They have 

30 days from the time they triggered the 

assessment to complete the assessment 

(and necessary corrective actions, if 

possible) and submit the assessment form 

to the state (with the timetable to 

complete any remaining necessary 

corrective actions not completed when the 

assessment form is submitted).
RTCR ACAGM - Interim Final 4-27

For corrective actions not completed by the time of submission of the assessment 

form (e.g., in the case where parts need to be ordered and may take longer than 30 days to be 

delivered and installed), the system must complete the corrective action(s) in compliance with a 

schedule determined by the state in consultation with the system. To facilitate the discussion 

during the consultation, the system may propose a schedule for the corrective action(s). The 

system must notify the state when each scheduled corrective action is completed. See 40 CFR 

141.859(c) and 141.859(d). 
RTCR ACAGM - Interim Final 5-1

5. Corrective Action

5.1. What is the RTCR’s requirement regarding corrective action? 

A corrective action is required when a PWS has triggered a Level 1 or Level 2 

assessment because of total coliform and/or E. coli positive samples AND that assessment has 

identified a sanitary defect that could have caused the contamination (40 CFR 141.859(c)). It is 

also possible that no sanitary defect will be identified during a Level 1 or Level 2 assessment and 

if so, no corrective action will be required (see 

Section 2.6 of this document in instances where no 

sanitary defect is identified) (40 CFR 141.859(b)(3)(i) 

and 141.859(b)(4)(i)). However, the state may 

recommend or require that the system take some sort 

of action (e.g., temporary disinfection) to make sure that the contamination is addressed even in 

the absence of an identified sanitary defect. See Section 5.3 of this document for some of the 

best practices systems can take following a coliform detection or an assessment trigger. 

The PWS should also consult with the state as necessary to complete corrective actions 

that the state will consider to be sufficient. The state may also initiate this consultation. This 

consultation should begin with the Level 1 or Level 2 assessment, which should outline the 

investigation that the system performed or will perform and the proposed actions to correct the 

problems that were identified. The system must submit a Level 1 or Level 2 assessment form to 

the state within 30 days after learning that it exceeded the trigger. The form must describe the 

sanitary defects detected (if any), the corrective actions completed and a proposed timetable for 

completing the corrective actions not already completed. A consultation with the state as early as 

possible in the assessment and corrective action phase will allow the system and the state to 

discuss all relevant information and appropriate timeframes to meet the rule requirements. See 40 

CFR 141.859(d). 

5.2. What corrective actions can PWSs take?

The type of corrective action that a system performs will depend on the cause of the 

contamination that it identified that resulted in a trigger for a Level 1 or Level 2 assessment. 

Total coliform and E. coli positive samples can result from a variety of causes. Once the 

system has identified those causes through the assessment process, the system will need to make 

corrective actions to restore the integrity of the distribution system. 

PWSs are required to correct any 

sanitary defect found during an 

assessment.
RTCR ACAGM - Interim Final 5-2

Discussions and informal surveys with states and systems9 have identified the following 

as some of the common causes of total coliforms and E. coli detections in the distribution 

system, a number of which are interrelated: 

• Failure to disinfect (or improper disinfection) after maintenance work on the

distribution system,

• Main breaks, especially in certain vulnerable locations such as under a stream or high

groundwater level,

• Holes in storage tank, inadequate screening and other defects which could allow

animals and/or fecal matter to enter the tank,

• Loss of system pressure (sometimes associated with main breaks or loss of power),

• Lack of regular flushing programs,

• Biofilm build-up in the distribution system, including biofilms at multiple locations or

that move throughout system or those associated with seasonal changes and/or loss of

disinfectant residual,

• Cross connections, especially at certain high-risk locations (e.g., hospitals, chemical

plants, chemical holding/storage facilities, funeral homes, etc.),

• Inadequate disinfectant residuals,

• Contaminated sampling taps, and

• Sampling protocol errors.

The specific cause(s) of total coliforms and E. coli in the distribution system will

likely differ from system to system. The Level 1 and Level 2 assessments are designed to help 

systems identify the specific causes so they can be 

appropriately addressed.

Table 5-1 describes some general actions that

systems can take in response to the common causes of 

total coliform or E. coli positive samples that resulted 

in the RTCR trigger, including additional sources of 

information for correcting the problem. Some actions 

can be performed in response to multiple types of 

causes and multiple actions may be needed in 

response to a single identified cause. Most of the corrective actions listed in Table 5-1 are 

described in more detail from Section 5.2.1 through Section 5.2.11 of this document, along with 

9 Informal surveys of their constituents were conducted from February to March 2010 by the American Water Works Association 

(AWWA), the Association of Metropolitan Water Agencies (AMWA) and the Association of State Drinking Water Agencies 

(ASDWA) to determine the common causes of coliform-positive results in the distribution system and the types of corrective 

actions taken in response to those positive results.

The results of the Level 1 or Level 2 

assessment may indicate that the system 

should employ the suggested corrective 

actions, measures or installation of 

devices (discussed in Sections 5.2.1 to

5.2.11 of this document) to address the 

identified issue; or, if the PWS has them 

already, improve their operation and use 

in their system.
RTCR ACAGM - Interim Final 5-3

examples that can help mitigate or eliminate the sources of coliform contamination. Table 5-2

summarizes these actions along with the general purpose for taking such actions. 

Corrective actions should be completed in accordance with state guidance and industry 

best practices. States often have guidance for design, construction, operation and maintenance of 

water systems. Emergency response planning and implementation of cross connection control 

programs are also described in state guidance in some locations. An example of state guidance is 

the Recommended Standards for Water Works, also known as the 10 States Standards (Great 

Lakes et al. 2007). In addition, drinking water system components installed as part of a

corrective action should be in compliance with National Science Foundation (NSF)/American 

National Standards Institute (ANSI) Standard 61 and other applicable standards. NSF/ANSI 

Standard 61 addresses drinking water system components that are in contact with finished 

drinking water and whether contaminants leach or migrate from the product/material into the 

drinking water at levels that are above acceptable levels in finished waters. For smaller noncommunity water systems that include premise plumbing, corrective actions should also be in 

compliance with local plumbing codes. 

In addition, Appendix D contains a listing of industry standards (e.g., American Water 

Works Association (AWWA) Standards), manuals and other reference materials that describe 

best practices and product specifications. Following these standards can help systems to ensure 

that a product (e.g., pipes, fittings, meters, etc.) or a process (e.g., main flushing, main 

installation, etc.) will provide satisfactory service. These standards can be valuable resources in 

implementing corrective actions. 
Table 5-1: Common Causes of Total Coliforms and E. coli in the Distribution System and Possible Corrective 

Actions to Address Them

Sanitary Defects10 / Conditions That May Point to Cause(s) of TC+ Possible Corrective Action(s) For Additional Information Cause of TC+/EC+ and EC+

Biofilms • Taste and odor complaints • Conduct unidirectional flushing to remove • Water Research Foundation,

• Colored or turbid water that biofilm and sediments from distribution system. Strategies for Managing Total

takes a long time to clear • Maintain adequate pressure in system to prevent Coliform and E. coli in

• Elevated HPC bacteria levels sloughing of biofilm by installing booster pump Distribution Systems, 2009.

• Numerous isolates with stations, variable frequency drives (VFDs), • Water Research Foundation,

similar genotypic profile elevated storage facilities, surge relief valves Factors Limiting Microbial

and surge tanks, and modifying high service Growth in Distribution Systems:

pumps. Install automatic pressure monitoring Laboratory and Pilot Scale

and control. Experiments, 1996.

• Replace/rehabilitate pipe where biofilm • Water Research Foundation,

sloughing is occurring. Assessing and Controlling

• Maintain disinfectant residuals in the Regrowth in Distribution Systems,

distribution system. 1990. 

• Apply temporary disinfection, shock • Water Research Foundation,

chlorination and/or booster disinfection in Factors Affecting Microbial

accordance with state guidelines. Growth in Model Distribution

• Manage water age by looping dead ends; Systems, 2000.

increasing volume turnover; and/or installing • Camper, A. K. et al., “Effect of

appropriate main sizes, automated flushing Distribution System Materials on

devices or mixing devices. Bacterial Regrowth.” Journal

AWWA, Vol. 95 Iss. 7, July 2003,

Page(s) 107-121.

10 Some of the causes of total coliforms and E. coli listed under this column may or may not necessarily be considered as a sanitary defect, based on what conditions the state 

considers as such. Whether the identified cause is considered a sanitary defect or not, the PWS should address it to prevent future occurrence of contamination.

RTCR ACAGM - Interim Final 5-4 
Sanitary Defects10

Cause(s) of TC+ 

and EC+

/ Conditions That May Point to

Cause of TC+/EC+ Possible Corrective Action(s) For Additional Information 

Contamination of 

water during main 

installation, repair or 

rehabilitation

•

•

•

•

Break/repair activities that 

could have allowed entry of 

contaminants or dislodged 

accumulated pipe debris into 

bulk water 

Pressure loss associated with 

break

Low disinfectant residual

Colored or turbid water 

•

•

•

•

Flush system (spot or routine).

Apply temporary disinfection, shock 

chlorination and/or booster disinfection in 

accordance with state guidelines.

Review/enhance existing procedures for main 

installation, repair or rehabilitation procedures. 

Maintain adequate pressure in the system by 

installing booster pump stations, VFDs, 

elevated storage facilities, surge relief valves 

and surge tanks, and modifying high service 

pumps. Install automatic pressure monitoring 

and control. 

• AWWA C651 (Standard for

Disinfecting Water Mains)

Cross-connections •

•

•

Pressure loss event within a 

portion of the distribution 

system

Total coliform-positive 

samples occur at high 

elevation and/or low 

pressure location(s)

Presence of a high-risk 

customer for backflow (e.g., 

industrial user) 

•

•

•

•

•

•

Eliminate cross-connection. 

Implement cross-connection control and 

backflow prevention (CCCBFP) program. 

Install backflow prevention assemblies and 

devices.

Flush system (spot or routine).

Apply temporary disinfection, shock 

chlorination and/or booster disinfection in 

accordance with state guidelines.

Maintain adequate pressure in system to prevent 

backflow and backsiphonage by installing 

booster pump stations, VFDs, elevated storage 

facilities, surge relief valves and surge tanks, 

and modifying high service pumps. Install 

automatic pressure monitoring and control. 

• Cross-Connection Control Manual,

EPA 816-R-03-002, EPA,

February 2003

RTCR ACAGM - Interim Final 5-5 
Sanitary Defects10

Cause(s) of TC+ 

and EC+

/ Conditions That May Point to

Cause of TC+/EC+ Possible Corrective Action(s) For Additional Information 

Errors in the 

sampling protocol 

(i.e., proper 

sampling protocols 

were not followed – 

e.g., tap was not

flushed, aerator was 

not removed, etc.) 

• Changes in sampler or

protocol

•

•

•

Review current protocol and if inadequate, 

identify alternate protocol.

Enhance training on site preparation, flushing 

protocols and sanitary sample collection and 

transport procedures.

Sanitize sample coolers and ice packs. Ensure 

that samples are shipped properly and securely 

(e.g., bottles do not tip or become contaminated 

during transport). 

•

•

Water Research Foundation, 

Sample Collection Procedures and 

Locations for Bacterial 

Compliance Monitoring, 2004 

Interactive Sampling Guide for 

Drinking Water System Operators 

CD (In English: EPA 816-C-06-

001; in Spanish: EPA 816-C-06-

003), available at: 

http://www.epa.gov/ncepihom/

Inadequacies of the 

sample site (e.g., 

unsanitary 

conditions, leaks and 

breaches, 

unprotected access, 

improper 

construction, 

improper location)

•

•

Changes in sampling site use

Presence of unsanitary 

conditions at the sampling 

site

•

•

•

•

Develop a sample siting plan that is 

representative of the water quality in the 

distribution system.

Install dedicated sampling taps.

Correct leaks or other site deficiencies and 

breaches.

Sanitize or replace sampling site.

•

•

Water Research Foundation, 

Sample Collection Procedures and 

Locations for Bacterial 

Compliance Monitoring, 2004 

Interactive Sampling Guide for 

Drinking Water System Operators 

CD (In English: EPA 816-C-06-

001; in Spanish: EPA 816-C-06-

003), available at: 

http://www.epa.gov/ncepihom/

RTCR ACAGM - Interim Final 5-6 
Sanitary Defects10

Cause(s) of TC+ 

and EC+

/ Conditions That May Point to

Cause of TC+/EC+ Possible Corrective Action(s) For Additional Information 

Inadequate 

disinfectant residual 

levels in the 

distribution system

•

•

•

•

•

Variable raw and/or treated 

water quality conditions 

Inadequate disinfectant at 

entry point 

Inadequate disinfectant at 

booster stations

Interruptions in disinfection 

processes

Increases in temperature that 

lead to accelerated 

disinfectant decay

•

•

•

•

Apply temporary disinfection, shock 

chlorination and/or booster disinfection in 

accordance with state guidelines.

Manage water age by looping dead ends; 

increasing volume turnover; and/or installing 

appropriate main sizes, automated flushing 

devices or mixing devices.

Install/upgrade on-line water quality monitoring 

and control. 

Flush system (spot or routine).

• AWWA G200 (Standard for

Distribution Systems Operation

and Management)

Intrusion through • Pressure loss or reduction in • Repair/replace leaky component. • Water Research Foundation,

pipe leaks, pipeline a portion of the distribution • Maintain adequate pressure in system by Verification and Control of

fracture cracks, system installing booster pump stations, VFDs, Pressure Transients and Intrusion

leaking joints, • Presence of leaks, cracks and elevated storage facilities, surge relief valves in Distribution Systems, 2004.

submerged air- other entry points and surge tanks, and modifying high service

vacuum/ air-release • High groundwater table pumps. Install automatic pressure monitoring

valves and and/or presence of sewers and control.

deteriorating seals

•

near the susceptible water

main

Numerous isolates with

unique genotypic profile

RTCR ACAGM - Interim Final 5-7 
Sanitary Defects10

Cause(s) of TC+ 

and EC+

/ Conditions That May Point to

Cause of TC+/EC+ Possible Corrective Action(s) For Additional Information 

Pressure loss (can 

result from events 

such as flushing, 

main breaks, power 

outages, fires or 

improper operations 

and management 

(operations and 

maintenance (O&M) 

practices)

•

•

Recent maintenance 

activities, main breaks, 

power outages, fires

Turbidity increase or 

fluctuations 

•

•

•

•

•

Flush distribution system (spot or routine). 

Apply temporary disinfection, shock 

chlorination and/or booster disinfection in 

accordance with state guidelines. 

Improve O&M practices.

Maintain adequate pressure by installing booster 

pump stations, VFDs, elevated storage facilities, 

surge relief valves and surge tanks, and 

modifying high service pumps. 

Install automatic pressure monitoring and 

control. 

•

•

AWWA C651 (Standard for 

Disinfecting Water Mains)

AWWA G200 (Standard for 

Distribution Systems Operation 

and Management)

Sediment build-up 

in storage tank or 

reservoir

•

•

•

•

Increased disinfectant 

demands 

Increase in turbidity, 

particularly in water samples 

collected when tank is 

draining 

Elevated HPC in samples 

from tank or reservoir 

Low disinfectant residual in 

samples from tank or 

reservoir 

•

•

Drain and flush tank or reservoir. 

Shock chlorination of tank or reservoir 

accordance with state guidelines.

in 

• AWWA C652 (Disinfection of

Water-Storage Facilities)

RTCR ACAGM - Interim Final 5-8 
Sanitary Defects10

Cause(s) of TC+ 

and EC+

/ Conditions That May Point to

Cause of TC+/EC+ Possible Corrective Action(s) For Additional Information 

Storage tank 

physical deficiencies 

like holes, 

inadequate 

screening, etc. (can 

allow entry of birds, 

animals, insects and 

other vectors that 

•

•

•

Presence of physical 

deficiencies

Recent work on or near the 

tank 

Recent vandalism, storm 

events or other events that 

could impact tank integrity

•

•

•

Repair broken parts of storage tank like the vent 

and hatch. 

Repair / install screens.

Install / improve security measures.

• AWWA C652 (Disinfection of

Water-Storage Facilities)

can fecally 

contaminate the 

water)

Contamination 

during 

flushing/firefighting 

activities 

•

•

Turbidity increase or 

fluctuations 

Color increase or 

fluctuations 

• Ensure unidirectional flushing approach is used

for flushing program and that water quality

objectives (i.e., chlorine, turbidity and iron) are

met prior to terminating flushing.

• Water Research Foundation,

Implementation and Optimization

of Distribution Flushing

Programs, 1992

• Pressure fluctuations • Water Research Foundation,

Deterioration of Water Quality in

Distribution Systems, 1987

• Water Research Foundation,

Development of Distribution

System Water Quality

Optimization Plans, 2005

Treatment 

breakthrough

•

•

•

Variable raw and/or treated 

water quality conditions 

Inadequate disinfectant at 

entry point 

Elevated HPC bacteria levels 

occur throughout the 

distribution system

•

•

•

Increase disinfectant residual. Apply temporary 

disinfection, shock chlorination and/or booster 

disinfection in accordance with state guidelines.

Flush system (spot or routine).

Assess performance of treatment processes and 

remedy cause of coliform breakthrough (e.g., 

replace filter, decrease particle loading, etc.).

• Small Systems Guide to Safe

Drinking Water Act Regulations,

EPA Number 816-R-03-017,

EPA 2003:

http://www.epa.gov/nscep

RTCR ACAGM - Interim Final 5-9 
Sanitary Defects10

Cause(s) of TC+ 

and EC+

/ Conditions That May Point to 

Cause of TC+/EC+ Possible Corrective Action(s) For Additional Information 

Vandalism and/or • Recent work or other events • Flush system (spot or routine). • AWWA G200 (Standard for

unauthorized access at a distribution system • Install / improve security measures (e.g., install Distribution Systems Operation

to facilities facility a fence, lock buildings, install alarms and and Management)

• Presence of broken or cameras) • Water Research Foundation,

disabled security equipment • Develop and implement an operations plan. Distribution System Security

• Develop SOPs. Primer for Water Utilities, 2005.

• Develop emergency response plan.

RTCR ACAGM - Interim Final 5-10
Table 5-2: List of Common Corrective Actions

Action Purpose

Disinfection (Section 5.2.1) Improve or maintain disinfectant 

distribution system.

residual in the 

Flushing (Section 5.2.2) 

Keep system clean and free of sediment.

Reduce disinfectant demand of pipe surfaces.

Remove stagnant, untreated or contaminated water.

Address water quality deterioration at dead-ends.

Replacement / Repair of Distribution System 

Components (Section 5.2.3) 

Valves 

Water mains 

Fittings 

Hydrants 

Meters 

Dedicated sample taps

Reduce potential sources / pathways of contamination 

from improper installation or material degradation. 

Maintenance of Adequate Pressure (Section

5.2.4) 

Booster pumping stations 

VFDs

Elevated storage facilities 

Surge relief valves 

Surge tanks

Minimize sudden changes in water velocity, which 

impact system pressure.

Reduce risk of backflow and intrusion contamination 

resulting from low pressures.

Reduce risk of hydraulic disturbances to pipe surface 

biofilm.

Maintenance of Appropriate Hydraulic 

Residence Time (Section 5.2.5) Mitigate water quality problems associated with 

Looping dead ends increased water age (e.g., higher DBP formation, 

Installing appropriate main sizes reduced disinfectant residual, increased microbial 

Automated flushing devices activity, nitrification and taste-and-odor problems). 

Storage facility modifications

Maintenance of Storage Facility (Section

5.2.6) 

Inspecting / cleaning of tanks 

Lining of storage tanks 

Vent / hatch repair 

Tank repair

Remove contamination from birds and insects. 

Remove accumulated sediment.

Protect against tank wall corrosion.

Prevent entry of vectors (e.g., birds, etc.) 

Implementation or Upgrade of a Cross 

Connection Control and Backflow Prevention 

Program (Section 5.2.7) 

Prevent flow of non-potable substances into the 

distribution system.

Sampler Training (Section 5.2.8) 

Reinforces proper sampling and sample handling 

procedures to obtain uncontaminated samples. 

Reduces errors in sampling results.

RTCR ACAGM - Interim Final 5-11
Addition or Upgrade of On-line Monitoring 

and Control (Section 5.2.9) 

Water quality monitoring & control 

Pressure monitoring & control 

Automatically control and monitor disinfectant 

dosages and water quality parameters (other than total 

coliforms).

Monitor pressure levels to identify physical problems 

in the system (e.g., pipe breaks, leaking valves, etc.).

Monitor potential locations for vandalism or security 

Addition of Security Measures (Section breaches that could lead to water contamination.

5.2.10) Increase public confidence in protection of their 

drinking water. 

Integrate all operations and maintenance functions to 

Development and Implementation of an meet flow, pressure and water quality goals.

Operations Plan (Section 5.2.11) Establish a routine distribution system sampling plan.

SOPs Implement an inspection and maintenance program to 

Sample siting plans reduce sanitary defects.

Routine inspections Define an emergency response plan for the 

Emergency response plan distribution system to reduce reaction time and 

Appropriately qualified operators minimize confusion in emergencies. 

Ensure around-the-clock responsiveness.

5.2.1. Disinfection

Many systems use disinfection (by applying either temporary disinfection, shock 

chlorination or booster disinfection) as a response to positive coliform results. It is also 

commonly used as a precautionary measure, especially when the cause of a positive coliform 

sample has not been identified, to help mitigate any potential contamination that could be present 

in the system. If the contamination requires a long-term solution, it may take time for the system 

to design and perform a corrective action. In the meantime, the system cannot serve the 

contaminated water to its customers. The state may require the system, as part of the corrective 

action, to apply chlorination until the contamination is eliminated or a corrective action is put in 

place. When temporary chlorination is applied in response to a coliform occurrence, the system

should notify its state. Chlorination should be kept in place until the state has reviewed the 

situation and has determined if the contamination has been addressed and the temporary 

disinfection can be suspended or if the disinfection needs to be continued. 

Temporary disinfection can be conducted at the point of entry to the distribution system 

or can be installed at a location in the distribution system to target a specific area. Depending on 

the extent of the problem revealed by the Level 1 or Level 2 assessment, system-wide or targeted 

disinfection (such as shock chlorination) may be an appropriate corrective action. 

RTCR ACAGM - Interim Final 5-12
RTCR ACAGM - Interim Final 5-13

For non-disinfecting systems or those using free chlorine, temporary/additional 

disinfectant in the form of sodium hypochlorite (bleach) is often used because it is easier to 

install and operate than gaseous chlorination or other disinfection methods, particularly on a 

temporary basis. It is a low cost option that can provide some protection to a portion of a 

distribution system or across an entire pipe network. However, care should be used in the storage 

of hypochlorite as age and temperature have been shown to be associated with the conversion of 

hypochlorite to perchlorate (Stanford et al. 2009). 

For non-disinfecting systems, before beginning disinfection, it is also important to know 

if there are water quality issues such as the presence of iron and manganese in the water that may 

react with the chlorine. If chlorination is going to be a long-term solution, the source water 

should be evaluated for DBP precursors and naturally occurring ammonia. 

It is important to note that temporary disinfection is better suited to deal with a single 

event and is not intended to deal with a chronic problem like source water contamination. 

Systems using chloramine as a secondary disinfectant should carefully balance chlorine addition 

with ammonia to maintain the desired chlorine to ammonia ratio for optimal chloramine 

formation. 

Booster disinfection facilities located throughout a distribution system can provide 

additional chemical treatment in the system. Booster disinfection can improve or maintain 

disinfectant residual levels in a distribution system. Prior to discharge into the distribution 

system, potable water from a treatment facility must have a certain disinfectant residual level to 

minimize microbial growth. These levels are defined by state and EPA regulations. Organics and 

reduced metals in the water also consume disinfectant residuals; therefore, it is vital to maintain 

an appropriate disinfectant residual level in the system in order to avoid increased levels of total 

coliforms in the system.

See Chapter 6 of this document for a discussion of simultaneous compliance issues 

systems should consider when using disinfection as a corrective action. 

5.2.2. Flushing

A water main flushing program helps to keep a system clean and free of sediment, can 

reduce the disinfectant demand of pipe surfaces and removes stagnant water and untreated or 

contaminated water that may have entered the system (Kirmeyer and Friedman 2000). Flushing 

can also be used to address water quality deterioration at dead-ends. The volume of water flushed 

is related to the length of flushing time and flow rate from the hydrant. Systems should flush 

until a disinfectant residual can be measured or some other water quality target is reached (other 

than just until the water appears clear). Systems could perform scheduled system-wide flushing 
RTCR ACAGM - Interim Final 5-14

and/or periodic unscheduled (or “spot”) flushing which can be used to address isolated water 

quality problems, including total coliform-positive samples. However, spot flushing should not 

be used as the only solution to positive coliform results or low residual events. Flushing should 

be used until the source of the problem and a more permanent fix have been identified. 

Upon obtaining a positive coliform sample, a common response is to flush the area near 

the sample site to draw in fresh water and remove any contaminated water that may be present. 

This unscheduled spot flushing is different from a routine flushing program in that the flushing 

only occurs when triggered by a water quality measurement, customer complaint or similar 

event. 

Minimum elements of a flushing scheduled/routine program are outlined in the AWWA 

G200 Standard (AWWA 2004) and involve: (1) a preventive approach to address local problems 

or customer concerns and routine flushing to avoid water quality problems; (2) use of an 

appropriate flushing velocity to address water quality concerns; and (3) written procedures for all 

elements of the flushing program including water quality monitoring, regulatory requirements 

and specific flushing procedures. 

5.2.3. Replacement / Repair of distribution system components

Distribution system components and appurtenances such as pipes, valves, fittings, 

hydrants, meters and sample taps are integral parts of the water system. These components are 

also potential sources of contamination if improper installation or material degradation allows 

leaks or other entry points for contamination into a distribution system. Inspection of 

distribution system components may indicate that they should be replaced or repaired as 

part of proper maintenance or detection during an assessment, whether or not it is 

identified as the cause of the leak or as a possible entry point for contamination (sanitary 

defect) (see Sections 5.2.3.1 to 5.2.3.6 of this document). Some components throughout the 

distribution system are located below grade, making a leak difficult to locate. However, a 

number of technologies have been developed to locate leaks below grade. Systems should 

complete any repairs or replacements with proper attention to prevent contamination of 

the distribution system. See the AWWA standards listed in Appendix D of this document for 

more information on installation, repair and replacement of distribution system components. 

5.2.3.1. Water mains

The condition of distribution system piping can be vital to the quality of water being 

conveyed to a community. Contaminants may enter through holes, breaks, cracks or joints in the 

piping. The condition of a pipe can vary based on type, age and location of the pipe. Depending 
RTCR ACAGM - Interim Final 5-15

on the condition of the pipe, the water main can be replaced or repaired to stop infiltration into 

the system.

5.2.3.2. Valves

Valves are located throughout a distribution system to isolate portions of the system as 

needed. Leaks at the connection points between the valve and the adjacent pipe, as well as a 

valve seat or valve body, can create a pathway for contamination. 

5.2.3.3. Fittings

There are many types of fittings located throughout a distribution system. The most 

common type of distribution system fitting is a cross. A cross has four connections, which make 

it more susceptible to leaks. Leaks can occur because of a crack on the fitting or through the 

gasket between the fitting and another appurtenance, e.g., a valve, cap or pipe. 

5.2.3.4. Hydrants

Hydrants are located throughout a distribution system to provide potable water at 

required fire flow pressures for emergency situations. Hydrant connections are tapped off the 

distribution system; therefore, these connections can be possible locations for coliform 

contamination to enter a distribution system. Replacing a damaged or faulty fire hydrant can help 

eliminate sources of contamination into the distribution system as it eliminates a pathway for 

contamination. Systems should attempt to control usage of the hydrants as much as possible to 

eliminate unauthorized use and install backflow prevention devices where possible. 

5.2.3.5. Meters

Meters are located at entry points to commercial, residential and industrial facilities to 

measure the amount of water that is consumed at a particular location. Sizes for each of the 

meters will likely vary based on the type and usage requirements of a facility. Contamination 

may enter through the connection points of the meter and the distribution system. Replacing a 

broken or faulty meter can help prevent contamination of the distribution system through leaks, 

as it eliminates a pathway for contamination.

5.2.3.6. Dedicated sample taps

Typical sample locations often include both customer taps and dedicated sampling 

stations. A dedicated sampling station is a device that is plumbed directly into a distribution 
RTCR ACAGM - Interim Final 5-16

system line to provide “improved access to the distribution system water and provide 

reproducible samples that are representative of water quality at the customer’s meter” (Kirmeyer 

and Friedman 2000). Installing dedicated sample taps can therefore minimize the occurrence of 

contamination that can result from improper sampling practices and minimize concerns about 

water quality in customer plumbing. 

Dedicated sampling stations should be of metal construction, have unthreaded nozzles or 

a design approved by the state and be located so as to be representative of the water in the 

distribution system. If they are to be used for coliform sampling under the RTCR, they should be 

installed in locations in accordance with the system sample siting plan. They are typically 

covered to protect them from birds, insects, dirt and other sources of outside contamination. 

Freezing of dedicated sampling taps has occurred in northern climates and that possibility should 

be considered when deciding whether and how to install such taps and which types to install. 

Some manufacturers have dedicated sampling taps that resist freezing. 

Additional guidance on selection of an appropriate sample tap, including factors such as 

type of tap and sink, can be found in Narasimhan et al. 2004. 

5.2.4. Maintenance of adequate pressure

Pressure losses can occur in the distribution system as a result of events such as flushing, 

main breaks, power outages, service line breaks and fires. Pressure transients (also called 

pressure surges or water hammer) can occur when an abrupt change in water velocity occurs due 

to a sudden valve closure, pump shutdown or startup or loss of power. The resulting pressure 

wave, with alternating low and high pressures, travels back and forth through the distribution 

system until the pressure is stabilized. Low pressure conditions in the distribution system can 

allow a flow reversal or backflow of non-potable water to enter the system from a cross 

connection or other source such as intrusion. Pressure transients can also create hydraulic 

disturbances that allow biofilm material on pipe surfaces to enter the bulk water. Systems should 

check with their states regarding distribution system pressure requirements. Industry guidelines 

suggest that system pressure should be maintained within the range of 35 to 100 psi at all points 

in the distribution system (AWWA 1996). The AWWA G200 standard indicates that the 

minimum residual pressure at the service connection under all operating conditions should be 

greater than 20 psi (AWWA 2004). Many states also have guidelines regarding distribution 

system operating pressure. Written SOPs for pump, hydrant and valve operation under routine 

and emergency conditions can help minimize sudden changes in water velocity that impact 

system pressure. 

Other actions that can help to maintain an adequate pressure in the distribution system 

include building new booster pump stations and elevated storage facilities, modifying existing 
RTCR ACAGM - Interim Final 5-17

high services pumps and installing variable frequency drives (VFDs), surge relief valves and 

surge tanks (see the following discussion, Sections 5.2.4.1 to 5.2.4.5 of this document). 

5.2.4.1. Booster pumping stations

Booster pumping stations are used in the distribution systems to move water from lower 

pressure zones to higher pressure zones and to maintain pressure at desirable levels. As the water 

system grows and changes, existing booster pump stations may no longer be able to maintain the 

desired pressure across the distribution system. In such cases, the system may be required to 

construct a new booster station. The construction of a completely new booster pump station is 

not always required to maintain an appropriate pressure in a water system. There may be 

situations where a modification or replacement of an existing pump is sufficient. 

5.2.4.2. Variable frequency drive (VFD)

A VFD, also called a variable speed drive, allows a booster pump to supply the required 

amount of flow based on system demand with a pressure set point to maintain constant system 

discharge pressure, controlled to within a few psi of an operator–adjustable system pressure set 

point. VFDs work with a system pressure transmitter to control the system pressure set point.

5.2.4.3. Elevated storage facilities

Elevated storage is provided within the distribution system to supply peak demand rates 

and equalize system pressures. In certain systems, elevated storage is more effective and 

economical than ground storage because by nature of its elevated location, pumping 

requirements may be reduced, and the storage can serve as a source of emergency supply since 

system pressure requirements can still be met temporarily when pumps are out of service. 

Elevated storage tanks are often cited in areas having the lowest system pressures during 

intervals of high water use. These areas are often those of greatest water demand or those farthest 

from pump stations. Elevated tanks are generally located at some distance from the pump station 

serving a distribution pressure level, but ideally are not placed outside of boundaries of the 

service area unless the facility can be located on a nearby hill. Elevated tanks are built on the 

highest available ground so as to minimize the required construction cost and the height 

requirements.

5.2.4.4. Surge relief valves

Surge relief valves provide pressure management by ejecting water out of a side orifice to 

prevent excessive high-pressure surges and can also be triggered to open on a downsurge in 
RTCR ACAGM - Interim Final 5-18

pressure in anticipation of an upsurge to follow. Systems should always use surge relief valves 

with caution for they can make low-pressure conditions in a line worse than they would be 

without the valve. 

5.2.4.5. Surge tanks

The four common types of surge tanks include pneumatic or closed tanks, open 

standpipes (or air chambers), one-way surge tanks (allows water to flow only from the tank into 

the pipeline) and two-way surge tanks (allows flow to and from the tank). If water is stored in 

these tanks for long periods of time, the water may lose its disinfectant residual and microbial 

growth and other water quality problems may result. Proper operations and maintenance of surge 

tanks is required to prevent poor quality or contaminated water from entering the distribution 

system.

Hydropneumatic tank systems are a popular way to provide pressure control and 

stabilization in smaller water distribution systems; however, they are not typically used in larger 

systems. A hydropneumatic tank system allows for fluctuations in water distribution system 

pressure and a potential cushion against water hammer. The system also minimizes booster pump 

on-off cycles so that a recommended frequency of 10-15 cycles per hour can be maintained. 

The pressure tank uses a compressed air head-space to maintain system pressure. As 

water system demand increases, water in the pressure tank discharges into the system and 

reduces the pressure tank’s water level, which expands the air cushion above the water and 

decreases the tank air pressure. When the air reaches a determined set point, the air compressor 

comes on to recharge the air space and cycles off when the high pressure set point is met. If the 

water demand continues to increase, the booster pumps will cycle on at the low water level and 

replenish the water level in the pressure tank. The pressure tank should be sized correctly, 

because its size determines the frequency of pump cycling.

5.2.5. Maintenance of appropriate water age, hydraulic residence time and mixing

Water quality problems associated with increased water age include reduced disinfectant 

residual, increased microbial activity, nitrification and/or taste and odor problems. As water 

travels through the distribution system, chlorine continues to react with natural organic matter 

(NOM) to form DBPs. Thus, increased water age can also lead to higher DBP concentrations. 

PWSs should develop an overall strategy to manage the water age in their distribution systems, 

while considering the need to have adequate storage for emergencies. Establishing a water age 

goal is system-specific depending on system design and operation, water demands and water 

quality (e.g., DBP formation potential). In the US, the average distribution system retention time 

is 1.3 days and the average maximum retention time is 3.0 days based on a survey of 800 
RTCR ACAGM - Interim Final 5-19

medium and large water utilities (AWWA and AwwaRF 1992). Water age can be controlled 

through a variety of techniques including management of finished water storage facilities, 

looping of dead-ends and re-routing of water by changing valve settings (see the following 

discussion, Sections 5.2.5.1 to 5.2.5.4 of this document). Additional guidance is provided in the 

AwwaRF report, Managing Distribution System Retention Time to Improve Water Quality

(Brandt et al. 2004). 

5.2.5.1. Looping dead-ends

Dead-end pipes often result in stagnant water conditions where water age increases, 

which can cause water quality problems. One of the solutions to address the stagnant water issue 

is looping of dead-ends. However, PWSs should carefully evaluate looping on a case-by-case 

basis as it may not actually reduce the long detention times present in those areas.

5.2.5.2. Installing appropriate main sizes

Most distribution systems have been designed to meet a minimum hydraulic capacity. 

Additional capacity is generally included at the design stage to accommodate for future growth 

or to allow more flexibility in the configuration of a distribution system network. A PWS may 

also have a policy to limit the number of different pipe diameters within the system in order to 

simplify construction and maintenance. Consequently, network pipes tend to be larger than is 

necessary to meet the daily demand from the network leading to increased retention time. Hence, 

there can be an option to replace mains with smaller diameter pipes but still maintain the 

required hydraulic capacity.

5.2.5.3. Installing automated flushing devices

Automated flushing devices are used to purge accumulated sediments at low spots and 

dead-ends of pipelines at regular intervals and to drain pipelines for repairs, maintenance and 

inspection. These devices are best suited to rural networks in which security of the units and 

disposal of the water flushed is less problematic. An additional drawback of installing these 

devices is the volume and value of the wasted water may be unacceptable. However, in networks 

with long pipe runs terminating in dead-ends, there may be few viable alternatives to flushing for 

controlling retention time.
RTCR ACAGM - Interim Final 5-20

5.2.5.4. Storage facility modifications

Most storage facilities have been designed focusing more on quantity, cost, service life, 

appearance and shape than on maintaining water quality. Water quality in storage facilities is 

affected by the mixing patterns that occur primarily during the filling cycle, the long-term 

residence time and the interaction between these two phenomena. Old water in stagnant zones 

can often have very high DBPs and low to no disinfectant residual. This water can be released 

into the system during periods of high demand. Increasing volume turnover reduces the average 

hydraulic residence time (HRT) in finished water storage facilities, thereby reducing DBP 

formation, loss of disinfectant and microbial growth. Kirmeyer and Friedman (2000) recommend 

complete turnover every three to five days but suggest that water systems establish their own 

turnover goal based on system-specific needs and goals. Improving mixing in finished water 

storage facilities can help eliminate stagnant zones. Mixing can be improved by increasing inlet 

momentum, changing the inlet configuration, increasing the fill time and by installing mixing 

devices within the storage facility (see the following discussion, Sections 5.2.5.4.1 to 5.2.5.4.3 of 

this document). 

It may be necessary to reduce the water volume in a storage tank or increase demand on 

the tank to achieve increased volume turnover. Decommissioning storage facilities may be an 

appropriate strategy to reduce water age if existing facilities are oversized and not needed for 

emergency conditions, fire protection or for maintaining system pressure. A professional 

engineer should review system needs, system design and operation to determine if the existing 

storage capacity and tank operation are appropriate.

5.2.5.4.1. Inlet / outlet configuration

Inlet and outlet configuration are critical in the development of proper mixing in a 

finished water storage facility. The inlet structure should be located and sized to disperse the jet 

into the storage facility as well as to maintain a jet sufficient for mixing. In particular, the 

location and orientation of the inlet pipe relative to the tank walls can have a significant impact 

on mixing characteristics. The physical modifications to the inlet pipe for improving mixing 

within the tanks include: 

• Changing the orientation of the inlet pipe; and/or

• Decreasing the inlet diameter to increase the jetting action.

The outflow configuration does not significantly influence mixing, but operation of the 

inlet and outflow is important because flow entering the tank and leaving the tank at the same 

time can negatively impact mixing and should be avoided. Furthermore, when the inlet/outlet is a 

common pipe, the ability to reduce the inlet diameter to achieve a higher inflow velocity and 
RTCR ACAGM - Interim Final 5-21

better jetting action will be constrained by the need to maintain an outflow capacity adequate to 

satisfy system operational and fire flow requirements. For this reason, it is recommended that 

PWSs eliminate common inlet/outlet pipes.

5.2.5.4.2. Installation of mixing devices

Mixing the storage facility contents to reduce stagnant zones can also be accomplished by 

installing mixing devices. Special precautions are recommended with mechanical mixing devices 

because of potential contamination to finished water by the mixer mechanism lubrication system. 

Multiple mixing devices may be needed so PWSs should consider the increased maintenance 

requirements inside the storage facility.

5.2.5.4.3. Increasing volume turnover

As mentioned earlier in this section, increasing the volume turnover reduces the average 

HRT in the storage tank. PWSs can accomplish turnover by making operational modifications to 

the storage tank such as increasing the water level fluctuation or drawdown between fill and 

draw cycles. The water level should be lowered in one continuous operation and not in small 

incremental drops throughout the day. This will help to mitigate microbial growth in the tank by 

decreasing the HRT or increasing the volume turnover by increasing the flow rate.

Operational modifications may be limited by the following considerations:

• Control of flow rates during tank filling may be needed to minimize the potential for

low pressure in the distribution system; and

• Changes in operating protocol for booster stations and other tanks to achieve turnover

while maintaining adequate pressure system-wide.

5.2.6. Maintenance of storage facility

Finished water storage tanks are an important component of a PWS’s distribution system. 

Tanks are usually designed for three purposes: reduce pressure fluctuations in the distribution 

system, equalize water demands and provide water reserves for emergencies such as fires and 

power outages. 

The two main categories of water storage tanks include ground storage tanks and elevated 

storage tanks (see previous discussion on elevated storage tanks in Section 5.2.4.3 of this 

document). Ground storage tanks can be below grade, partially below grade or at ground level in 

a distribution system and are usually constructed of a variety of materials, including steel, 
RTCR ACAGM - Interim Final 5-22

concrete and fiberglass reinforced plastic. Elevated storage tanks are typically constructed of 

steel.

Contamination from birds and insects can be a source of microbial contamination in the 

distribution system. Maintenance on a storage tank can significantly reduce the possibility of 

contamination or recontamination. Some actions PWSs can take include inspecting and cleaning, 

lining the interior of the tank, repairing vents and/or hatches and repairing the tank itself (see the 

following discussion, Sections 5.2.6.1 to 5.2.6.4 of this document). 

5.2.6.1. Inspection / cleaning of tanks

Tank inspections can provide useful information on the physical condition of the exterior 

and interior of the tank and on identifying potential sources of microbial contamination. 

Inspections can also identify the accumulation of sediment within storage tanks due to particle 

settling in the tank or the dissolving of cementitious materials of a concrete tank from soft, low 

alkalinity, low pH waters. There are several water quality issues associated with sediment 

buildup in a storage tank, including increased disinfection demand, microbial growth, DBP

formation and increased turbidity. 

5.2.6.2. Lining of storage tanks

Lining the interior of a water storage tank is another action that PWSs can take to reduce 

the potential for coliform contamination and recontamination of the distribution system. 

Corrosion and corrosion product buildup from excessive interior corrosion can also result in 

water quality issues such as increased disinfection demand, microbial growth and increased 

turbidity. 

5.2.6.3. Vent / hatch repair

One of the most common sources of contamination in a water storage tank is the 

improper design and maintenance of vents and roof hatches. These accessories can provide entry 

points for debris as well as microbial contamination from birds and insects. Aging water storage 

tanks with damaged tank covers can also be a source of microbial contamination. To prevent 

contamination and recontamination of the water supply, damaged vents, hatch roofs and tank 

covers should be repaired or replaced immediately. 
RTCR ACAGM - Interim Final 5-23

5.2.6.4. Tank repair

Aging water storage tanks can provide entry points for debris as well as microbial 

contamination from birds and insects and should be replaced or repaired immediately to prevent 

contamination and recontamination of the water supply. 

5.2.7. Implementation or upgrade of a Cross-connection Control and Backflow 

Prevention Program

Implementing or upgrading a Cross-connection Control and Backflow Prevention 

(CCCBFP) Program, including the installation of backflow prevention assemblies and devices, 

can prevent the flow of non-potable substances into the distribution system. When implementing 

the CCCBFP Program, PWSs should adhere to applicable state and/or local criteria, codes and/or 

regulations. Some codes or regulations may include documenting installation procedures and the 

periodic testing of backflow prevention assemblies. CCCBFP can prevent the introduction of 

non-potable substances into the public water supply due to backsiphonage or backpressure. 

Backflow prevention equipment installation and maintenance is generally the consumer’s 

responsibility. However, depending on how a PWS implements the CCCBFP, the customer and 

the PWS can share costs for the equipment and equipment installation, inspection, testing and 

maintenance. The PWS, on the other hand, is primarily responsible for the administration of 

CCCBFP and the inspection, review and approval of all backflow prevention assemblies and 

devices.

5.2.8. Sampler training

Implementation of a sampler training program provides guidelines for procedures that 

samplers must follow to collect valid, uncontaminated samples for analysis of total coliforms in 

the distribution system. Training sessions for operators reinforce proper sampling and sample 

handling procedures to obtain uncontaminated samples.

5.2.9. Addition or upgrade of on-line monitoring and control

Currently, monitoring of total coliforms is performed through grab samples at the 

treatment plant and throughout the distribution system. These grab samples are then analyzed in 

a laboratory to determine whether total coliforms are present or not in the grab sample. To ensure 

sufficient treatment has been provided, grab sample results, disinfectant dosages and certain 

water quality parameters, such as disinfectant residual levels, can be correlated. Since automatic 

monitoring is not available for total coliforms, PWSs can instead automatically control and 
RTCR ACAGM - Interim Final 5-24

monitor for disinfectant dosages and water quality parameters (see the following discussion, 

Sections 5.2.9.1 to 5.2.9.2 of this document). 

5.2.9.1. Water quality monitoring and control

A PWS’s ability to monitor disinfectant residuals in the distribution system can allow it

to determine if there is an area of possible contamination or an area that requires additional 

treatment. Low levels of disinfectant residuals in the system can be caused by an increase of 

organics in a system, which consume disinfectant residuals, or insufficient disinfectant dosages 

at the treatment facility. Maintenance of sufficient disinfectant residual levels in a distribution 

system is important in maintaining minimal levels of total coliforms in the system. 

PWSs can monitor disinfectant residual using routine grab samples, with adjustment of 

dosages based on results. Controlling and monitoring disinfectant dosages and water quality 

parameters can also be performed through the use of a SCADA system at the treatment facility. 

Disinfectant dosing equipment can be monitored and analyzers can be placed in the treatment 

process to monitor water quality parameters. Monitoring water quality parameters via SCADA in 

a distribution system is possible; however, it can be costly. Determining the number and location 

of the analyzers is challenging and highly dependent upon the system size. Typically, analyzer 

equipment will draw samples from an above grade pipe or a sample tap to an analyzer that is 

placed in a building. Sample locations will require analyzer equipment, a building, electric power 

and, in the case of some systems, integration to the PWS’s existing SCADA system. Method 

requirements for on-line amperometric chlorine monitors are more time intensive and difficult 

than grab sampling. 

5.2.9.2. Pressure monitoring and control

In addition to water quality monitoring, PWSs can monitor pressure levels throughout the 

distribution system. Installing online pressure monitoring and control will help minimize future 

incidents of pressure loss that can allow entry of contaminants into the distribution system. It can 

also help a PWS determine if there are any physical problems in the system, e.g., a crack in a 

pipe, a leaking valve, etc., that cause changes to the water quality of the system. Pressure 

readings can also be used to help locate areas of deficiency in a distribution system. Similar to 

the water quality monitoring, determining the number of pressure monitors and their locations is 

dependent upon the system size. Pressure monitoring locations will likely require the same 

equipment as water quality sampling locations. 

On-line distribution system monitoring through the SCADA system can alert operators if 

there are possible issues with the distribution system; however, monitoring the water quality or 
RTCR ACAGM - Interim Final 5-25

pressure will not identify the source of the contamination nor will it necessarily identify the 

location of the contamination. 

5.2.10. Addition of security measures

PWSs may need to install security measures in circumstances where the assessment or 

onsite inspection reveals vandalism or security breaches that could lead to water contamination. 

Measures that PWSs may take to correct security breaches include installing a fence or locking 

buildings to restrict access to the system. Other possible security measures include employing a 

full time, on-site security staff and using alarms and cameras to detect security breaches.

PWSs should prioritize their security measures and concentrate on the most vulnerable 

parts of their system, such as unstaffed facilities (e.g., finished water storage tanks). An 

important implementation issue is determining the extent to which the water system needs to be 

secured. This would depend on how widely spread the system/facility is, the number and 

complexity of the treatment trains, the extent of the watershed, the distance of the treatment plant 

from the influent wells, accessibility of the distribution system, etc.

Installing security measures can increase the public’s confidence in the protection of their 

drinking water and indeed can provide substantial protection against vandalism that might result 

in contamination of the water. However, security measures are not always foolproof or absolute 

in combating vandalism or security breaches.

5.2.11. Development and implementation of an operations plan

PWSs may need to develop an operations plan or improve their existing one when the 

assessment identifies gaps in the way the system is operated that could have led to or contributed 

to the sanitary defect identified. For example, a broken valve might have been prevented if 

routine inspections were part of the operations plan. An operations plan can integrate all 

operations and maintenance functions to meet the goals of flow, pressure and water quality. The 

AWWA G200-04 standard describes the critical requirements for the effective operation and 

management of drinking water distribution systems. According to this standard, a water system 

should develop SOPs, comprehensive monitoring plans, routine inspections and emergency 

response plans. 

5.2.11.1. Standard operating procedures

SOPs should be developed for each operation and maintenance function that affects the 

system’s water quality (e.g., flushing programs, storage facility inspections). The water quality 

goals for both the distribution system and the particular function should be specified in the SOPs. 
RTCR ACAGM - Interim Final 5-26

SOPs should be developed from information gathered from the various departments and crews 

involved in a given function. The SOPs should be written in terms that everybody will 

understand and they should include all activities needed to conduct the procedures and describe 

the labor, equipment and materials needed to complete the activity.

5.2.11.2. Sample siting plans

PWSs should establish a routine distribution system sampling plan that is representative 

of the entire distribution system (under the RTCR, PWSs are required to have a sample siting 

plan in place). At a minimum, the sample sites should include sites required for regulatory 

compliance monitoring (as those required by the RTCR and the GWR). Additional sites should 

be sampled as necessary to provide a complete picture of the water quality in the system. All 

samples should be collected in accordance with the latest edition of Standard Methods for the 

Examination of Water and Wastewater (as of the writing of this document, the latest version is 

that of APHA et al. 2005). 

5.2.11.3. Routine inspections

Routine inspections of various distribution system components such as finished water 

storage facilities, water mains, pump stations, chemical storage facilities, valves and fire 

hydrants are critical to ensure high-quality water. PWSs should implement inspection and 

maintenance programs of these components as part of the SOPs. 

5.2.11.4. Emergency response plan

A written emergency response plan for the distribution system allows operating personnel 

to respond efficiently, effectively and rapidly to an emergency situation. Water quality system 

safety and reliability are improved if a PWS has an emergency response plan. 

5.2.11.5. Appropriately qualified operators

EPA established an operator certification program with minimum professional standards 

for the operation and maintenance of water systems. The EPA program issued guidelines that 

specify standards for certification and recertification of operators. States implement the

minimum standards of the certification program guidelines. While the specific requirements vary

from state to state, the goal of the program is to ensure that skilled professionals are overseeing 

the treatment and distribution of safe drinking water and compliance with the Safe Drinking 

Water Act (SDWA). More information on the operator certification program can be found at: 

http://water.epa.gov/infrastructure/drinkingwater/pws/dwoperatorcert/index.cfm. 
RTCR ACAGM - Interim Final 5-27

Providing training sessions for operators reinforces proper operation and maintenance of 

water facilities and systems. These sessions can also help educate PWS staff on emerging

treatment technologies, regulatory requirements and other advances in the drinking water 

industry. 

5.3 What are some of the best practices PWSs can take?

Best practices are actions that PWSs should and/or might choose to take following a 

Level 1 or Level 2 trigger regardless of whether they have identified a sanitary defect or a likely

cause of the total coliform or E. coli occurrence (e.g., a single E. coli-positive sample). They can 

range from temporary measures to long term measures. 

In the survey conducted by AWWA, Association of Metropolitan Water Agencies 

(AMWA) and Association of State Drinking Water Agencies (ASDWA) (see footnote 9), most 

respondents indicated that follow-up actions are taken following a positive coliform result even 

when the underlying cause is unidentified. Systems take these actions to ensure public health 

protection and generally do not involve major construction or capital improvement. Examples of 

common actions that were reported are flushing, increasing disinfectant residual, collecting 

additional investigative samples, examining whether samples were collected from appropriate 

sample sites and re-training staff/sampler on proper sampling procedures. Based on the results of 

the survey, the list below includes these actions and a few other ones as examples of best 

practices that PWSs may take following an assessment trigger or a positive coliform result, 

regardless of whether the cause or the sanitary defect is identified. Some of them have already 

been discussed in Section 5.2 of this document. These actions are not mutually exclusive and 

PWSs may choose to implement a combination of them, if appropriate. PWSs should also 

consider implications for long-term sustainability and public health protection when deciding 

which of these actions to implement.

The RTCR also identifies a list of “best technologies, treatment techniques, or other 

means” (also known as best available technologies (BATs)) to help PWSs comply with the rule 

(see §141.63(e) of the RTCR). They include appropriate well placement and construction, 

maintenance of a disinfectant residual throughout the distribution system, proper maintenance of 

the distribution system, filtration and disinfection of surface water, implementation of a crossconnection control program and implementation of a wellhead protection program. PWSs may 

choose to take advantage of these BATs when they trigger an assessment in order to avoid future 

triggers and/or violations, even if they are unable to find a likely cause/sanitary defect. Some of 

these BATs are also discussed in the list below. 
RTCR ACAGM - Interim Final 5-28

• Apply disinfection – A discussion of disinfection practices is in Section 5.2.1 of this

document. Additional information on emergency disinfection practices can be found at

http://www.epa.gov/drink/emerprep/emergencydisinfection.cfm

• Change or update distribution system maintenance operations – A well-maintained

and operated distribution system is an important barrier in protecting water quality. Even

if water from an extremely clean source is adequately treated, breakdowns in the

distribution system can lead to waterborne illnesses. In particular, the contamination of

treated water can result from main breaks, inadequate water pressure that allows intrusion

or backflow of contaminants, deficiencies in storage tanks and inadequate separation of

water supply lines and sewers.

Proper maintenance of the distribution system includes appropriate pipe replacement and

repair procedures, main flushing programs, proper operation and maintenance of storage

tanks and reservoirs, cross-connection control and continual maintenance of positive

water pressure in all parts of the distribution system. Even if a Level 1 or Level 2

assessment does not reveal an underlying cause for the positive coliform samples, a PWS

may choose to change or update their distribution system maintenance operations as a

follow-up action. Many of these actions are described in Section 5.2.3 of this document.

• Perform unscheduled or spot flushing – A discussion of unscheduled or spot flushing

is in Section 5.2.2 of this document.

• Implement sampler training – A discussion of sampler training is in Section 5.2.8 of

this document.

• Review sample siting plan – The sample siting plan should ensure that the quality of the

water is representative of the distribution system. PWSs might consider reviewing and

revising the sample siting plan as a universal follow-up action, regardless of whether an

underlying cause for the positive coliform samples can be identified.

• Select appropriate sample sites – Part of a successful sampling plan is the selection of

clean, appropriate sample taps and sites from which to collect representative samples. In

addition to reviewing the sample siting plan, PWSs may wish to consider the use of

dedicated sample taps, which is discussed in Section 5.2.3.6 of this document.

• Collect additional follow-up samples – Collecting follow-up total coliform samples

after conducting a corrective action is a good practice to help determine the effectiveness

of the corrective action. This action could also enhance public health protection by

determining if there are still any sanitary defects that may not have been identified

initially. Note, however, that additional follow-up total coliform sampling in itself,

without any other corrective action, is not sufficient to address identified sanitary defects.

• Institute boil water orders – A number of systems have chosen to institute boil water

orders even in cases where total coliforms are detected but no E. coli is present. In some

states, boil water orders are a required follow-up action after a total coliform-positive

sample has occurred. However, it should be noted that requirements vary from state to
RTCR ACAGM - Interim Final 5-29

state and PWSs should follow state requirements for implementing boil water orders, 

whether they are required in response to a total coliform-positive or not. 

A boil water order requires that a PWS publicly advertise that water should be boiled 

prior to consumption. While a boil water order can be protective of public health, it also 

requires effort for consumers, has economic impacts to businesses and can undermine 

public confidence in the water supply. Therefore, a boil water order should not be 

implemented lightly and should be reserved for situations with significant potential to 

impact public health. A Level 2 trigger associated with an E. coli-positive may be more 

appropriate for a boil water order action than a Level 1 trigger associated with a total 

coliform-positive. Boil water orders may also be issued on a voluntary basis and may be 

helpful for educating sensitive populations. 
RTCR ACAGM - Interim Final 6-1 

6. Simultaneous Compliance with the RTCR and with the Requirements

of Other Drinking Water Rules

6.1. Using sanitary surveys to meet the requirements of the RTCR 

Some RTCR requirements can be met through a sanitary survey, such as conducting an 

assessment, review of monitoring frequency and the requirement for annual site visits for 

systems on reduced annual monitoring. This section discusses how states and PWSs can use the 

sanitary survey to meet these requirements. Note that the RTCR does not include new 

performance requirements for sanitary surveys, e.g., how and when to conduct sanitary surveys. 

6.1.1. Sanitary surveys and assessments

Under the RTCR, an assessment of the water system is required if triggered under the 

rule (and as described in Chapters 3 and 4 of this document) to identify possible sanitary defects 

within the distribution system. In addition to the RTCR requirements, the state must assure that a 

sanitary survey is conducted for each system every three or five years depending on the system 

type and other factors. The sanitary survey requirements for surface and ground water systems 

have been established for all system sizes and types under the Interim Enhanced Surface Water 

Treatment Rule (IESWTR) (USEPA 1998a) (40 CFR 142.16(b)(3)), and the GWR (USEPA 

2006b) (40 CFR 142.16(o)(2)(i)). There may be instances where the performance of an 

assessment or a sanitary survey can satisfy the requirements of the other. It is therefore 

important for PWSs to understand how these two types of evaluations can be integrated.

This section discusses the basic differences and the overlaps between sanitary surveys

and Level 1 and Level 2 assessments. It addresses what a sanitary survey is, how often it is 

performed, the objective of a sanitary survey, who performs them relative to Level 1 and Level 2

assessments, and the overlaps between assessments and sanitary surveys. It is not intended to 

represent guidance on the performance or requirements of conducting sanitary surveys. Other 

resources are available for that purpose. Sanitary survey resources, such as a prep course,

learner’s guide, and inspector’s field guide can be found online at 

http://www.water.epa.gov/learn/training/dwatraining/sanitarysurvey/ . 

6.1.1.1. What is a sanitary survey?

A sanitary survey is a comprehensive on-site evaluation of all water system components 

and operations and maintenance procedures. 
RTCR ACAGM - Interim Final 6-2 

A sanitary survey is defined in 40 CFR 141.2 as an: “onsite review of the water source, 

facilities, equipment, operation and maintenance of a public water system for the purpose of 

evaluating the adequacy of such source, facilities, equipment, operation and maintenance for 

producing and distributing safe drinking water.” 

There are eight required elements that must be included in the review of a water system 

during a sanitary survey:

• Source,

• Treatment,

• Distribution system,

• Finished water storage,

• Pumps, pump facilities, and controls,

• Monitoring and reporting and data verification,

• System management and operation, and

• Operator compliance with state requirements.

The performance of comprehensive and perio

PWSs should coordinate with their states

regarding how and when a combination 

of assessment and sanitary survey 

activities can be used to meet the 

requirements of both.

dic sanitary surveys is important in the 

identification and correction of significant 

deficiencies to ensure the long-term safety of 

drinking water supplies. Sanitary surveys are 

important tools for identifying potential 

vulnerabilities to fecal contamination. Each state 

is responsible for the definition of significant 

deficiencies and for providing examples of 

sanitary defects, so coordination with the state during both RTCR assessments and sanitary 

surveys is critical.

6.1.1.2. What are the differences and overlaps between a sanitary survey and a 

Level 1 or Level 2 assessment?

There are several differences between sanitary surveys and the assessments required 

under the RTCR, although the two sets of 

requirements can overlap. Some sanitary defects 

as determined during a Level 1 or Level 2 

assessment could also be considered to be 

significant deficiencies under a sanitary survey, 

such as breaches in storage facilities or problems 

with a well seal. However, there are significant 

deficiencies that would not be considered to be sanitary defects, such as failure to meet operator 

Sanitary defects that are identified 

during an assessment may or may not be 

considered a significant deficiency under 

other rules according to the guidelines 

set by each state.
RTCR ACAGM - Interim Final 6-3 

qualification requirements. This section explains some of the differences and elements in 

common between a sanitary survey and an assessment.

6.1.1.2.1. What is the difference in scope?

A sanitary survey is generally broader in scope than either a Level 1 or Level 2 

assessment. Although a sanitary survey includes some elements that are similar to those in an 

assessment (e.g., evaluation of the source water, the distribution system, storage facilities, etc.), a 

sanitary survey generally will cover additional items such as system management and operation 

that are beyond what an assessment requires under the RTCR. Because they are generally 

broader in scope, a state may in some situations allow a sanitary survey to be used to meet the 

requirements for a Level 1 or Level 2 assessment. 

The Level 1 and Level 2 assessments are targeted to identify sanitary defects that provide 

pathways of entry for microbial contamination or those that are indicative of a failure or 

imminent failure in a barrier that is already in place. Nevertheless, there may be some 

assessments that will note best operational practices, such as regular flushing programs, that can 

be used to improve water quality regardless of whether the assessment identifies sanitary 

defect(s). Furthermore, for some system sizes and types, such as simple systems with limited 

sources and distribution systems, a sanitary survey and an assessment may be substantially the 

same.

6.1.1.2.2. What is the difference in frequency and timing?

Sanitary surveys are performed periodically and routinely on a schedule. The state must 

complete sanitary surveys for all surface water systems (including ground water under the direct 

influence of surface water) no less frequently than every three years for CWSs and no less 

frequently than every five years for NCWSs. CWSs must have sanitary surveys completed by the 

state or an agent approved by the state no less than every three years, with the possibility of 

having the frequency reduced to no less than every five years if the system has an outstanding 

performance or meets certain criteria. NCWSs (both non-transient and transient non-community) 

are required to have sanitary surveys performed by the state or an agent approved by the state no 

less often than every five years. 

Level 1 and Level 2 assessments, on the other hand, are performed by a qualified PWS

staff and a party approved by the state, respectively, in response to treatment techniques triggers, 

so they are not on a routine schedule. In some situations, based on the timing and schedule of the 

sanitary survey, the sanitary survey may be used to meet the assessment requirements of the 

RTCR if acceptable to the state. Assessments must be conducted within 30 days of a system 

triggering the assessment.
RTCR ACAGM - Interim Final 6-4 

To the extent that the requirements to perform an assessment may be satisfied as part of 

the sanitary survey, PWSs and states may realize a cost savings by conducting a sanitary survey 

that also qualifies as an assessment instead of performing an additional separate assessment. 

Keep in mind, however, that the assessments conducted to meet RTCR requirements must be 

conducted within the required timeframe under the RTCR and may not be delayed to when the 

next sanitary survey is scheduled to be performed. Also, to meet the requirements of both, the 

person doing the assessment would also have to be qualified to conduct a sanitary survey, and 

vice versa, and the investigation would have to meet the minimum criteria specified by the state 

for both the assessment as well as the sanitary survey. 

6.1.1.2.3. Who conducts them?

Sanitary surveys must be conducted by the state or an agent approved by the state. A 

Level 1 assessment is a self-assessment completed by qualified PWS staff and reviewed by the 

state. A Level 2 assessment is conducted by a party approved by the state, which could be a 

representative of the state, by a state-approved third party or by qualified PWS staff member(s) if 

the state determines they possess the required qualifications.

6.1.2. Sanitary surveys and monitoring

The RTCR allows PWSs to transition to the new rule at their 1989 TCR monitoring 

frequency, even if a system is on reduced monitoring under the 1989 TCR, provided they meet 

certain criteria. For ground water systems serving 1,000 or fewer people, their monitoring 

frequency must be evaluated by their state during each sanitary survey conducted after the 

compliance effective date of the RTCR. The purpose of these special monitoring evaluations is 

to make sure that these systems are on the appropriate monitoring frequency and to ensure that 

the distribution system is evaluated in sufficient detail. These special monitoring evaluations

are not anticipated to significantly increase the burden of conducting sanitary surveys because 

the systems (serving 1,000 or fewer people) are relatively simple, and the evaluation is 

performed during the routinely scheduled sanitary survey. The addition of the special monitoring 

evaluation for the RTCR during the sanitary survey is also not changing the existing sanitary 

survey requirements under the IESWTR and the GWR. 

The results of a sanitary survey can also directly impact a system’s monitoring frequency 

under the RTCR. For a ground water system serving 1,000 or fewer people, the sanitary survey 

might uncover sanitary defects in the system that could affect its ability to qualify for reduced 

monitoring. To qualify for reduced monitoring, the system’s most recent sanitary survey must 

show that the system is free of sanitary defects. See Appendix A of this document for a 

summary of the RTCR requirements. 
RTCR ACAGM - Interim Final 6-5 

6.1.3. Sanitary surveys and annual site visits

For years in which the state performs a sanitary survey of an NCWS, which is at least 

every five years, a sanitary survey performed during the same year can also be used to satisfy the 

annual site visit requirement for systems wanting to qualify for and stay on annual monitoring 

under the RTCR. A voluntary Level 2 assessment may also be used to satisfy the annual site visit 

requirement.

6.2. Changing treatment practices to comply with the corrective action 

requirements of the RTCR 

The interrelated nature of regulations can be a challenge as adjustments to improve 

compliance for one rule may inadvertently affect a system’s ability to comply with another rule. 

Given that temporary disinfection is a common corrective action taken by systems that have 

experienced positive coliform results, a number of related issues are important for PWSs to keep 

in mind with respect to other drinking water rules. 

Non-transient non-community water systems (NTNCWSs) and CWSs that do not 

typically practice disinfection and are planning on adding temporary disinfection are subject to 

the Stage 1 and Stage 2 Disinfectants/Disinfection By-Products Rules (DBPRs) (40 CFR 

141.130 and 141.600) (USEPA 1998b; USEPA 2006a) for the monitoring period in which the 

disinfectant is used. PWSs should check with their 

state to determine what the requirements are for 

compliance with the DBPRs. For temporary 

disinfection by chlorine or chloramines, PWSs will 

have to ensure that maximum residual disinfectant 

levels (MRDLs) for chlorine/chloramines and MCLs for total trihalomethanes (TTHM) and the 

group of five haloacetic acids (HAA5) are not exceeded. This may require additional sampling at 

both the point of entry of the chlorinated water and at other distribution system locations. 

Alkalinity and pH adjustments and/or the addition of corrosion inhibitors are often used 

to meet Lead and Copper Rule (LCR) (40 CFR Part 141, Subpart I) requirements. For PWSs

using measures such as these, they should also be aware that the pH of the water can alter the 

efficacy of disinfectants used to meet the requirements microbial rules such as the RTCR. For a 

given level of inactivation, the higher the pH, the higher the disinfection detention time and/or 

chlorine residual concentration required. See the Revised Guidance Manual for Selecting Lead 

and Copper Control Strategies (USEPA 2003) for more information on simultaneous 

compliance with the LCR and other drinking water regulations. 

PWSs should always check with their

State before making any changes or 

additions to disinfection practices.
RTCR ACAGM - Interim Final 6-6 

PWSs should also be aware that changes in disinfectant residual may alter the corrosivity 

of the water. Chlorine is a powerful oxidant and reacts with many metals that are present in the 

distribution system. Rapid changes between high concentrations and low (or no) concentrations 

of oxidants can destabilize metal scales that form along the pipe wall, possibly allowing for 

metal release into the water. Aggressive flushing can result in discolored water and potential for 

customer complaints.
7. References

American Public Health Association (APHA), Water Environment Federation (WEF), and 

American Water Works Association (AWWA). 2005. Standard Methods for the 

Examination of Water and Wastewater, 21st Edition, Washington, DC. 

AWWA, 1996. Water Transmission and Distribution. Denver, CO. 

AWWA, 2004. G200 – Standard for Distribution Systems Operation and Management. Denver, 

CO.

AWWA, 2008. Reliable Coliform Sampling for Water Systems, DVD, Denver, CO.

AWWA and AwwaRF. 1992. Water Industry Data Base: Utility Profiles. Denver, CO. 

Brandt, M. J., J. Clement, J. Powell, R. Casey, D. Holt, N. Harris, and C.T. Ta. 2004. Managing 

Distribution System Retention Time to Improve Water Quality, Denver, CO: AWWARF. 

Clark, R.M., E.E. Geldreich, K.R. Fox, E.W. Rice, C.H. Johnson, J.A. Goodrich, J.A. Barnick, F. 

Abdesaken, J.E. Hill, and F.J. Angulo. 1996. A Waterborne Salmonella typhimurium

outbreak in Gideon, Missouri: results from a field investigation, International Journal of 

Environmental Health Research 6:187-193. 

Great Lakes – Upper Mississippi River Board of State and Provincial Public Health and 

Environmental Managers, Water Supply Committee. 2007. Recommended Standards for 

Water Works. Albany, NY. Available at: http://www.10statesstandards.com [15 July 

2014].

Kirmeyer, G.J and M. Friedman. 2000. Guidance Manual for Maintaining Distribution System 

Water Quality. Denver, CO: AWWARF and AWWA. 

Letterman, R.D., A. Amirtharajah, and C.R. O’Melia. 1999. Coagulation and Flocculation, in 

Water Quality and Treatment, 5th edition. R.D. Letterman, ed., AWWA, Denver, CO.

National Research Council (NRC) of the National Academies. 2006. Drinking Water 

Distribution Systems, Assessing and Reducing Risks. National Academy of Sciences, 

Washington, DC. 

RTCR ACAGM - Interim Final 7-1 
Narasimhan, R., J. Brereton, M. Abbaszadegan, A. Alum, and P. Ghatpande. 2004. Sample 

Collection Procedures and Locations for Bacterial Compliance Monitoring, Awwa 

Research Foundation, Denver, CO. 

Stanford, B., A. Pisarenko, S. Snyder, and G. Gordon. 2009. The Formation of Perchlorate, 

Bromate, and Other Contaminants in Hypochlorite Solutions: Implications for Water 

Utilities. Proceedings from Water Quality Technology Conference & Expedition. Seattle, 

Washington. 

USEPA. 1998a. National Primary Drinking Water Regulations: Interim Enhanced Surface Water 

Treatment Rule; Final Rule. 63 FR 69477 (April 28, 1998). 

USEPA. 1998b. National Primary Drinking Water Regulations: Stage 1 Disinfectant Disinfection 

Byproduct Rule; Final Rule. 63 FR 69390. (December 16, 1998). 

USEPA. 2001a. A Small Systems Guide to the Total Coliform Rule (EPA 816-R-01-017a). 

Available to order at: http://www.epa.gov/nscep [3 Sep 2014]. 

USEPA. 2001b. Distribution System Issue Paper: Potential Contamination Due to CrossConnection and Backflow and the Associated Health Risks. Available at: 

http://water.epa.gov/lawsregs/rulesregs/sdwa/tcr/distributionsystems.cfm [3 Sep 2014].

USEPA. 2003. Revised Guidance Manual for Selecting Lead and Copper Control Strategies 

(EPA-816-R-03-001). Available to order at: http://www.epa.gov/nscep [3 Sep 2014].

USEPA. 2006a. National Primary Drinking Water Regulations: Stage 2 Disinfectant Disinfection 

Byproduct Rule; Final Rule. 71 FR 388. (January 4, 2006). 

USEPA. 2006b. National Primary Drinking Water Regulations: Ground Water Rule; Final Rule. 

71 FR 65574. (November 8, 2006). 

USEPA. 2006c. Total Coliform Rule: A Handbook for Small Noncommunity Water Systems 

serving less than 3,300 persons: One of the Simple Tools for Effective Performance 

(STEP) Guide Series (EPA 816-B-06-001). Available to order at:

http://www.epa.gov/nscep [3 Sep 2014] 

USEPA. 2006d. EPA’s Interactive Sampling Guide for Drinking Water System Operators (CDROM). EPA-816-C-06-001. Available to order at: http://www.epa.gov/nscep [3 Sep 

2014].

RTCR ACAGM - Interim Final 7-2 
USEPA. 2013. National Primary Drinking Water Regulations: Revisions to the Total Coliform 

Rule; Final Rule. 78 FR 10270. (February 13, 2013). 

USEPA. 2014. National Primary Drinking Water Regulations: Minor Corrections to the 

Revisions to the Total Coliform Rule; Direct Final Rule. 79 FR 10665. (February 26, 

2014).

RTCR ACAGM - Interim Final 7-3 
APPENDIX A. Summary of the RTCR Requirements

Appendix A gives a summary of the RTCR requirements (USEPA 2013 and USEPA 

2014). Several tables are presented here to make it easier for the reader to refer to specific 

requirements of the RTCR. Note that the requirements presented here are the federal 

requirements of the RTCR. States may have additional requirements specific to their programs. 

Systems should check with their state to make sure they are complying with all the RTCR 

requirements specified by the state.

List of Tables

A-1 Summary of RTCR Requirements

A-2 Sample Siting Plan Requirement for State Review and Approval 

A-3 PWS Routine Monitoring Frequency

A-4 Routine Monitoring Frequency for PWSs Serving ≤ 1,000 Persons 

A-5 Routine Monitoring Requirements for GW NCWSs Serving ≤ 1,000 Persons (NonSeasonal)

A-6 Routine Monitoring Requirements for GW NCWSs Serving ≤ 1,000 Persons (Seasonal) 

A-7 Routine Monitoring Requirements for GW CWSs Serving ≤ 1,000 Persons

Acronyms Used in this Appendix

CWS Community Water System

EC E. coli 

EC+ E. coli-positive 

GW Ground Water 

MCL Maximum Contaminant Level

MCLG Maximum Contaminant Level Goal

NA Not Applicable 

NCWS Non-Community Water System

PN Public Notification

PWS Public Water System

RTCR Revised Total Coliform Rule

SW Surface Water

TC Total Coliforms

TC+ Total Coliform-positive 

TCR Total Coliform Rule

TT Treatment Technique 

RTCR ACAGM - Interim Final A-1
Table A-1: Summary of RTCR Requirements

Element RTCR requirements

Rule construct

§§ 141.52, 141.63, 

141.853, 141.859

•

•

•

The RTCR sets an E. coli (EC) maximum contaminant level goal (MCLG) of 

zero and an EC maximum contaminant level (MCL) and a coliform treatment 

technique (TT) based on total coliform (TC) and/or EC monitoring results.

Compliance is based on the presence or absence of TC and EC and is 

determined each calendar month the PWS serves water to the public (or each 

calendar month that sampling occurs for systems on less-than-monthly 

monitoring). See sections on “Assessment” and “Violations and Public 

Notification (PN)” in this table for conditions when the coliform TT and EC 

MCL are violated.

Assessment and corrective action (if necessary) are required if PWS has a 

coliform treatment technique trigger. See sections on “Assessment” and 

“Corrective Action” in this table.

Transition from the 

1989 TCR to the 

RTCR

§§ 141.854 to 

141.857

•

•

PWSs continue on their existing 1989 TCR monitoring schedule when the 

RTCR is effective. 

Ground water (GW) systems serving 1,000 or fewer persons remain on their 

1989 TCR schedule unless or until the conditions occur as described below or 

unless otherwise directed by the state.

o Non-community water systems (NCWSs) on quarterly/annual monitoring

remain on that schedule unless/until they have an event that triggers

increased monitoring. See Table A-5 and Table A-6 in this appendix.

o Community water systems (CWSs) on reduced monitoring remain on that

schedule unless/until they have an event that triggers them to return to

monthly monitoring. See Table A-7 in this appendix.

o Monitoring schedules will be evaluated during the “special monitoring

evaluation” conducted by the state as part of the periodic sanitary survey.

RTCR ACAGM - Interim Final A-2
Element RTCR requirements

Routine Monitoring • Total coliform samples must be collected at sites that are representative of

§§ 141.853 to water quality throughout the distribution system according to a written sample

141.858 siting plan subject to state review and revision. See Table A-2 in this appendix

for additional information regarding the sample siting plan and which elements

•

•

•

•

•

of it require state approval before implementation.

Samples must be collected at regular time intervals throughout the month

except some small systems may collect them on the same day. See Table A-3

in this appendix for the minimum number of samples PWSs must collect each

month.

The number of monthly samples is based on population served. Reduced

monitoring is available for GW systems serving 1,000 or fewer people that

meet certain criteria.

Systems on less than monthly monitoring may be triggered to increase their

monitoring if certain conditions occur.

See Table A-5, Table A-6 and Table A-7 in this appendix for summaries of the

monitoring requirements (i.e., reduced monitoring and increased monitoring

criteria) for GW systems serving 1,000 or fewer people.

Each total coliform-positive routine sample must be tested for the presence of

EC and three repeat samples must be taken.

11 Monitoring provisions are included for seasonal systems, which require them

to monitor monthly, have a sample siting plan and to demonstrate stateapproved start-up procedure. Reduced monitoring may be available for some

small seasonal GW systems that meet certain criteria. See Table A-6 in this

appendix.

Repeat Monitoring

§§ 141.853, 141.858

•

•

All PWSs must take 3 repeat samples after a TC+ sample at locations specified 

in the sample siting plan.

For GW PWSs serving 1,000 people or fewer, a single sample can meet both 

the triggered source water requirements of the GWR and the repeat sample 

requirements of the RTCR, but only if the state approves the use of the single 

sample to meet both rule requirements and the use of EC as the fecal indicator. 

Otherwise, the system must take an additional source sample to comply with 

the GWR.

Additional Routine 

Monitoring

§§ 141.854, 141.855

• A PWS taking routine samples less than monthly is required to take a

minimum of 3 routine samples the following month it serves water to the

public after a TC+ sample, unless the state waives the requirement.

11 A seasonal system is defined as a non-community water system that is not operated as a public water system on a year-round 

basis and starts up and shuts down at the beginning and end of each operating period.

RTCR ACAGM - Interim Final A-3
Element RTCR requirements

Assessment

§ 141.859

•

•

•

•

The PWS must conduct a Level 1 assessment if it exceeds any of the following 

triggers:

o For systems taking ≥ 40 samples per month, the PWS exceeds 5.0% TC+

samples for the month; or

o For systems taking < 40 samples per month, the PWS has ≥ 2 TC+ samples

for the month; or

o The PWS fails to take every required repeat sample after any single routine

TC+ sample.

The PWS must ensure that a Level 2 assessment is conducted either by the 

state or a state-approved party (which could include a qualified PWS 

employee(s)) if it exceeds any of the following triggers:

o The PWS has an EC MCL violation.

o The PWS has a second Level 1 trigger within a rolling 12-month period, or

in 2 consecutive years for systems on annual monitoring.

The system must complete the assessment as soon as practical after failure to 

take a repeat sample or after notification of results (i.e., after it determines that 

an assessment trigger has been exceeded).

Assessment results and description of corrective action(s) taken must be 

submitted to the state within 30 days after determination of exceeding the 

trigger. The state must determine if the assessment is sufficient, whether or not 

a sanitary defect is found.

Corrective Action

§ 141.859

•

•

System must correct all sanitary defects found in the assessment.

For corrections not completed by the time the assessment form is submitted, 

the system must be in compliance with a state-determined schedule and must 

notify the state when completed.

Violations and 

Public Notification 

(PN)

§§ 141.153, 141.202, 

141.203, 141.204, 

141.860

•

•

EC MCL violation – when any of the following occurs; requires Tier 1 PN. 

o EC+ repeat sample following a TC+ routine sample

o TC+ repeat sample following an EC+ routine sample

o Failure to take all required repeat samples following an EC+ routine sample

o Failure to test for EC when any repeat sample is TC+

Coliform TT violation – when any of the following occurs; requires Tier 2 PN.

o Failure to conduct required assessment or corrective action within the

specified timeframe

o Failure of a seasonal system to complete a state-approved start-up procedure

RTCR ACAGM - Interim Final A-4
Element RTCR requirements

•

•

•

Monitoring violation – when any of the following occurs; requires Tier 3 PN.

o Failure to take every required routine or additional routine sample in a

compliance period

o Failure to analyze for EC following a TC+ routine sample

Reporting violation – when any of the following occurs; requires Tier 3 PN.

o Failure to submit a monitoring report or completed assessment form after a

system properly conducts monitoring or assessment

o Failure to notify the state following an EC+ sample as required by §

141.858(b)(1)

o Failure to submit certification of completion of state-approved start-up

procedure by a seasonal system

Consumer Confidence Reports – language specific to the RTCR to be included 

in report is provided in §§ 141.153(c)(4), (d)(4) and (h)(7).

Reporting and 

Recordkeeping

§ 141.861

•

•

A system must report the following to the state (in addition to those required 

by § 141.31):

o Notification of an EC+ sample or EC MCL violation by the end of the day

or before the end of the next business day if the state office is closed. In the

case of an MCL violation, the system must also issue a Tier 1 PN.

o A coliform TT violation by the end of the next business day after learning of

the violation. A coliform TT violation also requires a Tier 2 PN.

o A monitoring violation within 10 days after learning of the violation; also

requires a Tier 3 PN.

o Submission of the assessment form within 30 days of being triggered into

doing an assessment. A system must notify the state when each scheduled

corrective action is completed for corrections not completed when the form

was submitted.

o For a seasonal system, certification that it has completed a state-approved

start-up procedure.

A system must keep records of the following (in addition to those required by 

§ 141.33):

o Any assessment form and documentation of corrective actions completed for

no less than five years.

o Any repeat sample taken that meets the state criteria for extending the 24-

hour period for collecting repeat samples.

RTCR ACAGM - Interim Final A-5
Table A-2: Sample Siting Plan Requirement for State Review and Approval

Requirement

Is the system required 

to submit the plan / 

element of the plan to 

the State?

Is the plan / element of 

the plan subject to 

State review/revision?

Does the plan / element 

of the plan require 

State approval before 

implementation?

Sample siting plan

(other than below)

§ 141.853(a)(1)

No.

The state can review the 

sample siting plan 

during the sanitary 

survey or other contact 

between the state and 

the system.

Yes No

Alternative repeat 

sampling locations

(other than +/- 5 service 

connections) Yes Yes No

§ 141.853(a)(5)(i)

Less than monthly 

monitoring for 

seasonal systems

§ 141.854(i)(2)(i)

Yes Yes Yes

Use of dual purpose 

samples Yes Yes Yes

§ 141.853(a)(5)(ii)

RTCR ACAGM - Interim Final A-6
Table A-3: PWS Routine Monitoring Frequency

Minimum number of Minimum number of 

Population served TC samples per Population served TC samples per 

month month

1,000 or fewer See Table A-4 59,001 to 70,000 70

1,001 to 2,500 2 70,001 to 83,000 80

2,501 to 3,300 3 83,001 to 96,000 90

3,301 to 4,100 4 96,001 to 130,000 100

4,101 to 4,900 5 130,001 to 220,000 120

4,901 to 5,800 6 220,001 to 320,000 150

5,801 to 6,700 7 320,001 to 450,000 180

6,701 to 7,600 8 450,001 to 600,000 210

7,601 to 8,500 9 600,001 to 780,000 240

8,501 to 12,900 10 780,001 to 970,000 270

12,901 to 17,200 15 970,001 to 1,230,000 300

17,201 to 21,500 20 1,230,001 to 1,520,000 330

21,501 to 25,000 25 1,520,001 to 1,850,000 360

25,001 to 33,000 30 1,850,001 to 2,270,000 390

33,001 to 41,000 40 2,270,001 to 3,020,000 420

41,001 to 50,000 50 3,020,001 to 3,960,000 450

50,001 to 59,000 60 3,960,001 or more 480

§ 141.857 (b)

RTCR ACAGM - Interim Final A-7
Table A-4: Routine Monitoring Frequency for PWSs Serving ≤ 1,000 Persons

System Type Increased Baseline Reduced Transition to the RTCR

CWS GW NOT 

APPLICABLE 1 / month 1 / quarter Same frequency under the 1989 TCR

SW NOT 

APPLICABLE 1 / month NA NA (1 / month) 

NCWS SW NOT 

APPLICABLE 1 / month NA NA (1 / month) 

GW non-seasonal 1 / month 1 / quarter 1 / year Same frequency under the 1989 TCRa

GW seasonal NOT 

APPLICABLE 1 / month 

1 / quarter 

or 

1 / year

Same frequency under the 1989 TCRb

§§ 141.854 and 141.855 

a For annual monitoring, system must have site visit by the state or voluntary Level 2 assessment in 1st and subsequent years.

b

 For quarterly monitoring, system must identify vulnerable period for monitoring. For annual monitoring, system must identify vulnerable period 

for monitoring and have site visit by the state or voluntary Level 2 assessment in 1st and subsequent years.

RTCR ACAGM - Interim Final A-8
Table A-5: Routine Monitoring Requirements for GW NCWSs Serving ≤ 1,000 Persons (Non-Seasonal)

Baseline monitoring frequency: Quarterly (§ 141.854(b))

Reduced monitoring (annual) 

criteria

§ 141.854(e)

Increased monitoring criteria

§ 141.854(f)

Return to baseline (quarterly) 

monitoring criteria

§ 141.854(g)

Return to annual monitoring

criteria

§ 141.854(h)

The state may reduce the 

monitoring frequency for a welloperated system to no less than 

annual monitoring if the system 

demonstrates that it meets the 

following criteria:

1. The system has a clean

compliance history for a

minimum of 12 months.

2. The most recent sanitary

survey shows that the system is

free of sanitary defects or has

corrected all identified sanitary

defects, has a protected water

source and meets approved

construction standards.

3. The state has conducted an

annual site visit within the last

12 months and the system has

corrected all identified sanitary

defects. The system may

substitute a Level 2 assessment

that meets the criteria in

§141.859(b) for the state

annual site visit.

A system on reduced monitoring 

must begin either monthly or 

quarterly monitoring (in the month 

or quarter following the event, 

respectively) if any of the 

following conditions occur: 

To Monthly 

(from quarterly or annual) 

• The system triggers a Level 2

assessment or two Level 1

assessments under the

provisions of §141.859 in a

rolling 12-month period.

• The system has an E. coli

MCL violation.

• The system has a coliform

treatment technique violation.

• For systems on quarterly, the

system has two RTCR

monitoring violations or one

RTCR monitoring violation

and one Level 1 assessment in

a rolling 12-month period.

The state may reduce the 

monitoring frequency for a system 

back to quarterly monitoring, after 

it has been triggered into monthly 

monitoring, if it meets the 

following criteria:

1. Within the last 12 months, the

system must have a completed

sanitary survey or a site visit

by the state or a voluntary

Level 2 assessment by a party

approved by the state, be free

of sanitary defects and have a

protected water source.

2. The system must have a clean

compliance history for a

minimum of 12 months.

The state may reduce the 

monitoring frequency for a system 

back to annual monitoring, after it 

has been triggered into a more 

frequent monitoring, if it meets 

the following criteria:

1. Must meet “return to baseline

monitoring” criteria.

2. An annual site visit by the

state and correction of all

identified sanitary defects.

The system may substitute a

voluntary Level 2 assessment

by a party approved by the

state for the state annual site

visit in any given year.

3. The system must have in place

or adopt one or more

additional enhancements to

the water system barriers to

contamination.

• Cross connection control,

as approved by the state.

RTCR ACAGM - Interim Final A-9
Reduced monitoring (annual) 

criteria

§ 141.854(e)

Increased monitoring criteria

§ 141.854(f)

Return to baseline (quarterly) 

monitoring criteria

§ 141.854(g)

Return to annual monitoring

criteria

§ 141.854(h)

To Quarterly 

(from annual) 

• The system has one RTCR

monitoring violation.

•

•

•

•

An operator certified by 

an appropriate state 

certification program or 

regular visits by a circuit 

rider certified by an 

appropriate state 

certification program.

Continuous disinfection 

entering the distribution 

system and a residual in 

the distribution system in 

accordance with criteria 

specified by the state.

Demonstration of 

maintenance of at least a 

4-log removal or 

inactivation of viruses as 

provided for under § 

141.403(b)(3). 

Other equivalent 

enhancements to water 

system barriers as 

approved by the state.

RTCR ACAGM - Interim Final A-10
Table A-6: Routine Monitoring Requirements for GW NCWSs Serving ≤ 1,000 Persons (Seasonal)

Baseline monitoring frequency: Monthly (§ 141.853(i)(2))

Reduced monitoring (quarterly) 

criteria

§§ 141.854(g) & 141.854(i)(2)(ii) 

Reduced monitoring (annual) criteria

§§ 141.854(h) & 141.854(i)(2)(iii)

Return to monthly or quarterly monitoring 

criteria

§ 141.854(f)

The state may reduce the 

monitoring frequency to no less 

than quarterly monitoring if the 

system demonstrates that it meets 

the following criteria:

1. System must have an

approved sample siting plan

that designates the time period

for monitoring based on sitespecific considerations (e.g.,

during periods of highest

demand or highest

vulnerability to

contamination). Seasonal

systems must collect

compliance samples during

this time period.

2. Within the last 12 months, the

system must have a completed

sanitary survey or a site visit

by the state or a voluntary

Level 2 assessment by a party

approved by the state, be free

of sanitary defects and have a

protected water source.

The state may reduce the monitoring frequency for a welloperated system to no less than annual monitoring if the 

system demonstrates that it meets the following criteria:

1. System must meet “reduced quarterly monitoring”

criteria.

2. An annual site visit by the state and correction of all

identified sanitary defects. The system may substitute a

voluntary Level 2 assessment by a party approved by

the state for the state annual site visit in any given year.

3. The system must have in place or adopt one or more

additional enhancements to the water system barriers to

contamination.

• Cross connection control, as approved by the state.

• An operator certified by an appropriate state

certification program or regular visits by a circuit

rider certified by an appropriate state certification

program.

• Continuous disinfection entering the distribution

system and a residual in the distribution system in

accordance with criteria specified by the state.

A system on a reduced monitoring frequency 

must begin monthly or quarterly monitoring 

(in the month or quarter following the event, 

respectively) if any of the following conditions 

occurs:

Monthly 

(from quarterly or annual) 

• The system triggers a Level 2 assessment

or two Level 1 assessments under the

provisions of §141.859 in a rolling 12-

month period.

• The system has an EC MCL violation.

• The system has a coliform treatment

technique violation.

• The system has two RTCR monitoring

violations.

• The system has one RTCR monitoring

violation and one Level 1 assessment in a

rolling 12-month period for a system on

quarterly monitoring.

RTCR ACAGM - Interim Final A-11
Reduced monitoring (quarterly) 

criteria

§§ 141.854(g) & 141.854(i)(2)(ii) 

Reduced monitoring (annual) criteria

§§ 141.854(h) & 141.854(i)(2)(iii)

Return to monthly or quarterly monitoring 

criteria

§ 141.854(f)

• Demonstration of maintenance of at least a 4-log

3. The system must have a clean removal or inactivation of viruses as provided for Quarterly 

compliance history for a under § 141.403(b)(3). (from annual) 

minimum of 12 months.

• Other equivalent enhancements to water system • The system has one RTCR monitoring

barriers as approved by the state. violation.

RTCR ACAGM - Interim Final A-12
Table A-7: Routine Monitoring Requirements for GW CWSs 

Baseline monitoring frequency: Monthly (§ 141.855(b))

Serving ≤ 1,000 Persons

Reduced monitoring (quarterly) criteria

§ 141.855(d)

Return to monthly monitoring criteria 

§ 141.855(e)

The state may reduce the monitoring frequency to no 

less than quarterly monitoring if a system demonstrates 

that it meets the following criteria:

1. The system is in compliance with the state-certified

operator provisions.

2. The system has a clean compliance history for a

minimum of 12 months.

3. The most recent sanitary survey shows the system

is free of sanitary defects (or has an approved plan

and schedule to correct them and is in compliance

with the plan and the schedule), has a protected

water source and meets approved construction

standards.

4. The system meets at least one of the following

criteria:

• An annual site visit by the state that is

equivalent to a Level 2 assessment or an

annual Level 2 assessment by a party approved

by the state and correction of all identified

sanitary defects (or an approved plan and

schedule to correct them and is in compliance

with the plan and schedule).

• Cross connection control, as approved by the

state.

• Continuous disinfection entering the

distribution system and a residual in the

distribution system in accordance with criteria

specified by the state.

• Demonstration of maintenance of at least a 4-

log removal or inactivation of viruses as

provided for under § 141.403(b)(3) of the

GWR.

• Other equivalent enhancements to water

system barriers as approved by the state.

A system on a quarterly monitoring frequency 

must return to a monthly monitoring frequency in 

the month following the occurrence of any of the 

following events: 

• The system loses its certified operator.

• The system triggers a Level 2 assessment or

two Level 1 assessments in a rolling 12-month

period.

• The system has an E. coli MCL violation.

• The system has a coliform treatment technique

violation.

• The system has two RTCR monitoring

violations in a rolling 12-month period.

RTCR ACAGM - Interim Final A-13
APPENDIX B. Example Assessment Forms

The following are examples of Level 1 and Level 2 assessment forms developed by the Total 

Coliform Rule Distribution System Advisory Committee Technical Work Group. States may 

develop their own forms that address the five minimum elements of an assessment.

RTCR ACAGM - Interim Final B-1 
CONCEPT EXAMPLE

Level 1 Assessment Form

(Developed by the Technical Workgroup Supporting the Total Coliform Rule Distribution System Advisory Committee)

RTCR ACAGM - Interim Final B-2 

System Name: Source Water: PWSID #

System Type: Population Served: PWS Address:

Operator in Responsible Charge (ORC): Phone:

City, State:

County:

Person that collected TC samples if different than ORC: Phone:

Address, City, State, Zip:

Date Assessment Completed:

Reviewed? 

Questions

(check if 

completed 

or type 

N/A)

Issue(s) 

Found? 

(Y/N)

Issue Description Corrective Action Taken (Including Date)

1. Evaluate sample site.

-condition or location of tap

-regular use of connection

2. Sample protocol followed and reviewed. -flush tap

-remove aerator

-no swivel

-fresh sample bottles

collection of TC samples?

3.

 

 

 

-

-

-

-

H

operation and maintenance activities that could have introduced total coliform 

a

sample storage acceptable

any reported loss of pressure events (5 psi) 

ny in

ave any of the following occurred at relevant facilities prior to the 

terruptions in the treatment process

EXAMPLE -reported vandalism and/or unauthorized access to facilities 

 -visible indicators of unsanitary conditions reported 

 -Has there been a fire fighting event, flushing operation, sheared hydrant, etc.

 

4. Have there been any recent 

-sources introduced

-treatment or operational changes 

-potential sources of contamination

operational changes to the system?

5. Distribution System

-system pressure

-cross connection

-pump station

-air relief valves 

-fire hydrants or blow off

-breaks

-repairs

6. Storage Tank -screens 

-security

-access opening

-condition of tank

-vent

-drain overflow

-pressure tank

-O&M
CONCEPT EXAMPLE

Level 1 Assessment Form

(Developed by the Technical Workgroup Supporting the Total Coliform Rule Distribution System Advisory Committee)

EXAMPLE

Questions

Reviewed? 

(check if 

completed 

or type 

N/A)

Issue(s) 

Found? 

(Y/N)

Issue Description Corrective Action Taken (Including Date)

7. Treatment Process -interruptions

-POE/POU

-softeners

-O&M

8. Source – Well -sanitary seal

-vent screened

-air gap

-cross connection

-security

-pump to waste line

9. Source – Spring -condition of spring development

-condition of spring box

-security

10. Source - Surface Water Supply -heavy rainfall

 -rapid snowmelt

Note: Form to be completed based on data and documents available to the PWS operator in charge, maintained on file and returned to the Primacy Agency within 30 days of triggering the assessment. 

Additional Comments:

Print name of person completing form: Date: 

Signature:

Reserved for State

1. Assessment has been successfully completed.

2. Likely reason for total coliform-positives occurrence is established.

3. System has corrected the problem.

4. Was a reset requested and / or granted? – Rationale

5. Name of State reviewer:

RTCR ACAGM - Interim Final B-3 
CONCEPT EXAMPLE

Level 2 Assessment Form

(Developed by EPA and the Technical Workgroup Supporting the Total Coliform Rule Distribution System Advisory Committee)

System Name: Source Water: PWSID #

System Type: Population Served: PWS Address:

Operator in Responsible Charge (ORC): Phone:

City, State:

County:

Person that collected TC samples if different than ORC: Phone:

Address, City, State, Zip:

Date Assessment Completed:

RTCR ACAGM - Interim Final B-4 

 Questions Reviewed? (check if 

completed or type N/A)

Issue(s) Found? 

(Y/N) Issue Description Corrective Action Taken 

(Including Date)

1. Evaluate sample site

a. What is the condition of the tap?

(Provide comments)

b. What is the location of the tap?

(Provide comments)

c.

d.

What is the regular use of the connection?

(Provide comments)

Have there been any plumbing changes or 

or change?

construction? If yes, when and what was the repair EXAMP LE 

e. Have there been any plumbing breaks or failure? If 

yes, when?

List any identified cross connections after the service 

f. connection or in premise plumbing.

(Provide comments)

g. Were all of the backflow prevention 

operational and maintained?

devices present, 

Were there any low pressure events or changes in 

h. water pressure after the service connection or in the

premise plumbing? If yes, when?

Are there any treatment devices after the service 

i. connection or in premise? Point of Entry (POE) Point of Use (POU)

(Circle response, if applicable)

j. Other comments on sample site?
CONCEPT EXAMPLE

Level 2 Assessment Form

(Developed by EPA and the Technical Workgroup Supporting the Total Coliform Rule Distribution System Advisory Committee)

 Questions Reviewed? (check if 

completed or type N/A)

Issue(s) Found? 

(Y/N) Issue Description Corrective Action Taken (Including Date)

2. Sample protocol followed and reviewed

2. Sample protocol followed and reviewed

a. Flush tap, remove aerator, no swivel, fresh sample

bottles, sample storage acceptable

3. Have any of the following occurred at relevant

facilities prior to the collection of TC samples?

a. Were there any operation and maintenance activities

that could have introduced total coliforms?

b. Have there been any interruptions in the treatment

process?

c. Has the system lost pressure to less than 5 psi?

d. Have there been any 

access to facilities?

vandalism and/or unauthorized 

e. Are there any visible indicators of unsanitary 

conditions observed? 

f.

Have there been any analytical results or any 

additional samples collected, including source 

samples which were positive (not for compliance)? EXAMP 

g.

H

being waterborne (e.g., Does the community public 

health official indicate that an outbreak has occurred.)

ave there been any community illness suspected of 

 LE 

h. Did the water system receive any TCR monitoring

violations in the past 12 months? If yes, when.

i. What was the most recent date on which satisfactory

total coliform samples were taken? Date: ______________

j. Have there been a fire fighting event, flushing

operation, sheared hydrant, etc.

k. Other comments on records and maintenance?

4. Have there been any recent treatment 

operational changes?

or 

a. Have any inactive sources recently been introduced

into the system (e.g., auxiliary systems)?

b. Have there been any new sources introduced into the

system?

c. Is there evidence of any potential sources of

contamination (main breaks, low pressure, high

RTCR ACAGM - Interim Final B-5 
CONCEPT EXAMPLE

Level 2 Assessment Form

(Developed by EPA and the Technical Workgroup Supporting the Total Coliform Rule Distribution System Advisory Committee)

 Questions Reviewed? (check if 

completed or type N/A)

Issue(s) Found? 

(Y/N) Issue Description Corrective Action Taken (Including Date)

turbidity, loss of disinfection, etc.)?

5. Distribution System

a. System pressure: Is there evidence that the system

experienced low or negative pressure? If yes, when?

b. List any identified cross connections.

c. Pump station: Are there any sanitary defects in the

pump station? Are pump(s) operable?

d. Last pump maintenance/service date.

(Respond if applicable) Date: _____________ Maintenance Performed?

e. Air relief valves: Is the valve vault subject to

flooding or does the vent terminate below grade?

f. Fire hydrant/blow off: Are any located in an area

with a high water table or pits?

g.

Is the distribution system secured to prevent

unauthorized access?

h. Are the backflow prevention devices at high risk sites 

present, operational and maintained? 

i. Have there been any water main repairs or additions? 

If yes when, and what was the repair or addition? EXAMPLE 

j. Have there been any 

when?

water main breaks? If yes, 

k. Was there any scheduled flushing of the distribution 

system? If yes, when? 

l. Is there any evidence of intentional contamination in

the distribution system?

m. Other comments on the distribution information.

6. Storage Facilities

a. Are the overflow and vents properly screened?

b. Is the facility secured to prevent unauthorized access?

c. Does the Access opening 

seal tightly?

have the proper gasket and 

d. Could the physical condition of tank be a source 

contamination?

of 

RTCR ACAGM - Interim Final B-6 
CONCEPT EXAMPLE

Level 2 Assessment Form

(Developed by EPA and the Technical Workgroup Supporting the Total Coliform Rule Distribution System Advisory Committee)

 Questions Reviewed? (check if 

completed or type N/A)

Issue(s) Found? 

(Y/N) Issue Description Corrective Action Taken (Including Date)

e. Is the Vent turned down and maintain an approved air

gap at the termination point?

f. Does the Drain/overflow line terminate a minimum

of 12" air gap?

g.

If present, Is the Pressure tank maintaining an

appropriate minimum pressure?

h. Is proper O&M being performed?

i. Was there any observed physical deterioration of 

tank?

the 

j. Were there any observed leaks?

k. Is there any evidence of intentional contamination at

the storage tank?

l. Have there been any facility maintenance?

painting/coating) If yes, when?

(i.e. 

m. Is facility 

schedule?

maintenance occurring per appropriate 

n. Does the tank "float" on the distribution system or are

there separate inlet and outlet lines?

o. What is the measured chlorine residual (total/free) of

the water exiting the storage tank today? Residual ____________ 

p.

Are there any unsealed openings in the storage

facility such as access doors, vents or joints? 

q. Other comments on the storage system

7.

a. Trea

Treatment Process

tment devices operational and maintained?

. (If applicable) EXAMPLE 

b. Is there any recent installation 

equipment?

or repair of treatment 

c. Were there any recent changes in the treatment

process? If yes, when, what was the change?

d.

Were there any interruptions of treatment (lapses in 

chemical feed, turbidity excursions, disinfection)? If 

yes which part, when and for how long?

What is the free chlorine residual measured 

e. immediately downstream from the point of

application?

Residual: _____

RTCR ACAGM - Interim Final B-7 
CONCEPT EXAMPLE

Level 2 Assessment Form

(Developed by EPA and the Technical Workgroup Supporting the Total Coliform Rule Distribution System Advisory Committee)

 Questions Reviewed? (check if 

completed or type N/A)

Issue(s) Found? 

(Y/N) Issue Description Corrective Action Taken (Including Date)

f. Did a review of the filter turbidity profiles reveal any

anomalies?

g. Were there any failures to meet the CxT calculations?

h. Were the flow rates above the rated capacity?

i. Were there any anomalies on the settled water

turbidities? 

j. Other comments on the treatment system.

8. Source – Well

a. Is the sanitary seal intact? EXAMPLE 

b. Is the vent screened? 

c. Does the vent and pump to waste terminate in an 

approved air gap?

d. Are there any unprotected cross connections at 

wellhead?

the 

e. How is the well used?

(Circle if applicable) Primary Backup Emergency Not a PWS Not Drinking Water

f. How far does the casing extend above grade? Height ____________ Comments:

g. Is the well cap vented?

h. Is there evidence of standing water near the

wellhead?

i. Is the wellhead secured to 

access?

prevent unauthorized 

j. Have there been any sewer spills, source water spills

or other disturbances?

k.

Other comments on the well system. (Are there 

aspects of well construction and operation that would 

bear on observed positives?) 

9. Source – Spring

a. What is the condition of the spring development?

b. What is the condition of the spring box?

c. Is the spring secured to prevent unauthorized access?

RTCR ACAGM - Interim Final B-8 
CONCEPT EXAMPLE

Level 2 Assessment Form

(Developed by EPA and the Technical Workgroup Supporting the Total Coliform Rule Distribution System Advisory Committee)

 Questions Reviewed? (check if 

completed or type N/A)

Issue(s) Found? 

(Y/N) Issue Description Corrective Action Taken (Including Date)

d. Other comments on the spring system.

10. Source - Surface Water Supply

a. Have there been any sewer spills, source water spills

or other disturbances?

b. Have there been any Algal blooms?

c. Has source water turnover occurred?

d. Other source water comments

11. Environmental Events

a. Has there been heavy rainfall?

b. Has there been any rapid snow melt or flooding? 

c.

Have there been changes in available source water

(e.g., significant drop in water table, well levels, 

reservoir capacity, etc.)

 

d. Have there been any Interruptions to electrical 

power? 

e. Have there been any extremes in heat or cold? E MPLE 

Note: Form to be completed based on data and documents available to the PWS operator in charge, maintained on file and returned to the Primacy Agency within 30 days of 

triggering the assessment. 

Additional Comments:

XA

Print name of person completing form: Date: 

Signature:

Reserved for State

1. Assessment has been successfully completed. Name of State Reviewer:

RTCR ACAGM - Interim Final B-9 
APPENDIX C. Examples of Completed Assessments

This appendix provides examples of completed Level 1 and Level 2 assessment forms (using the 

forms presented in Appendix B). Some states are already requiring some form of assessment and 

the completion of an assessment form whenever a PWS has a total coliform-positive sample. 

Those states provided EPA with some of the completed assessments performed by their 

respective PWSs. EPA developed the examples in this appendix based on the assessment forms 

provided by the states. Personal information about the PWS or any person mentioned in the 

example forms is fictitious in nature. They are provided to show the types of information that are 

expected to be included in the form. 

Table C-1: List of Examples

Population 

Served 

Example 

No. System Type Source Water 

(Number of 

routine TC 

samples per 

month)

Assessment 

Type Identified sanitary defect

1 NCWS (nontransient) Ground 

Water

120 (1) Level 1 None 

2 CWS Ground 

Water

24,200 ( 25) Level 1 Air release valve 

submerged in flooded vault 

3 CWS Spring 5,500 (6) Level 1 Small fractures in 

main

the water 

4 CWS Ground 

water 

under the 

direct 

influence 

985,000 (300) Level 1 Pressure loss that resulted 

in stagnant water in one of 

the tanks to be pulled into 

the distribution system

of surface 

water

5 CWS Ground 

water

2,250 (3) Level 2 Unsanitary conditions 

around a well 

6 NCWS 

(transient)

Ground 

water

200 (1 / 

quarter)

Level 2 Inadequate chlorination 

after a repair / replacement 

activity

RTCR ACAGM - Interim Final C-1
Assessment Form Instructions

1. Fill in system information under the first section of the form. The following information must

be provided at a minimum:

• System Name

• Source Water (GW, SW, GWUDI, Purchased)

• System Type (CWS, NTNCWS, TNCWS)

• Population Served

• Operator in Responsible Charge (ORC)

• Phone

• City, State

• PWSID #

• PWS Address

2. Respond to all Questions 1-10:

• Type “” in the box for the items that were reviewed and checked or “N/A” if the item is

not applicable to the system.

• Print “Yes” or “No” in the “Issue(s) found?” column.

• Describe any issues found and corrective action taken.

• Be sure to include dates of any corrective actions taken.

3. Sign and date form on last page. Form must be completed based on data and documents

available to the PWS operator in charge, maintained on file and sent to the primacy agency

within 30 days of triggering the assessment.

RTCR ACAGM - Interim Final C-2
Example No. 1 – Level 1 Assessment 

UTILITY PROFILE

Buttermilk Falls Country Club is a non-transient, non-community water system that gets its 

water from a ground water source. It collects 1 routine sample per month. The system does not 

have any records of past violations. 

DESCRIPTION OF THE PROBLEM

In November 2009, the routine monthly sample and one of its associated repeat samples came 

back positive for total coliforms. This triggered a Level 1 assessment. 

ASSESSMENT AND CORRECTIVE ACTION

All applicable items listed in the Level 1 assessment form were all checked. Nothing unusual 

was found and all of the subsequent repeat samples came back negative. 

RTCR ACAGM - Interim Final C-3
CONCEPT EXAMPLE NO. 1

Level 1 Assessment Form

System Name: Buttermilk Falls Country Club Source Water: Ground Water PWSID # 1234567

System Type: NTNCWS Population Served: 120 PWS Address: 

Operator in Responsible Charge (ORC): J. Griffin Phone: 012-345-6789 123 Anyway St., Buttermilk Falls, MS 10000

City, State: Buttermilk Falls, MS

County: Hoover

Person that 

Labs 

collected TC samples if different than ORC: C. Gary, HHH Phone: 123-456-7890

Address, City, State, Zip: 222 Second St., Buttermilk Falls, MS 12121

Date Assessment Completed: 11/12/2009

Reviewed

Questions

and 

checked? 

(Type “” 

if completed 

or “N/A”)

Issue(s) 

found? 

(Y/N)

Issue Description Corrective Action Taken (Including Date)

1. Evaluate sample site.

-condition or location of tap

-regular use of connection

 No

2. Sample protocol followed and reviewed. -flush tap

-remove aerator

-no swivel  No

-fresh sample bottles

-sample storage acceptable

3. Have any of the following occurred at relevant facilities prior to the

collection of TC samples? -any interruptions in the treatment process

-any reported loss of pressure events (5 psi) 

-operation and maintenance activities that could have introduced total coliform 

-reported vandalism and/or unauthorized access to facilities 

-visible indicators of unsanitary conditions reported 

-Has there been a fire fighting event, flushing operation, sheared hydrant, etc.

 No

4. Have there been any recent 

-sources introduced

-treatment or operational changes 

-potential sources of contamination

operational changes to the system?

 No

5. Distribution System

-system pressure

-cross connection

-pump station

-air relief valves  No

-fire hydrants or blow off

-breaks

-repairs

RTCR ACAGM - Interim Final C-4 
CONCEPT EXAMPLE NO. 1

Level 1 Assessment Form

Reviewed

Questions

and 

checked? 

(Type “” 

if completed 

or “N/A”)

Issue(s) 

found? 

(Y/N)

Issue Description Corrective Action Taken (Including Date)

6. Storage Tank

-screens 

-security

-access opening

-condition of tank

-vent

N/A

-drain overflow

-pressure tank

-O&M

7. Treatment Process -interruptions

-POE/POU

-softeners

N/A

-O&M

8. Source - Well -sanitary seal

-vent screened

-air gap

-cross connection

 No

-security

-pump to waste line

9. Source - Spring -condition of spring development

-condition of spring box

-security

N/A

10. Source - Surface Water Supply -heavy rainfall

 -rapid snowmelt

N/A

Note: Form to be completed based on data and documents available to the PWS operator in charge, maintained on file and returned to the Primacy Agency within 30 days of triggering the assessment. 

Additional Comments:

At this time, the obvious cause of the total coliform-positive results has not been identified.

Reserved for State

1. Assessment has been successfully completed.

2. Likely reason for total coliform-positive occurrence is established.

3. System has corrected the problem.

4. Was a reset requested and / or granted? – Rationale

5. Name of State reviewer:

RTCR ACAGM - Interim Final C-5 
RTCR ACAGM - Interim Final C-6

Example No. 2 – Level 1 Assessment

UTILITY PROFILE

Silver Lake is a mid-sized community water system that supplies treated ground water to 

approximately 24,200 people. It collects 25 routine samples per month. 

DESCRIPTION OF THE PROBLEM

The system received a notice of violation for failing to take all of the required repeat samples 

after a total coliform-positive sample was detected, triggering the system to have a Level 1 

assessment. 

ASSESSMENT AND CORRECTIVE ACTION

Upon thorough inspection of the distribution system, an air release valve was found submerged 

in a flooded valve vault. A permanent sump pump will be installed in the vault based on a 

schedule approved by the State. Shock chlorination measures were performed in accordance with 

State guidelines on the portion of the line where the air release valve was located. 
CONCEPT EXAMPLE NO. 2

Level 1 Assessment Form

RTCR ACAGM - Interim Final 

System Name: Silver Lake Source Water: Ground Water PWSID # 2345671

System Type: CWS Population Served: 24,200 PWS Address:

Operator in Responsible Charge (ORC): J. Troy Phone: 012-345-6789 123 Anyway St., Silver Lake, MI 10000

City, State: Silver Lake, MI 

County: Hamilton 

 

 

 

Person 

Labs 

that collected TC samples if 

 

different than ORC: B. Black, CDE Phone: 123-456-7890

Address, City, State, Zip: 111 First St., Gold Water, MI 20000 

Date Assessment Completed: 02/12/2010 

Reviewed

Questions

and 

checked? 

(Type “” 

if completed 

or “N/A”) 

Issue(s) 

found? 

(Y/N)

Issue Description Corrective Action Taken (Including Date)

1. Evaluate sample site. -condition or location of tap

 -regular use of connection

 No 

2. Sample protocol followed and reviewed.

 -flush tap

 -remove aerator

 -no swivel  No 

 -fresh sample bottles

 -sample storage acceptable

3. Have any of the following occurred at relevant facilities prior to the 

collection of TC samples?

 -any interruptions in the treatment process

 -any reported loss of pressure events (5 psi) 

 -operation and maintenance activities that could have introduced total coliform 

 -reported vandalism and/or unauthorized access to facilities 

 -visible indicators of unsanitary conditions reported 

 -Has there been a fire fighting event, flushing operation, sheared hydrant, etc.

 No 

4. Have there been any recent -sources introduced

 -treatment or operational changes 

 -potential sources of contamination

operational changes to the system?

 No 

5. Distribution System -system pressure

 -cross connection

 -pump station

 -air relief valves 

 -fire hydrants or blow off

 -breaks

 -repairs

 Yes

Visual inspection of distribution 

system conducted on 2/11/10 revealed 

a potential contamination source at 

end of distribution system. An air 

release valve was found submerged in 

a flooded vault.

Sump pump to be installed at potential 

contamination site on 2/20/10. State approved 

corrective action beyond the 30-day period. Shock 

chlorination performed in accordance with State 

guidelines on portion of water line where air valve 

is located.

C-7
CONCEPT EXAMPLE NO. 2

Level 1 Assessment Form

RTCR ACAGM - Interim Final C-8

Reviewed

Questions

and 

checked? 

(Type “” 

if completed 

or “N/A”) 

Issue(s) 

found? 

(Y/N)

Issue Description Corrective Action Tak

6. Storage Tank

-screens 

-security

-access opening

-condition of tank  No -vent

-drain overflow

-pressure tank

-O&M

7. Treatment Process -interruptions

-POE/POU

-softeners

 No

-O&M

8. Source – Well -sanitary seal

-vent screened

-air gap

-cross connection

 No

-security

-pump to waste line

9. Source – Spring -condition of spring development

-condition of spring box

-security

N/A

10. Source - Surface Water Supply -heavy rainfall

 -rapid snowmelt

N/A

en (Including Date)

Note: Form to be completed based on data and documents available to the PWS operator in charge, maintained on file and returned to the Primacy Agency within 30 days of trigg

Additional Comments:

ering the assessment. 

Print name of person completing form: Adam Lockland Date: 02-12-2010

Signature:

Reserved for State

1. Assessment has been successfully completed.

2. Likely reason for total coliform-positive occurrence is established.

3. System has corrected the problem.

4. Was a reset requested and / or granted? – Rationale

5. Name of State reviewer:
RTCR ACAGM - Interim Final C-9 

Example No. 3 – Level 1 Assessment

UTILITY PROFILE

Eagle Cliff is a community water system that receives its water from a spring source and serves 5,500 

people. It collects 6 routine samples per month. 

DESCRIPTION OF THE PROBLEM

In July 2009, the routine sample and one of its associated repeat samples both came back total 

coliform-positive triggering a Level 1 assessment. 

ASSESSMENT AND CORRECTIVE ACTION

Upon inspection of the distribution system piping, small factures were found in the water main leading 

from the spring source to a water tank. The piping was replaced and additional samples were taken to 

determine whether coliforms were still present in the system. The results came back negative. 
CONCEPT EXAMPLE NO. 3

Level 1 Assessment Form

System Name: Eagle Cliff Source Water: Spring PWSID # 3456712

System Type: CWS Population Served: 5,500 PWS Address:

Operator in Responsible Charge (ORC): F. Langdon Phone: 012-345-6789 456 Anyway St., Eagle Cliff, AL 10000

City, State: Eagle Cliff, AL

County: Hoover

Person that collected TC samples if different than ORC: C. Heart Phone: 123-456-7890

Address, City, State, Zip: 333 Third St., Eagle Cliff, AL 10000

Date Assessment Completed: 9/1/2009

RTCR ACAGM - Interim Final C-10

Reviewed

Questions

and 

checked? 

(Type “” 

if completed 

or “N/A”)

Issue(s) 

found? 

(Y/N)

Issue Description Corrective Action Taken (Including Date)

1. Evaluate sample site.

-condition or location of tap

-regular use of connection

 No

2. Sample protocol followed and reviewed.

-flush tap

-remove aerator

-no swivel  No

-fresh sample bottles

-sample storage acceptable

3. Have any of the following occurred at relevant facilities prior to the

collection of TC samples?

-any interruptions in the treatment process

-any reported loss of pressure events (5 psi) 

-operation and maintenance activities that could have introduced total coliform 

-reported vandalism and/or unauthorized access to facilities 

-visible indicators of unsanitary conditions reported 

-Has there been a fire fighting event, flushing operation, sheared hydrant, etc.

 No

4. Have there been any recent 

-sources introduced

-treatment or operational changes 

-potential sources of contamination

operational changes to the system?

 No

5. Distribution System

-system pressure

-cross connection

-pump station

-air relief valves 

-fire hydrants or blow off

-breaks

 Yes Small fractures detected 

line from spring to tank.

in raw water Raw water line replacement completed on 

8/30/2009

-repairs

6. Storage Tank

-screens 

-security

-access opening

-condition of tank  No -vent

-drain overflow

-pressure tank

-O&M
CONCEPT EXAMPLE NO. 3

Level 1 Assessment Form

RTCR ACAGM - Interim Final C-11

Reviewed

Questions

and 

checked? 

(Type “” 

if completed 

or “N/A”)

Issue(s) 

found? 

(Y/N)

Issue Description Corrective Action Taken (Including Date)

7. Treatment Process -interruptions

-POE/POU

-softeners

 No

-O&M

8. Source - Well -sanitary seal

-vent screened

-air gap

-cross connection

N/A

-security

-pump to waste line

9. Source - Spring -condition of spring development

-condition of spring box

-security

 No

10. Source - Surface Water Supply -heavy rainfall

 -rapid snowmelt

N/A

Note: Form to be completed based on data and documents available to the PWS operator in charge, maintained on file and returned to the Primacy Agency within 30 days of triggering the assessment. 

Additional Comments:

Print name of person completing form: Michael Taylor Date: 09-01-2009

Signature:

Reserved for State

1. Assessment has been successfully completed.

2. Likely reason for total coliform-positive occurrence is established.

3. System has corrected the problem.

4. Was a reset requested and / or granted? – Rationale

5. Name of State reviewer:
RTCR ACAGM - Interim Final C-12

Example No. 4 – Level 1 Assessment

UTILITY PROFILE

Eggleston Glen is a large municipal water system that is supplied by a ground water source under 

the direct influence of surface water (GWUDI). The system treats its water before serving it to its 

985,000 customers. It collects over 300 routine samples per month. 

DESCRIPTION OF THE PROBLEM

In August 2009, more than 5.0% of the monthly total coliform samples came back positive 

triggering a Level 1 assessment. Many of the positive samples were in the same general location 

in the distribution system and in proximity to a large ground storage tank. Several days prior to 

the collection of the positive samples, the system experienced pressure loss for a period of 4 

hours while the media in the GAC filters at one of the plants was being changed out. During this 

time the tank levels dropped to near empty. 

ASSESSMENT AND CORRECTIVE ACTION

Normally stagnant water from the tank entered the distribution system during the pressure loss 

event causing the total coliform-positive results. The tank was taken off-line, cleaned and shock 

chlorinated in accordance with State guidelines before putting it back on service. The distribution 

system near the tank was also flushed to improve water turnover. 
CONCEPT EXAMPLE NO. 4

Level 1 Assessment Form

RTCR ACAGM - Interim Final C-13

System Name: Eggleston Glen Source Water: GWUDI PWSID # 4567123

System Type: CWS Population Served: 985,000 PWS Address:

Operator in Responsible Charge (ORC): J. Griffin Phone: 012-345-6789 123 Anyway St., Eggleston Glen, CO 10000

City, State: Eggleston Glen, CO

County: Hoover

Person that 

Labs 

collected TC samples if different than ORC: V. Lewis, GHG Phone: 123-456-7890

Address, City, State, Zip: 444 Fourth St., Littletown, CO 20000

Date Assessment Completed: 8/28/2009

Reviewed

Questions

and 

checked? 

(Type “” 

if completed 

or “N/A”)

Issue(s) 

found? 

(Y/N)

Issue Description Corrective Action Taken (Including Date)

1. Evaluate sample site.

-condition or location of tap

-regular use of connection

 No

2. Sample protocol followed and reviewed.

-flush tap

-remove aerator

-no swivel  No

-fresh sample bottles

-sample storage acceptable

3. Have any of the following occurred at relevant facilities prior to the

collection of TC samples? -any interruptions in the treatment process

-any reported loss of pressure events (5 psi) 

-operation and maintenance activities that could have introduced total coliform 

-reported vandalism and/or unauthorized access to facilities 

-visible indicators of unsanitary conditions reported 

-Has there been a fire fighting event, flushing operation, sheared hydrant, etc.

 Yes

Loss of system pressure for 4 hours 

while changing media in GAC filters. 

Tank level dropped to near empty. 

This may have allowed "old" water to 

enter the system from system tank.

Distribution system flushed on 8/15/2009, 

especially near the tank to improve turnover. Tank 

was taken off-line, cleaned and shock chlorinated 

in accordance with State guidelines before putting 

it back on service. Chlorine will be checked at 

sample location at least two times per month. 

4. Have there been any recent 

-sources introduced

-treatment or operational changes 

-potential sources of contamination

operational changes to the system?

 No

5. Distribution System

-system pressure

-cross connection

-pump station

-air relief valves  No

-fire hydrants or blow off

-breaks

-repairs
CONCEPT EXAMPLE NO. 4

Level 1 Assessment Form

RTCR ACAGM - Interim Final C-14

Reviewed

Questions

and 

checked? 

(Type “” 

if completed 

or “N/A”)

Issue(s) 

found? 

(Y/N)

Issue Description Corrective Action Taken (Including Date)

6. Storage Tank

-screens 

-security

-access opening

-condition of tank  No -vent

-drain overflow

-pressure tank

-O&M

7. Treatment Process -interruptions

-POE/POU

-softeners

 No

-O&M

8. Source - Well -sanitary seal

-vent screened

-air gap

-cross connection

 Yes See item No. 1

-security

-pump to waste line

9. Source - Spring -condition of spring development

-condition of spring box

-security

 No

10. Source - Surface Water Supply -heavy rainfall

 -rapid snowmelt

N/A

Note: Form to be completed based on data and documents available to the PWS operator in charge, maintained on file and returned to the Primacy Agency within 30 days of triggering the assessment. 

Additional Comments:

Print name of person completing form: John Gilmore Date: 08-28-2009

Signature:

Reserved for State

1. Assessment has been successfully completed.

2. Likely reason for total coliform-positive occurrence is established.

3. System has corrected the problem.

4. Was a reset requested and / or granted? – Rationale

5. Name of State reviewer:
RTCR ACAGM - Interim Final C-15

Example No. 5 – Level 2 Assessment

UTILITY PROFILE

Warsaw Falls is a community water system that gets its water from ground water sources. It 

serves a population of 2,550 people and collects 3 routine samples every month. 

DESCRIPTION OF THE PROBLEM

In January 2010, the system had an E. coli MCL violation (a routine sample that was E. colipositive followed by a repeat sample that was total coliform-positive) that triggered a Level 2 

assessment. 

ASSESSMENT AND CORRECTIVE ACTION

The Level 2 assessment revealed unsanitary conditions around one particular well that was 

located in a parking lot, which may or may not have been the source of the contamination. The 

system operator noted the need to re-locate or significantly improve the well due to its location 

and the poor condition of the well casing. The system coordinated with the State to develop 

interim measures and to work out a schedule to perform the remaining corrective action beyond 

the 30-day period. The pressure tank was also recently replaced but was not believed to be the 

source of the contamination as the whole system was shock chlorinated after the tank was 

replaced.
CONCEPT EXAMPLE NO. 5

Level 2 Assessment Form

RTCR ACAGM - Interim Final C-16

System Name: Warsaw Falls Recreation Center Source Water: Ground Water PWSID # 5671234

System Type: CWS Population Served: 2,550 PWS Address:

Operator in Responsible Charge (ORC): Peter Garrison Phone: 012-345-6789 123 Anyway St., Warsaw 

10000

Falls, FL 

City, State: Warsaw Falls, FL

County: Ford

Person that collected TC samples if different than ORC: J. Smith, ABC Labs Phone: 123-456-7890

Address, City, State, Zip: 012 Main St., Bigtown, FL 11111

Date Assessment Completed: 02/10/2010

 Questions

Reviewed 

and 

checked? 

(Type “” 

if 

completed 

or “N/A”)

Issue(s) 

found? 

(Y/N)

Issue Description Corrective Action Taken 

(Including Date)

1. Evaluate sample site

a. What is the condition of the tap?

(Provide comments) Good

b. What is the location of the tap?

(Provide comments) Good

c. What is the regular use of the connection?

(Provide comments)

Raw water 

tap for 

sample 

collection

d. Have there been any plumbing changes or construction?

yes, when and what was the repair or change?

 If  No

e. Have there been any plumbing breaks or failure? If 

when?

yes,  No

f.

List any identified cross connections after the service 

connection or in premise plumbing. 

(Provide comments)

None

g. Were all of the backflow prevention 

operational and maintained?

devices present,  No

h.

Were there any low pressure events or changes in water 

pressure after the service connection or in the premise 

plumbing? If yes, when?  No
CONCEPT EXAMPLE NO. 5

Level 2 Assessment Form

RTCR ACAGM - Interim Final

 Questions

Reviewed 

and 

checked? 

(Type “” 

if 

completed 

or “N/A”)

Issue(s) 

found? 

(Y/N)

Issue Description Corrective Action Taken 

(Including Date)

i.

Are there any treatment devices after the service connection 

or in premise? 

(Circle response, if applicable)

Point of Entry (POE) Point of Use (POU)

j. Other comments on sample site?

2. Sample protocol followed and reviewed None

a. Flush tap, remove aerator, no swivel, fresh sample bottles,

sample storage acceptable

 No

3. Have any of the following occurred at relevant facilities

prior to the collection of TC samples?

a. Were there any operation and maintenance activities that

could have introduced total coliforms?

 No

b. Have there been any interruptions in the treatment process?  No

c. Has the system lost pressure to less than 5 psi?  No

d. Have there been any 

to facilities?

vandalism and/or unauthorized access  No

e. Are there any visible indicators of unsanitary conditions

observed?

 Yes

Unsanitary conditions around well 

including garbage and parking lot runoff.See item 8.

f.

Have there been any analytical results or any additional 

samples collected, including source samples which were 

positive (not for compliance)?

 No

g.

Have there been any community illness suspected of being 

waterborne (e.g., Does the community public health official 

indicate that an outbreak has occurred.)

 No

h. Did the water system receive any TCR monitoring

violations in the past 12 months? If yes, when.

 No

i. What was the most recent date on which satisfactory total

coliform samples were taken?

Date: 

Dec 2009

j. Have there been a fire 

sheared hydrant, etc.

fighting event, flushing operation,  No

k. Other comments on records and maintenance? None

C-17
CONCEPT EXAMPLE NO. 5

Level 2 Assessment Form

RTCR ACAGM - Interim Final C-18

Reviewed 

and 

 Questions

checked? 

(Type “” 

if 

completed 

or “N/A”)

Issue(s) 

found? 

(Y/N)

Issue Description Corrective Action Taken 

(Including Date)

4. Have there been any recent treatment 

changes?

or operational 

a. Have any inactive sources recently been introduced into the

system (e.g., auxiliary systems)?

 No

b. Have there been any new sources introduced into the

system?

 No

c.

Is there evidence of any potential sources of contamination 

(main breaks, low pressure, high turbidity, loss of 

disinfection, etc.)?

 No

5. Distribution System

a. System pressure: Is there evidence that the system

experienced low or negative pressure? If yes, when?

 No

b. List any identified cross connections.  No

c. Pump station: Are there any sanitary defects in the pump

station? Are pump(s) operable?

 No

d. Last pump maintenance/service date.

(Respond if applicable)

Date: 

12/2006

Maintenance Performed? 

Mechanical seal replaced

e. Air relief valves: Is the valve vault subject to flooding or

does the vent terminate below grade?

 No

f. Fire hydrant/blow off: Are any located in an area with a

high water table or pits?

 No

g. Is the distribution system secured to prevent 

access?

unauthorized  No

h. Are the backflow prevention devices at high risk sites

present, operational and maintained?

 No

i. Have there been any water main repairs or additions? If yes

when, and what was the repair or addition?

 No

j. Have there been any water main breaks? If yes, when?  No

k. Was there any scheduled flushing of the distribution

system? If yes, when?

 No

l. Is there any evidence of intentional contamination in the

distribution system?

 No

m Other comments on the distribution information. None
CONCEPT EXAMPLE NO. 5

Level 2 Assessment Form

RTCR ACAGM - Interim Final C-19

Reviewed 

and 

 Questions

checked? 

(Type “” 

if 

completed 

or “N/A”)

Issue(s) 

found? 

(Y/N)

Issue Description Corrective Action Taken 

(Including Date)

6. Storage Facilities

a. Are the overflow and vents properly screened?  No

b. Is the facility secured to prevent unauthorized access?  No

c. Does the access opening 

tightly?

have the proper gasket and seal  No

d. Could the physical condition of tank be a source 

contamination?

of  No The pressure tank was recently 

replaced.

Whole system was shock chlorinated after 

the tank replacement. It is not believed 

there is correlation between the bacteria 

found and the work on this tank.

e. Is the vent turned down and maintaining an approved air

gap at the termination point?

 No

f. Does the drain/overflow line terminate at a minimum of 12"

air gap?

 No

g. If present, is the pressure tank maintaining an appropriate

minimum pressure?

 No

h. Has proper O&M been performed?  No

i. Was there any observed physical deterioration of the tank?  No

j. Were there any observed leaks?  No

k. Is there any evidence of intentional contamination at 

storage tank?

the  No

l. Has there been any facility maintenance (i.e.

painting/coating)? If yes, when?

 No

m Is facility maintenance occurring per appropriate schedule?  No

n. Does the tank "float" on the distribution system or are there

separate inlet and outlet lines?

 No

o. What is the measured chlorine residual (total/free) of the

water exiting the storage tank today?

Residual 

N/A

p. Are there any unsealed openings in the storage facility such

as access doors, vents or joints?

 No

q.

Other comments on the storage system None
CONCEPT EXAMPLE NO. 5

Level 2 Assessment Form

RTCR ACAGM - Interim Final C-20

Reviewed 

and 

 Questions

checked? 

(Type “” 

if 

completed 

or “N/A”)

Issue(s) 

found? 

(Y/N)

Issue Description Corrective Action Taken 

(Including Date)

7. Treatment Process. (If applicable)

a. Treatment devices operational and maintained? N/A

b. Is there any recent installation 

equipment?

or repair of treatment N/A

c. Were there any recent changes in 

yes, when, what was the change?

the treatment process? If N/A

d.

Were there any interruptions of treatment (lapses in 

chemical feed, turbidity excursions, disinfection)? If yes 

which part, when and for how long?

N/A

e. What is the free chlorine residual measured 

downstream from the point of application?

immediately Residual: 

N/A

f. Did a review of the filter turbidity profiles reveal any

anomalies? N/A

g. Were there any failures to meet the C x T calculations? N/A

h. Were the flow rates above the rated capacity? N/A

i. Were there any anomalies on the settled water turbidities? N/A

j. Other comments on the treatment system. None

8. Source – Well

a. Is the sanitary seal intact?  No

b. Is the vent screened?  No

c. Does the vent and pump to waste terminate in an approved

air gap?

 No

d. Are there any unprotected cross connections at 

wellhead?

the  No

e. How is the well used?

(Circle if applicable) Primary Backup Emergency Not a PWS Not Drinking Water

f. How far does the casing extend above grade? Height 

14 inches Comments:

g. Is the well cap vented?  No
CONCEPT EXAMPLE NO. 5

Level 2 Assessment Form

RTCR ACAGM - Interim Final C-21

 Questions

Reviewed 

and 

checked? 

(Type “” 

if 

completed 

or “N/A”)

Issue(s) 

found? 

(Y/N)

Issue Description Corrective Action Taken 

(Including Date)

h. Is there evidence of standing water near the wellhead?  Yes After heavy rain events, there is 

standing water for a day or two.

i. Is the wellhead secured to prevent unauthorized access?  No

j. Have there been any sewer spills, source water spills or

other disturbances?

 No

k.

Other comments on the well system. (Are there aspects of 

well construction and operation that would bear on observed 

positives?)

Well needs significant rehabilitation or 

relocation, requiring more than 30 

days. Coordinated with district 

engineer to develop schedule and 

interim measures. Well will be kept offline to greatest extent possible, with the 

State to be notified and chlorine 

disinfection to be applied at 2 mg/L 

whenever well is put on-line. 

Engineering feasibility study and 

corrective action recommendation and 

proposed completion schedule due to 

State by 3/10/10. Corrective action and 

completion schedule approved by State 

by 3/25/10.

9. Source – Spring

a. What is the condition of the spring development? N/A

b. What is the condition of the spring box? N/A

c. Is the spring secured to prevent unauthorized access? N/A

d. Other comments on the spring system. None

10. Source - Surface Water Supply

a. Have there been any sewer spills, source water spills or

other disturbances? N/A

b. Have there been any algal blooms? N/A

c. Has source water turnover occurred? N/A

d. Other source water comments None
CONCEPT EXAMPLE NO. 5

Level 2 Assessment Form

RTCR ACAGM - Interim Final C-22

 Questions

Reviewed 

and 

checked? 

(Type “” 

if 

completed 

or “N/A”)

Issue(s) 

found? 

(Y/N)

Issue Description Corrective Action Taken 

(Including Date)

11. Environmental Events

a. Has there been heavy rainfall?  Yes See Item 8.

b. Has there been any rapid snow melt or flooding?  No

c.

Have there been changes in available source water (e.g., 

significant drop in water table, well levels, reservoir 

capacity, etc.)

 No

d. Have there been any interruptions to electrical power?  No

e. Have there been any extremes in heat or cold?  No

Note: Form to be completed based on data and documents available to the PWS operator in charge, maintained on file and returned to the Primacy Agency within 30 days of 

triggering the assessment. 

Additional Comments:

Print name of person completing form: Chris Weaver Date: 02/03/2010

Signature:

Reserved for State

1. Assessment has been successfully completed. Name of State Reviewer:
RTCR ACAGM - Interim Final C-23

Example No. 6 – Level 2 Assessment

UTILITY PROFILE

Chimney Bluffs Community Church is a transient non-community water system that gets its 

water from a ground water source. It serves a population of about 200 people and takes a routine 

sample every quarter. 

DESCRIPTION OF THE PROBLEM

The system had two total coliform-positive samples in July 2009 and again in March 2010 

triggering a Level 2 assessment (2 Level 1 assessments within a rolling 12-month period). Since 

the system does not have anyone approved by the State to perform a Level 2 assessment, the 

Operator in Responsible Charge (ORC) identified an assessor approved by the State from the 

State website.

ASSESSMENT AND CORRECTIVE ACTION

The system noted three possible sources of contamination: 1) inadequate/improper chlorination 

of an in-line conditioner after replacement of pressure tank and plumbing; 2) need for 

replacement of filters in the reverse osmosis system; and 3) use of a swivel faucet at the 

sampling site. The system suspected the first possible source as the cause of the contamination 

and chlorinated the in-line conditioner in March 2010. The old swivel faucet was also replaced.
CONCEPT EXAMPLE NO. 6 

Level 2 Assessment Form

RTCR ACAGM - Interim Final C-24

System Name: Chimney Bluffs Community Church Source Water: Ground Water PWSID # 6712345

System Type: TNCWS Population Served: 200 PWS Address:

Operator in Responsible Charge (ORC): Mary Spelling Phone: 012-345-6789 123 Anyway St., Chimney Bluffs, AZ

City, State: Chimney Bluffs, AZ 1000

County: Jackson

Person that collected TC samples if different than ORC: A. Brown, ABC Labs Phone: 123-456-7890 

Address, City, State, Zip: 7556 Desert Ave, Tempe, AZ 99999

Date Assessment Completed: 04/06/2010

Reviewed 

and 

Questions

checked? 

(Type “” 

if 

Issue(s) 

found? 

(Y/N)

Issue Description Corrective Action Taken 

(Including Date)

completed 

or “N/A”)

1. Evaluate sample site

a. What is the condition of the tap?

(Provide comments) Fair

b. What is the location of the tap?

(Provide comments)

Church 

rectory

Potable 

What is the regular use of the connection? water source c. (Provide comments) for the 

rectory

d. Have there been any plumbing changes or construction?

yes, when and what was the repair or change?

 If  No

e. Have there been any plumbing breaks or failure? If 

when?

yes,  No

f.

List any identified cross connections after the service 

connection or in premise plumbing. 

(Provide comments)

In-line water 

conditioner

g. Were all of the backflow prevention 

operational and maintained?

devices present,  No

Were there any low pressure events or changes in water 

h. pressure after the service connection or in the premise  No

plumbing? If yes, when?

i.

Are there any treatment devices after the service connection 

or in premise? 

(Circle response, if applicable)

Point of Entry (POE) Point of Use (POU)
CONCEPT EXAMPLE NO. 6 

Level 2 Assessment Form

RTCR ACAGM - Interim Final C-25

Questions

Reviewed 

and 

checked? 

(Type “” 

if 

completed 

or “N/A”)

Issue(s) 

found? 

(Y/N)

Issue Description Corrective Action Taken 

(Including Date)

j. Other comments on sample site? None

2. Sample protocol followed and reviewed

a. Flush tap, remove aerator, no swivel, fresh sample bottles,

sample storage acceptable

 Yes Sample site had old swivel faucet. Faucet replaced on 3/30/10.

3. Have any of the following occurred at relevant facilities

prior to the collection of TC samples?

a. Were there any operation and maintenance activities that

could have introduced total coliforms?

 Yes

The pressure tank and plumbing in and 

around the pump room were recently 

replaced. System includes an in-line 

water conditioner. It is unknown if 

water conditioner was chlorinated or 

by-passed during the chlorination prior 

to putting tank and plumbing back in 

service.

Water conditioner chlorinated on 

3/30/2010 and put back in service.

b. Have there been any interruptions in the treatment process?  No

c. Has the system lost pressure to less than 5 psi?  No

d. Have there been any 

to facilities?

vandalism and/or unauthorized access  No

e. Are there any visible indicators of unsanitary conditions

observed?

 No

f.

Have there been any analytical results or any additional 

samples collected, including source samples which were 

positive (not for compliance)?

 No

g.

Have there been any community illness suspected of being 

waterborne (e.g., Does the community public health official 

indicate that an outbreak has occurred.)

 No

h. Did the water system receive any TCR monitoring

violations in the past 12 months? If yes, when.

 Yes July 2009

i. What was the most recent date on which satisfactory total

coliform samples were taken?

Date: 

Dec 2009

j. Have there been a fire 

sheared hydrant, etc.

fighting event, flushing operation,  No

k. Other comments on records and maintenance? None 
CONCEPT EXAMPLE NO. 6 

Level 2 Assessment Form

RTCR ACAGM - Interim Final

Reviewed 

and 

Questions

checked? 

(Type “” 

if 

completed 

or “N/A”)

Issue(s) 

found? 

(Y/N)

Issue Description Corrective Action Taken 

(Including Date)

4. Have there been any recent treatment 

changes?

or operational 

a. Have any inactive sources recently been introduced into 

system (e.g., auxiliary systems)?

the  No

b. Have there been any new sources introduced into the

system?

 No

c. 

Is there evidence of any potential sources of contamination 

(main breaks, low pressure, high turbidity, loss of 

disinfection, etc.)?

 No

5. Distribution System

a. System pressure: Is there evidence that the system

experienced low or negative pressure? If yes, when?

 No

b. List any identified cross connections.  No

c. Pump station: Are there any sanitary defects in the pump

station? Are pump(s) operable?

 No

d. Last pump maintenance/service date.

(Respond if applicable) Date: N/A Maintenance Performed?

e. Air relief valves: Is the valve vault subject to flooding or

does the vent terminate below grade?

 No

f. Fire hydrant/blow off: Are any located in an area with a

high water table or pits?

 No

g.

Is the distribution system secured to prevent 

access?

unauthorized  No

h. Are the backflow prevention devices at high risk sites

present, operational and maintained?

 No

i. Have there been any water main repairs or additions? If yes

when, and what was the repair or addition?

 No

j. Have there been any water main breaks? If yes, when?  No

k. Was there any scheduled flushing of the distribution

system? If yes, when?

 No

l. Is there any evidence of intentional contamination in the

distribution system?

 No

m Other comments on the distribution information. None

C-26
CONCEPT EXAMPLE NO. 6 

Level 2 Assessment Form

RTCR ACAGM - Interim Final C-27

Questions

Reviewed 

and 

checked? 

(Type “” 

if 

completed 

or “N/A”)

Issue(s) 

found? 

(Y/N)

Issue Description Corrective Action Taken 

(Including Date)

6. Storage Facilities

a. Are the overflow and vents properly screened? N/A

b. Is the facility secured to prevent unauthorized access? N/A

c. Does the access 

tightly?

opening have the proper gasket and seal N/A

d. Could the physical condition of tank be a source 

contamination?

of N/A

e. Is the vent turned down and maintaining an approved air

gap at the termination point?

N/A

f. Does the drain/overflow line terminate at a minimum of 12"

air gap?

N/A

g. If present, is the pressure tank maintaining an appropriate

minimum pressure?

N/A

h. Has proper O&M been performed? N/A

i. Was there any observed physical deterioration of the tank? N/A

j. Were there any observed leaks? N/A

k. Is there any evidence of intentional contamination at 

storage tank?

the N/A

l. Has there been any facility maintenance (i.e.

painting/coating)? If yes, when? N/A

m. Is facility maintenance occurring per appropriate schedule? N/A

n. Does the tank "float" on the distribution system or are there

separate inlet and outlet lines? N/A

o. What is the measured chlorine residual (total/free) of the

water exiting the storage tank today?

Residual 

N/A

p. Are there any unsealed openings in the storage facility such

as access doors, vents or joints? N/A

q. Other comments on the storage system None
CONCEPT EXAMPLE NO. 6 

Level 2 Assessment Form

RTCR ACAGM - Interim Final

Reviewed 

and 

Questions

checked? 

(Type “” 

if 

completed 

or “N/A”)

Issue(s) 

found? 

(Y/N)

Issue Description Corrective Action Taken 

(Including Date)

7. Treatment Process. (If applicable)

a. Treatment devices operational and maintained?  No

b. Is there any recent installation 

equipment?

or repair of treatment  Yes

The filters were replaced in the 

reverse osmosis system that feeds 

the faucets connected to the 

rectory and the kitchen.

Filter replacement has never been the 

source of contamination in the past 

and is not believe to be related to this 

event.

c. Were there any recent changes in

yes, when, what was the change?

the treatment process? If  No

d.

Were there any interruptions of treatment (lapses in 

chemical feed, turbidity excursions, disinfection)? If yes 

which part, when and for how long?

 No

e. What is the free chlorine residual measured immediately

downstream from the point of application?

Residual: 

N/A

f. Did a review of the filter turbidity profiles reveal any

anomalies? N/A

g. Were there any failures to meet the C x T calculations? N/A

h. Were the flow rates above the rated capacity? N/A

i. Were there any anomalies on the settled water turbidities? N/A

j. Other comments on the treatment system. None

8. Source – Well

a. Is the sanitary seal intact?  No

b. Is the vent screened?  No

c. Does the vent and pump to waste terminate in an approved

air gap?

 No

d. Are there any unprotected cross 

wellhead?

connections at the  No

How is the well used? e. (Circle if applicable) Primary Backup Emergency Not a PWS Not Drinking Water

f. How far does the casing extend above grade? Height 

______ Comments:

C-28
CONCEPT EXAMPLE NO. 6 

Level 2 Assessment Form

RTCR ACAGM - Interim Final

Questions

Reviewed 

and 

checked? 

(Type “” 

if 

completed 

or “N/A”)

Issue(s) 

found? 

(Y/N)

Issue Description Corrective Action Taken 

(Including Date)

g. Is the well cap vented?  No

h. Is there evidence of standing water near the wellhead?  No

i. Is the wellhead secured to prevent unauthorized access?  No

j. Have there been any sewer spills, source water spills 

other disturbances?

or  No

k.

Other comments on the well system. (Are there aspects of 

well construction and operation that would bear on observed 

positives?)

Well needs significant rehabilitation or 

relocation, requiring more than 30 

days. Coordinated with district 

engineer to develop schedule and 

interim measures. Well will be kept offline to greatest extent possible, with the 

State to be notified and chlorine 

disinfection to be applied at 2 mg/L 

whenever well is put on-line. 

Engineering feasibility study and 

corrective action recommendation and 

proposed completion schedule due to 

State by 3/10/10. Corrective action and 

completion schedule approved by State 

by 3/25/10.

9. Source – Spring

a. What is the condition of the spring development? N/A

b. What is the condition of the spring box? N/A

c. Is the spring secured to prevent unauthorized access? N/A

d. Other comments on the spring system. None

10. Source - Surface Water Supply

a. Have there been any sewer spills, source water spills or

other disturbances? N/A

b. Have there been any algal blooms? N/A

c. Has source water turnover occurred? N/A

C-29
CONCEPT EXAMPLE NO. 6 

Level 2 Assessment Form

RTCR ACAGM - Interim Final

Questions

Reviewed 

and 

checked? 

(Type “” 

if 

completed 

or “N/A”)

Issue(s) 

found? 

(Y/N)

Issue Description Corrective Action Taken 

(Including Date)

d. Other source water comments None

Environmental Events

a. Has there been heavy rainfall?  No

b. Has there been any rapid snow melt or flooding?  No

c.

Have there been changes in available source water (e.g., 

significant drop in water table, well levels, reservoir 

capacity, etc.)

 No

d. Have there been any interruptions to electrical power?  No

e. Have there been any extremes in heat or cold?  No

Note: Form to be completed based on data and documents available to the PWS operator in charge, maintained on file and returned to the Primacy Agency within 30 days of 

triggering the assessment. 

Additional Comments:

Print name of person completing form: John Marshall Date: 04/08/2010

Signature:

Reserved for State

1. Assessment has been successfully completed. Name of State Reviewer:

C-30
APPENDIX D. Industry Standards for Operating a 

Public Water System

Presented in this appendix is a list of standards, manuals and other reference materials that may 

be useful to public water systems when implementing the corrective actions discussed in 

Chapter 5 of this document. This is not an exhaustive list. Systems should check with their 

States to determine if there are different or additional standards they should be adhering to. 

List of Standards and Manuals 

The American Water Works Association (AWWA) has developed standards based on the 

collective knowledge of its membership. The information contained in these standards has been

collected and improved over many years and has gone through rigorous review and development. 

AWWA Standards are typically minimum best practices and help to ensure that a product (e.g., 

pipes, fittings, meters, etc.) or a process (e.g., main flushing, main installation, etc.) described in 

a standard will provide satisfactory service. 

Standard Number Topic 

AWWA A100 Water Wells

AWWA B300 Hypochlorites

AWWA B301 Liquid Chlorine

AWWA C104/A21.4 Cement-Mortar Lining for Ductile-Iron Pipe and Fittings for Water

AWWA C110/A21.10 Ductile-Iron and Gray-Iron Fittings for Water

AWWA C111/A21.11 Rubber-Gasket Joints for Ductile-Iron Pressure Pipe and Fittings

AWWA C115/A21.15 Flanged Ductile-Iron Pipe with Ductile-Iron or Gray-Iron Threaded 

Flanges

AWWA C116/A21.16 Protective Fusion-Bonded Epoxy Coatings for the Interior and Exterior 

Surfaces of Ductile-Iron and Gray-Iron Fittings for Water Supply 

Service

AWWA C150/A21.50 Thickness Design of Ductile-Iron Pipe-Erratum: 02/2003

AWWA C151/A21.51 Ductile-Iron Pipe, Centrifugally Cast, for Water- Erratum

AWWA C153/A21.53 Ductile-Iron Compact Fittings, for Water Service

AWWA C200 Steel Water Pipe - 6 in. (150 mm) and Larger

AWWA C203 Coal-Tar Protective Coatings and Linings for Steel Water Pipelines -

Enamel and Tape - Hot Applied

AWWA C205 Cement-Mortar Protective Lining and Coating for Steel Water Pipe - 4 

in. (100 mm) and Larger - Shop Applied

AWWA C206 Field Welding of Steel Water Pipe

AWWA C207 Steel Pipe Flanges for Waterworks Service - Sizes 4 in. Through 144 in. 

(100 mm Through 3,600 mm)

RTCR ACAGM - Interim Final D-1
Standard Number Topic 

AWWA C208 Dimensions for Fabricated Steel Water Pipe Fittings

AWWA C209 Cold-Applied Tape Coatings for the Exterior of Special Sections, 

Connections, and Fittings for Steel Water Pipelines

AWWA C210 Liquid-Epoxy Coating Systems for the 

Water Pipelines

Interior and Exterior of Steel 

AWWA C213 Fusion-Bonded Epoxy Coating for the 

Water Pipelines

Interior and Exterior of Steel 

AWWA C214 Tape Coating Systems for the Exterior of Steel Water Pipelines

AWWA C215 Extruded Polyolefin Coatings for the Exterior of Steel Water Pipelines

AWWA C216 Heat-Shrinkable Cross-Linked Polyolefin Coatings for the Exterior of 

Special Sections, Connections, and Fittings for Steel Water Pipelines

AWWA C217 Petrolatum and Petroleum Wax Tape Coatings for the Exterior of 

Connections and Fittings for Steel Water Pipelines

AWWA C218 Coating the Exterior of Aboveground Steel Water 

Fittings-Third Edition

Pipelines and 

AWWA C222 Polyurethane Coatings for the Interior 

and Fittings-First Edition

and Exterior of Steel Water Pipe 

AWWA C224 Two-Layer Nylon-11-Based Polyamide Coating System for the Interior 

and Exterior of Steel Water Pipe, Connections, Fittings, and Special 

Sections

AWWA C225 Fused Polyolefin Coating systems for the Exterior of Steel Water 

Pipelines-First Edition

AWWA C300 Reinforced Concrete Pressure Pipe, Steel-Cylinder Type

AWWA C301 Prestressed Concrete Pressure Pipe, Steel-Cylinder Type-Erratum -

January 2000

AWWA C302 Reinforced Concrete Pressure Pipe, Noncylinder Type

AWWA C303 Concrete Pressure Pipe, Bar-Wrapped, Steel-Cylinder Type

AWWA C304 Design of Prestressed Concrete Cylinder Pipe

AWWA C400 Asbestos-Cement Pressure Pipe, 4 in. Through 16 in. (100 mm Through 

400 mm), for Water Distribution Systems

AWWA C401 The Selection of Asbestos-Cement Pressure Pipe, 4 in. Through 16 

in.(100 mm Through 400 mm), for Water Distribution Systems

AWWA C402 Asbestos-Cement Transmission Pipe, 18 in. Through 42 in. (450 mm 

Through 1,050 mm), for Water Supply Service

AWWA C403 Selection of Asbestos-Cement Transmission Pipe, Sizes 18 in. Through 

42 in. (450 mm Through 1,050 mm), for Water Supply Service 

AWWA C500 Metal-Seated Gate Valves for Water Supply Service

AWWA C502 Dry-Barrel Fire Hydrants

AWWA C503 Wet-Barrel Fire Hydrants

AWWA C508 Swing-Check Valves for Waterworks Service, 2-in. Through 24-in. (50-

mm Through 600-mm) NPS

AWWA C509 Resilient-Seated Gate Valves for Water Supply Service

RTCR ACAGM - Interim Final D-2
Standard Number Topic 

AWWA C512 Air Release, Air/ Vacuum, and Combination Air Valves for Waterworks 

Service

AWWA C515 Reduced-Wall, Resilient-Seated Gate Valves for 

Second Edition

Water Supply ServiceAWWA C600 Installation of Ductile-Iron Water Mains and Their Appurtenances

AWWA C602 Cement-Mortar 

Larger

Lining of Water Pipelines in Place - 4 in. (100 mm) and 

AWWA C605 Underground Installation of Polyvinyl Chloride 

and Fittings for Water-First Edition

(PVC) Pressure Pipe 

AWWA C606 Grooved and Shouldered Joints

AWWA C651 Disinfecting Water Mains

AWWA C652 Disinfection of Water-Storage Facilities

AWWA C653 Disinfection of Water Treatment Plants

AWWA C654 Disinfection of Wells

AWWA C700 Cold-Water Meters - Displacement Type, Bronze Main Case

AWWA C701 Cold-Water Meters - Turbine Type, for Customer Service

AWWA C702 Cold-Water Meters - Compound Type

AWWA C703 Cold-Water Meters - Fire Service Type

AWWA C704 Propeller-Type Meters for Waterworks Applications

AWWA C706 Direct-Reading, Remote-Registration Systems for Cold-Water Meters

AWWA C707 Encoder-Type Remote-Registration Systems for Cold-Water Meters

AWWA C708 Cold-Water Meters - Multijet Type

AWWA C710 Cold-Water Meters - Displacement Type, Plastic Main Case

AWWA C712 Cold-Water Meters - Singlejet Type-First Edition

AWWA C713 Cold-Water Meters Fluidic-Oscillator Type-First Edition

AWWA C800 Underground Service Line Valves and Fittings

AWWA C900 Polyvinyl Chloride (PVC) Pressure Pipe and Fabricated Fittings, 4 in. 

Through 12 in.(100 mm Through 300 mm), for Water Distribution

AWWA C901 Polyethylene (PE) Pressure Pipe and Tubing, 1/2 in. (13 mm) Through 3 

in. (76 mm), for Water Service

AWWA C903 Polyethylene-Aluminum-Polyethylene & Cross-linked PolyethyleneAluminum-Cross-linked Polyethylene Composite Pressure Pipes, 1/2 In. 

(12 mm) Through 2 In. (50 mm), for Water Service

AWWA C905 Polyvinyl Chloride (PVC) Pressure Pipe and Fabricated Fittings, 14 

Inches Through 48 Inches (350mm Through 1,200mm), for Water 

Transmission and Distribution

AWWA C906 Polyethylene (PE) Pressure Pipe and Fittings, 4 in. (100 mm) Through 

63 in. (1,575 mm), for Water Distribution and Transmission

AWWA C907 Injection-Molded Polyvinyl Chloride (PVC) Pressure Fittings, 4 In. 

Through 12 In. (100 mm Through 300 mm), for Water Distribution

AWWA C909 Molecularly Oriented Polyvinyl Chloride (PVCO) Pressure Pipe, 4 in. 

Through 12 in. (100 mm Through 600 mm), for Water Distribution

RTCR ACAGM - Interim Final D-3
Standard Number Topic 

AWWA C950 Fiberglass Pressure Pipe

AWWA D100 Welded Steel Tanks for Water Storage

AWWA D102 Coating Steel Water-Storage Tanks

AWWA D103 Factory-Coated Bolted Steel Tanks for Water Storage

AWWA D104 Automatically Controlled, Impressed-Current Cathodic Protection for 

the Interior of Steel Water Tanks

AWWA D110 Wire- and Strand-Wound, Circular, Prestressed Concrete Water Tanks

AWWA D115 Circular Prestressed Concrete Water Tanks with Circumferential 

Tendons-First Edition

AWWA D130 Flexible-Membrane Materials for Potable Water Applications

AWWA G100 Water Treatment Plant Operation and Management-First Edition

AWWA G200 Distribution Systems Operation and Management

Manual Number Topic 

AWWA M2 Instrumentation and Control, 3rd ed. (2001)

AWWA M14 Recommended Practice for Backflow (2004)

Installation, Field Testing, and Maintenance of Fire Hydrants, 4th ed. 

AWWA M17 (2006)

Water Chlorination and Chloramination Practices and Principles, 2nd ed. 

AWWA M20 (2006)

AWWA M28 Rehabilitation of Water Mains, 2nd ed. (2001)

AWWA M42 Steel Water Storage Tanks (1998)

AWWA M44

Distribution Valves: Selection, 

Maintenance, 2nd ed. (2006)

Installation, Field Testing, and 

Fundamentals and Control of Nitrification in Chloraminated Drinking 

AWWA M56 Water Distribution Systems (2006)

Other Reference Materials

• Local plumbing codes – Systems should check with their municipality or State if there are

local plumbing codes they should be following.

• “Recommended Standards for Water Works” (also known as the “10 States Standards”)

(Great Lakes et al. 2007)

RTCR ACAGM - Interim Final D-4