AWWA COMMENT PERIOD ON AWWA C652, Disinfection of Water-Storage Facilities

AWWA COMMENT PERIOD ON AWWA C652, Disinfection of Water-Storage Facilities
September 19, 2025

AWWA solicits public comments on all proposed new AWWA Standards, and on all proposed revisions, reaffirmations, or withdrawals of existing AWWA Standards. The referenced standards project is being considered for approval and the publication of this notice begins the 45-day public comment period for AWWA and ANSI. An electronic public review copy of the proposed standard can be obtained for review during the comment period by emailing ETS Support (ETSsupport@awwa.org). Comments must be submitted in writing to the AWWA contact listed below no later than the last day of the comment period specified herein. Such comments shall be specific to the section(s) of the standard under review and include sufficient detail, so as to enable the reader to understand the commenter’s position, concerns and suggested alternative language, if appropriate.

AWWA Comment Period closes on November 3, 2025.

Send comments to:
Ian Nebendahl, inebendahl@awwa.org
303.347.6283 phone

The review copy will be edited for publication and may also be revised as appropriate based on any comments received during the public comment period. Therefore, this copy is not suitable for continued utilization and is intended only for comment purposes.

Final publication of the standard may take several months. When it is available, a notice will be published in the official notice section of Journal – American Water Works Association. The standard becomes an effective AWWA standard on the first day of the month following such publication in Journal – American Water Works Association.

SCOPE
This standard for disinfection of water-storage facilities describes materials, facility preparation, application of disinfectant to interior surfaces of facilities, and sampling and testing for the presence of coliform bacteria, chlorine residual, and acceptable aesthetic water quality.  The standard also includes disinfection procedures for underwater inspection and/or cleaning of potable-water-storage facilities but does not describe the technical aspects of underwater inspection and/or cleaning. All new storage facilities shall be disinfected before they are placed in service. Depending upon the nature of work performed on an existing tank and the potential for contamination, disinfection and/or sampling only may be appropriate.  Storage facilities dewatered for purposes of entering the tank and performing painting, repairs, or other highly invasive activities shall be disinfected and sampled.  In some cases, the tank may remain in service, or isolated, for minimally intrusive activities such as ROV or diver inspections. Where rigorous sanitary procedures have been followed, only sampling may be required. This standard is meant to be used for tanks within public water systems and is not intended for storage tanks within premise plumbing systems in buildings. Premise plumbing components in buildings use a wide variety of materials, including some that may not be compatible with the chlorine concentrations in this standard.
Prior to the start of work, a Disinfection Plan, and when warranted a Dechlorination Plan, shall be prepared (see Appendix A for the types of information to include in a Disinfection and Dechlorination Plan). The plan ensures that appropriate equipment, chemicals, monitoring and reporting, and other requirements have been identified and addressed, including the steps needed to handle the flows that may require dechlorination per ANSI/AWWA C655.

MAJOR REVISIONS
Major changes made in this revision of ANSI/AWWA C652 are as follows:

1. A disinfection methods summary was added to the Foreword (II.A) and to new Appendix B. Previous Appendix B was renamed Appendix D.
2. ANSI/AWWA D101 was added to the Foreword (II.A) as guidance for inspections.
3. New Section II.B. Chemical Handling Precautions was added to the Foreword.
4. New item 7 was added to III.A. Purchaser Options and Alternatives in the Foreword to prompt purchaser to indicate the desired first course of action in case of initial positive coliform sample results.
5. A requirement for preparing a Disinfection and Dechlorination Plan was added to the Scope (Sec.1.1), and guidance was added in new Appendix A. Previous Appendix A was renamed Appendix C.
6. The definitions for chloramines and chlorine, total were revised, the definitions for chlorine, free and chlorine residual were replaced with free chlorine (also called free available chlorine (FAC)) and total chlorine residual (also called total residual chlorine (TRC)), and the following terms and definitions were added: contact time and highly-chlorinated water (also called superchlorinated water) (Sec. 3).
7. Allowance for 6 h retention time was added in cases where an active mixing system is used to uniformly distribute disinfection chemical throughout the storage facility (Sec. 4.3.1.4 and Sec. 4.3.3).
8. Removed the 10 mg/L chlorinated water for drain piping in Method 2 (Sec. 4.3.2.1 and Sec. 4.3.2.2).
9. In case of initial positive coliform sample results, the first course of action was changed to two options, either repeat sample testing or chlorination followed by resampling (Sec. 5.1.1.1).
10. Clarification added for the analysis of total coliform, Escherichia coli, and sufficient results to activate water storage tanks for use (II. Special Issues).
11. Removal of “total coliform(s)” and changed to “coliform(s)” to make language more consistent and reduce repetitiveness throughout the standard. Kept “total coliform” in II. Special Issues to indicate overall coliforms during testing.