AWWA COMMENT PERIOD ON AWWA C653, Disinfection of Water Treatment Plants

AWWA COMMENT PERIOD ON AWWA C653, Disinfection of Water Treatment Plants

November 6, 2026

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 December 21, 2026.

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 Therefore, this copy is not suitable for continued utilization and is intended only for comment purposes.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 describes chlorination materials, procedures, and requirements for disinfection of new treatment facilities and existing water treatment facilities temporarily taken out of service for cleaning, inspection, maintenance, painting, repair, or any other activity or event that might lead to contamination of water. Typically, this standard applies to treatment components, including filter basins, filter media, clearwells, pump suction wells, and associated piping and appurtenances located downstream from the filter influent, or from the first point of application of disinfectant in the treatment process, or all portions of a facility if no primary disinfection is

provided. The disinfection method employed is surface contact with a high-strength chlorine solution for a specific time period. The absence of coliform bacteria in addition to the use of proper disinfection practices is confirmation that the disinfection process has been accomplished in compliance with this standard.

MAJOR REVISIONS Major changes made to the standard in this revision include the following:

1. A requirement for preparing a Disinfection and Dechlorination Plan was added to the Foreword (I.A) and Scope (Sec. 1.1), and guidance was added in new Appendix A.

2. New Section II.B. Chemical Handling Precautions was added to the Foreword.

3. New item 8 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.

4. The term chlorine, free was changed to free chlorine (also called free available chlorine (FAC)) and the definition was clarified. The following terms and definitions were added: primary disinfection and secondary disinfection. The definition for wastewater was removed (Sec. 3).

5. Clarifications regarding hydrating, dissolving, and dispersing calcium hypochlorite granules/tablets were added (Sec. 4.3.3).

6. Disinfection process for GAC filters was clarified (Sec. 4.4.3.5).

7. A 16 h stagnant period between disinfection and initial sampling was added, and the time between repeat samples was changed from 24 h to 16 h (Sec. 5.1).

8. Section 5.1 Bacteriological Sampling descriptions and options were rewritten for accuracy and clarity to be consistent with other disinfection of facilities sampling procedures.