AWWA C651-23 Disinfecting Water Mains

This standard describes essential procedures for the disinfection of new and repaired potable water mains, including water mains used for temporary service when replacing or repairing existing water mains. New or temporary water mains shall be disinfected before they are placed in service. Water mains taken out of service for inspection, repair, or other activities may or may not require disinfection and sampling, depending on the risk of contamination and/or the duration of inactive service. It describes the process for evaluating the risk under different conditions. This standard is meant to be used for water mains within public water systems and is not intended for 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. This standard can be referenced in specifications for the disinfection of water mains and can be used as a guide for the necessary preparation of water mains, application of chlorine, and subsequent sampling and testing for free chlorine residuals and the presence of coliform bacteria. The stipulations of this standard apply when this document has been referenced and only to the disinfection of water mains.