Book Synopsis
The California (CA) Surface Water Treatment Regulation (SWTR) expands on the US-EPA SWTR by requiring domestic water suppliers using surface water source(s) to conduct a sanitary survey of their water supply watersheds at least once every 5 years. This guidance manual assists domestic water suppliers in defining the scope of their watershed sanitary surveys and provides information on the methods and sources of information for conducting watershed sanitary surveys. Although the completion of a Watershed Sanitary Survey is a CA regulatory requirement, this guidance may be used by any state or utility for evaluation of their respective watersheds.
This guidance manual, first developed in 1993 and updated in 2025, was prepared by the CA/NV Section, AWWA: Source Water Quality Committee in conjunction with the CA State Water Resources Control Board, Division of Drinking Water (DDW). The manual was reviewed by DDW field and senior staff and will be used by engineers within DDW districts.