Drinking Water Source Assessment and Protection (DWSAP) Program

CDPH's Division of Drinking Water and Environmental Management (DDWEM) established the California DWSAP Program to provide information to communities that wish to develop local programs to protect their sources of drinking water. The DWSAP Program has two primary elements  Drinking Water Source Assessment and Source Protection.

Drinking Water Source Assessment

The drinking water source assessment is the first step in the development of a complete drinking water source protection program. The assessment includes: A delineation of the area around a drinking water source through which contaminants might move and reach that drinking water supply; an inventory of possible contaminating activities (PCAs) that might lead to the release of microbiological or chemical contaminants within the delineated area; and a determination of the PCAs to which the drinking water source is most vulnerable.

The California DWSAP Program Document (PDF, 1.6MB), including the oversized Table 5-1, describes procedures for conducting drinking water source assessments. It conveys the goals and objectives that we seek to accomplish with the DWSAP program, along with methods that are technically appropriate and easily understood.

Since 1997, DDWEM's Drinking Water Program, with the assistance of others—34 counties, the California Rural Water Association, and more than 500 water systems—completed assessments for nearly all the public drinking water sources in the state.

For a list of the water systems with completed assessments, see Completed Assessments and List of Sources (PDF).Table 1 presents the status of assessments as of September 2003, in terms of system type and source type. As of December 31, 2004, California completed assessments for 16,152 drinking water sources (from 7,543 public water systems).

Summaries of assessments are available for viewing Note that assessment summaries may not be available for some sources. This is because:

  • The assessment has not been completed. Contact the local CDPH Drinking Water Program district office (PDF) or the water system to find out when the assessment is scheduled to be completed.
  • The source is not active. It may be out of service, or new and not yet in service.
  • The assessment was not submitted electronically. This site only provides access to assessment summaries submitted electronically.

Table 1. Overall Status of Source Water Assessments,
as of September 30, 2003

Water System Type No. of Public Water Systems % Complete No. of Groundwater Sources % Complete No. of Surface Water Sources % Complete
Community 2,962 91 8,988 94 708 82
Non-Transient 1,448 95 1,866 96 85 93
Transient 3,031 96 3,472 97 218 89
Total 7,441 94 14,326 95 1,011 85


The 1996 federal Safe Drinking Water Act amendments require each state to develop and implement a Source Water Assessment Program. Section 11672.60 of the California Health and Safety Code requires the Department of Health Services (DHS, the precursor to CDPH) to develop and implement a program to protect sources of drinking water, specifying that the program must include both a source water assessment program and a wellhead protection program. In response to both of these legal mandates, DHS developed the DWSAP Program.

California's DWSAP Program addresses both groundwater and surface water sources. The groundwater portion of the DWSAP Program serves as the states wellhead protection program. In developing the surface water components of the DWSAP Program, DHS integrated the existing requirements for watershed sanitary surveys.

Number of Sources Statewide/Resources for Assessments

There are more than 15,000 active drinking water sources in California. The resources available for the assessments were approximately $7.5 million from the federal Drinking Water State Revolving Fund, or roughly a few hundred dollars per source. Although DHS was responsible for performing these assessments, some public water systems performed their own assessments conducted them in conformance with the DHS procedures.

Schedule and Timeline

DHS submitted the DWSAP Program Document (PDF, 1.6MB ) in January 1999. US EPA approved the DWSAP as California's wellhead protection program in January 1999. In November 1999, US EPA gave final approval of the DWSAP Program as California's sources water assessment and protection program. DHS was responsible for the completion of all assessments by May 2003. As of that date, over 92 percent of the assessments were completed, with work continuing.

Water systems that planned to conduct their own assessments were required to submit their final assessments to DHS no later than December 31, 2002.

DWSAP Program Development

In 1997-1998, as the DWSAP Program was being developed, DHS published various drafts of the DWSAP Program Document, and gave numerous presentations about the Program to inform the public and to obtain public input. During this period, DHS met with advisory groups formed to help develop the DWSAP Program.

For more, go to: