Water Quality Assessment

The Federal Clean Water Act (CWA) gives States the primary responsibility for protecting and restoring surface water quality. Under the CWA, States that administer the CWA must review, make necessary changes, and submit the CWA section 303(d) list to the U.S. Environmental Protection Agency (U.S.EPA). CWA Section 305(b) requires each State to report biennially to U.S.EPA, on the condition of its surface water quality. The U.S.EPA has issued guidance to States which requires the two reports to be integrated. For California, this combined report is called the California 303(d)/305(b) Integrated Report.

For 303(d), State and Regional Water Boards assess water quality monitoring data for California’s surface waters every two years to determine if they contain pollutants at levels that exceed protective water quality standards. Water body and pollutants that exceed protective water quality standards are placed on the State’s 303(d) List. This determination in California is governed by the Water Quality Control Policy for developing California’s Clean Water Act Section 303(d) List. U.S.EPA must approve the 303(d) List before it is considered final.

Placement of a water body and pollutant that exceeds protective water quality standards on the 303(d) List, initiates the development of a Total Maximum Daily Load (TMDL). In some cases other regulatory programs will address the impairment instead of a TMDL.

For 305(b) Report, State and Regional Water Boards place the water body segment that were assessed into one of U.S.EPA’s five Integrated Report beneficial use report category. For this assessment available data are used to evaluate most common beneficial uses including aquatic life, drinking water supply, fish consumption non-contact recreational, and swimming.


Colorado River Salinity

The Colorado River Salinity Control Forum has released its 2014 Review, Water Quality Standards for Salinity, Colorado River System report, and is available at the Forum’s website at www.coloradoriversalinity.org. The Forum will accept public comments through September 15, 2014. Comments should be addressed to the Forum’s Executive Director, Don Barnett at email to dbarnett@barnettwater.com or by regular mail at:

Colorado River Basin Salinity Control Forum
106 W. 500 S., Suite 101
Bountiful, UT 84010

Questions should be addressed to Executive Director Barnett at (801) 292-4663

After approval by the forum, the report will be considered by the State Water Resources Control Board for its approval as well as by water quality agencies in other Colorado River Basin States.

Water Quality Goals

  • California Integrated Report – includes the Clean Water Act Section 303(d) List and Section 305(b) Report.
  • A Compilation of Water Quality Goals
    Numeric water quality thresholds from the literature for over 860 chemical constituents and water quality parameters. The text of the report explains, with examples, how these thresholds may be used to assess protection of beneficial uses of water resources in the context of California's quality standards. A summary of relevant statutes, regulations, plans, and policies and links to original references are included.

Statewide Mercury Program

TMDL - Total Maximum Daily Load Program

  • TMDL - Total Maximum Daily Load Program

Impaired Water Bodies