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My Water Quality: Impaired Water

Which Lakes, Streams, or Ocean Locations Are Listed By The State As Impaired?

Preparing fish

This interactive map shows which of California's waters are listed as impaired for uses related to fish or shellfish consumption by humans and which pollutants are involved. Also shown are the Total Maximum Daily Load (TMDL) projects to reduce pollutants to acceptable levels.

View 2010 303(d) Listing and current TMDL Information:

  • Click on a water body (shown in RED), or
  • Select (or type) the county in the County box, then select the water body from the Water Body menu, or
  • Select (or type) the water body name directly in the Water Body box
  • Use the magnifier tool to zoom into an area of interest (more highlighted water bodies will appear)
  • Click on the state outline tool to return to a statewide view

Impaired Water Bodies

Listing a water body as impaired in California is governed by the State Water Board's 303(d) Listing Policy.

The State and Regional Water Boards assess water quality data for California's waters every two years to determine if they contain pollutants at levels that exceed protective water quality criteria and standards. This biennial assessment is required under Section 303(d) of the federal Clean Water Act.

The map shows California waters that were placed on the State's 2010 303(d) list and which pollutants they contain that adversely impact fish and/or shellfish consumption related uses as they relate to human exposure to pollutants.

Total Maximum Daily Loads (TMDLs)

Water Board LogoPlacement of a water body and its offending pollutant on the 303(d) list, initiates the development of a Total Maximum Daily Load (TMDL) by the appropriate Regional Water Board. TMDLs may establish "daily load" limits of the pollutant, or in some cases require other regulatory measures, with the ultimate goal of reducing the amount of the pollutant entering the water body to meet water quality standards.

This map also provides the current status of TMDL development for these water bodies containing pollutants that adversely impact fish and/or shellfish consumption related uses as they relate to human exposure to pollutants