Which waters are listed as impaired for swimming?
This interactive map shows which of California's waters are listed as impaired for contact recreation related factors and which pollutants are involved. Also shown are potential sources of pollutants and the Total Maximum Daily Load (TMDL) projects to reduce pollutants to acceptable levels.
Listing a water body as impaired in California is governed by the State Water Board's 303(d) Listing Policy.
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 most current (2010) 303(d) list and which pollutants they contain that adversely impact water contact recreation, including swimming, surfing, scuba diving, snorkeling, and other related uses where incidental water ingestion may occur.
Placement of a water body and its offending pollutant on the 303(d) list, initiates the development of a Total Maximum Daily Load (TMDL). 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 water contact recreation, including swimming, surfing, scuba diving, snorkeling, and other related uses where incidental water ingestion may occur.