Total Maximum Daily Loads (TMDLs) and the 303(d) List of Impaired Water Bodies

Total Maximum Daily Loads (TMDLs) are action plans to restore clean water. Section 303(d) of the federal Clean Water Act requires that states identify water bodies -- bays, rivers, streams, creeks, and coastal areas -- that do not meet water quality standards, and the pollutants that impair them. TMDLs examine the water quality problems, identify sources of pollutants, and specify actions that create solutions. They are adopted by the Regional Water Board as amendments to our Region's Basin Plan. For more information about TMDLs, click here.

Within our region, the 2010 303(d) list includes more than 270 listings in 88 water bodies. Water Board staff are currently developing TMDL projects to address more than 160 of these listings. (One TMDL may address multiple listings. For example, the Diazinon/Pesticide Toxicity TMDL for urban creeks addressed more than 30 impaired creeks or creek segments.)

Completed TMDL Projects: Guadalupe River Watershed Mercury Napa River Pathogens Napa River Sediment Richardson Bay Pathogens San Francisco Bay Mercury San Francisco Bay PCBs Sonoma Creek Pathogens Sonoma Creek Sediment Tomales Bay Mercury Tomales Bay Pathogens Urban Creeks Pesticide Toxicity Walker Creek Mercury TMDL Projects in Development: Lagunitas Creek Sediment Napa River Nutrients North San Francisco Bay Selenium San Francisquito Creek Sediment Pescadero and Butano Creeks Sediment Sonoma Creek Nutrients San Pedro Creek and Pacifica State Beach Bacteria TMDL Walker Creek Sediment Suisun Marsh

Click on the map above to view a larger image.

Fact Sheets

Cleaning up PCBs in San Francisco Bay, June 2012 (PDF file).
Fact sheet produced by the San Francisco Bay Water Board

How TMDLs Are Adopted: The Basin Planning Process, February 2004 (PDF file)
Fact sheet produced in cooperation with the Clean Estuary Partnership (CEP)

Legacy Pollution: What Does it Mean for the Health of the Bay, March 2003, (PDF file)
Fact sheet produced by the CEP.

TMDLs: Taking Action for Clean Water, September 2002 (HTML version)