Under CWA section 303(d), states are required to submit to U.S. EPA a list identifying waters within its boundaries not meeting water quality standards (impaired waters) and the water quality parameter (i.e., pollutant) not being met (referred to as the 303(d) List). States are required to include a priority ranking of such waters, taking into account the severity of the pollution and the uses to be made of such waters, including waters targeted for the development of total maximum daily loads (TMDLs).The current list, approved by the EPA, is the 2012 303(d) List. The Water Quality Control Policy for Developing California's Clean Water Act Section 303(d) List (Listing Policy) describes the requirements for developing the 303(d) list in California.
In addition to the impaired water body list required by Clean Water Act Section 303(d), Clean Water Act section 305(b) requires states to report to U.S. EPA on the overall water quality conditions of their surface waters, not just those that are impaired (this is referred to as the 305(b) Report). Both Clean Water Act section 303(d) and section 305(b) requirements are being satisfied through the 2012 California Integrated Report. (See "2012 Integrated Report" tab)
In California, the 303(d) list is made up of three of the Integrated Report categories, 4a, 4b, and 5. These categories contain water bodies that have listed pollutants that are still requiring the development of a TMDL, are being addressed by a U.S. EPA approved TMDL, or a U.S. EPA approved action other than a TMDL. Below are the Integrated Report Category Reports that make up the 303(d) list and the Factsheets that contain the supporting information for listing decisions: