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303(d) List of Impaired Waterbodies

What is the 303(d) list?

Section 303(d) of the 1972 Federal Clean Water Act requires states to identify waterbodies that do not meet water quality objectives and are not supporting their beneficial uses. Each state must submit an updated list, called the 303(d) list, to the U.S. EPA every two years. In addition to identifying the waterbodies that are not supporting beneficial uses, the list also identifies the pollutant or stressor causing impairment, and establishes a priority for developing a control plan to address the impairment. The list also identifies waterbodies where 1) a TMDL has been approved by U.S. EPA and an implementation is available, but water quality standards are not yet met, and 2) waterbodies where the water quality problem is being addressed by an action other than a TMDL and water quality standards are not yet met. 

Current Status of the 2008/2010 303(d) List and 303(d)/305(b) Integrated Report for the Central Coast

On July 10, 2009, the Central Coast Water Board approved staff's recommendations for changes to the 303(d) list of impaired waterbodies.

On November 12, 2011, U.S. EPA gave final approval to the 2008-2010 List of Impaired Waterbodies. 

You may access information on California’s Final 2008-2010 Clean Water Act Section 303(d) List and related documents at http://www.waterboards.ca.gov/water_issues/programs/tmdl/integrated2010.shtml.

For questions on the 2008-2010 California Integrated Report contact Mary Hamilton of the Central Coast Water Board at madams@waterboards.ca.gov.  

To subscribe to the State Water Resources Control Board's email list for the 2010 California Integrated Report, subscribe to the "Integrated Report" email list.

How and when does the 303(d) list get updated? And how can I participate?

Pursuant to Section 303(d) of the 1972 Federal Clean Water Act, the state must submit an updated list to the U.S. EPA every two years. The State Water Resources Control Board (State Water Board) initiates the process to update the list by soliciting data and information from the public. Staff at the Regional and State Water Boards consider this data, along with data available to the Water Boards, in preparing the updated list. Once received, the data and information is evaluated consistent with the Policy for Developing California's Clean Water Act Section 303(d) List. You may access this policy at http://www.waterboards.ca.gov/water_issues/programs/tmdl/303d_listing.shtml. The policy requires that the Regional Water Boards approve an updated list for waters in each region and submit this list for subsequent approval by the State Water Board as part of the updated list for the state. The U.S. EPA then must approve the state list.

What happens when a water body is placed on the 303(d) list?

Once a waterbody is placed on the 303(d) list, Regional Board staff evaluates the nature of the impairment and begins developing a Total Maximum Daily Load (TMDL), if appropriate and necessary.   For each TMDL developed, staff will also develop an implementation or water quality control plan for each water body and associated pollutant/stressor on the list. The TMDL and the implementation plan serve as the means to attain and maintain water quality standards for the impaired water body. During each 303(d) listing cycle the water bodies on the list are prioritized in order to facilitate scheduling and budgeting to develop TMDLs and implementation plans.

  • This page last updated Dec. 1, 2011.