Central Coast Region - Clean Water Act Section 303(d) List of Water Quality Limited Segments (the 303(d) List)

What is the 303(d) List?

Section 303(d) of the Federal Clean Water Act requires states to develop, update, and submit to the United States Environmental Protection Agency (USEPA) for approval, a list of waterbodies that are polluted (the 303(d) List). Under Title 40 Code of Federal Regulations (40 CFR) Section 130.7(d)(1), states are required to submit the 303(d) List biennially to the USEPA. 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 (typically a Total Daily Maximum Load or TMDL) to address the impairment.

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

The State Water Resources Control Board (State Water Board) initiates the process to update the 303(d) List by soliciting data and information from the public. Staff at the Regional and State Water Boards considers these data, along with data available to the Water Boards, in preparing the updated 303(d) List. In California, the State and Regional Water Boards to follow the "Water Quality Control Policy for Developing California's Clean Water Act Section 303(d) List" when developing updates to the List. This policy describes the process by which the State and Regional Water Boards comply with the requirements of the Clean Water Act in developing the List. The policy requires that the Regional Water Boards adopt an updated 303(d) List for waters in each region and include public participation. Updates to the List are then submitted 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.

In addition, pursuant to CWA Section 305(b), states must prepare a report on the water quality and condition of waters (305(b) Report) to identify waters that are attaining water quality standards as well as those that are not. The 305(b) Report does not require approval. However, USEPA will compile the data from the state 305(b) Reports and transmit the summaries in their "National Water Quality Inventory Report" to Congress.

The State and Regional Water Quality Control Boards prepare a single Integrated Report that meets the reporting requirements of CWA sections 303(d) and 305(b).

The most current EPA approved 303(d) List (the 2014 and 2016 303(d) List), and Integrated Report.

The 2014 and 2016 303(d) List contains updates for six of the nine Regional Water Quality Control Boards, including the Central Coast Region. The next opportunity for the Central Coast Region to approve updates to the 303(d) List will be the 2020 303(d) List.  The process for updating the 2020 303(d) List will begin in Summer 2018 with a notice soliciting data from the public. To receive notifications by email of the public data solicitation and other important updates, please subscribe to the Central Coast Water Board's email subscription list (see link at the bottom of this page).

EPA Approved 2012 303(d) List

The 2012 303(d) List contains updates for three Regional Water Boards (North Coast, Lahontan, and Colorado River Basin) as well as the carryover decisions from the previously approved 2008/2010 303(d) List's for the other six Regional Water Boards (including the Central Coast).

On July 30, 2015, the U.S. EPA issued its final decision regarding the waterbodies and pollutants added to California's 303(d) List. This replaces the 2010 California Clean Water Act section 303(d) List as California's current 303(d) List.

Though the Central Coast Water Board was not included in the 2012 assessment cycle, you may access information on California's Final 2012 Clean Water Act Section 303(d) List and related documents.

EPA Approved 2008/2010 303(d)

The 2008/2010 303(d) List is the most recent updated 303(d) List for the Central Coast Water Board. On July 10, 2009, the Central Coast Water Board adopted the 2008 changes to the 303(d) List. The final 2008 Integrated Report was incorporated into the statewide 2010 Integrated Report that was approved by the State Water Board on August 4, 2010. On October 11, 2011, U.S. EPA gave final approval to the 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.html.


For questions on the California Integrated Report contact Mary Hamilton of the Central Coast Water Board via email at: Mary.Hamilton@waterboards.ca.gov.


To subscribe to the interested parties email lists for the Central Coast Water Board and State Water Board, click on the following links: