Santa Ana Region - 303(d) List of Water Quality Limited Segments & 305 (b) Condition Report

California Integrated Report

The Federal Clean Water Act section 303(d) list of water quality limited segments and section 305(b) condition report are combined as the “Integrated Report” and submitted to the U.S. Environmental Protection Agency. The Federal Clean Water Act Section 303(d) requires that States assess the quality of their surface waters every two years and publish a list of those waters not meeting the water quality standards established for them. The 305(b) condition report assigns an overall water quality condition to all assessed waterbody segments. Water quality standards include beneficial uses, water quality objectives necessary to protect these uses and the antidegradation policy, and are found in the Water Quality Control Plan (“Basin Plan”). Waterbodies are included on the 303(d) List of Water Quality Limited Segments after evaluation of existing water quality data using the methodology for determining impairment identified in the Water Quality Control Policy for Developing California's Clean Water Act Section 303(d) List (“Listing Policy”) and the Functional Equivalent Document, both adopted by the State Water Resources Control Board.

For waterbodies placed on the 303(d) List of Water Quality Limited Segments, states are required to develop a pollution control plan, typically a Total Maximum Daily Loads (TMDLs) or an approved alternative restoration plan, for the pollutant(s) that are causing standards impairment. A listed waterbody remains on the list until a restoration plan is adopted and the water quality standards are attained, or there are sufficient data to demonstrate that water quality standards have been met to delist per the Listing Policy.

Each integrated report consists primarily of assessments from the three Regional Water Quality Control Boards that are identified "on-cycle" by a notice of solicitation. Since the 2020-2022 California Integrated Report cycle, the State Water Board has been administering the public process, including board hearings and facilitating the public comments. While the Regional Water Boards play a significant role in the development of the integrated report, the Regional Water Boards no longer conduct individual board hearings and public comment periods.

Please refer to the State Water Board’s webpage for documents not shown on this page.

2028 Integrated Report (In Progress)

The Regional Water Boards “on-cycle” for the 2028 Integrated Report are: Central Coast, Central Valley (Sacramento-San Joaquin River Delta and Tulare Lake Basin), and San Diego.
The 2028 Integrated Report is currently in progress.

• Data solicitation period occurs between April 18, 2022 and October 23, 2024. Please refer to the public notice for more information.

2026 Integrated Report (In Progress)
The Regional Water Boards “on-cycle” for the 2026 Integrated Report are: North Coast, Lahontan, and Colorado River Basin. The Regional Water Board conducting “off-cycle” assessments is the Central Valley (San Joaquin River watershed).
The2026 Integrated Report is currently in progress.

• Data solicitation period occurs between April 18, 2022 and October 21, 2022. Please refer to the public notice for more information.  

2024 Integrated Report (Current)
The Regional Water Boards “on-cycle” for the 2024 Integrated Report are: San Francisco Bay, Los Angeles, and Santa Ana. The Regional Water Boards conducting “off-cycle” assessments are: Central Coast, Central Valley (Sacramento River watershed), and San Diego.
The 2024 Integrated Report was partially approved and partially disapproved by the U.S. EPA.

• USEPA’s Partial Approval and Partial Disapproval of California’s 2024 List of Impaired Waters: Letter (December 13, 2024)
• The first revised proposed Final Staff Report is now available.
• The proposed Final Staff Report and Responses to Comments are now available.
• The public comment period occurs between February 16, 2023 and April 3, 2023. Please refer to the public notice for more information on how to submit a public comment and attend the public hearing on March 21, 2023.
• The draft Staff Report and appendices for the 2024 Integrated Report is now available.
• Data solicitation period occurs between June 28, 2020 and October 16, 2020. Please refer to the public notice for more information.