Harmful Algal Blooms Water Quality Objectives for California Inland Surface Waters, Enclosed Bays, Estuaries, and Coastal Lagoons
The State Water Resources Control Board (State Water Board) is developing statewide water quality objectives for harmful algal blooms (HABs) and a program of implementation to reduce the risk and occurrence of HABs in California’s inland surface waters, enclosed bays, estuaries, and coastal lagoons. The objectives and program of implementation will be proposed as state policy for water quality control and as a statewide water quality control plan.
The new water quality objectives being proposed consists of both numeric and narrative water quality objectives. The numeric water quality objectives will protect the municipal an domestic supply (MUN) and water contact recreation (REC-1) beneficial uses from four cyanotoxins, which are microcystins, cylindrospermopsin, anatoxin-a, and saxitoxins. The narrative water quality objective will be applicable to all beneficial uses to protect from the detrimental effects of HABs.
The project was previously called the Biostimulation, Cyanotoxins, and Biological Conditions Provisions and was focused on developing statewide numeric objectives for nutrients and other indicators of eutrophication or biostimulation.
Project Goals
The project aims to establish water quality objectives and implementation requirements crucial for consistent protection of California's waters, specifically to:- Protect the municipal and domestic water supply (MUN) and water contact recreation (REC-1) beneficial uses from HABs and reduce the risk and occurrence of HABs in all inland surface waters, enclosed bays, estuaries, and coastal lagoons.
- Establish consistent, statewide HABs water quality objectives and a coordinated, consistent program of implementation to attain them.
Project Updates
A presentation from October 23, 2026, is available that describes the project scope, project necessity, future steps, and opportunities for public engagement. The presentation and a video recording of the presentation can be accessed with the links below.
If you have any questions about the presentation or the project, or if you would like to discuss the project, please reach out to us at: dwq-ipsi@waterboards.ca.gov.
Related Links
- State Water Resources Control Board, Cyanobacteria and Cyanotoxins in Drinking Water
- SWAMP Freshwater and Estuarine Harmful Algal Bloom (FHAB) Program
- SWAMP HABs Wiki Page
- California Cyanobacteria and Harmful Algal Bloom (CCHAB) Network
- OEHHA Drinking Water Notification Levels
- OEHHA suggested Action Levels to Reduce Potential Adverse Health Effects of Six Cyanotoxins
- USEPA Harmful Algal Bloom Fact Sheet
- USEPA Drinking Water Health Advisories for Cyanotoxins
- USEPA Additional Information about Cyanotoxins in Drinking Water
- USEPA Health Effects for Anatoxin-a
- USEPA Health Advisory for Microcystins
Public Meetings
Notifications for upcoming public meetings, including public workshops, State Water Board information items, and public hearings will be posted here.If you want to receive email notifications, please subscribe to the email list Freshwater Plans and Policies under the Water Quality Section.
Contact
For additional information
(Page last updated 11/9/26)
Water is a precious resource in California, and maintaining its quality is of utmost importance to safeguard the health of the public and the environment.
