Help is out there for local health agencies, water managers, park rangers, the public, and others.

Drinking Water

Releases of cyanotoxins by harmful algal blooms create concerns for drinking water sources, treatment of drinking water, and the safety of drinking water.

  • Frequently Asked Questions
  • The State Water Resources Control Board’s Division of Drinking Water is developing a communication strategy and resources for drinking water treatment plants to ensure the provision of safe drinking water.
  • The U.S. Environmental Protection Agency posted Health Advisories in May 2015 to provide guidance for drinking water on the cyanotoxins microcystin and cylindrospermopsin.
    • Health Advisories and health effects support documents
      Non-regulatory concentrations of the two algal toxins in drinking water at or below which adverse human health effects are not anticipated to occur over a ten-day exposure period.
    • Support document for managing cyanotoxins in drinking water
      Provides information and a framework that public water systems (PWSs) and others can consider using to inform their decisions on managing the risks from cyanotoxins to drinking water. Includes a potential stepwise approach PWSs could use to inform their decisions on whether and how to monitor, treat, and communicate with stakeholders.


Monitoring of cyanoHAB is critical to understanding the dynamics of a bloom, deciding on best management strategies, and protecting aquatic life and public health. There are many challenges to monitoring due to available resources, size and dynamics of the water body, and laboratory analytical techniques. The State Water Board's Surface Water Quality Monitoring Ambient Monitoring Program (SWAMP) is focused on developing a statewide monitoring strategy for cyanotoxins, guidance for field and laboratory protocols, and a satellite monitoring program to be a first alert system for cyanoHABs in larger water bodies.  For more information on current monitoring projects, please contact

Laboratory Resources

It is important to detect the presence of cyanobacteria and cyanotoxins in drinking and recreational water, as well as detecting bioaccumulation in freshwater and marine organism tissues. Having rapid and accurate detection methods - including visual and qualitative methods along with quantitative laboratory techniques - are critical to ensure the proper management of cyanoHABs. The State Water Board's Office of Information Management & Analysis is focused on bringing together laboratories to develop cyanoHAB data comparability and improve cyanoHAB data interpretation. Laboratories that are interested in joining the Cyano Lab Network, please contact

Control and Treatment of Blooms

Measures to prevent, mitigate, remediate blooms in surface waters and drinking water supplies

Freshwater Incident Response and Interagency Coordination

The documents provided below were developed by an interagency team representing California State government organizations charged with responsibilities to address harmful algal blooms (HABs) through either notification or management tasks and activities. The team broke into two groups, one focused on incident response and interagency coordination and communication and the other focused on how to coordinate and best communicate this critical information to the public. These documents are "working drafts" and may be updated regularly to be made more useful to the teams and stakeholders using them. If you have any comments on these documents or questions about their use please contact Greg Gearheart at or (916) 341-5892.

State Agency Contacts

The following table provides contact information for staff at state agencies participating in the interagency HAB incident coordination workgroup.

Organization Contact Information
HAB Hotline
State Water Resources Control Board, Lead HAB staff;
State Water Resources Control Board, Interagency Coordination Lead
State Water Resources Control Board, Division of Drinking Water View this map to select appropriate district office contact
Regional Water Board Map View the map on left to select appropriate region listed below (Regions 1-9)
Region 1, North Coast;
Region 2, San Francisco Bay
Region 3, Central Coast
Region 4, Los Angeles
Region 5, Central Valley
Region 6, Lahontan
Region 7, Colorado River
Region 8, Riverside;
Region 9, San Diego;
Department of Fish and Wildlife, Wildlife Investigation Branch;
Cal EPA, Office of Environmental Health Hazard and Assessment;
Tracking California / California Department of Public Health;

Related Programs and Organizations

Please see below for Freshwater and Estuarine HAB-related Programs and Organizations organized geographically (international, national, statewide, or by Water Board Region; resources within each region are listed alphabetically). Contact Joseph Westhouse with any updates or additions. For marine HABs, please see California Harmful Algal Bloom Monitoring and Alert Program (CalHABMAP).