FAQs for HAB Signs

What types of signs are used for HABs in California?

• Planktonic (water column) HAB Signs



• Toxic Algal Mat Signs

How can I keep myself and my family safe from HABs?

• Check if a waterbody has a reported bloom by checking the HAB Reports Map, contacting the waterbody manager, and looking for posted planktonic HAB advisory signs (Caution, Warning, Danger). Learn more about HAB advisory signs, and what to do if a waterbody has a planktonic HAB advisory sign posted below.
• Check if a waterbody has toxic algal mats and follow advisories on any posted signs for toxic algal mats. More information is available on the FAQs for Toxic Algal Mats page.
• Even if no advisory signs are posted, practice Healthy Water Habits at your local lake, river, or stream.
  • Check to see if the water has a scum or is discolored.
  • Heed all instructions on posted advisories if present.
  • Avoid algae and scum in the water and on shore.
  • Keep an eye on children and pets (dogs).
  • If you think a HAB is present, do not let pets and other animals go into or drink the water, or eat scum and algal accumulations on the shore.
  • If you think a HAB is present, reduce potential for inhalation of sprays or mists by avoiding areas downwind of the bloom, and activities near the bloom that could kick up spray, such as boating at higher speeds, water skiing, or splashing.
  • Don’t drink the water or use it for cooking.
  • Wash yourself, your family, and your pets with clean water after water play.
  • If you catch fish, throw away guts and clean fillets with tap water or bottled water before cooking.
  • Avoid eating shellfish if you think a HAB is present.
• Learn more about potential impacts to you and your family or your pets, and report any suspected HAB or potential HAB-related illness.

What are planktonic HAB advisory signs, and when are they posted?

• Planktonic HAB advisory signs (Caution, Warning, or Danger) are used to inform you of current conditions and recommended actions to keep you, your family, and your pets safe from HABs. More details are included with each sign below.
• Planktonic HAB advisory signs may be voluntarily posted when:
  • cyanobacteria or cyanotoxins are detected in the water column above the voluntary guidelines for cyanobacteria in California recreational waters, or
  • a potentially HAB-related human or animal illness is reported.
  

  

  
• Note that there are no Federal or State regulatory requirements to post recreational health advisory signs for HABs occurring within freshwater and estuarine waterbodies.
• These signs only address direct use of surface water for drinking and cooking, not using water from a faucet. See frequently asked questions on potential HABs in drinking water. If you have questions about the source(s) of your drinking water and the treatment processes, contact your local water supplier.

What should I do if I see a CAUTION sign at the waterbody I am visiting?

• Follow the recommended actions shown on the Caution sign:
  • You can swim in this water, but stay away from algae and scum in the water.
  • Do not let pets and other animals go into or drink the water, or eat scum on the shore.
  • Keep children away from algae in the water and on the shore.
  • Do not drink the water or use it for cooking.
  • For fish caught here, throw away guts and clean fillets with tap water or bottled water before cooking.
  • Do not eat shellfish from this water.

What should I do if I see a WARNING sign at the waterbody I am visiting?

• Follow the recommended actions shown on the Warning sign:
  • No swimming.
  • Do not let pets and other animals go into or drink the water, or eat scum on the shore.
  • Stay away from scum, and cloudy or discolored water.
  • Do not eat shellfish from this water.
  • Do not use this water for drinking or cooking. Boiling or filtering will not make the water safe.
  • For fish caught here, throw away guts and clean fillets with tap water or bottled water before cooking.

What should I do if I see a DANGER sign at the waterbody I am visiting?

• Follow the recommended actions shown on the Danger sign:
  • Stay out of the water until further notice.
  • Do not let pets and other animals drink or go into the water, or go near the scum.
  • Stay away from scum, and cloudy or discolored water.
  • Do not eat fish or shellfish from this water.
  • Do not use this water for drinking or cooking. Boiling or filtering will not make the water safe.

When are HAB advisory signs removed?

• All HAB advisory signs are removed after a bloom and mats are no longer visible and cyanotoxins are consistently below the thresholds in the voluntary guidelines for cyanobacteria in California recreational waters.

What are HAB general awareness signs, and when are they posted?

• Either type of general awareness sign can be voluntarily posted year-round at waterbodies where HABs may occur.



• The general awareness sign for toxic algal mats advises visitors to assess the location to determine if mats are present. If you see algal mats, then follow the advisories and make sure no children, dogs, or adults touch or ingest any mat material.
  



• The planktonic HAB general awareness sign provides you with general information about HABs, potential symptoms, and general precautions. Either the condensed version shown here or a more detailed version may be posted.