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  • Toxic Algae

    Blue-green algae (cyanobacteria) occur naturally and can produce toxins.

    What is a toxic algae bloom?

    Algae bloom occur in fresh water with the right amount of sunlight, temperature and nutrients. These conditions cause rapid growth of algae, which can float to the surface to form a scum. These scums often look like green paint, but algae can also form in dense clumps that resemble pellets in the water. Wind and weather conditions can change the amount and location of algae.

    Toxic algae can make you sick.

    If you swallow water with toxic algae, it can make you sick within minutes to hours. Kids are more at risk because their bodies are smaller. Talk to your doctor if you have these symptoms:

    • Muscle weakness.
    • Vomiting.
    • Diarrhea.
    • Nausea.

    Skin contact with toxic algae can cause irritation or a rash. This is a different rash than Swimmer’s Itch.

    If you think you got sick after swimming, contact us via email or at (253) 649-1420.

    Toxic algae can make your pets sick, too.

    Reports of dogs getting sick or dying after swimming in ponds, lakes, and streams are more common during the summer. After playing in water, pets are more likely to get sick from toxic algae because:

    • Their bodies are small.
    • They may drink water containing a large amount of toxic algae.
    • They lick or groom their fur.

    Talk to a vet if your pet shows these symptoms:

    • Lethargy.
    • Vomiting.
    • Diarrhea.
    • Convulsions.
    • Difficulty breathing.
    • General weakness.

    Resources to keep your pet healthy

    Can I eat fish from toxic algae contaminated water?

    Avoid eating fish from areas with visible algae. Always clean fish well and discard guts.

    What should I do if I see an algae bloom?

    • Don’t drink lake water.
    • Don’t play in water with visible algae.
    • Keep your family and animals away.
    • When in doubt, stay out. 
    • Let us know. If you see algae at a lake that is not already posted with Health Department signs, call us at (253) 649-1420.

    You can also help us track algae blooms. Get involved with our Algae Watch Volunteer Group. Email to sign up.

    You can help prevent toxic algae blooms.

    Animal waste, human waste and fertilizers contain nutrients that algae need to grow.

    • Reduce fertilizers.
    • Maintain your septic system.
    • Pick up after your pets, don’t feed waterfowl and keep livestock away from the water.
    • Plant native plants between your yard and the water to reduce runoff and prevent erosion.

    Which lakes does the Health Department test?

    • Bay Lake
    • Clear Lake
    • Harts Lake
    • Lake Minterwood
    • Ohop Lake
    • Palmer Lake
    • Silver Lake
    • Spanaway Lake
    • Tanwax Lake
    • Lake Tapps
    • Lake Whitman

    Additional testing and information

    If you don’t see a lake you’re interested in on this list, the state’s toxic algae monitoring program can help. You can report and test a bloom through their program. You can also find all toxin test results for Washington Lakes tested through this program.

    You can contact us for limited guidance on lakes that have toxic algae.  

    Find out more!


    Contact or (253) 649-1420.