Harmful Blue-green Algae Blooms

Blue-green algae are microscopic organisms that can form dense blooms in surface waters. People and animals should avoid blooms because blue-green algae can cause health effects.

Know It

It might be a blue-green algae bloom in surface water if you see:

  • Strongly colored water (blue-green, green, yellow, white, brown, purple, or red).
  • Paint-like appearance.
  • Floating mats or scums.

Avoid It

Always stay away from blooms in surface waters. View DEC's list of reported blooms:

  • Don’t swim, fish, boat, or wade in areas with blooms.
  • Don’t eat fish caught from areas with blooms.
  • Rinse with clean water if you, your family or pets have contact with blooms.

If you are not on a public water supply and are using surface water:

  • Bloom or no bloom, never drink, prepare food, or make ice with untreated surface water. You may also consider not using it for washing, especially if it looks cloudy.
  • During a bloom, don’t drink, prepare food, or make ice with surface water, even if you treat the water yourself.
  • Boiling water will not remove blue-green algae or their toxins. Learn more.

If you are on public water:

  • Your water is treated, disinfected and monitored for drinking and household use. Learn more.

Report It

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