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Harmful Algal Blooms (HABs)

Surface Water Monitoring and Assessment Unit

Arizona Harmful Algal Blooms

Posted on: Sept. 37, 2023 - 9:08 p.m.

Algae are microscopic organisms that can be found naturally in all types of water. Sometimes algae rapidly grow out of control, or bloom. In Arizona, a bloom of blue-green algae can produce toxins (poisons), which can cause serious illness in people and animals, and in rare cases can be deadly. These blooms are known as harmful algal blooms or HABs.

What Does Harmful Algae Look Like?

Harmful blue-green algae can:

  • Look like pea soup or spilled green paint
  • Discolor or leave streaks in the water
  • Be surface scum, mats or films
  • Appear as green dots or globs floating below the surface

Examples | View/Download >

Practice Healthy Recreational Water Habits

Enjoying the outdoors is an important part of an active, healthy lifestyle. ADEQ recommends following these simple, healthy habits in waters with visible algae:

  • STAY AWAY from algae and scum in the water – AND – keep children and pets away from algae in the water or on the shore
  • DO NOT DRINK or use this water for cooking

Boating and fishing are acceptable in blue-green algae blooms, but people should take care to follow the advice above and avoid contact or ingestion of the water.

You can help protect public health by reporting possible harmful algal blooms. If you observe an algal bloom, ADEQ recommends:

Another type of algae commonly found in Arizona is golden algae. A bloom of golden algae can cause a fish kill, but there is no evidence that golden algae is harmful to humans or animals. However, it is advised that people not eat fish impacted by a golden algae bloom. Fish kills and golden algae blooms can be reported to the Arizona Game and Fish Department | Learn More >


View our Fact Sheet for frequently asked questions and answers | View/Download >