The North Dakota Department of Environmental Quality has issued blue-green algae advisories for the following North Dakota lakes:

*Current as of 8/25/2021

  • Bowman-Haley Dam (Bowman County)
  • Froelich Dam (Sioux County)
  • Patterson Lake (Stark County)
  • Antelope Lake (Pierce County)
  • Jamestown Reservoir (Stutsman County)
  • Lake LaMoure (LaMoure County)
  • Alkali Lake (Stutsman County)
  • Pipestem Reservoir (Stutsman County)
  • South Hoffer (Sheridan County)
  • Buffalo Lodge Lake (McHenry County)
  • Dead Colt Creek Dam (Ransom County)
  • Alkali Lake (Sargent Lake)
  • Boom Lake (LaMoure County)
  • Barnes Lake (Stutsman County)
  • Reule Lake (Stutsman County)
  • Bylin Dam (Walsh)
  • South Golden Lake (Steele County)

A water advisory means the water may contain blue-green algae that can be harmful to humans and pets.

People that swallow or come into contact with water containing cyanotoxins can become sick with diarrhea and vomiting; or experience numb lips, tingling fingers and toes, dizziness, rashes, hives, and skin blisters. Pets and livestock may also suffer adverse health effects, which could result in death. There are no known antidotes for the cyanotoxins produced by blue-green algae. Children and pets are at a higher risk than adults for illness because of their smaller size.

Know it.
Blue-green algae can look like grass clippings floating in the water, clumps/puffballs, or green cottage cheese. It can also make the water appear like spilled green paint or green pea soup.

Avoid it.
Respect advisories and warnings announced by the NDDEQ. All water advisories and warnings are posted at under the map tab.
Do not swim, water ski, or boat in areas where the water is discolored or where you see foam, scum, or mats of green or blue-green algae on the water; or let pets swim in or drink from affected waters.

If you or your pet accidentally swims in water that might have a cyanobacteria bloom, rinse off with fresh water as soon as possible.
Do not irrigate lawns with pond or lake water that looks scummy or has an awful odor.

Report it.
Report suspected blue-green algae blooms to the NDDEQ at 701-328-5210 or on the NDDEQ’s Harmful Algal Bloom webpage at Because it can take time to receive laboratory test results, NDDEQ urges people to be cautious and avoid waters that look discolored, scummy, or have a foul odor.