TOPEKA, Kan.(KSNW) – This Fourth of July weekend, the Kansas Department of Health and Environment (KDHE) and the Kansas Department of Wildlife and Parks and Tourism (KDWP) urges individuals who may be on Kansas lakes to be aware of potential blue-green algae and to understand that harmful algal blooms are unpredictable and may develop rapidly. 

If you observe a scum, a paint-like surface on the water, small floating blue-green clumps or filaments, or the water is an opaque green, avoid contact and keep pets away.  These are indications that a harmful bloom may be present. Pet owners should be aware that animals that swim in or drink water affected by a harmful algal bloom or eat dried algae along the shore may become seriously ill or die.

KDHE, in conjunction with KDWP, has also issued several public health advisories for Kansas lakes due to blue-green algae.

Active Advisories


  • Atchison County State Fishing Lake, Atchison County (new)
  • Brown State Fishing Lake, Brown County (new)
  • Herington Reservoir (New City Lake), Dickinson County
  • Gathering Pond at Milford, Geary County (new)
  • Milford Lake Zone C, Geary County (upgrade 7/1)
  • Marion Reservoir, Marion County
  • Agra City Lake, Phillips County (new)
  • Webster Reservoir, Rooks County
  • Jerry Ivey Pond, Saline County
  • Big Eleven Lake, Wyandotte County


  • Mission Lake Horton, Brown County (new)
  • Herington City Lake (Old Lake), Dickinson County
  • Milford Lake Zones A and Zone B, Geary County (new)
  • Horsethief Reservoir, Hodgeman County (new)
  • Perry Zone C, Jefferson County (new)
  • South Lake, Johnson County
  • Big Hill Lake, Labette County
  • Marion County Lake, Marion County
  • Melvern Outlet Pond, Osage County
  • Overbook City Lake, Osage County (new)
  • Pomona Reservoir, Osage County (new)
  • Atwood Township Lake, Rawlins County

Advisories Lifted 7/1/21

  • Keith Sebelius Reservoir, Norton County

When a warning is issued, KDHE recommends the following precautions be taken:

  • Lake water is not safe to drink for pets or livestock.
  • Lake water, regardless of blue-green algae status, should never be consumed by humans.
  • Water contact should be avoided.
  • Fish may be eaten if they are rinsed with clean water and only the fillet portion is consumed, while all other parts are discarded.
  • Do not allow pets to eat dried algae.
  • If lake water contacts skin, wash with clean water as soon as possible.
  • Avoid areas of visible algae accumulation.

A watch means that blue-green algae have been detected and a harmful algal bloom is present or likely to develop. People are encouraged to avoid areas of algae accumulation and keep pets and livestock away from the water.

During the watch status, KDHE recommends the following precautions be taken:

  • Signage will be posted at all public access locations.
  • Water may be unsafe for humans/animals.
  • Avoid areas of algae accumulation and do not let people/pets eat dried algae or drink contaminated water.
  • Swimming, wading, skiing and jet skiing are discouraged near visible blooms.
  • Boating and fishing are safe. However, inhalation of the spray may affect some individuals. Avoid direct contact with water, and wash with clean water after any contact.
  • Clean fish well with potable water and eat fillet portion only.

KDHE investigates publicly-accessible bodies of water for blue-green algae when the agency receives reports of potential algae blooms in Kansas lakes. Based on credible field observation and sampling results, KDHE reports on potentially harmful conditions.

For information on blue-green algae and reporting potential harmful algal blooms, click here.