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King County to get the poop on swim beach water quality and help protect swimmers’ health all summer long


The King County Swimming Beach Monitoring Program is underway to test for poop and toxic algae in the water at the most popular lake beaches countywide. Free alerts are available to help residents keep their families and pets safe. Sign up at


As the warmer weather beckons, people are beginning to slowly test the social-distancing waters of local lakes, figuratively speaking. Literally making sure the water at your local beach is safe (from potential poop pollution and toxic algae) for swimming and water recreation is as important as recreating responsibly.

King County takes water samples to test for fecal (poop) bacteria and algal toxins at 28 lake swimming beaches every week throughout the summertime swim season, including popular spots like Green Lake, as well as Juanita Beach and Magnuson Park on Lake Washington. Poop can make its way into swimming areas in a number of ways, including from dogs, from geese and other birds, and from humans (e.g., toddlers and babies in diapers).

Signing up for King County’s beach alerts provides weekly updates to let people know if any of the county’s most visited freshwater swimming beaches are exceeding thresholds for either bacteria or algal toxins in the water. People can sign up to receive a weekly status update – or just alerts when a beach is closed – at

The monitoring program tests for fecal (poop) bacteria every week throughout the summer as way to protect the health of lake-goers. Some beaches are also tested for algal toxins every week, while other beaches are tested only if there is a visible algal bloom. If a beach is closed due to high concentrations of either bacteria or algal toxins in the water, closure signs will be posted at the beach and will be posted on the Swim Beach Monitoring program website. 

The bacteria we measure is used to indicate the presence of poop in the water. More poop in the water increases the risk people can get sick. When the concentrations exceed the thresholds, that’s when Public Health – Seattle & King County makes the determination that a beach should be closed to water recreation to protect public health.

Marine beaches such as Golden Gardens, Alki Beach or Seahurst Park are monitored through the Washington State Department of Ecology BEACH program.

Like parks and trails, beaches – where social distancing can be maintained – are open to the public. However, individuals and families visiting lake shorelines and beaches should continue to adhere to social distancing guidelines:

  • It is still safest to stay home, but if you head out wear a mask.
  • Don’t go out when you are sick.
  • Recreating with your immediate household only is safest. Follow local guidance on spending time with others outside your household.
  • Don’t stray too far from home when recreating and keep rural communities safe by minimizing stops and bringing all that you’ll need for your outing, such as water and hand sanitizer.
  • Stay six feet apart.
  • Be prepared to go somewhere else if your destination seems crowded.
  • Keep your activities within your comfort and skill level to reduce the risk of injury and adding to the strain on our health care and emergency services.
  • Take any garbage with you, including disposable face masks and gloves, to help protect others.

Additionally, here are four simple ways to help keep poop out of water: 

  • Only take your dog to a designated dog beach.
  • Don’t feed geese and other birds at the beach. The more they hang out at the beach or on a dock, the more poop gets washed into the water.
  • Use swim diapers for babies and toddlers.
  • Wash off before entering the water.


About the King County Water and Land Resources Division

The Water and Land Resources Division works to protect the health and integrity of King County’s natural resources. Employees work to reduce flood risks, monitor water quality and restore wildlife habitat; manage, and reduce the harmful impacts from stormwater, noxious weeds and hazardous waste; create sustainable forestry and agriculture; and protect open space to support all of these efforts.