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  1. Lakes
  2. Major lakes data

Major lakes monitoring

We are committed to monitoring the water quality of the County's lakes to ensure their continued health, as well as the health of the public who utilize the lake's many resources. We invite you to learn more about our program by looking through the pages listed on the left. This site contains detailed graphs of water quality data, photographs of water sampling, and general information about the water quality of King County's lakes.

Map Legend:  Map icon for active siteactive site   Map icon for inactive siteinactive site

If you have a question about the program, please contact the Science Section Lakes and Streams Team at lakes@kingcounty.gov, or call the Water and Land Resources Department Reception Desk at 206-477-4800

Lake News

Seasonal Fish Die Off

From May through July we typically see quite a few dead three-spined sticklebacks in the shallow waters around our large lakes and along the Lake Washington Ship Canal. For more information and photos of these fish visit; the Lakes FAQ page .

Catching and eating fresh fish

Some fish are safer to eat than others. Check out the Public Health Insider blog post to learn where to fish, and what to fish for, throughout King County.

Toxic Algae Blooms

Toxic algal blooms typically peak in the late summer and early fall. Check out the Northwest Toxic Algae website to learn where toxic algae blooms have been reported throughout the state.