Lake Services and Information
- Small lakes recreation guide
Your one-stop resource for information that will help you enjoy and use dozens of beautiful small lakes in King County.
- Swimming beach water temperature, bacteria and algae toxins
- Boating regulations fact sheet - King County
Learn about speed limits, personal flotation devices, operation of personal watercraft, motorized boat bans and other restrictions on specific King County Lakes.
- King County Code Section 12.44: Public Peace, Safety and Morals (Acrobat pdf)
- Boating regulations - Revised Code of Washington (RCW) Chapter 79A.60*
Swimming beach water quality
Subscribe to water quality alerts or weekly status of freshwater swimming beaches across King County:
Lake water quality
- Graphs and data for major lakes
- Graphs and data for small lakes
- Combined sewer overflow real-time map - Seattle area
- Swimming beach water quality and temperature
2017 aquatic environment - indicators and performance.
- Learn about water quality in King County’s lakes, key factors influencing their condition, King County actions, and how you can help.
- Sediment quality evaluation in Lake Sammamish, Lake Union, and Lake Washington
Report of chemical and biological substances, their distribution and toxicity, and benthic communities at various sample sites.
- Streams monitoring
Keeping watch for pollution in streams draining to Lake Washington, Lake Sammamish and the Green/Duwamish River.
- Metropolitan Water Pollution Abatement Advisory Committee (MWPAAC)
Created by state law, the MWPAAC advises the King County Executive and Council on reducing water pollution.
- Environmental laboratory
Collects water quality samples from lakes and other water bodies in King County, and performs analysis at its labs for trace metals, organics, conventionals, microbiology and aquatic toxicology.
- Map of trophic state of King County lakes
- Hydrography - interactive map
Note: this link will open a new browser window
Zoom in to your area of interest. In the layers list, click "Hydrography" and the layers you need such as "Lakes and large rivers."
- King County lakes map (734 Kb Adobe Acrobat)
This color map includes cities as of December, 1999; lakes, lake names in western King County, rivers, and streams.
Lake resources, guides and references
Learn about King County's program to protect shorelines, promote public access, and establish priorities for shoreline uses for the county's large lakes, rivers and Puget Sound.
- Introduction to lakes - Each has a life of its own
- Lakes fact sheets
Learn about lake topics from algae to zebra mussels.
- Aquatic plants (including weeds)
- Lake stewardship
Learn how to take care of lakes.
During summer months, some King County lakes host leeches! Read the leech page to learn about the value of leeches, their life cycle, and feeding and reproduction.
- Lakes glossary
- History of King County's regional wastewater treatment utility
Read how our region worked to keep our lakes and Puget Sound clean and healthy, including the early days of sewage treatment and disposal in King County, the birth of Metro and development of regional facilities to process the waste produced by our metropolitan area.
- The birth of Metro (external link)
- Lake Washington story
A discussion about the value of Lake Washington, its past pollution problems and subsequent efforts to clean up the lake.
- Lake Sammamish story
An overview of Lake Sammamish and its value to people and wildlife, the lake's past pollution problems and subsequent efforts to keep the lake clean.
- Department of Natural Resources and Parks
- Water and Land Resources Division
- Wastewater Treatment Division
News and announcements
Aug. 3, 2020
External article, Seattle Times
King County beaches closed for fecal bacteria — can we cry fowl and blame Canada geese?
Oct. 21, 2019
External article, Seattle Times
6,000 pounds of dog poop a day: Kirkland locked in dirty war
Jun. 17, 2019
External report, KING5 News
Is that algae safe? How to identify blooms in Washington waters
Spawning Grounds trailer
Documentary about restoring kokanee populations in Lake Sammamish and its tributary streams, by restoring habitat.