Help Keep Our Water Clean!

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The City of Sammamish is committed to keeping our water clean!

And you can help ...


In 2020, we are launching a new rainwater pollution prevention campaign. The City of Sammamish will share information and tips that will help our community protect Lake Sammamish and native species, like our local mascot “the little red fish” – kokanee salmon! You can help by participating in surveys, challenges, activities, and encouraging others to join in too!


Summer is a great time for outdoor activities like car washing and pressure washing. The City would like to help you do those activities with the

The City of Sammamish is committed to keeping our water clean!

And you can help ...


In 2020, we are launching a new rainwater pollution prevention campaign. The City of Sammamish will share information and tips that will help our community protect Lake Sammamish and native species, like our local mascot “the little red fish” – kokanee salmon! You can help by participating in surveys, challenges, activities, and encouraging others to join in too!


Summer is a great time for outdoor activities like car washing and pressure washing. The City would like to help you do those activities with the protection of our lakes and streams in mind. In addition, we would like to learn more about the car-washing and/or pressure-washing that takes place in our community. Please participate by utilizing these best management practices and completing a quick survey.


Best Management Practices for Car Washing and Pressure Washing



Is Car Washing Illegal?
No. Washing your vehicle is not illegal. But the discharge of the soapy, dirty wash water into the storm drain is technically a violation of federal, state, and City regulations. City storm drains are not filtered and lead through our waterways directly to Lake Sammamish!


What About Soaps?
All soaps, including biodegradable ones, can harm our waterways. Soaps break the surface tension of water, lowering the oxygen level which is harmful to our Kokanee salmon and other aquatic life. The worst soaps contain phosphates, which can cause unwanted algae blooms in surface waters. And don’t forget — car wash water is a mixture or soap, oil, grease, and heavy metals – all of which are harmful to the Lake Sammamish ecosystem.


What’s the story with pressure washing?

Pressure washing can be harmful to Lake Sammamish too. Those same heavy metals, chemicals and oils that are on your car are also on your driveway. To prevent water pollution from pressure washing, steps must be taken to collect and dispose of wastewater properly.


So What Can You Do To Keep Our Waters Clean?

  • Take your car to a commercial car wash facility that discharges its wash water to the sewer system, where it is treated or recycled.
  • When washing your car at home, wash it on the lawn (or other vegetated area) to keep the water out of the storm drain. Mild, soapy water will not hurt your lawn; it will actually water it!
  • Wash your car on an area that drains to your lawn/vegetated area.
  • Use waterless car wash products, available at auto parts stores, supermarkets, and online. This saves water too!
  • Divert dirty water to vegetation when pressure washing OR collect dirty water and have a wastewater collection company pick it up for safe treatment.


Remember: Only Rain Down the Storm Drain!