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RainWise—Private property owners can be part of the stormwater pollution solution

With every storm, rain carries pollutants off our roofs, driveways and other hard surfaces. These pollutants end up in our creeks, the Duwamish River, our lakes, and Puget Sound. During big storms, the sheer volume of this “stormwater” can cause sewer overflows and polluted runoff.

RainWise helps private property owners install rain gardens and cisterns to help manage the rain that falls on their roofs. These installations can also add attractive landscaping, provide water for summer irrigation, and may reduce flooding. 

Check out to find out if you qualify for rebates, see examples of rain gardens and cisterns, and learn more about how to get RainWise.

How to become RainWise

RainWise rebates cover most or all of the cost of installing cisterns and rain gardens on private properties in eligible combined sewer overflow basins. The average rebate has been around $4,400.

Here is how you get started:

  • The first step is to check your eligibility at
  • The next step is to find a contractor. If you can't attend one of our events, email us at with the subject line "Contractor Matchmaking" and we will help you find the best contractor for your needs.

Learn more

Check out our library of webinars and resources at

Information available in Vietnamese, Chinese and Spanish .

Visit our blog, clean water stories, for rainwise articles.

Download the following documents to learn more about this program.

Not eligible for RainWise?

Green Stormwater Mini-Grants are available in the King County Wastewater Treatment Division service area.

Here are some other resources: GSI Western WA Resources

a blue cloud with two agency logos - Seattle Public Utilities and King County

Visit the 700 Million Gallons website for more information.


Email or
call the Garden Hotline at 206-633-0224.

girl in pink dress walking through a rainwise gardenRainWise rebates pay for rain gardens! 

Man in blue shirt and brown pants adjusting a valve on a cistern, located next to his house. Cisterns capture winter rain and slowly release it back into the sewer system, helping to stop overflows.

RainWise, by the numbers

Janice Johnson
CSO Control Program