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The RainWise Program celebrates a pollution prevention milestone


The installation of rain gardens and cisterns in Seattle's oldest neighborhoods is now keeping 20 million gallons of stormwater out of the regional sewer system each year, helping to control overflows that occur in local waterways during heavy rains.


RainWise, a joint program run by King County and Seattle Public Utilities, has attained a major goal in controlling overflows of stormwater and sewage during heavy rains. The program now captures runoff from over 2 million square feet of impervious, rooftop surface – imagine, a roof equivalent in size to Volunteer Park.

This overall collection has been achieved piece by piece, in cooperation with over 1,500 private property owners in the Seattle area who have taken advantage of RainWise rebates to date. RainWise rebates cover up to 100 percent of the cost to professionally install rain gardens and cisterns, which capture rooftop rainwater runoff on-site rather than sending it to the sewer. This represents roughly 45 acres of surface area control, and results in over 20 million gallons of rainwater runoff kept from the system annually.

Reducing the input of stormwater runoff into Seattle’s sewer system has become increasingly important as local populations and urban surfaces, like rooftops, parking lots, and roads, have grown. The RainWise Program is part of a larger plan to reduce combined sewer overflows (CSOs), which occur during heavy rains when stormwater overwhelms the sewer system causing it to overflow into local waterways. Because CSOs include polluted runoff and sewage, they pose a risk to public health and the environment.

But rain gardens and cisterns do more than reduce overflows in the sewer system. They also provide amenities for property owners and to community gathering spaces.

Sarah J., a Greenlake-area resident joined the RainWise program in 2016. “Getting RainWise was surprisingly fast and easy. But my favorite thing is something I didn't anticipate - the community love that comes with it. People stop and slow down by our property now, and if I'm outside I get to have lots of great conversations with my neighbors and visitors about rain gardens and cisterns. I feel proud to have done this for our neighborhood and our region.”

RainWise started as a residential program but has recently expanded to include worship centers and commercial and apartment buildings. Prospect UCC Church pastor Meighan Pritchard described her church’s involvement in the RainWise program as “tangible evidence of our willingness to walk the talk about caring for our environment. We talk about environmental justice and climate change and are pleased to be taking this step to mitigate stormwater runoff in our community.”

More than 50,000 properties in Seattle are eligible for RainWise rebates. Visit to find out if the home you own or rent qualifies, discover upcoming webinars and events, and learn more about the program’s environmental benefits. Workshops and events are free and open to the public.