Protecting Seattle’s Waterways
Sewage Overflow Prevention
Seattle waterways will benefit from upcoming projects to prevent sewage overflows and polluted stormwater runoff.
Every year, rain washes millions of gallons of untreated sewage and stormwater into the city’s waterways, threatening human and aquatic health and our quality of life. In 2012, more than 154 million gallons of raw sewage and stormwater spilled into Seattle’s creeks, lakes, the Ship Canal, the Duwamish River, and Elliott Bay. These combined sewage overflows (CSOs) create significant health and environmental risks.
Now, the City of Seattle has negotiated a first-of-its-kind proposed agreement (pdf) that will prevent sewage overflows by allowing the city to use the most cost-effective and environmentally-beneficial projects to control and treat both stormwater and sewage. To learn more about these projects and solutions:
- Review the long-term Plan to Protect Seattle’s Waterways.
- Read the Community Guide to the Plan - Spring 2013 (pdf).
- Watch the video overview of the Plan to Protect Seattle's Waterways.
- Take the survey to submit your comments by June 20, 2013.
For more detailed information:
- View real-time reports of raw sewage overflows (updated hourly).
- Read the full 2010-2015 CSO Reduction Plan Amendment (pdf) to clean up our waterways.
- See a map of Seattle CSO locations (pdf).
Overflow Reduction Projects
Annual overflows have been reduced from 30 billion gallons per year in 1970 to 190 million gallons in 2010. But we must continue work on the following projects to finish the job in order to protect Seattle’s waterways and comply with the Clean Water Act.
- Retrofit Projects
- Green Stormwater Infrastructure Projects
- Large Storage Projects:
Windermere Basin | Genesee Basin | Henderson Basin
Over the next 13 years, the program is expected to spend about $500 million on projects to implement the proposed agreement. Funding the plan to protect our waterways will increase a typical single-family customer’s drainage and wastewater bill by an estimated $58.76 per year by 2025.
The proposal is also expected to save customers approximately $375 million in future operating and maintenance costs over that same time because Seattle Public Utilities (SPU) has been able to demonstrate that the way it inspects and maintains the sewer system has significantly reduced the risk of pipe breaks and sewage spills.
Find out how you can help to Restore Our Waters.