Sewage Overflow Prevention
(Combined Sewer Overflow Reduction)
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 2010, more than 190 million gallons of combined raw sewage and stormwater spilled into our creeks, lakes, the Duwamish Waterway, and Puget Sound - creating 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. Read more.
Real-time reports of raw sewage overflows
(updated hourly).
View information about the Long-term Control Plan to guide the development of projects to be constructed over the next 15 years.
Read the plan to clean up our waterways over the next five years 2010 – 2015 Plan (pdf).
See map of CSO locations (pdf).
Annual overflows have been reduced from 30 billion gallons per year in 1970 to 190 million gallons in 2010. But we must finish the job in order to protect Seattle’s waterways and comply with the Clean Water Act.
Green Stormwater Infrastructure Projects
Large Storage Projects:
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.