Michael S. Regan 16th Administrator, United States Environmental Protection Agency | Official Website
SEATTLE (June 26, 2024) – The U.S. Department of Justice, the U.S. Environmental Protection Agency, and the Washington Department of Ecology announced today that they have reached an agreement in principle with King County and the City of Seattle to expand their efforts to reduce discharges of untreated combined sewage and stormwater into local waterways.
In 2013, Ecology and EPA found that the city and county’s interconnected combined sewer system regularly violated state and federal clean water laws by sending untreated or undertreated wastewater into Lake Washington, Lake Union, the Duwamish River, and Puget Sound. Both entities signed consent decrees committing to major infrastructure investments to mitigate these issues.
Citing increasing rainfall intensity due to climate change, supply-chain disruptions, and rising construction costs in Seattle, the city and county requested modifications to the 2013 consent decrees in 2019. The new agreements extend some project completion dates from 2030 to 2037 and commit to significant increases in wastewater storage and treatment capacity.
The modifications include improvements to several major projects:
- **King County’s Mouth of the Duwamish Wet Weather Treatment Facility**: This facility may now include outfalls owned by Seattle. Options include increasing treatment capacity by more than 25% to 190 million gallons per day or increasing storage to 150 million gallons. The new projected completion date is 2034.
- **West Duwamish/Terminal 115 CSO Control Project**: This project will store nearly one million gallons more than originally planned. Delays are related to construction on a contaminated site. The new projected completion date is 2029.
- **Ship Canal Water Quality Project**: This project aims to reduce combined-sewer discharges into the Lake Washington Ship Canal by an average of 84% per year. Delays are attributed to Covid-19, supply chain issues, and tunneling obstructions. The new projected completion date is 2027.
- **Montlake and University Storage Projects**: These projects may be combined or remain separate facilities. Stored volumes will increase significantly for both sites with a new projected completion date of 2037.
“This agreement underscores what’s possible when all parties come together to advance shared values and goals,” said Casey Sixkiller, Regional Administrator for EPA’s Region 10 office in Seattle.
"Climate resilience is one of our greatest environmental priorities,” said Laura Watson, director of the Washington Department of Ecology.
In December 2022, King County completed its Georgetown Wet Weather Treatment Station with support from a $134.5 million EPA loan under the Water Infrastructure Finance and Innovation Act (WIFIA). Since 2015, Ecology has awarded low-interest loans totaling $266.5 million to Seattle and $395.3 million to King County for combined sewer overflow control projects.
In addition, EPA awarded a $194 million WIFIA loan in 2024 for various clean-water investments at West Point Treatment Plant.
The new agreements must be approved by both the King County Council and the Seattle City Council before being lodged with the U.S. District Court for public comment for 30 days.
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