Combined Sewer Overflow Reports & Requirements

Seattle Public Utilities must comply with clean water regulatory requirements and legal agreements. On this page we provide links to the legal and regulatory documents that are requirements within our work and the related annual reports. (Linked documents are archived in PDF on the Washington State Department of Ecology website and will open or download in a new tab/window.)

We also have a lot of programs and projects underway to reduce Combined Sewer Overflows and are current working on a plan for called the Seattle Overflow Action Plan.

Requirements

Wastewater Consent Decree

Since 2013, the City of Seattle has had a legal agreement (Consent Decree) to reduce sewer overflows (SSOs) and combined sewer overflows (CSOs) with the Environmental Protection Agency, Department of Justice, and the Washington State Department of Ecology.

Seattle entered into this Consent Decree (PDF) on July 2013 and has a modified Consent Decree (PDF) as of May 22, 2025. We have released several plans as Consent Decree Requirements including the 2015 Plan to Protect Seattle’s Waterways, 2015 Long Term Control Plan, and the 2015 Integrated Plan. We are now working on the Seattle Overflow Action Plan.

Wastewater NPDES Permit

Seattle must meet state and federal regulatory requirements in order to comply with the Clean Water Act. The program is regulated via a National Pollutant Discharge Elimination System (NPDES) permit. These are our current permits:

One requirement in the current permit is to provide realtime online reporting of overflows in Seattle.

Annual Reports

We track our progress complying with our NPDES Permit through Annual Reports. Our current annual report:

City of Seattle 2024 Annual Wastewater Report (PDF).

Previous reports are posted on the Washington State Department of Ecology website (PDF):

2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 | 2014 | 2013 | 2012 | 2011 | 2010

Public Utilities

Andrew Lee, General Manager and CEO
Address: 700 5th Avenue, Suite 4900, Seattle, WA, 98104
Mailing Address: PO Box 34018, Seattle, WA, 98124-5177
Phone: (206) 684-3000
SPUCustomerService@seattle.gov

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Seattle Public Utilities (SPU) is comprised of three major direct-service providing utilities: the Water Utility, the Drainage and Wastewater Utility, and the Solid Waste Utility.