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CSO / SSO Consent Decree

As of July 2013, Seattle has entered into a historic agreement – a Consent Decree (pdf) – with the Environmental Protection Agency, Department of Justice, and the Washington State Department of Ecology to reduce sanitary sewer overflows (SSO) and combined sewer overflows (CSO) into Seattle's receiving water bodies. Some key points about the history and desired outcome include:

  • Long-Term Effort
    Seattle has a long history of reducing sewage overflows since the 1960s and 70s. During the last two decades, Seattle has been implementing control systems to reduce these overflows even more.
  • Landmark Agreement
    The Consent Decree formalizes our approach to finish the job of reducing sewage overflows to protect public health and the environment. It was the first to provide a unique opportunity for Seattle to integrate stormwater control into the plan for CSO control. We may implement stormwater control projects ahead of CSO projects, provided the stormwater projects provide greater environmental benefit.
  • Commitment to Protect
    We have committed to spend approximately $500 million on capital improvements between 2010 and 2025 to reduce CSOs to protect Seattle waterways and a quality environment. When completed, Seattle will have achieved greater than 95% reduction in all its CSOs.

For more information on our efforts to control stormwater and sewage overflows, see the Plan to Protect Seattle's Waterways.