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Wastewater Treatment

King County, Washington

For questions about the Wastewater Treatment Division website, please send an e-mail message or contact us at:

King Street Center
201 S. Jackson St., Suite 500
Seattle, WA 98104-3855
Phone: 206-477-5371
Fax: 206-684-1741
Telecommunication device for the deaf (TTY): 711

Get Directions to our office location in Seattle, Washington.

Staff Contacts

Regionwide Projects

Lower Duwamish Waterway Superfund 

King County continues to work on Superfund activities to address historically contaminated sediments in the waterway. King County will also maintain its involvement in the Lower Duwamish Waterway Group (external link) in 2016, which is currently working with EPA and the state Department of Ecology to identify a Superfund cleanup strategy.

Conveyance System Improvements 

The utility is engaging in activities that guide the planning, design, and construction of new pipeline improvements and expansions within the utility’s 420-square-mile service area.

Conveyance System H2S Corrosion Rehabilitation

King County will repair and replace sewer pipelines throughout its service area that are deteriorating or damaged as a result of corrosion caused by hydrogen sulfide gas, which commonly occurs in sewage.

WTD Resiliency and Recovery Program

King County plans to assess and retrofit sewer infrastructure and buildings in preparation for potential seismic events. The program goal is to protect public safety by avoiding or minimizing critical system damage that could occur during a natural disaster.