skip to main content

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

Being a good neighbor during construction

craneconcrete pipe segmentsHorizontal drill diagrammicrotunnellingpump station

Wastewater system - under construction


Did you know?

Construction on King County's regional wastewater treatment system began in the 1960s. Today, the system serves 1.5 million people across a 420-square-mile area in King, Snohomish and Pierce counties.

King County is undertaking a number of projects in the coming years to expand and improve our regional wastewater treatment system. Some of the projects are part of the Regional Wastewater Services Plan, a 30-year plan to protect public health and the environment in our region, while others are simply routine maintenance or upgrades.

What can neighbors expect?

Construction sites for Wastewater Treatment Division projects are busy. Crews could range from three or four people to a dozen or more depending on the size of the project.

Heavy equipment like backhoes, cranes, cement trucks and generators are common, and this equipment does generate noise. People might also see specialized equipment being delivered to the site, like a tunnel boring machine. While work is taking place, excavation and earthwork activities tend to create dust or mud. Construction vehicles and possible road closures or detours could affect traffic.

Before construction starts, King County staff routinely holds small neighborhood meetings to discuss the project and answer questions for construction site neighbors. When construction starts, near neighbors will always have a point of contact for asking questions or reporting concerns.

Heavy equipment used in most of our projects can generate noise.

What's going on out there?

The Wastewater Treatment Division undertakes several types of projects to ensure our treatment system stays efficient and has enough capacity.

Related information


This Web page is also available as a brochure (Acrobat PDF, 2.1MB).