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Wastewater Treatment Division (WTD) and Novel Coronavirus (COVID-19)

WTD operations staff remain on the job 24/7 to ensure the region’s wastewater treatment service continues. Following the guidance of Seattle-King County Public Health, our offices are closed to the public and all facility tours are suspended until further notice. Please check back periodically for updates.

For questions about COVID-19, we encourage people to visit the Public Health – Seattle & King County website: and subscribe to the Public Health Insider blog:

The Brightwater Treatment Plant is located along State Route 9, north of Woodinville, in unincorporated Snohomish County.

The plant is part of King County's regional wastewater treatment system.

Every day Brightwater treats wastewater from homes, offices, schools, agencies, businesses and industries in north King County and south Snohomish County.

Brightwater has the capacity to treat an average of 36 million gallons of wastewater per day (mgd). By 2040, treatment capacity may be expanded to 54 mgd. These capacities are for average wet-weather flows.

The plant design integrates landscape, architecture, wildlife habitat, engineering, art, and education.

rsz_15542899027_2e66be2cd7_zBrightwater Treatment Plant

View more photos on our Flickr site  .

Contact us

24 hour emergency and odor reporting:  206-263-9500
Administration:  206-263-9465

22505 State Route 9 S.E.
Woodinville, WA 98072-6010;

Directions and map


View WTD news releases