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Brightwater Treatment Plant

Brightwater Treatment Plant

The Brightwater Treatment System is an integral part of King County’s regional wastewater treatment system, beginning operations in 2011. Today, the Brightwater Treatment Plant is consistently recognized for award-winning design and compliance with state and federal effluent permit limits.

June 2023 Update

View the Spring 2023 Brightwater Newsletter to learn if Brightwater treats your dirty water, explore what it’s like to work inside the treatment plant, and to plan your visit.

Aerial photo of Brightwater treatment plantBrightwater Treatment Plant

The Brightwater Treatment Plant is located just north of Woodinville. Brightwater helps to support the regional system by letting us shift flows from the South Treatment Plant and the West Point Treatment Plant, while providing important treatment capacity to meet the region’s growth.

At Brightwater, we treat wastewater by combining standard biological treatment processes with a state-of-the-art membrane filtration system that traps bacteria and organic material. The Brightwater Treatment System collects wastewater from Northeast King County and Southeast Snohomish County. After advanced treatment at the Brightwater plant, clean water is either sent to Puget Sound or treated to a recycled water standard and used for industrial purposes or irrigation.

Brightwater can 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.

Learn more:

  • See how Brightwater’s Treatment System works here
  • Get the facts on the Brightwater Treatment System’s operations here
  • Understand Brightwater’s odor control and how to report concerns here
  • Learn how Brightwater contributes to a sustainable future for the surrounding community and environment
  • Explore educational opportunities, trails, and natural areas here
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

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