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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

Brightwater Treatment System Banner

Brightwater Project

Facility operations 

Completed fall 2012

In response to increased growth in our region, King County has built a new regional wastewater treatment system called Brightwater. Treatment plant operations began in September 2011. The conveyance system and outfall began full operations in fall 2012.

The new facilities include a treatment plant, conveyance (pipes and pumps taking wastewater to and from the plant), and a marine outfall.

This Web site provides information about the project, including:

Tours, environmental education, open space, trails

Brightwater Education Center
The Brightwater Center is now open. The park grounds are open dawn to dusk everyday. The Brightwater Education and Community Center is open to the public Monday-Thursday 10 a.m. - 4 p.m.


Entrance sign to the Brightwater Treatment Plant
Video: Brightwater grand opening
 (September 24, 2011). Local dignitaries and community members joined King County Executive Dow Constantine to celebrate an extraordinary regional investment in clean water with the start of Brightwater Treatment Plant operations.

Video: installation of membrane bioreactor filters (MBRs) at the treatment plant (April 2011)
Video: Installation of membrane bioreactor filters (MBRs) at the treatment plant
 (April 2011) 

Brightwater serves portions of King and Snohomish counties and supports our mission to protect public health and the environment.

Odor Control at Brightwater

Brightwater Operations

News releases

Related information

Contact us if you need more information about Brightwater.

King County Brightwater Project

22505 State Route 9
Woodinville, WA 98072
E-mail: Brightwater
Phone: 206-477-5506
TTY Relay: 711

For construction-related questions and urgent issues, please contact the Brightwater construction information line at 206-205-5989.

Driving directions to Brightwater project office.