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Learn more about the Brightwater Treatment Plant and Brightwater Center.

Completed – Fall 2012

In response to increased growth in our region, King County has built a new $1.86 billion regional wastewater treatment system called Brightwater to serve the northern portion of the King County service areaTreatment plant operations began in September 2011. The conveyance system and outfall began full operations in fall 2012.

Map of Brightwater project facilitiesBrightwater treatment system  . View more detailed 11x17 inches map  .

The new facilities include:

  • The Brightwater Wastewater Treatment Plant is located in unincorporated Snohomish County, north of Woodinville. The plant is designed to have the capacity to treat an average of 36 million gallons of wastewater per day (mgd). By 2040, treatment capacity could be expanded to 54 million mgd.
  • The conveyance system is the tunnels, pipes, and other facilities that carry wastewater to and from the treatment plant. The Brightwater system includes 13 miles of pipeline built in underground tunnels, shallower connector pipes, and an influent pump station to send wastewater to the plant.
  • The marine outfall consists of twin, 5-foot-diameter pipes with a diffuser at the end where highly treated wastewater from the Brightwater Treatment Plant is discharged into Puget Sound. The mile-long, 600-foot-deep outfall extends off of Point Wells.
Brightwater Treatment Plant opening (September 24, 2011) from King County DNRP on Vimeo 

operations phase

24 hour emergency and odor reporting:

Contact Brightwater Treatment Plant at  206-263-9500.

Project photos

The following links point to Flickr photo albums .

Project videos

The following links point to DNRP Vimeo  videos.

Video: First flow of clean test water to come into the Brightwater Plant from the Influent Pump Station in Bothell, 2.8 miles away! (May 2011)Brightwater plant test (May 2011)
Video length: 17 seconds

Video: installation of membrane bioreactor filters (MBRs) at the treatment plant (April 2011).Installation of membrane bioreactor filters (MBRs) at the treatment plant (April 2011)
Video length: 2 minutes, 32 seconds

Video: Earth Week at Brightwater Center (April 2011) Earth week at Brightwater Center (April 2011)
Video length: 2 minutes, 4 seconds


Smooth sailing for Brightwater outfall pipelines (September 2008)Smooth sailing for Brightwater outfall pipelines (September 2008)
Part 1 – the first outfall pipeline was submerged on September 10, 2008
Part 2 – the second outfall pipeline was submerged on September 12, 2008

Brightwater treatment plant introduces tunneling equipment (September 2007)Brightwater Treatment Plant introduces tunneling equipment (September 2007)
Video length: 1 minute, 46 seconds

Brightwater habitat restoration tours, April 2007Take a tour of the Brightwater habitat restoration (April 2007)
Video length: 4 minute, 16 seconds