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Brightwater Treatment Plant
Find information and facts about Brightwater Treatment Plant located near Woodinville, including the treatment process, capital and improvement projects, and visiting the facility and grounds.
Updates
June 2026
At Brightwater, we are continuing to invest in projects, engage with communities, and educate people of all ages about our wastewater system. Read our recent Brightwater email to learn more! Subscribe to our Brightwater email updates to stay informed.
Projects in the trails area and inside the plant
On June 10 and 11, WTD and EarthCorps crews will install plants on rafts in Otter (Lower) Pond in the trails area. This helps cool the water and support a healthy ecosystem. The pond will not be accessible during this work.
This spring and summer, crews are installing new membrane filters inside the treatment plant. We’re replacing Brightwater’s advanced membrane filtration system after it reached the end of its useful life. The system uses long, straw-like fiber membranes to remove bacteria, viruses, and micro-sized particles. These new filters are more efficient and advanced, which helps save maintenance time and money.
We love connecting with you at community events!
On April 25, members from WTD’s Education and Community Services team hosted a table at the Bee-utiful Woodinville Earth Day event. We spoke with 100 people about Brightwater during this sunny, outdoor community event. The people we spoke with learned how Brightwater recycles resources from the wastewater treatment process.
Do you want us to meet with your community group or organization?
Is there a community event you’d like us to be at?
Email us at Brightwater@kingcounty.gov. We’d love to chat more!
When you're at Brightwater, always keep your dog on a leash and pick up their poo. This makes sure everyone, including other people, pets, and wildlife, can safely enjoy this space too! The Brightwater trails area serves people of all ages and abilities, and wildlife. Thousands of children and adults enjoy these spaces all year long. We rely on you, our human visitors, to make sure everyone feels welcome and safe in these spaces.
Read the recent Brightwater email.
Sign up for Brightwater emails to stay up to date!
Visit Brightwater’s Public Engagement web page to read past emails, newsletters, and blog stories about Brightwater.
Located just north of Woodinville, Brightwater Treatment Plant (Brightwater) began operating in 2011. Brightwater is part of King County’s regional wastewater treatment system. In addition to treating wastewater, Brightwater features an education and event center, natural areas and trails, and public art.
Brightwater serves around 300,000 people and businesses in north King and south Snohomish Counties. On average, Brightwater treats around 20 million gallons of wastewater (mgd) per day. During peak flows when we get a lot of rain, Brightwater treats around 35 mgd.
Brightwater operates all day, every day to protect public health and the environment. The facility is nationally recognized for its award-winning design and its consistent compliance with state and federal discharge limits.
Learn more
- See how Brightwater’s Treatment System works.
- Get facts about Brightwater's operations.
- Learn how Brightwater contributes to a sustainable future for the surrounding community and environment.
- Explore educational opportunities, trails, and natural areas.