King County Wastewater Treatment Division

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King County Wastewater Treatment Division We protect public health and enhance the environment by treating and recycling wastewater.

In the 1950s, wastewater flowed largely untreated into Lake Washington and Puget Sound and many rivers and smaller lakes, fouling water and making a sullied mess of local beaches. In 1958 the voters created Metro and developed a regional wastewater treatment system based on watersheds as opposed to political boundaries. Shortly after Metro was formed, construction began on the county's two existing regional treatment plants, West Point in Seattle's Magnolia neighborhood and South Treatment Plant in Renton, which were officially up and running by 1966. By the late 1960s, regional water quality began improving dramatically. In 1994, King County assumed authority of Metro and its legal obligation to treat wastewater for 34 local jurisdictions and local sewer agencies that contract with King County.

Recently, Margo Iniguez Dawes, our Capital Equity Program Manager, and Eli Weiss, Partners in Water Program Manager, co-...
10/15/2026

Recently, Margo Iniguez Dawes, our Capital Equity Program Manager, and Eli Weiss, Partners in Water Program Manager, co-facilitated a workshop at WEFTEC, the Water Environment Federation’s annual conference for water professionals.

Their session, “Building an Equitable Utility Workforce: Models, Partnerships & Practice,” explored WTD’s approaches to workforce development, from internal programs to community partnerships. Margo and Eli also led discussions on how utilities and partner organizations can strengthen their own workforce programs and create more inclusive pathways into the water sector.

Building an inclusive workforce helps utilities better serve their communities and protect clean water.

10/08/2026

When West Point Treatment Plant in Seattle first opened 60 years ago, our original raw sewage pumps were state‑of‑the‑art, and they’ve been protecting public health and the environment ever since. Our team of operators, mechanics, electricians, and others — including Charles, who’s been with King County for 30+ years(!) — have cared for them, kept them running, and made sure we can continue to clean wastewater 24/7.

After decades of tough, corrosive work, these pumps are ready for a well‑earned retirement. Now we’re replacing them, so future generations have a reliable, efficient system for decades to come!

Learn more about this critical project at https://kingcountywtd.com/2025/05/08/west-point-readies-for-new-pump-system-to-replace-its-aging-heartbeat/

Visual description: A King County employee speaks on camera as crews use cranes and other heavy equipment to remove and replace large pumps inside a wastewater treatment facility.

Curious about careers that help protect clean water? Join us virtually on Oct. 28 at 4 p.m. for the second Clean Water C...
10/07/2026

Curious about careers that help protect clean water? Join us virtually on Oct. 28 at 4 p.m. for the second Clean Water Careers Panel, featuring staff who work in engineering and community services. You don’t need to have attended the first panel to join. High school students and recent graduates are welcome!
Register at tinyurl.com/careerspanel2

Guess that view!Our work protects local waterways, and we often have amazing views from our plants, pump stations, and r...
10/06/2026

Guess that view!

Our work protects local waterways, and we often have amazing views from our plants, pump stations, and regulators. Swipe through the slides to find out where these photos were shot, courtesy of WTD team member Matt Simon.

Swim over and tackle your wastewater questions at Issaquah Salmon Days this weekend! Well‑maintained, reliable wastewate...
10/01/2026

Swim over and tackle your wastewater questions at Issaquah Salmon Days this weekend!

Well‑maintained, reliable wastewater systems don’t just protect public health — they help protect salmon, too. Learn how our clean water projects like the Sammamish Plateau Diversion and the Coal Creek Sewer Upgrade keep our regional system running safely, creating healthier habitats for salmon to live and grow. We’ll also hook you up with tips for keeping local waterways healthy. 🐟

Catch us at the Issaquah Salmon Hatchery, 10 a.m. to 6 p.m., Saturday and Sunday. See you there!

Learn more at salmondays.org

09/29/2026

All five of our treatment plants have unique qualities that make each one special. Check out our operators, engineers, and equipment at Brightwater Treatment Plant near Woodinville, working 24/7 to protect public health and the environment.

Want to explore for yourself?
✅ Tour the treatment plant
✅ Wander the surrounding trails
✅ Visit the Brightwater Education Center

Discover more at kingcounty.gov/Brightwater.

Visual description: A montage shows Brightwater’s treatment facilities, water flowing through treatment channels, and workers at a construction site. It ends with people walking on nearby green trails, including one with a dog.

Did you know? We regularly host public tours at our treatment plants across our service area — and they’re open to every...
09/23/2026

Did you know? We regularly host public tours at our treatment plants across our service area — and they’re open to everyone. Bio‑nerds, wastewater‑curious folks, families, local explorers… if you’re at least 9 years old, you’re in!

Want to join a tour? Head to our Events page at kingcounty.gov/wtd/events.

Wondering how fun they are? Check out a recent article on a Brightwater Treatment Plant tour in the Everett Herald and their Sound & Summit magazine! https://www.heraldnet.com/2026/09/10/fafo-flush-and-find-out/

09/21/2026

Our Coal Creek Sewer Upgrade project team has been “micro-tunneling” in Bellevue since July — digging as deep as 120 feet underground.

This complex but critical work replaces aging pipeline from the 1960s and 1990s and adds capacity needed to serve the growing communities of Bellevue and Newcastle.

More people = more wastewater = bigger pipe!

Learn more about this exciting project at kingcounty.gov/CoalCreekSewer.

Bellevue Utilities

Visual description: A yellow tunnel boring machine with a lime-green cutting head works in a deep trench surrounded by trees. Workers survey the site as a crane operates overhead. Close-ups show the cutter head spinning and spraying water, along with the machine’s controls and screens.

09/17/2026

We’re excited to share our Vision for Clean Water — the future we envision for the year 2100. Shaped by input from community members, partner organizations, and wastewater professionals, the Vision helps guide us as we make decisions, plan projects, and solve challenges together. Learn more at kingcounty.gov/VisionforCleanWater

Visual Description: A montage features rivers, streams, and shorelines across the Puget Sound region, along with community members, wastewater infrastructure, and King County staff working at treatment plants.

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201 S Jackson Street
Seattle, WA
98104

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