Hi, Neighbor 👋

South Treatment Plant is a real workhorse. Built in 1965, South Treatment Plant is part of a regional wastewater system that sits on 94 acres in Renton, Washington and works around the clock to clean the water we use in our homes, schools, businesses, and industries. With approximately 866,200 people across 240 square miles, it serves the largest geographic area in our service area.

The King County Wastewater Treatment Division's mission is to protect public health and enhance the environment by collecting and treating wastewater while recycling valuable resources for the Puget Sound region.

If you live, work, or go to school on the east or south sides of Lake Washington, chances are your wastewater gets sent to the South Treatment Plant. (That includes cities such as Renton, Kent, Auburn, Bellevue, Issaquah, and Sammamish areas.) It cleans water from our showers, toilets, sinks, and laundry machines before releasing treated flows into Puget Sound.

The treatment plant, with pipes, pumps, tanks, and motors, is really an ecosystem supporting microorganisms (good bugs) that do the job of cleaning wastewater. But what makes the plant run is more than 130 staff of operators, mechanics, engineers, construction managers and administrative support. People are at the heart of this operation.

Crews at South Treatment Plant protect our health and our environment by cleaning the water we use before returning it to the environment. They also manage this process to recover valuable resources. Recycled water can be used for industrial processes, washing streets, and irrigation instead of using drinking water. They can harvest energy from the treatment process to power the plant. Biosolids become a nutrient-rich soil amendment for managed forests and farms.

Check out this  blog post  to learn about what day to day operations are like at South Treatment Plant!

King County's Wastewater Treatment Division transformed its approach to workforce development to recruit and train the next generation of talent by establishing a six-month training academy with paid, on-the-job positions that prepares candidates for state certification and a path toward long-term career-service employment.

The Operator-in-Training Program has filled a critical labor shortage by filling more than 70 wastewater operator positions and increasing the racial and gender diversity across our workforce.

"Our transformative approach to workforce development has produced the next generation of highly skilled operators we need to protect the water quality of King County and Puget Sound. The award-winning Operator-in-Training Program demonstrates our ability to be nimble and responsive to the current labor market, making it possible for us to recruit, train, and promote talented professionals committed to environmental stewardship."

Cool stuff is happening here, right? We want to be a good neighbor and share what we do. So here are other opportunities for the community.

We provide  educational field trips  for students in grades 4 through 12 that are free of charge. In addition to the wastewater treatment process, students and educators can learn about the water and nutrient cycles, pollution prevention, water conservation, and stormwater engineer problems and solutions. Check out our  online education resources  as well.

"CitySoil Farm is a really unique project. It's on the wastewater treatment plant's facility. It uses renewable resources. It's a community space where people can come and learn about how their food is grown, and taste the food, and take some home." - Courtnee (Dirt Corps)

 CitySoil Farm  was once an unused area of the treatment plant grounds. Now the 1.5 acres has been transformed into a teaching farm and native tree nursery that showcases sustainable farming and accessible, local food. We use renewable resources such as compost made from  Loop biosolids  and  recycled water .

We have volunteer  events  that help increase the public's awareness of recycled water and biosolids. We welcome groups to contact us and schedule a visit.

Our communities benefit from partnerships with CitySoil Farm. In 2024, CitySoil delivered 3,156 pounds of fresh produce to the  White Center Food Bank , including culturally specific foods requested by the food bank.

There's plenty of construction happening inside the South Treatment Plant that's important to us being a good neighbor. Teams are hard at work planning, designing and building better systems to control odors, make facilities safer for workers, and improve energy efficiency.

These projects protect ratepayer investments through improving system reliability, reducing maintenance costs, and protecting worker safety and the environment.

South Treatment Plant was expanded to its current capacity of 115 million gallons per day for average flows and 325 million gallons per day during peak storms in 2001.

The Waterworks Gardens are more than just a pretty landscape for people to enjoy. This garden has a job protecting our waters by cleaning and controlling stormwater runoff (aka rainfall that lands on hard surfaces like pavement or concrete and picks up pollutants on the way down to a sewer pipe or water body).

Waterworks Gardens uses its marshes and ponds to filter and clean water from hard surfaces such as roads and parking lots at the South Treatment Plant. After passing through the Waterworks Gardens, treated stormwater flows into Springbrook Creek. The gardens are open between dawn and dusk year-round.

We also have a  WaterWorks Grant Program  that supports investments in clean water and the community by awarding funds to organizations that improve water quality within the Wastewater Treatment Division's  service area .

Sustainability is defined as the long-term viability, health, and robustness of environmental, social, and economic systems.

For all of us at the Wastewater Treatment Division, this means: 

• Healthy natural environments 

• Equity, social justice, and vibrant communities 

• Cost-effective capital investments, operations, and   maintenance 

• Resilience to future disruptions and climate adaptation   

Being a steward of the environment goes hand in hand with being a good neighbor. For years, South Treatment Plant has been making choices that protect the environment. We recycle water and reuse heat energy to reduce our carbon footprint. We recover valuable resources from wastewater and return nutrient-rich biosolids to the soil. If you’d like to learn more about these programs, see below. 

South Plant is part of a vibrant and diverse region. We want to deepen our connections with the community that we serve. King County is working to center equity and social justice, through   its Equity and Social Justice (ESJ) Strategic Plan. Yet, we recognize that we can do more in how we show up for Black, Indigenous, and other People of Color (BIPOC) in our community.  We want to broaden our understanding of our impact and how we can be better neighbors. To do this, we plan to pursue connections with local community-based organizations. 

We want to continue providing the community with information about happenings at the South Treatment Plant. If you'd like to be added to a future email list, please contact Hodo Hussein at hodhussein@kingcounty.gov.

For more information about educational programs or tours at South Treatment Plant, contact Katelyn Leeuw at  katelyn.leeuw@kingcounty.gov  or (206)263-1008.

To learn more about CitySoil Farm or to volunteer, contact Charity Villines at cvillines@kingcounty.gov.

To report odors, call the 24-hour hotline at 206-263-1760.

Visit  www.kingcounty.gov/KeepWaterClean  for tips on how to improve water quality.

South Treatment Plant works around the clock to serve our communities with award-winning wastewater treatment, protecting public health and our waters. Keep up to date and join us for tours, programs, and news about sustainable improvements for our future.