Skip to main content

South Treatment Plant

Find information and facts about South Treatment Plant located in Renton, including the treatment process, capital and improvement projects, and visiting the facility and grounds.

April 2024

Earth Day is April 22

At King County WTD, we think it’s important to treat every day like its earth day. Learn more about our sustainability programs.

At South Treatment Plant we are working on several projects that will continue to help protect human health and the environment. For us, sustainability means reusing valuable resources and managing cost-effective operations and capital investments that ensure a healthy natural environment and vibrant communities for everyone. Learn more about South Plant projects, what’s new, career opportunities and how to stay informed.

Last year we sent out a survey to South Plant neighbors. We asked about their experience of living/working near the plant. One hundred people responded! We are so appreciative of your feedback, thank you. We will be sending out a follow-up newsletter and sharing it on our website this Spring.

Aerial picture of south treatment plant

Aerial view of South Treatment Plant in Renton.

Located in Renton, South Treatment Plant (South Plant) began operating in 1965. South Plant features a 1.5-acre demonstration farm, CitySoil, that produces more than 5,000 pounds of food for a local foodbank. South Plant is our most visited facility, hosting robust on-site educational programming for school groups and plant tours. The facility is also host to a septage disposal facility for commercial haulers. South Plant treats an average of 90 million gallons of wastewater per day from communities in Auburn, Bellevue, Issaquah, Kent, Renton, and Sammamish.

Learn more