King County's Wastewater treatment process

The process used at our two regional treatment plants provides secondary treatment (preliminary, primary and secondary treatment, and disinfection). The image below shows the basic steps in the treatment process. Move your mouse over the image and click on the "hot links" to view more information about programs and processes.

Besides our principal work of treating wastewater, we provide odor control, have pilot projects to try out new wastewater treatment technologies, and strive to be a good neighbor during construction.

To find out more about King County's wastewater system:

• Visit the home pages for the regional South and West Point treatment plants, and the local Carnation and Vashon treatment plants. 
• View facts at a glance about the King County Regional Wastewater System, including:
  • local sewer utilities
  • service area
  • sewer rate
  • annual budget
  • system and treatment plant facts and data (for most recent year available)
• View King County wastewater (NPDES) permits (for discharged treated wastewater) issued by the Washington State Department of Ecology.
• Learn about the history of King County's Regional Wastewater Treatment Utility.
• View division brochures and other resources.