King County, Washington, protects water quality and prevents water pollution by providing wastewater treatment to 17 cities and 17 local sewer utilities. The county's Wastewater Treatment Division serves about 1.5 million people, including most urban areas of King County and parts of south Snohomish County and northeast Pierce County. More about our system and facilities.
Fly over the Duwamish. The Lower Duwamish Waterway is an economic engine, cultural icon, and vital regional transportation corridor. No matter where we live in King County, no matter how we use the river, we all have a stake in protecting it -- it’s Our Duwamish.