King County Wastewater Treatment Division (WTD)

King County’s Wastewater Treatment Division (WTD) has been committed to protecting and improving water quality for more than 50 years. To our agency, success means clean water. It means honoring our legacy while keeping a promise to another generation that our beautiful environment will be there for them to enjoy.

WTD prevents water pollution by cleaning the wastewater produced from approximately 1.6 million people, including most urban areas of King County and parts of Snohomish and Pierce Counties. Our employees build and operate treatment facilities; enforce regulations that reduce harmful waste; reuse products of the treatment process; and educate the public on ways to protect our water resources.