PER- and POLY-FLUOROALKYL SUBSTANCES (PFAS)
In January 2022, the Washington State Department of Health (DOH) implemented new standards for public drinking water systems to begin testing for Per- and Polyfluoroalkyl Substances (PFAS). PFAS are a large family of chemicals in use since the 1950s to make a wide variety of stain-resistant, water-resistant, and non-stick consumer products, including food packaging, outdoor clothing, and non-stick pans. In Washington State, PFAS have been used in certain types of firefighting foams utilized by the U.S. military, local fire departments, and airports.
Highline Water District sampled all its groundwater sources for PFAS. Results of the DOH sampling program confirmed that one District source, the Tyee Well, has between 11.9-13.1 parts per trillion (ppt) of the substance Perfluorononanoic Acid (PFNA). DOH established a State Action Level (SAL) of nine (9) ppt for PFNA. No other District source was found to have PFAS substances exceeding the SAL.
The District has voluntarily suspended Tyee Well operations until we complete a more extensive investigation and develop sufficient treatment options moving forward. There is no longer any exposure to PFAS from the Tyee well. The Tyee well contributes about 4.5% of the District's overall water production annually and serves a limited area within the District's service boundary.
The District has sent public notification to each water service address that may have received water at or above the SAL. If you did not receive a letter from the District, you are not located in an area receiving water that would exceed the SAL. You can view a map of the public notification area here.
Highline Water District is committed to providing clean and safe water to our customers. You can find the Frequently Asked Questions about PFAS on the menu to the left, or you can click here. The District will maintain this page to keep you informed about PFAS and associated decisions affecting the public water system.
