Filtration SystemOverview

Polyfluoroalkyl substances, or PFAS, are chemicals that have been used in industry and consumer products worldwide since the 1940s, according to the Centers for Disease Control and Prevention (CDC). These chemicals have been used to make nonstick cookware, water-repellent clothing, stain-resistant fabrics and carpets, some cosmetics, some firefighting foams, and products that resist grease, water, and oil.

“While it is difficult to show that substances directly cause health conditions in humans, scientific studies have shown that exposure to some PFAS in the environment may be linked to harmful health effects in humans and animals,” the CDC states.

Issaquah participates in the Environmental Protection Agency’s (EPA) unregulated contaminant monitoring program, which found PFAS in the aquifers that supply Issaquah’s groundwater wells. In 2016, the City installed a filtration system on a well that had increased levels of detection. Issaquah has then continued to be proactive in addressing PFAS by increasing the use of regional water sources, and remaining at the national forefront of treatment.

The City meets all standards set for safe drinking water. While some PFAS compounds exist in the finished water, the levels are so low that State and Federal compliance sampling methods show “non-detect” as the test results.

Learn more about Issaquah's water quality via its annual report.