Cleaning up: PFAS contamination in the Lower Issaquah Valley

In 2015, testing detected PFAS in some of the groundwater in the Lower Issaquah Valley. PFAS, or per- and polyfluoroalkyl substances, are a family of manufactured chemicals that persist in the environment. Some of them are toxic and can accumulate in people, wildlife, and the environment.


Watch our new video about the Lower Issaquah Valley cleanup sites and a pilot project to remove PFAS from groundwater.


Early studies indicated that the likely source of contamination was a type of firefighting foam historically used in training activities. Two drinking water systems, the City of Issaquah and the Sammamish Plateau Water and Sewer District, have wells in the Lower Issaquah Valley. Both have taken a variety of measures to ensure that their water is safe to drink.

In 2018, Eastside Fire & Rescue, the City of Issaquah, and Ecology formed the Lower Issaquah Valley PFAS Partnership to investigate sources of PFAS and how it moves through groundwater in the area. 

We’re now moving into a formal cleanup of the contaminated soil and groundwater. Ecology has organized the contaminated areas into two cleanup sites, EFR HQ IVES (Eastside Fire & Rescue Headquarters and Issaquah Valley Elementary School) and Rainier Trail & Memorial Field.

We’ve prepared legal agreements and related documents that require the City of Issaquah and Eastside Fire & Rescue to investigate the contamination and prepare a draft cleanup action plan. 

Public comment period and meetings

We’ve opened our first public comment period for these sites. You can comment on our initial documents from April 22 through June 6, 2024.

We are hosting two public meetings: