The PFAS Project Lab

Studying Social, Scientific, and Political Factors of Per- and Polyfluoroalkyl Substances

Issaquah, Washington

Suspected contamination source: Firefighting foam used at Eastside Fire Rescue, and firefighting foam sprayed during a tanker fire in 2002 (Town meeting, 2016)

A New York Times Magazine article released in January 2016 entitled “The Lawyer Who Became DuPont’s Worst Nightmare” mentioned Issaquah as one of four water districts across the nation with a concerningly high level of perfluorooctanoic acid (PFOA). In response to residents’ worries, the city temporarily shut off the city’s Gilman Well No. 4 during the first week of March to look at treating the well for PFASs. The following month, the city invested $1 million in a water treatment system to clean the water in Well No. 4.

Issaquah participated in the EPAs Third Unregulated Contaminant Monitoring Rule (UCMR3) from 2013-2015. PFOS had been found in Well No. 4 at a level of 600 parts per trillion (ppt) in 2013 and 472 parts per trillion (ppt) in 2015 (Jennings, 2017). As of 2016 the EPA’s lifetime health advisory level for combines PFOA/PFOS in drinking water is 70 ppt.

According to town documents, an environmental consulting group identified the Eastside Fire and Rescue (EF&R) property as potential source location “based on the initial groundwater sampling results, [and] a south-trending distribution of PFOS in groundwater from City Well 4, toward MW05”.

Issaquah is mixing contaminated well water with other well water in order to dilute the chemical.  An agenda bill at city council asked for $150,000 to treat Gilman Well #4 for PFOS in March 2016. State Department of Health is working with the city public works in order to ensure levels meet Federal EPA’s PHA.

Additional Resources

Media Coverage:

Full citations are available on the second page of the full contamination site tracker. We ask for your additions, changes, questions and comments be sent to

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