EPA and Eastern Washington University sampling results

After receiving sampling results from a third party showing PFAS were in groundwater at the Spokane International Airport in 2023, Ecology completed two independent studies with other organizations. The results helped us understand where PFAS are coming from and where they're going in the northeast West Plains.

Eastern Washington University study

In August 2023, Ecology awarded the City of Medical Lake a grant to develop a model of PFAS contamination in the West Plains. Medical Lake worked with Dr. Chad Pritchard at Eastern Washington University to complete groundwater sampling and analysis, model development, and public outreach.

In 2024 and 2025, researchers collected groundwater samples from 30 locations four times a year. They sampled another 160 locations once each. They used this data to develop a model of PFAS in the West Plains. We expect the final report in June 2026, and will share a results summary and link to the full report here. We are already using the data to inform decisions.

EPA sampling

In March and June 2024, we worked with EPA to sample 411 private wells in the eligible sampling area. 236 wells, or 57%, had PFAS above safe drinking water standards.

EPA's 2024 results

Sample results	Locations	Percent of wells sampled
Wells that don't have PFAS	111	27%
Wells with PFAS below drinking water standards	64	16%
Wells with PFAS above drinking water standards	236	57%
Total wells sampled	411	100%

EPA created this map to summarize where samples were taken without showing private well locations. The boxes on the map are Public Land Survey System sections. The pie charts show the percentage of sampled wells within an area where PFAS was over drinking water standards, and by how much. The size of the circle indicates how many wells in that area were sampled. The smallest circle is one well; the largest is 40.

See "Geographic summary" below for a text description of this results map. Click the map to open a larger PDF version.

The areas north of Highway 2 had the highest levels of PFAS. Some more than 20 times the drinking water standard.
The small number of samples taken south of the Spokane International Airport mostly did not have PFAS; however, directly east of the airport and south of Interstate 90, some wells had PFAS up to five times the drinking water standard.
Samples taken south and west of the Fairchild Air Force Base were below drinking water standards for PFAS.

2024 sampling results meetings

We held two community meetings with EPA to help people understand their sampling results. You can download the presentation slides and view the online meeting recording (YouTube) to learn more.