Preliminary Results

Last updated: November 11, 2026

NoteKey Takeaway

Household PFAS filters certified to NSF/ANSI 53 effectively and consistently reduce PFAS in private well water, but some instances of breakthrough have been found. We are continuing to investigate why and when breakthrough occurs in certified household PFAS filters, but the most effective way to protect your water quality is to ensure that your filter cartridge or filter media are replaced regularly, following the manufacturer’s recommendations.

To help us continue to understand PFAS filter effectiveness, consider enrolling your filter here.

To date we have completed testing for 19 households with certified PFAS filters across the West Plains. Our initial results for these 19 households for the six PFAS with current drinking water limits are shown below.

These are aggregated, deidentified results for all participating households to date, including:

Hover over the graphs to explore the results and see exact concentration data compared to current WA allowable limits for public drinking water utilities.

ImportantPreliminary Research Results Disclaimer

These research findings are preliminary and have not yet undergone formal scientific peer review. They are shared publicly in the interest of transparency and timely communication with participating households and the broader community. Our goal is to support informed decision-making and increase awareness of strategies to reduce PFAS exposure through private well water.

These findings are subject to revision as additional data are collected, analyzed, and reviewed. They should not be considered definitive conclusions or interpreted as independent certification, endorsement, or verification of the performance of any commercial water treatment product by the research team or the University of Colorado Boulder.

Preliminary results — Updated November 2026