PFAS Findings


Per- and Polyfluoroalkyl Substances (PFAS) is a group of man-made chemicals that spread to the environment and break down very slowly over time. The term PFAS refers to a group of thousands of chemicals with a similar chemical structure. They are found in many different consumer, commercial, and industrial products.  As a result of their widespread use and persistent structure, many PFAS have been found in people’s blood and in the environment including water. Scientific studies have shown that exposure to some PFAS may be linked to harmful health effects.

In Illinois, PFAS is more likely to be present in groundwater than surface water like the Great Lakes.  Despite this, Chicago proactively sampled our drinking water for PFOS, a type of PFAS, in 2011 as part of a larger study on emerging contaminants and the detailed results are on our website:

City of Chicago :: City of Chicago Emerging Contaminant Study

Also, Chicago’s drinking water was sampled for chemicals within the PFAS group in 2014 during the U.S. EPA Unregulated Contaminant Monitoring Rule 3, in 2020 as part of the Illinois EPA PFAS Study, and in 2024 during the U.S. EPA Unregulated Contaminant Monitoring Rule 5. All studies yielded non-detect results, which means if any PFAS were present, it was at such a low level that the laboratory instruments couldn’t detect it.

Click here to see the detailed results.

PFAS/PFOS Levels in the City of Chicago 

Click here to see the detailed results

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