USGS Publishes PFAS Groundwater Contamination Report and Map

On October 24, 2024, the U.S. Geological Survey published a report and map sharing the findings of a study using predictive modeling to understand where PFAS may contaminate public and private wells that supply drinking water. These national estimates of PFAS occurrence are intended to help members of the public, water suppliers, and regulators understand the potential for PFAS contamination, guide future studies, and inform strategic planning for water resources. The accompanying interactive, online map allows users to see the probability of PFAS occurrence but does not include estimates of PFAS concentrations. These predictive results are intended to be evaluated at state, regional, and national scales rather than at individual household levels. These results also do not account for any subsequent actions taken by states, municipalities or individuals to treat drinking water.

The USGS study findings estimate that approximately 71 to 95 million people in the Lower 48 states may rely on groundwater supplies of drinking water that have detectable concentrations of PFAS. The findings estimate state levels of occurrence and provide data according to population percentages for at least one of 24 types of PFAS. The most frequently detected compounds were PFOA, PFOS, and PFBS. The estimates find that:

• The states with the largest populations relying on public water supplies with potentially contaminated groundwater sources are Florida and California.
• The states with the highest population percentages relying on potentially contaminated groundwater sources of drinking water are Massachusetts and Connecticut.
• The states with the largest populations relying on private wells with potentially contaminated groundwater sources are Michigan, Florida, North Carolina, Pennsylvania, New York and Ohio.

For more information and to view the report and map, visit the USGS website.