What is it?
A family of thousands of human-made chemicals (sometimes called 'forever chemicals') used in non-stick cookware, firefighting foam, water-repellent fabrics, and industrial processes. They persist in the environment and in human bodies for decades.
Why it matters
PFAS exposure is associated with kidney and testicular cancer, immune system effects, developmental harm in children, and elevated cholesterol. EPA finalized the first enforceable drinking-water limits in 2024.
Reference value
EPA's 2024 drinking water standard is 4 parts per trillion for PFOA and PFOS (two of the most studied PFAS). Detections above 4 ppt require utilities to take action.
Data source
EPA UCMR5 + ECHO PFAS detections · View source →