In April 2024, the US Environmental Protection Agency finalized the first national, legally enforceable drinking water standard for six PFAS under the Safe Drinking Water Act. For PFOA and PFOS — two of the most widely discussed PFAS compounds — the enforceable limit was set at 4 parts per trillion (ppt). This marked an important shift: PFAS in drinking water is no longer only a research or environmental issue, but one that has entered a clearer regulatory framework.

PFAS, or per- and polyfluoroalkyl substances, refers to a large group of synthetic chemicals used for decades in industrial processes and consumer products because they resist heat, water, oil and staining. Among them, PFOA and PFOS have drawn particular attention because of their persistence in the environment and their long history of use. They are often called “forever chemicals” because they break down very slowly and can remain in soil and water for long periods.

Once released, these chemicals can move through soil, surface water and groundwater, and may enter drinking water sources.Over 98% of the US population has been found to have four types of PFAS (PFOS, PFOA, PFNA, PFHxS) in their bloodstream (serum). These long-chain PFAS compounds have the ability to accumulate and persist in the human body for many years.