How much PFAS in drinking water is considered safe?

In 2024, EPA announced the first enforceable limits in drinking water for two PFAS commonly found in northwest Georgia — PFOS and PFOA. Those limits, set at 4 parts per trillion (ppt), are to take effect in 2031. Previously, EPA had issued nonenforceable health advisory levels, which federal regulators lowered over the past two decades.

All figures are presented in parts per trillion:

Note: While EPA has said no amount of these PFAS are safe in drinking water, the latest guidelines represent the lowest levels feasible for implementation.
Chart: Justin Price & Pete Corson, The Atlanta Journal-ConstitutionSource: U.S. Environmental Protection Agency