Last year, the Environmental Protection Agency set the first federal drinking water limits for PFAS, or perfluoroalkyl and polyfluoroalkyl substances, finding they increased the risk of cardiovascular disease, certain cancers and babies being born with low birth weight.

In a decision with consequences for tens of millions of Americans, the Trump administration is expected to soon say whether it intends to stand by those strict standards and defend the limits against a water utility industry challenge in federal court.