You don’t need to live downstream from a chemical plant to be drinking PFAS-contaminated water. The EPA has been so lax at regulating these “forever” chemicals (which they were warned about since 2001) that it is now, literally, raining plastics. PFAS has infiltrated everyone’s water.

PFAS Contamination of Drinking Water Far More Prevalent Than Previously Reported, Environmental Working Group, 22 January 2020

New laboratory tests commissioned by EWG have for the first time found the toxic fluorinated chemicals known as PFAS in the drinking water of dozens of U.S. cities, including major metropolitan areas. The results confirm that the number of Americans exposed to PFAS from contaminated tap water has been dramatically underestimated by previous studies, both from the Environmental Protection Agency and EWG’s own research.

Based on our tests and new academic research that found PFAS widespread in rainwater, EWG scientists now believe PFAS is likely detectable in all major water supplies in the U.S.
…
Of tap water samples from 44 places in 31 states and the District of Columbia, only one location had no detectable PFAS, and only two other locations had PFAS below the level that independent studies show pose risks to human health. Some of the highest PFAS levels detected were in samples from major metropolitan areas, including Miami, Philadelphia, New Orleans and the northern New Jersey suburbs of New York City.

In 34 places where EWG’s tests found PFAS, contamination has not been publicly reported by the Environmental Protection Agency or state environmental agencies.

Note that since this graph was produced, the EPA lowered their “safe” limit … dramatically.

EWG’s samples … were analyzed by an accredited independent laboratory for 30 different PFAS chemicals, a tiny fraction of the thousands [4700!] of compounds in the family of per- and polyfluoroalkyl substances.
…
PFAS are known as “forever chemicals” because once released into the environment they do not break down, and they build up in our blood and organs. Exposure to PFAS increases the risk of cancer, harms the development of the fetus and reduces the effectiveness of vaccines. Biomonitoring studies by the federal Centers for Disease Control and Prevention show that the blood of nearly all Americans is contaminated with PFAS.
…
Since the EPA program ended [in 2015] there has been no further nationwide testing of public water systems for PFAS. … An expert at the Water and Environmental Technology Center at Temple University, in Philadelphia, said about PFAS contamination: “If you sample, you will find it.”

Bottled water:

There is no government requirement for PFAS testing of bottled water, no public information about potential PFAS contamination of water supplies that manufacturers use for production of bottled water, and no guarantee that the levels of PFAS in bottled waters are lower than those of tap water.

Even if people or water plants treat the water…

The most effective choice for in-home treatment of PFAS-tainted tap water is a reverse osmosis system that combines an activated carbon filter with a reverse osmosis membrane.

… there is the problem of where to dispose of the filters. Not a landfill, not an incinerator, certainly not a river. We are back to square one. The answer? Stop producing PFAS! Sadly, our government is addicted to the money that industry injects them with.

Related:
Rainwater In Parts Of US Contains High Levels Of PFAS Chemical, Says Study, The Guardian, 17 December 2019
Levels high enough to potentially impact human health and trigger regulatory action, which only targets two of 4,700 variants

It’s Literally Raining PFAS Around The Great Lakes, Say Researchers, Michigan Live, 8 June 2021