I live in upstate NY and I've never heard of anyone testing for PFAS. In our schools they do bi-yearly drinking water tests for lead and a handful of other things, but not PFAS.
It also just might be where chemical plants or recycling centers are located. My brother used to work at a chemical recycling plant in New Jersey, there's a LOT of those kinds of plants in New Jersey. Surely the goal is 0 spills or accidental dumping but there's no way that's 100% fool proof so surely where this stuff has been created/treated/recycled there's going to be higher concentrations.