But, getting back to the OP's point: water treatment in the USA varies dramatically between municipalities. Some use Chlorine, but others use different process

But, getting back to the OP's point: water treatment in the USA varies dramatically between municipalities. Some use Chlorine, but others use different processes, be it chemical or filtration, to clean water. Older water infrastructure can't support chloramine, a replacement for chlorine, because it causes water to leech metals used in pipes. So older infrastructure in poor neighborhoods still use chlorine, but older, wealthy places might use nice filters and no chemicals. It varies a lot, even with houses separated by a few miles.