“Most big cities”
Big cities spent a great deal of money on getting good water.
Croton water for New York City and Loch Raven water for Baltimore come to mind.
Indeed they do. I used to fish in some of the WSSC reservoirs that feed Montgomery and Prince George counties in Maryland. Very nice, well maintained, clean infrastructure. Of course, the fish, frongs, turtles, beavers, deer, birds and other critters relieve themselves in it ... but human visitors are admonished to "Commit No Nuisance".