Back outta boston, we used a well (lots of clat, etc...), and we treated it with a water softener (full of salt) system and some blue tube to filter it. Water was great, although the pressure was reduced a bit. Same thing up at camp, but that 200ft well full of lake water doesn't need softening, but we just use a simple can filter up there for the kitchen and bathroom sinks.
Our city water in Maine comes from Sebago lake and needs nothing. what a treat! (That being said, the water that goes through the purifier on the fridge is horrible!)