Originally Posted by
fireworksboy
Heck, I read somewhere about a study of municipal tap water and something like 14% of that was bad enough to make the average person sick.
I think this is the key. You're body gets used to certain impurities in water based on where you live since that's what you drink all the time. However, if you go anywhere else the water might make you sick since you're not used to that amount/type of impurities. Does that make the water unsafe? no, of course not, but it might still make you sick.