I concur 100% with the above. I buy bottled water for drinking, and for everything else (ice, foods washed or prepared with water, etc etc., ) the tap is fine. This includes home cooked foods with urban (right from the tap, no special hotel filtration) water.

Foreign water supplies (i.e., foreign meaning not the one you are used to) can always cause some sort of upset because of different native microorganisms. Not that you can't get sick, but Chile overall has one of the "cleanest" food supplies of anywhere I've traveled.