Literally, water that comes out of the faucet in sinks (that's regulated by the EPA).

Thank you, Mike. My main question is whether the distinction between "tap" and "faucet" is not maintained in this context in AmE or not, since as far as I know, "tap" isn't used in American English. I also remember seeing an American movie in which one of the actors (an American) asked the waiter for "tap water".

You could also just ask for “ ice water”. In a restaurant the server may ask if you want lemon. In that case they will add a slice of lemon to your water glass.