>>814276>Why don't Americans drink tap-water?Question makes false assumption.
In many places in the US the tap water is safe to drink just out of the faucet. But people will also install faucets specially for filtering water for drinking, pic related, generally a long thin faucet next to a larger one is for tap water.
Also many refrigerators incorporate automatic ice makers and a faucet function in the door. So there's a replaceable water filter in there.