I was watching David Letterman interviewing Denzel Washington. Mr Washington said that one reason he was in such good physical shape was that he drinks a lot of water, to which Mr Letterman replied with something like "line up at the tap, everybody". This surprised me, as I had never previously heard any speaker of US English use the word "tap" in that way. Prior to this, I had only ever heard US English speakers say "faucet". Is it some regional quirk that brings Mr Letterman's usage nearer that of British (and related) English?