They obviously did that to let us know he has been in there for a while. You may or may not know that when you get to Clems house, you can take a drink of water! did you see how much he drank? he took a sip from a cup...if that was me, with a big gaping leg wound and had not drank for 2 days i would have stuck my mouth under the TAP and stayed there for a while!
and YES! the taps would have still been working by that point, but he did not even try! he seemd more occupied wioth listening to a random persons answering machine!