The following is based on the presumption your year coach has an entry door air seal, as I'm not as astute as others as to which ones do or don't:
It could be a damaged air bladder, a faulty valve to it, an inoperative switch or bad wiring to the valve, or its pressure regulator may need adjustment. It is possible to cut the bladder if the door is slammed while the coach is in gear (the bladder is inflated). I think you could check the bladder by leaving the door open, keep the coach braked, and put the coach in gear to see if it inflates.
You can also check the regulator; I have never messed with that myself, but I guess it has a knob you can turn to adjust the pressure to the air seal bladder. It's conceivable someone working under the right front of the coach inadvertantly bumped and moved the regulator's knob. The book says the pressure should be between 3 and 4 psi, and not to exceed 5 psi, but I'm not sure how you'd measure that. At any rate, the regulator and valve should be under the front cap on the curb side - you may be able to follow a line or tube between it and I'd guess the forward side of the door frame.
On our coach there is no obvious way of adjusting the door since it is on a piano style hinge. You should be able to stand back and tell if the door doesn't align fairly well with the frame. The latch can be adjusted, but that's probably not contributory to your leak unless its not closing firmly. One can tweak the scissor brace at the top also. The screen door does have 3 adjustable hinges tied into the piano hinge. But unless radically askew, they shouldn't affect water leakage.
Joel