If you're really gung-ho, you can try live-trapping the little stinker and taking him to the shelter. I've been trying to do that for ages with the orange tom that kept spraying our car tires and garbage cans.

If you're not feeling up to that, I second the thought of either keeping the hose handy or borrowing a dog. Tom has left the premises permanently since he discovered that we had a dog (the dog absolutely adores cats--likes to lick them--but he didn't know that).