its probably not the hatch unless it has huge rust holes in it. its most likely either the rubber gaskets under the lower glass trim that goes around each stud which secures it to the hatch, or the wiper motor hole... but probably that first thing i said. or, it could be that the water drain channel that runs around the tail lights are clogged w/ crap that the water pools up just above the tail lights and leaks down thru the tail light gaskets.