check the door seal rubber for splits/cracks allowing the water to enter.
the seal itself may have shrunk, mark around the door plate, then undo and move it (the striker plate) further inwards to put more tension on the rubber when door shut re-tighten the pins if door now won't shut, you have the original position of the plate marked to reposition it back to where you started from
wirecutterman, June 2011
