mine was the same only wet on drivers side, whens its been raining or chuck some water over it, check the door rubber at the bottom, if its really wet then water has built up and ran down in to the foot well, firstly check the trim at the bottom is fitted correctly, then remove the scuttle board and check drain holes mine was bloked with dead leaves, the other reason can be that the windscreen rubber (top reighthand corner) may need sealing