Water in rear doors?

[blackbetty14]

I've noticed my rear doors have water in them when I open them and I can see water drain out the bottom. When the doors are closed the seal is tight at the bottom of the door so the water doesn't drain out. I would rather not have water inside my doors as they clearly stay closed most of the time. Literally just opening the doors water will come out for a min or so not like a stream but a constant drip. I also don't want this to rust out.