How do you remove the water that has come in to the backdoor of a Toyota Avalon after it rains?

Go to a carwash, and use one of their vacuums.

I had the same problem on my Avalon xls. I had to pry the rivets off on the bottom of my rear driver door and that allowed me to drain the door which was holding a considerable amount of rain water. I let it drain and installed new rivets and did not see a problem occur again. Weird I guess but I am glad to see I am not the only one....

My mechanic drilled a small diameter hole at the bottom of the door so the water would always be able to drain out. No problems since he did that.