XSeries-forum

I was cleaning all the dirt out of the cars today. In the rear footwells i have large rubber over mats that i made to stop the mud from the kids spoiling the car.
Anyway, i lifted the mats to clean and found that the rear driver side is wet on the floor. I have a feeling that the rubber mat has been trapped in the bottom of the door which may have let water in, however, if that's not the cause, what is a common leak area in the back?

Other sources are detached water barrier membranes in the rear doors.  You need to remove the door card to get at them.  Blocked sunroof drains may also do it if memory serves.

Well well. I think ive fixed the leak. It was the bottom of the inner rear door seal where water was getting in.i had newspaper there last week and it was soaked after rain one night.
So, I loosened the door catch plate on the body and pushed it in a few mm thus allowing the door to be slightly tighter when its shut. 
Last night it threw it down and the newspaper was bone dry this am. Ha. In your face rain..