BMW: water problem, rubber hoses, water leaks

Question
hi.  i have a 2002 540i that recently has started taking on water behind the front seat.  first it was on the driver's side.  i took it to the dealer and they said that something had been ripped off on the underside.  it has been raining so they said rain water was coming through the bottom.

now, i have water soaked on the passenger side right in front the back seat.  i have not been driving through any rain.  could the air conditioning ducts be the culprit?

Answer
Water can be very problematic to diagnose but it you have time and a good selection of hand tools it is eminently fixable. I am not sure of how you want me to answer this question. Do you want a walk through or just some things to tell your mechanic to check. First look for body plugs in the floor that have been pressed up into the carpet by road debris. Next check the foam vapor barriers behind all 4 door panels, the door panels will  have to be removed. If any vapor barriers are torn from previous door repairs like the body shop or a window regulator replacement those will definately cause a water leak into the floor boards. Or even if the adhesive has just let loose and they aren't stuck to the door shell any more. Another cause could be the sunroof drains. The sunroof cassette has a drain at each corner that is attached to metal tubes in the body via rubber hoses. These hoses come loose over the years by water freezing and walking the tubes off. You can check those by opening the sunroof and pouring a little water down the outside edges of the sunroof cassette and watch for the water to come out of the bottom of the car. If the car has been in the body shop the doors themselves could not be hitting the seals all the way. It is unlikely that the ac drains are causing the leak as there is one on each side of the transmission tunnel. Since you have water on both sides that means they both would be leaking and I have never seen that. I would say start with the vapor barriers. Those are probably 90% of the water leaks I fix. Next guess would be the sunroof drains. Good luck with the repair.