BMW Repair: E46 Door membrane leak - carpet removal, 3m butyl tape, carpet removal

Question
Hi,
Ive recently purchased a 2003 E46 coupe, and the following day discovered a puddle under the rear passenger footwell (drivers side).

As per information from this forum - Im suspecting the door membrane is at fault (will investigate tonight), however I would like to get under the carpet to attempt to soak up as much of the water as possible.

Could you advise the best way to do this?  Is it possible to lift one side of the carpet up to soak up the water and try to dry it out?

Answer
The water leak is very common. The membrane is reffered to as a "vapor barrier", but I think that name is quite incorrect. Reseal it with 3m butyl tape (ribbon sealer). Or it may be torn from a prior repair. To get the carpet up pop out the rear seat bottom and pry up the sill plate. This will give you some access to the floor. I would recommend that you take out the front seat and front sill plate to get more access. Note: Do not turn the key on with the front seat unplugged or you will set an airbag fault.
            Good luck, Kimber