I had a huge puddle in the rear passenger footwell too, but also found that the front passenger carpets (and everything underneath) was soaking wet. Took ages to find the leaks but eventually found two - one from the grommet under the scuttle tray (plenty of silicone sealed that up a treat) and another from the passenger door. It wasnt the door itself not sealing against the body, but the inner door under the door card. Once the door card was off, it was clear to see it had always leaked! Obviously the numpty who fitted the door inner was drunk and had dropped it, as the front bottom corner was bent and the foam rubber seal not even touching. Everytime it rained, water ran inside the door as it is supposed to, but also ran out just under the front left speaker. The only reason I noticed this leak was when I was a passenger, and noticed the rubber seal attached to the car body was wet - but had never noticed this on the drivers side.
When I had taken out the passenger seat and rear seats, took off a fair bit of trim to pull the carpet up and saw how sodden the underlay was - and realised how pointless it was using my hairdryer to try and dry it out as I had been!! I couldnt be ar$ed to take up all the carpet, so raised it was much as possible...took a stanley knife and fresh blade, and cut a huge section out! Brutal I know, but it would never be a
problem once the carpet was refitted. I left the carpet in my workshop and it took about 3 days to fully dry! To make sure that the rest of the car was dry underneath, I took some 40mm flexi ducting (just happened to have 25m reel in the workshop), cut a load of slots along its length, fashioned a connector and plugged it into the far left passenger airvent (after removing it first...obviously) and then ran it under the carpet in all directions. I couldnt really drive around with the carpet all in the air, so this seemed the most sensible solution. Everytime I drove too and from work, I just closed all but one vent, and directed everything down the ducting. It worked a treat! It did like a little like I'd trapped Doctor Octopus under the carpet - but meh!
The one good thing to come from all this, was that I was finally able to cure the annoying rattles in the passenger door when listening to music. Dynomatting both doors does make a hell of a difference to the sound - better, tighter bass in my opinion!
