I have a 2002 Passat and noticed the passenger side back seat floor was soaked a number of times. I pulled the floor pan plug and a ton of water came out. I have heard of the A/C related problem but it was cold when I discovered the water so I wouldn't have been running the A/C. I am looking for other ideas on the problem before I take it to the dealer. I do have a sun roof, thought that might be the origin.

 

I had this problem with my passat,it was coming from the bulk head if you go under the bonnet to where the battery is housed.just uderneath the battery there is a drain hole that gets clogged up.there is another hole on the right hand side under the brake servo unit.when they get clogged up the bulk head fills with water and comes over the bulk head under the dash and runs underneath the carpets to the back of the car when parked on a hill