KyleB

Check the drains for your evaporator, they're near the center of the car. If you're getting water buildup even when it isn't raining, and you haven't been washing the car, then there's only one other source of water that I can think of and it's the A/C evaporator.

FaintReality

I was getting a puddle in rear passenger side floor board. Removed rear fender liners and pulled out the rubber grommets and all is good now. Rear passenger grommet was clogged so the lines were backing up.

H F

The fist thing to do is make sure all the drains are working properly. There is a total of six drains. 3 per side. Two are under each cabin filters and drain out behind the front wheels . Make sure that under the cabin filters are clean and no leaves and debris . Pour water into holes on the plastic piece between the fender and the cabin filters by the hinges. If water don't immediately run out behind the front tire. Remove the wheel and the plastic well cover look under the filters and youll see a rubber 90 with a cross shaped rubber cap. Remove it and run some weed wacker wire up the drain and gently blow air thru . Toss the rubber cap because that is the problem .. It gets clogged with broken leaves and dirt..Retest with water they should drain out immediately.

The next two front sunroof drains exit under the top front door hinges,, and drain out inside the door jamb out the gap btw the door and fender at the bottom corner of the door.
Park the car front downward like down the driveway. Open the sunroof pour water down both side tracks and the water will come out at the bottom front corner of the door. Those drains rarely clog, because they dont have the rubber piece on the end. like the rear and cabin filter drains.

The last two rear sunroof drains. Park the car pionted up the driveway pour water down the tracks the water will exit under the rear well covers and out behind the rear wheels. If water don't immidiately drain out ..Remove the wheel take out the plastic cover roughly at the top of the wheel well look up and youll see a cross shaped rubber piece remove it and Toss it, its prolly clogged. . Get some weed wacker wire about three feet run it up the drain till u feell the wire bump the top of the sunroof cartrage..Blow gently with air, then water test they should drain instantly ....

Once u done all that , the drains are clean and will function properly , and can rule out all the drains. That will prolly take care of the problem ... Check out this thread,,, http://www.bimmerfest.com/forums/sho...d.php?t=691644

One more thing , relocate the modules under the spare tire inside the styrofoam flat cover. They relocate to the sides behind the trunk side covers. I would do that ASAP. !!.. Since your getting water in the car.

agofberg

Many BMW vehicles come with this built in feature - a mini-bathtub. Water is replenished after it rains. \I'm surprised the dealer didn't explain this unique and absolutely free feature! You are not alone, mine floods all the time. Can't reach the rear sun roof drains. The BMW dealer is happy to clean them for several hundred dollars.

Mike986

Reading the earlier posts, you don't need to pay the dealer if you can remove the back wheels, loads of fixings for the shield inside the wheel arch then pull out 2 rubber drain plugs.
My 545i 2004 had water under the back seat on one side. Removing that drain plugs has dried out the car and no longer do my back windows steam up. Took a few weeks running around with the AC turned on to dry out.