[sqwinny]

The drain that's located behind the door panel is the culprit. It was a common issue on e90s as well.

I have a post with a video where I commented it somewhere …

Water leak-hopefully fixed https://f30.bimmerpost.com/forums/sh....php?t=1643300

[Fliplegend]

This is a common issue with BMW's period. It's called a vapor barrier and over time, the seal just disintegrates which allows water in.

[hiperco]

Thanks for the replies, but again I need to state that IT IS NOT COMING IN THROUGH THE DOOR. When I pour water into the driver side drain (corner of windshield), the water somehow gets through the firewall and onto the driver side floor.

[AndrewC1989]

Originally Posted by hiperco

Bumping this old thread in hopes that the OP got this issue resolved, and can report back what it was. I have the same issue (2016 340xi), with A LOT of water making its way into the back passenger area on the driver's side. I have narrowed it down to water coming through the firewall when the driver side drain is overwhelmed with water. Initially the drain was clogged, but it has been cleaned and now the water only comes in if I pour a lot of water into the drain such that the water flows rearward towards the firewall.

I took off the accelerator pedal and it there is a lot of dampness there. Hard to tell if its a clue, or just that its a low spot. Could be coming in where the throttle wire goes through the firewall?

Its most definitely not coming in through the doors or sunroof etc, as I have done a very focused pour of water from a bottle into the drain.

Any insights welcome, this is driving me nuts.

I could have sworn my leak was coming from the dash, roof, or windshield but it ended up being the vapor barrier in the door. The water would pool under the pedals and dry up quickly near the door making it seem like the leak wasn't coming from that area so it threw me off. I'd bring the car to the dealer and see what they say. My indie couldn't find the issue but BMW was able to resolve it immediately.

[tangobretta]

Originally Posted by hiperco

Thanks for the replies, but again I need to state that IT IS NOT COMING IN THROUGH THE DOOR. When I pour water into the driver side drain (corner of windshield), the water somehow gets through the firewall and onto the driver side floor.

Did you ever bottom this out, I'm just experiencing extremely similar symptoms on my F30. Cant 100% determain if its the 'driver drain' or the water exiting down the outerwall of the car (between the front wing and door) I can actually see/feel the water around the rubber flap which leads to the firewall above the foot pedals.

Much appreciated on any reply.

Thanks TB

[CajunBMW]

Originally Posted by tangobretta

Did you ever bottom this out, I'm just experiencing extremely similar symptoms on my F30. Cant 100% determain if its the 'driver drain' or the water exiting down the outerwall of the car (between the front wing and door) I can actually see/feel the water around the rubber flap which leads to the firewall above the foot pedals.

Much appreciated on any reply.

Thanks TB

I can't state exactly what you have wrong, but for me in my old e46, I had all 4 door vapor barrier go and in each case I had water in the foot well around that door. The car was 17 years old when it was totaled but those issue with the vapor barrier were my issues with water leaks. I think the back passenger door had the issue 3-4 times. The multiples were covered by the 2 year warranty by my dealership. I guess I also had the hose that drains the sunroof clog once too. Hope that helps. Good luck getting to the bottom of your issue.

[avanleur]

I experienced a very wet passenger side floor after my regular car wash installed a brand new, very high-powered car washing system.
I just want to know from WHERE the water entered!!

[Marcoadj13]

Having a similar issue but the water would be under my rear seats instead of the carpets. Any ideas?

[hiperco]

Originally Posted by hiperco

Bumping this old thread in hopes that the OP got this issue resolved, and can report back what it was. I have the same issue (2016 340xi), with A LOT of water making its way into the back passenger area on the driver's side. I have narrowed it down to water coming through the firewall when the driver side drain is overwhelmed with water. Initially the drain was clogged, but it has been cleaned and now the water only comes in if I pour a lot of water into the drain such that the water flows rearward towards the firewall.

I took off the accelerator pedal and it there is a lot of dampness there. Hard to tell if its a clue, or just that its a low spot. Could be coming in where the throttle wire goes through the firewall?

Its most definitely not coming in through the doors or sunroof etc, as I have done a very focused pour of water from a bottle into the drain.

Any insights welcome, this is driving me nuts.

It seems that the issue in my case was a badly worn/cracked windshield seal. After replacing it, there has been no more leaking.

[amancuso]

Originally Posted by hiperco

It seems that the issue in my case was a badly worn/cracked windshield seal. After replacing it, there has been no more leaking.

There are no windshield "seals" on these cars, just cowl and decorative trim. The windshield is sealed to the frame with an adhesive when it is installed. That is what makes it "water tight".

[BrennanF30]

Just like to open this topic again as I too am having the same issue with my 2013 F30.

Soaking wet drivers side rear footwell, huge puddle of water in the footwell, I have a UK car so this is the right hand side of the car.

It’s been raining for the past 3 days continuously so I have been sponging out the water from the footwell for the past 3 days. It’s been raining for the past hour, I’ve just went out and checked and there is a puddle of water yet again.

I’m getting really frustrated with this now. Does anyone know what the first course of action would be? Someone mentioned seals or water vapour inside the rear door. Do I really need to take the door card off to try and solve this issue?

[im_an_alien]

Originally Posted by BrennanF30

Just like to open this topic again as I too am having the same issue with my 2013 F30.

Soaking wet drivers side rear footwell, huge puddle of water in the footwell, I have a UK car so this is the right hand side of the car.

It’s been raining for the past 3 days continuously so I have been sponging out the water from the footwell for the past 3 days. It’s been raining for the past hour, I’ve just went out and checked and there is a puddle of water yet again.

I’m getting really frustrated with this now. Does anyone know what the first course of action would be? Someone mentioned seals or water vapour inside the rear door. Do I really need to take the door card off to try and solve this issue?

At a minimum you'll have to remove the door card and inspect the vapor barrier, there is a very high likelihood it will be the problem.

[BrennanF30]

Originally Posted by im_an_alien

At a minimum you'll have to remove the door card and inspect the vapor barrier, there is a very high likelihood it will be the problem.

As a bit of an amateur on these things, is the rear door card easy to remove?

[im_an_alien]

Originally Posted by BrennanF30

As a bit of an amateur on these things, is the rear door card easy to remove?

Very simple. Lots of vids on YT. If it takes you longer than 5 minutes something is wrong with you...

[davethefish]

Originally Posted by hiperco

It seems that the issue in my case was a badly worn/cracked windshield seal. After replacing it, there has been no more leaking.

mine has been doing the same on the drivers side footwell.
I had the carpets up and the water is coming through the firewall bulkhead somewhere the whole bottom edge of the rubber seal running the length is wet.
but it seems to be worst near the right hand corner. so it must be getting in somewhere higher up.

Initially i had 2" of water sloshing around inside the front and rear drivers side footwell.
i found there there was a gap for some reason on the top edge of the wiper panel where is seals against the windscreen, that when i flattened it down again it reduced the water getting in a lot.
but it's still getting some water in.
what part exactly did you have replaced?