Hi guys 2020 s3 hatch. Noticed the fitted mat which covers boot floor was wet through. Both side areas also wet. No obvious areas i can see when hose pipe used on rear of the car. Fuel cap drain seems ok as i can poor water on and it drains under car. Hatch seal seems fine as well as car only done 29k. Any ideas appreciated before i strip both side panels off for better view. Thanks 

40 minutes ago, Rickj63 said:

Hi guys 2020 s3 hatch. Noticed the fitted mat which covers boot floor was wet through. Both side areas also wet. No obvious areas i can see when hose pipe used on rear of the car. Fuel cap drain seems ok as i can poor water on and it drains under car. Hatch seal seems fine as well as car only done 29k. Any ideas appreciated before i strip both side panels off for better view. Thanks 

Hi the hose idea wont work as tap water has a much higher surface tension than rain water, so borrow a watering cans worth out of a neighbours water butt or use distilled water.

Steve.

Will give it a shot. Thanks 

Hello Richard,

Aren’t there vents in the lower rear side panels which can let water in? 
Seem to recall some earlier posts referencing these. Your model?? 
Well worth doing a forum search - far more reliable than my memory! 
Kind regards,

Gareth. 

Yes there certainly is. Might take out and put some clear sealant and refit. 

The rear screen wash can leak into the boot if the motor seal fails. Would be worth checking this point before squirting sealant all over the shop.

8 minutes ago, cliffcoggin said:

The rear screen wash can leak into the boot if the motor seal fails. Would be worth checking this point before squirting sealant all over the shop.

Who mentioned squirting sealent all over the shop? 

Not understanding Richard.

Did you manage to resolve this? I have the same on 2015 A3 and I vacuumed out 6L of water from the passenger footwells.
 

I found that the storage boxes in the boot were all wet and it seems as though water is making its way downhill into the footwells from there. Had a garage look at it and they think it’s the bumper vents into the storage boxes. 

I’m about to take the rear bumper off to replace the bumper vents into the storage boxes, but I remain a little bit sceptical due to the volume of water involved. That said, I cannot find water coming in anywhere else, apart from these vents. 

Edited December 27, 2025Dec 27 by saulbusbycozic
Added info

I had water leaking into my boot (2015 A3 Sportback) and it was the wiper motor seal had failed.

On 12/27/2025 at 9:36 AM, saulbusbycozic said:

Did you manage to resolve this? I have the same on 2015 A3 and I vacuumed out 6L of water from the passenger footwells.
 

I found that the storage boxes in the boot were all wet and it seems as though water is making its way downhill into the footwells from there. Had a garage look at it and they think it’s the bumper vents into the storage boxes. 

I’m about to take the rear bumper off to replace the bumper vents into the storage boxes, but I remain a little bit sceptical due to the volume of water involved. That said, I cannot find water coming in anywhere else, apart from these vents. 

how did you go on here ?

On 1/19/2026 at 4:56 PM, enc said:

how did you go on here ?

Not resolved, however I have finally received replacement vents from VAG and i am planning to remove the bumper to fit them this weekend. I am also going to inspect the wiper motor, although i've not seen water tracking down from that area of the boot lid - it seems to be in the storage boxes only. 

Please let us know the outcome.

On 1/21/2026 at 6:54 AM, saulbusbycozic said:

Not resolved, however I have finally received replacement vents from VAG and i am planning to remove the bumper to fit them this weekend. I am also going to inspect the wiper motor, although i've not seen water tracking down from that area of the boot lid - it seems to be in the storage boxes only. 

When you say “large boxes” are you referring to the sections on either side, behind the grey panels? 

Were the replies of any help to you Saul? Have you solved the problem?

I am still looking for the problem. I've not yet been able to replace the vents in question. I've since been advised on a split in the hose to the rear washer 

Thanks. I look forward to reading the outcome.