Today I have removed more than 4L of rainwater by running a carpet shampoo machine over the carpet in driver's footwell of a 2007 A3 Cabriolet.

I'm writing this with one hand while the other is holding the sucky thing in the corner beside the accelerator pedal (the wettest bit) where I can see it is still sucking up more. I don't know whether 4L will become 5. 

Where on earth can all that water have been? (Apart from in the clouds of course.)

We got (very) wet carpets a couple of weeks ago immediately after I washed & re-proofed the roof, it seemed suspiciously close to co-incidental but rainwater sat on the roof in lovely looking beads so I don't think it was soaking in & worming it's way down the A pillar.

Booked it in to our lovely garage & they cleaned out the drainage channels, which I think helped but certainly didn't cure the problem - as this weekend's rain has proven.

I know we have lots of spongy stuff for sound deadening under the carpets but enough to hold 5 of your best European litres?

Does abody have any idea where that water can have been and more importantly how to keep more out???

Thank you. 

Stuart 

Have a look at the battery tray as the water drains can get blocked. Also on my similar aged A6 I had a similar issue and it was water getting through the pollen filter housing. 

The problem you've got is that there might be a computer in the floor known as the CCM which can start playing up when wet. I know as I've had this issue with my A6.  

Stuart.

While it is possible the water is rain coming in through the heater if its drain hole is blocked, or the heater matrix is leaking engine coolant into the cabin, or the windscreen sealant has perished, the obvious candidate has got to be the rag top.

The fabric may be intact, but it must have some sort of seal around the edge which may have been damaged. I have never dealt with a soft roof so I can not be any more specific. You also said cleaning the drainage channels helped, so if they are accessible can you test each one by pouring a little water through them to see if they really are clear?

Thank you Steve & Cliff, sorry to be so long acknowledging your suggestions. Unfortunately didn't find the solution but since discovered a proper pool in the spare wheel well so attention now on something wrong at the back end & water woking it's way forward from there.

I'll update when there is better news in case it helps someone else.

Could be the rear light seals or the seal where the roof meets the boot. 

5 hours ago, Steve Q said:

Could be the rear light seals or the seal where the roof meets the boot. 

Wondered about that so will give it a closer look when the rain stops. Although maybe now is when I should look...

Got it booked into my garage to have high pressure air blown up the drainage channels & see whether that helps.  (But garage is very popular so three weeks to wait & keep mopping up!!)

Will keep thinking where else it could be getting in.