Hi Mark
Thank you for explaining all the above. I only found this thread today as I now have the same problem on my 2020 A6. Rear footwell behind drivers seat flooded but I have already dried out the carpet and foam myself and have no electronic problems luckily. But when i took it for a spin today, water entered the rear footwell again (while i had the carpet lifted still). So this sounds to me that water is still trapped inside somewhere. I am wonderkng about the gromments mentioned in a thread above. Are these gromments under the plastic panel that protects the fuel filter? Must this panel be removed to access these gromments? And are these gromments located towards the centre of the car or are they located towards the sill? I think i will remove these gromments also.
Appreciate your help