From my years of owning an A6, I know about the plenum chamber drains, but a combination of me not having checked them for a few weeks, and last night's torrential rain has resulted in my son getting in the back seat today and saying "Dad, why is the floor wet?"

So the right rear footwell was underwater (about 1 inch), and the driver's footwell carpet is damp. When I move the seat forward and push the carpet down, it floods in from under the carpet where the air con vent comes through, so the whole under carpet area is flooded.

The left (passenger) side seems dry, which surprised me as I thought that was the usual leak point.

The plenum chamber under the battery and brake servo was full of water. I siphoned it out this morning, and I'll lift the battery to clear the drains tonight.

From my previous reading here, and a quick search, it seems that it might be getting in around the engine ecu, so I'll check that later too.

The question is:
What is there under the right hand footwells? I know the CCM is under the left side, but is there anything which'll need checking under the driver's side, or can I just lift the edge of the carpet and start drying it out?