Rear passenger footwell soaked

[MoRS6+]

Had this on my old A6 4.2. I used the following guide to fix mine as the Passat is virtually the same chassis as the '6. Thing is though, the battery is at the back on the RS6, but presume that drain hole is still there and could still be blocked.

Linky: http://www.weirdlittlebiscuit.com/passat/leak/index.htm

Good luck.