Well, here in 2016 we have the same issue - very strong mold smell, seems to be coming from drivers rear seat area floor. Had ServePro completely clean carpet and dry (while still installed) and fumigate with anit-mold chemicals, but it is coming back. We noticed during the winter that the carpets were damp, and we figured it was snow & water tracked in by peoples shoes. The carpets have not been wet since even after the severe storms here lately, so I hesitate to say its from the drain tube, and it is definitely not from rear trunk leaks like I've read about elsewhere (pulled out cargo floor for a look and its totally OK).
Curious what ever the original poster found/did.
