I've had my 2005 mustang for close to a year now and never had problems with leaking until this month. There was almost a foot of water on the driver side rear footwell. I read it could be a drain hole and to park my car so the front is slanted down and now there is water in 2 spots on the driver side front. Not a puddle but still pretty bad. After it happened the 1st time I bought a water proof car cover which covered the entire car wheels and all front to back. After a week of rain which stopped last night i went to get an oil change this morning and the front driver footwell was soaking wet again. Nothing else was wet anywhere inside or outside, not a drop of water except the soaking wetness on the floor. The inside top is not wet at all, seats not wet at all, no other area of the floor is wet at all. The most confusing part is i have rubber floor mats and there is not a drop of water on top of the floor mat but soaking wet under. Where could it be coming from? The car has been in water before and this month is the 1st time i've had a problem with leaking. Even december it was in the rain perectly fine. I had a leak test done before i got the car and it was fine. I just had a basic inspection done today when i got oil changed and they didn't say anything in their routine inspection other than i need a new air filter (unless that can cause this problem)