Hello, my name is ***** ***** I'll be happy to assist you! I have an associates degree in automotive technology, I’m ASE certified with 15 total years in the field. Let me gather some information to help.
Sorry to hear you have a water leak!
So I fully understand can you tell if the water is leaking in from the outside when it rains or going through a carwash?
Or is it coming from the inside? Like the drain water from using the Air conditioner isn't draining and backing up into your heater box?
For instance there is a few inches of foam padding under the carpet that can be very hard to dry out once it is saturated. In the shop we usually have to partially lift the carpets up and blow fans in for hours until it is dry. My fear is that as soon as you sop up the water on the top the foam is still saturated and seems like the water just keeps getting in.
If you push on the carpet and its a puddle then its soaked into the foam pretty good.
the most common cause of a soaked floor near a door, especially in the rear is the vapor barrier inside the door panel is not sealed.
The vapor barrier is a seal of plastic separating the interior door panel from the water that runs down the window on the outside. Usually the barrier loses it's seal and allows water to leak.
Before I speculate to much let me know your thoughts so far?