I had this EXACT thing happen to my car once (a 94 convertible), but from the rain, and not from a car wash. The carpet under my (the driver's) feet was a lake. Also there was no other water ANYWHERE. Not on the seat, dash, door panel, kick panel, steering wheel, windsheild, headiner, inside of top behind the headliner, gas and brake pedal, or the steering column under the dash. Nothing else was wet. Not any other area on the carpet either. I even looked at the carpet compared to everything else. I figured out the angles, and tried to find how the water could be there, but on nothing else. I made a mini plumb bob and hung it from my window, every half inch, to see if the water could come in that way, and not hit the door. NOPE. I asked around on here, and no one knew. My g-pa said something about a drain valve at the bottom of the windshield. If it get's clogged with leaves or whatever, water could spill over and maybe enter the car, behind the dash. So I took that plastic piece off under the winsheild wiper, and saw some confusing mess with no answers. This went on for almost a month. I gave up, and never found out why. Eventually the smell of wet socks went away, and that leak had never happened again. You washed your car though. When I go to a car wash, it involes two people. One on each side with a rag, to cover the spots as the water shoots in. My weather stripping is wearing out, and that's why. So go to a car wash, but stay inside, and you'll see what's happening. Water comes from all angles, so it's easy for your carpet to get wat and nothing else. When I wash my car, my trunk used to get wet, because the water comes up the body of the car, and goes under that black metal strip, then finds it's way into the trunk. It took me two weeks to find and stop that leak. But it could be possible you need new weather stripping on the top. Or do what I did and just don't wash your car anymore.