My son has a 02 Impreza WRX with a very wet interior floor on both the drivers and passengers side, front and rear.
I pulled up some of the front carpet on both sides, and its not only on the "flat" part of the carpet, but its also very wet on the part of the carpet the slopes upward toward the firewall.
I've soaked the car down and I haven't seen any obvious leaks. I also tried doing a pressure test (took a vacuum and hooked it up so it blew air, made a sealed connection where the middle of the rear seat folds down, and pressurized the interior). I soaked every window and door seam with soapy water looking for it to bubble, but I saw nothing.
I'm wondering if it could be leaking from the wheel well area through the firewall somehow. I've also read where the a/c drain tube could be blocked and causing a leak, but would that cause both sides of the car to be wet?
Playing around some more I found what I believe is a drain tube in the engine compartment side of the firewall, on the passenger side. I'm not sure what its supposed to drain, so I poured some water down the windshield thinking that it would drain that water as it ran into the cowl by the wipers. All of that water ended up draining out on the ground from behind the drivers side wheel, from behind the black plastic that covers the inside of the wheel well.
Next I ran the defroster for a while, to see if it was the evaporator drain tube, but that water too drained out from behind the drivers side wheel.
Any ideas on what that drain tube is supposed to drain and where to look next?