i have a 2007 accord coupe, no sunroof. I bought it used. When it rains heavily, the rear passenger side carpet/floor gets soaked, from UNDER the floormat (the top of the floormat is dry.) I have had the car water tested by bodyshop, for hours at a time, and no one can replicate the leak. When i'm sitting in the car and it's pouring rain -- sitting in parking lot, not driving -- i see the drip come in at base of floor, about an inch rear of where the seatbelt attaches. Prior to my owning the car, it was clearly in an accident on the right side, bec when the carpet was pulled up, there was all kinds of broken glass under the carpet. Mechanic has taken out the seats, taken apart the door, and cant figure it out. It gets so bad that last winter i had to use icescraper to get frost off the windshield INside the car.

The Honda dealer uses some independent agent called The Water Doctor and if they find the leak they supposedly guarantee their work, but i've read some bad things about them online, that they price gauge, also that if their work doesnt fix the problem they make up excuses so it doesnt seem like they erred, and you're just out the money with no solution. Advice, please, much appreciated!

 

If it leaks water, it should leak air. Try rigging an exhaust fan (fan in window w/ towels stuffed around) to opposite side of car and "sniffing" w/ a smoke stick (incense stick or other smoke generator; cigar?). Smoke should be drawn in at leak site.

Suspect that a gasket is not fitting properly allowing water to enter, or perhaps a crack in the body. Since you saw a leak while car was sitting still, the leak must have a gravity path (perhaps door jamb).

good luck