Hi ive had a honda hrv since 2017. Still going strong. After finding water in the rear boot well 2 inches of the stuff. I tried and checked everywhere to find out where it was getting in. But to no avail. But it had been 2 possibly 3 yrs since id been under there. I that time ive breathed a lot and put loads of wet and damp gun bangs in car. Proper wet gear.
While looking for the leak i removed the carpets from the boot. Guess what? There water proof. All the water was on the carpet not on metal work. But to my surprise under the carpet theres two drain holes that were clear so it was the carpet that was stopping the water getting out. To top it off there is no or very little ventilation in the cars body work. Even the back lights are sealed away from the interior of the car. The car doors are double sealed to. So ive come to the conclusion the damp comes in from what i bring in. Ie. breathing and being wet.
I checked the air con and the windows the sun roof
Everything. It don’t leak. Its what i let in.
I have replace the carpet in the boot. With just a mat. I haven’t had the problem since.