I few months ago I noticed that there was a water stain on my backseat, which is odd because no one is ever back there. I ignored it though, until my back floorboards were getting wet as well. I opened up my trunk then and got to the spare tire only to discover that there was a good inch of water in there (and the tire was covered in rust and mold...). I then decided to take everything out and put plastic back there to at least catch the water, which I thought was getting through the weatherstripping. We had a storm last night and it poured rain for a good few hours so this morning I went out to see if I'd caught any water. Somehow the water is still coming in, but the top of the plastic is dry. The water is collecting under it - although the backseat has stayed perfectly dry since I have put the plastic in the trunk.

Just wondering if anyone has had a similar problem or would have any ideas as to how the water could be getting in.

 

its the seals on your taillights my did that to so i used clear weather striping on the seals and that stoped the water from soaking the floors.
look under your spare tire and it will be full of water you need to take out you back seats and pull the carpet out of your trunk so you can dry up all the water

 

Tailights seals for sure. Make sure your spare tire well isn't a pond. I stripped my entire interior to completely dry everything out and make sure no mold would form.