I have a serious trunk leak even when the car is sitting still for several week. on 2009 Chevrolet Cobalt

I inherited my mother's car when she died. First I noticed things left in the trunk were damp, now I find several inches of water around the spare tire and battery. Even when the car has not been driven for several weeks there is more and more water in the trunk. I noticed there was a gap where the rear antenna was and had that replaced but it did nothing to stop the water. I took it back to the dealer who said it was the rear window and then I took it to an auto glass installer and they said it is not the window. I do not have a skylight in the car either. This seems to be a flaw in the design to me. Has anyone found out what is causing this large amount of water in the spare tire/battery area?

by in Matawan, NJ on January 20, 2013
2 answers
ANSWER by on January 20, 2013
check the rubber seal around trunk lid
ANSWER by on January 20, 2013
poss yrk seal has flattened and leaks or is torn