[bcpianoman]

Water in the trunk is a common problem but it might be an easy fix. When mine leaked it was because of the power antenna drain or the sunroof drain pipe. They are plastic hoses that can be checked (more by feel than by vision) behind the trunk interor on the driver's side. Remove the access panel to the driver's side tail light and feel around deep towards the front of the car. You should feel two plastic lines, both with joints that are connected only by a slight interference fit (different sizes of course). With mine, one of the plastic lines had separated. All I had to do was reconnect one of the lines where it had separated by reinserting the top portion into the larger bottom portion and voila - problem solved.

If that isn't your problem then do a search. There are a number of threads here dealing with this problem.