I have a 2004 subaru legacy sedan and I was washing my car this weekend and noticed that the rear lens had a slight bit of moisture in it and a little bit of water, but seems that is has dryed out now and no more water nor moisture. Seems wierd to me, to much water pressure when I washed the car? Sprayed top much at it? Did fine some water in the trunk on the mat but nothing below where the spare tire was. So I will keep my eye on it when it rains, I know that I have not seen any water in there before nor leaks but I would appreciate some feedback and helping me out to figure out what to do, or is there anything to perform to figure it out. Thanks

Check the quality and fit of the rubber molding seal around the trunk lid to see if it is possibly split, or has come loose. Readjust or reglue as needed. That may fix the problem of water entering the trunk.

 

As far as water in the tail light lens, that too could result from a bad trunk seal, crack in the lens, or poor lens seal. You may want to apply some "Seal All" around any suspected places where water could enter the tail light unit. Seal All is a clear contact adhesive and sealant. You could also use clear silicone bathroom caulk to do the job. It is available in any hardware store.