So I opened the barn doors to the suburban on Saturday to the lovely smell of mildew. Found out the rear floor was soaking wet under the liner. Floor was dry in the passenger compartment. Right side of rear is what was wet. Left side, by the spare tire, was dry. Thoughts on what could be causing this? No spilled water bottles (that was the first thing I checked). It was dry 2 weeks ago. It rained 2 days last week.