Ford Repair: What could cause the front passenger floor to be soaking wet?, rain water, plain water

Question
I just purchased a 2001 Ford Focus from a dealer.  It has been raining but the windows and door have not be left open.  When I went to get my bag off the floor on the front passenger side, the mat was saturated.  Any ideas what may have caused this?  Could it be the beginnings of a mechanical problem?
Thanks for any info you could give.  

Answer
Donna-

  First of all, check (by smell) if the wetness is plain water or coolant.  Sometimes when a heater core goes bad and leaks it spills out onto the floorboards.  If it's plain water (like rain water), then it could just be a weatherstripping leak that's letting water in.  Hope this helps.

Steve