The evaporator for the a/c is located on the passenger side. There is a hose that connects to the evaporator and goes through the floor board to the outside of the vehicle. This is to allow the water to run out.
If this hose gets knocked off the evaporator or gets clogged it will usually leak onto the passenger floor.
Make sure someone didn't accidentally kick it off. If it's connected, take it to a shop that can blow some air through it to remove a clog. Good Luck.
〉 Answered on Jul 17th, 2007 by Lori Johnson, Owner and Instructor at Ladies Start Your Engines