I have a 2001 3.5L TJ Sedan. Rainy here today so needed the de-mister going (with the air con on). After returning to the car after a couple of hours i noticed a pool of water in the passenger side foot well. The passenger window had been closed and there was no indication of any leaks from anywhere but from near the floor. Has anyone had this problem before? Sounds like i have some sort of leak in the air con unit but I would have thought that this would come from somewhere behind the dash rather than emanate from the floor. I suspect i will need to take to an air-con repairer. Has anyone had a similar experience?

YES! this was in my TJ VRX - it only happened when it would rain heavily, or anything more than a sprinkle really, there would be a puddle on passenger floor even though everything seems sealed off etc.... unfortunatley i never figured out where it came from???

check for a blockage in the evaporator box drain pipe. Also check for excessive leaf litter under your front deck garnish, particularly on the sides where the water drains away.
If these are ok then you may have a windscreen leak.
are you sure it is water and not coolant, because the heater core seals are known to leak.

Ash, its definitley water. Where is the evaporator drain pipe? Suppose i can google. Car does get a lot of leaf litter. This could be the cause. Cheers

IIRC, passenger side lower firewall, in the engine bay

Check that the plastic guard beneath your front left windshield wiper on the outside isn't lifting away from the window. If it is, replacing it with a brand new one from Mitsubishi ($25) will solve your problem :)