Q&A

 Master

Sounds like your heater core is leaking, its located behind the glove box. You need a tech to double check this because its probably leaking coolant and that means your vehicle could overheat due to low coolant level.

 Journeyman

There is only three places where the water can come from and your going to have to determine which it is. The heater core can leak into the floorboard,this won't be plain water but coolant mixture. The carpet will feel slimy/oily if it is coolant. The A/C could be stopped up draining back into the car, or a water leak from rain. A rain leak could be from the door, windsheild, body seam, etc. The carpet and maybe the seats may need to be removed to let the carpet dry to keep from mildew forming under the carpet. May sure you get it totally dry before reassembly.