The heater core (a small radiator for your heat) is leaking, I would suggest a new heater core as they are about as cheep to replace as they are to repair.
Passenger's side? Could be a leaking heater core
Antifreeze will be leaking in the floorboard on the passenger side, there will be a smell of antifreeze through the vents.
heater core is leaking.
The heater core is leaking. The whole dash has to come out to fix it. Even master mechanics dread a heater core repair. Try some alumapowder in the radiator. Try some of this, it really works and stops leaks without plugging up the radiator.
Probably a leaking heater core.
bad door seals
If that water is engine coolant, the heater core is leaking.
your heater core is leaking i would replace it.
The most likely culprit is the heater core.. its usually located under the dash on the passenger side.. if it starts leaking you will have water on the passenger side floorboard.. also the radiator fluid will be low.. Another possibility is the drain from the ac is clogged... alowing condenced water from the ac process to dump in the passenger side floorboard.. the heater core and the ac drain are located in the same area...
Either the heater core is leaking or you have a leak at the windshield or the cowl. If the fluid tastes sweet it is coolant and your heater core is leaking.
your ac might be clogged or your draining hose is clogged. its in that area