If your vehicle has a sunroof, the drain tube may have popped out of it's outlet. This tube runs down inside the roof support on the passenger side of the windshield, running down just in front of the passenger door behind some plastic. I have a 2003 XRS. It had a really musty smell that we traced to the front passenger side carpet. When I pulled the carpet back, it was dripping wet. The air conditioner drain hose had pulled away from the firewall and was draining into the floor pan. I replaced the tube into the hole and have not had any trouble since.
Check the front passenger floor pan toward the fire wall.
Floor at passenger side? Could be heater core needs replacing Other possibilities: door seal windshield seal
Are you running the air conditioner? If the drain line is plugged, it will leak water (condensation) onto the passenger side floor.
It's just water. It is normal. When you run your A/C, the part under the dash that gets cold, called an evaporator, gets water accumulated on it. Its just like when you have a cold drink, moisture from the air condenses on it and drips down the glass. The same thing happens to your evaporator. There is a little black hose that sticks out under where your passenger's feet are. This hose is there to drain the dripping water out, so it doesn't fill up the floor inside the car.
heater core may be leaking or hole in floor
Is it blood, oil, water, or urine?
There is a drain on the outside firewall that is clogged.
you could have a heater core leaking or your windshield is leaking and the water is running down behind the dash and onto the floor.
bad heating core
Probably have a leak in the heater core>
Heater. Core
Water on the passenger side floor would be a plugged up AC drain. The drain is located under the hood, at the lowest point on the HVAC box on the firewall. However if the floor is wet with engine coolant, the heater core is leaking.