If you have your air conditioning running it is the moisture that is pulled out of the air when it is being cooled. That water is then expelled outside of the car
If it is water it is probably the condensation drain plugged up with crud. If it is engine coolant it is probably the heater core leaking.
It can be one of 3 things. My first guess would be a leaking heater core considering the area where it is leaking. Are you sure this is water and not coolant. If it tastes sweet or is slick to the touch, it is coolant and you have a leaking heater core that must be replaced. Secondly it can be the windshield seal that is leaking. And 3rd it may be that the drain holes below the windshield cowl are stopped up allowing water to enter the passenger compartment.
This would be caused by a leaking heater core, or a leak in the plumbing associated with it.
the ac drain is stopped up locate under hood on passenger side on fire wall
It wasn't an impala, but I had a car that leaked and would fill the floorboard on the passenger side. It was due to a drain that was plugged with dirt, leaves, etc. that ran down from the windshield and would normally drain out under the car.
Leaking from the water pump at the back on the passenger side.
heater core leaking
drain for the air conditioner heater case could be stopped up,or a heater core leaking... !!!!
If it is leaking under the truck it is not the heater core that is leaking. It would leak inside the vehicle on the passenger side. There is a drain tube for the A/C that is under the vehicle on the passenger side, and water from that with the A/C on is normal. If it is coolant, check the heater hose connections at the firewall. If you find that the heater core is actually leaking, replace it. No other repair is permanant.
its water make sure the drain hole for the AC is not cloged
It could be the heater core leaking.
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.