Leaking heater core
Probably on the passenger side, under the glove box. The heater core is leaking, you should probalbly smell something sweet with the car running. That's the anti freeze.
check your pinion seal
If it's the front passenger side ,I would say your heater core is 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.
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
This would be caused by a leaking heater core, or a leak in the plumbing associated with it.
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.
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.
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.
Leaking from the water pump at the back on the passenger side.
My 2002 Wrangler came from the factory with the same problem. There is a seal or gasket around the main body or "Tub" -around the fire wall or top of the hood-and it was leaking there and dripping under the dash. They had a factory rep replace it and it hasn't leaked since. The other possibility that older Wranglers have is they leak at the gasket under the windshield, but the 2002 seems a bit young for that so the other is more likely in my opinion.