Are you sure it's not coolant?
If it's coolant on the drivers floor, then you have a bad heater core.
If it is water, then you'll have to find the AC drain hole (pass side firewall) and gently blow compressed air into it to unplug it. You may run into the same problem later because the debris is still in there. To fix it permanently, you will have to open the evaporator compartment and clean it out.
The best way to tell if it's draining properly is to run the AC on max and check the ground below the passenger firewall for dripping water.
If there's quite a bit of dripping water, then it's draining properly. If you have very little or no water dripping, then the drain hose is plugged or partially plugged.