your drain line for your ac evaporator core is plugged up. A service station can blow this out for you.
Inspect the roof of your car and to find the source of the leak. Ask a friend to stay inside the car while you spray water over the roof. Your friend should be able to identify where the water is coming in.Check common problem areas, such as the seal around the windshield or sunroof and the drain tubes
because of condensation
Could be a head gasket problem.
you have a leak in your heater core which is attached to your radiator and heats the air inside your car interior
There is a conditioning system drain hose. Eventually it starts to leak inside of the car. Fix the hose.
If your car smells of petrol inside, and you have not been using a petrol-like solvent to clean something inside the car, you probably have a fuel leak and should have the car checked by someone able to detect and fix a leak.
if you have a gas leak.
I am assuming you have a leak inside your car. If that is the case you probably have a heater core leaking. If that is not the problem please ask again with more specifics and I'll try to pick up for you.
usually due to Engine Oil problem. or even the radiator has problem like no water inside or it is broken
make be there is a gas leak
Evaporation.
happened to me .when car was stationery no leak ,but when driving the water pump opens and you lose water .so you dont see the problem unless the car is moving.had to replace thermostat housing.