If it's not related to outside weather, then check the drain for your AC condenser.
Heater core is leaking.
It is either a leaking heater core or the air conditioning evaporator drain plug is clogged.
heater core may be leaking or hole in floor
your windshield seal has failed
There is a small radiator inside between the driver and passanger sides for your heater. It is probably leaking there.
more than likely the windshield is leaking and the water is running behind the dash onto the floor.
check your blower motor, located under the dash board. its on the passenger side. if the leak is on the drivers side, i have no clue. but my hubby's car is leaking water from the blower motor on the passenger side. found out at the car wash...
Leaking heater core or leaking windshield. If it taste sweet, it is coolant and the heater core is leaking. i have a 96 and i found that the fire wall has rusted out from the drain holes under the hood and the rack has pulled oof This is a very common problem with the 92-96 Berettas, I am almost positive that it is NOT a leaking windshield or leaking heater core. The water leak is because of a factory defect. There is a gap in the seam in the fresh air inlet under the hood in the cowl area(passenger side). The water usually ends up on both passenger and drivers side. I have had 3 Berettas and they all have had this problem!
Condensation from air conditioning?
If it is just plain water, then you have either a leaking windshield or more than likely a stopped up A/C drain line. Look under the car passenger side and find the drain line and unclog it. If, on the other hand you have coolant leaking, then you have a leaking heater core, which must be replaced. Taste and smell the liquid. If it smells and taste sweet it is coolant and not just water.
Are you running the air conditioner? If the drain line is plugged, it will leak water (condensation) onto the passenger side floor.
with a towel