Water on floor

Good morning,

The first suspect is the windshield. Over time, the seal around the windshield starts to fail and rain water can leak into the car from the are of leaking

The outside air vent. That is another point of leaking. It is under the grille by the wipers. The sealer rots away over time and then the water starts to leak into the car.

You are going to need to get under the dash and try to pin point the exact area of failure. It may mean you going to a self serve car wash and have someone blast the front windshield with high pressure water while you are under the dash looking for the leak point.

Roy