Why does the floor on the driver's side get wet when it rains?
The drain around the wind shield wipers has a drain that is plugged up. Or the drain for the A/C is plugged up.
Check weatherstripping all around. I had this problem and I checked them by looking and they all LOOKED good. It wasn't until I actually removed and cleaned and put back that the rain stopped getting on the passenger's side floor. It was by accident that I did that step but I was glad, I would have never figured. During the winter I locked my keys in the car and called AAA. The driver went in on side of leak between window and door jam and just moved the strippiing or whatever and caused the leak I think. Good luck.
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