Q: Passenger side floorboard getting wet in rain.

Hello, if the car has a sunroof that’s where I would start. This would require two people to perform a proper diagnosis. Using a garden hose you would run across the top of the car and look for a leak. The sunroof could have plugged drain tubes allowing the water to not drain correctly. Some panel may need to be removed for inspection, to see if water is draining on the backside of the trim down to the floor. If the are no leaks from the sunroof the door seals and the heater box should be checked in a similar fashion. If the vehicle is still under warranty you may want to take it to the dealer since it will be repaired free of charge. If you are outside of warranty you may want to enlist the aid of a mechanic to remove the panel and help locate the leak.