After rain, passenger side floor, front & back, flooded; no visible opening

Do you have a sunroof? these drains are notorious for clogging up and overflowing. Unfortunately not only do you have to clear out the drains, the carpets need to come out. I would ask the dealer to "diagnose". mine did the same thing and they fixed it for free because of some lawsuit that happened. My car is way out of warranty too.