Why would water enter a 2002 BMW 325 when it rains into the passenger foot floor?
sounds like there could be a plug knocked out of the firewall on the passengers side which would allow water to enter when you hit some puddles and splashed up
What is the cause of a puddle of water in the rear passenger floor in a Ford Focus It happens only when it rains and even when the car is stationary?
There are details you didn't give us. If your washroom floor drain only clogs when it rains, that may be a feature, not a bug. There are backflow traps that can be installed in floor drains to keep them from backing up and getting sewer water all over the floor. If your washroom floor is in the basement, the fact that it's clogging when it rains may be saving you from a big, nasty cleanup…