Hi, I have the same experience with my pickup. There are two possible sources of the water seeping in. One, from your evaporator (aircon) if the flooring becomes wet even when it is not raining and if the passenger side is the first area to get wet. The solution, have it checked with Mang Mario or from other reliable AC shops. The other is when the flooring becomes wet only when the car gets soaked in rain. The most likely culprits in this case are the rubber trims (door and windows) of your car. To address this, you need to inspect trims and seal them with a Silicone sealant or you can have it checked by your favorite detailing shop. You can also have them inspect the flooring under the carpet for holes etc.