2007 Mazda4 Rear passenger side floor boards and carpet soaked in water
 

I checked all the door trunk and front seals. This only happens when driving on heavy rain and only the back passenger side floor boards. There seams to be some sort of a valve that might be malfunctioning or something. I've attached an image. If anyone knows what it is please let me know.
https://cimg9.ibsrv.net/gimg/www.maz...5f341de7cb.jpg
Rear Passenger side floor board

Do you have a sunroof?