After driving during heavy rain passenger floor mats were found soaked with water. An immediate investigation with a bright work light found water dribbling from the square heater box opening next to the fan housing onto the plastic console and passenger floor mats. This happened twice previously and only after driving through heavy rain; however, on the 2 previous occasions I found leaves cluttered around the wiper area/cowling and assumed this was the cause. Also, I waited too long to investigate the problem so there was no evidence of water dribble from the fan box, only a wet floor mat. Of course this should not be happening.....air should come from the fan/heater box, not water !! My concern....is there a potential to cause an electrical short with the fan or controls. A web search did find 1 hit on this problem, for a different year Rav 4.....rain dripping from the fan box soaking the floor mat. This posting indicated the problem is with a poorly fitting cowl in the wiper area (from a retired Toyota mechanic I think).....sounds like a quality control problem. I have not brought this issue to the dealer and will along with other complaints posted recently on this site. Toyota continues the slide.....overwhelmed by product design issues and manufacturing quality issues.