Water leaking into trunk
 

I am dealing with a 2015 Camry SE and I found a concerning amount of water on the drivers side of the trunk. It was discovered after a detail and after we had a very windy rainstorm. I also discover a vent with a flap in the inner fender right by the water. Is it possible that this was all caused by the windstorm blowing rain into the car ?? The water was very clean, indicating that it was fresh. It has not been setting in this area for very long. The is no rust where the water was sitting.

Yes, the vent you found can leak water into the side trunk well.

The bumper cover needs to be removed to access the vent.

Some owners have drilled a small hole in the bottom of the well to allow the water to have a drain out point.