Thought I'd put my 2-cents in here. I have a 2011 Silverado crew cab we've have had some heavy rain here in the Pacific N.W. When I opened the front drivers door and the rear door on the drivers side I could hear a lot of water sloshing around. The two very small drain holes on each door were plugged I took a heavy duty needle pulled out some of my dogs hair and finished with compressed air if not found I'm sure it would have leaked inside the truck.