Hello, my name is Brian and I own a 2012 Tahoe LTZ. We had some bad rains if you can believe it in Southern California. I drove the Tahoe and heard water sloshing around. To my surprise water had accumulated in the right rear passenger door and was sloshing around. How can this be and has anyone else had this happen. And before anyone chimes in, no the doors were fully shut and the window fully closed at all times prior to the incident. I don't use that door much.
Please advise

Please advise