2005 Yukon xl leaking water in rear floor

[rancher352]

My 2005 XL just started leaking water on the passenger side rear floor. I have checked all door seals and gaskets which are perfect. I found the rear a/c was on, which i must have bumped while cleaning the car 3 days ago. Someone suggested the rear drain hose might be clogged due to my living on limerock roads. I can't find any schematics showing the location. My Yukon is always parked under roof except when traveling. Any help would be great.