Cadillac Repair: Floorboard leak, fleetwood cadillac, soda straw

Question
I have a 1995 fleetwood cadillac that has water leaking in the passenger side front floorboard. I can see dripping water up under the carpet. What can I do to find out what is causing this to leak?

Answer
If you put the vehicle up on a lift so you can access the small condensation drain hose located at the bottom of the evaporator casing it is plugged up with crud. All you need to do is clean it out with a soda straw or something SOFT that you can push up inside the tube to release the blockage.