Most ANYTHING can leak and there can be many causes for the leak so there certainly won't be a SINGLE way to fix it. When they're made properly and maintained in good condition they don't leak (just like your main roof).
I've only had mine leak twice. (Uh-oh. NOW I've done it!)
One time was during a monsterous thunder/rain/hail/tornado storm that we went through early this year, and the second was when I power-washed the exterior. Each time it was a very small amount and easily cleaned up, maybe a cup of water or so on the carpet. Not bad!
-Lab
2004 Nissan Titan SE Crew Off-Road & Big Tow, LT Tires
2006 Jayco JayFlight 29FBS
Equal-i-zer Hitch
Prodigy Brake Control
Member of clubtitan.org
"Hershey" the Chocolate Lab (Best Friend)
"I asked God for a true friend: He sent me a Labrador Retriever."