One of the problems that I had with my rig was an RV low point water leak. The problem happened when I tried to connect my water line to an external water source.
The leak made it so I was not able to pressurize my water tank. This was a problem when we wanted to take our rig out on the road for a long weekend so I needed to find a way to repair it.
Please note that every rig is designed differently so what I did may not be the best solution for repairs to your rig. My hope, however, is that seeing what I did to repair my coach, will help you think about your own rig and help you find a way to get your problem solved in the best way possible.