Originally Posted by mike.t
Must be missing something. I thought you did not use the water pump when connected to city water.
You don't. The pumps only purpose is to pump water from the fresh water tank.
There is a check valve on the water pump. If the pump is not used very often sometimes the valve sticks.
Add water to the tank. Remove the hose from the fill connection. Then open a couple of the faucets. Turn the pump on and off a half dozen times and maybe the valve will unstick. If it doesn't then you will have to remove the pump and take it apart and free the check valve by hand. I have never had to do it but there are a few threads that tell you how to do it. From what I have read it does not appear too hard to do. The hard part is getting to the pump to remove it. Good luck.