i have a 2016 catalina floor plan number is fs223. when i am connected to city water at the park, it fills my fresh water tank, where do i need to start to look for what is causing this too happen?
I've never had city water get past my pump and back into the tank. If if did I'd do what CharlesinGA says.......if that didn't work, I'd put a Shark-Bite check valve on the downstream side of the pump and be done with it.