I believe that the pump automaticly acts as a check valve when you are hooked to a city water connection, not allowing water to flow past it and fill the fresh water holding tank. Was the camper winterized with antifreeze, and if not, is the camper in an area where it couldn't freeze in the winter? I suspect maybe it froze and something in the pump froze and cracked, causing it to leak...
'97 Jayco Eagle 314BHS
'03 Tahoe LT 5.3L