A picture would be nice are you sure you are connected to the city water inlet? It may be that our check valve on the potable water pump has stuck open and your filling the tank and its over flowing. Also remember even when at home connect a pressure regulator to your supply hose some city systems have very high pressure.
Jake my sidekick (yellow Lab) 10/04 - 05/20
2017 RAM 2500 CC 4X4 Cummins Diesel
2016 Flagstaff 26 FKWS
AF&AM & El Korah Shrine of Idaho