Is your fresh water tank overflowing? Not joking, Many Rv's have a "Quick Fill Valve" these work one of two ways.. Both the same if properly operated
IN the proper operation you set it one way it fills the Fresh Tank, the other way it passes water to the RV... But what happens if you set it half way in between (This is where they split)
Mine, allows the water pump to "Recurculate" water back to teh fresh tank, Both sides are "half open" city water will also divide and overflow the fresh tank as well as low pressure to the house.
Some, I suspect, may not pass water at all if set to the "Mid point"
ALso as others have suggsted check any screens (inlet washer screen) filters, make sure the City Water is ON. and so on and so forth.
