Dock side water causing fresh water tank to fill

[five o clock somewhere]

1988 415 searay aft deck.
High-pressure and low pressure 12v fresh water pumps with pressure tank.My fresh water holding tank is filling with my dock side water hooked up and turned on? It is dripping out my over flow hose.I believe the 12v fresh water pumps are to stop this from happening? One of the two pumps must be allowing water to enter the holding tank and over fill? Anyone had this issue?

 

[hughespat57]

You can rebuild the pump if a kit is available that should fix the valves seeping back to the tank.
Or just add a check valve after the pump.