RV Repair: Water fill on 92 Mini winni 27 rq RV, mini winni, water leaks

Question
When hooked to city water fill, I noticed that the water holding tank fills and comes out the holding tank fill door, and water leaks at the pump.???  Is there a check valve or one way valve on this system to keep city water connection from filling the water tank?
Thanks for your time.   David Camper

Answer
yes, there should be a way to separate the two.  I believe the pump would do that.  I wonder if your pump is bad and allowing water to pass and leak.  

If the pump leaks one way, does it also leak when the water tank is filled?  Pump may be cracked in the head.  

If the pump does not leak while pumping holding tank, or while not pumping but water in holding tank, and if the pump works; then you may want to buy a manual valve to isolate the two water systems.  Otherwise, the pump may need replacing.  

Good luck