Water coming out of inlet port on trailer?!

I installed a new water pump in my trailer today because I could not get the original pump to pump water. We put water in the fresh water tank for this process. No hose is connected to the inlet port on the left rear of the trailer where I think that the city water connection would be. I think that I connected the hoses yo the pump correctly. I flipped the pump switch and now receive water to the kitchen sink as well as to the bathroom sink. The problem is that water is bring pumped out of the inlet port where you would connect the water hose for city water. Did I do something wrong, of is there a valve that had gone bad at the inlet port? Or.....?? Please help! Thanks in advance!