Where does the water come from in a sump pump hole?

Ok, I know the answer is rain and ground water. But, I just replaced my sump pump and noticed two pipes that lead into the hole (embedded in the cement floor) that had water coming out of them. Where do those pipes typically bring water in from? Foundation water? I also have a big fat pipe sticking through the lid of the sump hole that I am guessing is for ventilation or radon or something. Thanks!