Ok, my father in law wanted to put a shower outside for the pool. He decided to attach it to the well outside. The only way he could turn the well pump on was from a breaker and did not want to have to turn a breaker on constantly just to use the pump. i told him to put a pressure switch in. I installed the pressure switch and the outlet side of the pump along with a PSI guage. When i turned the pump on it began to run but the pressure would not build up past 50. And when I tried to adjust the pressure switch to go lower it would just kick on and off and the pressure guage would bounce all over the place. I was told it could be a couple things. One being that the inlet pipe needs to have a check valve installed so the water cant go back down the well. Another suggestion was to prime the well pump. I will try to prime it again but it does have plenty of water flow coming out when the pump is on but when i turn it off it drops automatically down to 0. not a slow drop but a quick right to 0 drop. The pump doe not have a external tank. It goes right from the well through the pump into the outlet pipe. Anyone know why the pressure wont build up?