When the switch is closed on the hose and the pump is up (so water is going into the tank) the green pump always allows water to drip out from the bottom. The water at my house has about the highest pressure possible in the area since the pumping station is just a few houses away. Under the high pressure, the green pump always lets water out. if it doesn't then you probably are tightening the bottom too tight. All the connections should be very tight, but the bottom plug on the hose should be a little looser.