I disagree HJ, if the droppipe has no leaks what so ever, there is no check valve in the pump or anywhere in the droppipe but there is one at the top of the well to hold the pressurized side of the system there. The water level is lets say 100 feet. The pump shuts off, what is going to hold that water up in that column of droppipe. I say there will be a vacuum created from the top of the pipe down to around the theoretical 32 feet. If the water level in the well is say 15 feet, then the water can drop to that depth or somewhere in between depending on the physics that I can not explain.
Make sense?
No, but if it did, then when you stick a straw into a glass of water and hold your finger over the end and then pull it out, according to your "theory" the water would drop down to the level of the water in the glass. But it doesn't. And when I want to start a siphon, I immerse the hose in the water, hold my finger over the end and then pull it up and over the rim of the sink and place it in a bucket. Again, if your "theory" were correct the water would drop back down in the hose and thus not start the siphon. And water heaters would never have to be given an air input source to drain the water out of them because it would always drop down to the level of the drain valve.