Pumps

Lift limitation on fluid pumps

The lift limitation of a pump is just the height of a column of water that can be supported by a vacuum (can't suck any harder than that!). This will vary depending on the weather (how barometers were first found to be useful). The atmosphere has about 15lbs/sqin pressure 'at sea level' so this is what is 'pushing' the water up the column that has a vacuum on the other end.

A jet pump is a neat way to get around this since it takes some of the pressurized water on the output side of the pump (where it can PUSH really hard) and sends it back down to PUSH up on the water at depth, minimizing the height that the pump has to PULL. But this will not work for the really deep wells.