100 Level

101 - Chapter 4

PSI and Head


The pressure any given pump creates is constant and can be measured in pounds per square inch (psi), but pressure is easier to visualize in feet of Head, the maximum height in feet that a pump can push a column of water. In water gardening, most pumps are rated by Head Height rather than psi, so it’s an important concept to understand. One psi will push a column of water 2.31 above the surface of the water the pump is sitting in, which is the same as saying that the pump produces 2.31 feet of Head. The Shut-off Head Height is the maximum height the pump can push water to; a 23’ Shutoff means the pump produces about 10psi.