What Is Pump Head?

The pump must overcome elevation, pressure, and friction in the piping system. Static head comes from level or pressure differences when there is no flow. Friction head comes from liquid moving through pipes, valves, fittings, and equipment.

As flow rises, friction usually rises. A partly closed discharge valve adds resistance. A fouled pipe or clogged check valve can do the same. The pump settles at a point where its ability matches the system resistance.

Operators often use suction and discharge pressure to estimate pump head. The exact calculation must account for gauge location, liquid, and elevation. For an introductory check, a change in pressure at similar flow can still warn that the system has changed.

Head is not the same as discharge pressure alone. Suction pressure can add to or subtract from the pump's work. The height between gauges also matters. Use the plant calculation sheet when a formal pump test is required.