A jockey pump, or a pressure maintenance pump, is a small apparatus that works in conjunction with a fire pump as part of a fire protection sprinkler system. A jockey pump is designed to keep the pressure elevated in a fire suppression system so that the main fire pump is prevented from running unless absolutely necessary. It consists of a motor, a pump, and a controller.

When a fire sprinkler is exposed to heat, the pressure in the system drops significantly and a valve opens, releasing water. The main fire pump provides the pressure to the system that creates water flow when this occurs. The jockey pump maintains the normal pressure in the system at an artificially high level. When just one sprinkler is activated, the pressure drops so drastically that the fire pump starts working, and the fire department is alerted. The jockey pump works as part of the fire pump’s control system, "riding" on top of the larger pump like a jockey.

There are two basic types of jockey pumps. A positive displacement regenerative turbine pump uses low horsepower to generate high pressure at a low flow rate, but it operates on close tolerances. When these tolerances degrade even slightly, the pump may no longer be able to generate enough pressure. It also has the potential to produce a very high pressure, and cause pipes to burst. The other type of pump, the centrifugal pump, is a simpler machine, and is not subject to such tolerances.

A jockey pump usually is run by an electric motor and should never be linked to power within the fire pump controller. Both three-phase and single-phase electric motors are acceptable options. Single-phase motors have lower horsepower capabilities, which may in turn limit the pump's performance, depending upon the amount of pressure and the flow required. Nevertheless, both three-phase and single-phase motors typically allow the pump to function in the same way.

The controller is the component that causes the jockey pump to start. It is activated by a drop in pressure or by a selector switch. A three-phase controller includes these pressure and selector switches, along with a contactor, circuit breaker or a disconnect switch, and overload protection. A single-phase controller may be just as complicated, or it may have only pressure and toggle switches. Both are acceptable options for use with a jockey pump.