Static head measures the total vertical distance that a pump raises water. It has two components: static lift and static discharge. Static lift measures the elevation difference between the water source and the pump, while static discharge measures the elevation difference between the discharge point and the pump. Pump head describes pressure in terms of distance, usually in feet or meters. Pressure can be converted between units of distance and units of force per unit area: 2.31ft of head equals 1 psi (pound per square inch) of pressure.

Subtract the elevation of the water source from the elevation of the centre line of the pump to determine static lift.

Subtract the elevation of the centre line of the pump from the elevation of the discharge point of the water to determine the static discharge.

Add static lift and static discharge to obtain the total static head.

#### Tip

Ensure that the signs are correct throughout your calculations. For example, static lift will be positive if the water source lies below the pump, but negative if it lies above the pump. Drawing a diagram of the system may help you visualise the elevation changes.

#### Tips and warnings

- Ensure that the signs are correct throughout your calculations. For example, static lift will be positive if the water source lies below the pump, but negative if it lies above the pump. Drawing a diagram of the system may help you visualise the elevation changes.