A pumping system in which a pump (5) is controlled by a programmed controller (22) in response to input signals from an inlet pressure transducer (3) and an outlet pressure transducer (15) and in certain circumstances inputs from various flow sensors (4,19). The controller (22) can be programmed to allow the pump (5) to prematurely operate before an outlet pressure reaches a low pressure threshold, when usage of the liquid is high. The controller (22) can be programmed to detect a lack of prime of the pump (5), to restore prime once the pump (5) has lost prime, and to prevent successive on/off pump cycles when the outlet flow is continuous and at a moderate or low level.