Abstract: There is disclosed apparatus and method for determining pumping head requirements for an operating pumping system by subtracting a desired delivery head or pressure from an actual head. The difference represents overpressure, and this overpressure is subtracted from a measured pump total dynamic head to establish the pumping head requirement of the system. The pumping head requirement data is recorded together with other data indicating a measured fluid flow rate. The data so recorded is in a form for plotting a system head curve. Once the system head curve is available it is possible to modify the supply system so as to avoid pumping at a pressure in excess of that which may be required for any given flow rate condition. Such avoidance of overpressure pumping produces an energy saving in the operation of the pumping system.