Look on the pump's meter and determine the amount of water pumped and kilowatt-hours consumed. The volume of water might be measured on the pump in liters, so that will have to be converted.
Divide the number of liters by 1 million to determine the number of megaliters. For example, 4 million liters would be 4 megaliters.
Divide the number of megaliters by the number of kilowatt-hours to calculate megaliters per killowatt-hour. In the example, if it took 800 kilowatt-hours, then you would calculate 0.005 megaliters per kilowatt-hours.
Invert this figure to calculate the number of kilowatt-hours per megaliter. In the example, you would get 200 kilowatt-hours per megaliter.