So many different types of equipment are available to meet the many variations in pumping requirements that no attempt will be made in this paper to compare the efficiency of one type of equipment with another; that is, centrifugal pumps as against airlift or plunger pumps for wells, or horizontal centrifugal pumps against reciprocating pumps for work from surface reservoirs. Briefly stated, the value of efficiency in any pumping equipment is the monetary saving which will accure to the owner throughout the life of a pump, due to the more effective use of power purchased or generated to drive the pump, whether it be electric power purchased, or coal, fuel oil, natural gas, or gasoline purchased to generate electric power, or to operate the driving mechanism. Let us take the horizontal centrifugal pump, direct connected to an electric motor, for which current is purchased from some utility company. Depending upon its location and the size of the city, electric power can be purchased through most companies at various rates, from about 0.7 to 3 cents per kilowatt hour. We will assume that its cost is 1 cent per kilowatt hour, as this is a fair average except in very small towns. Centrifugal pumps have been developed to the point where efficiencies now range up to as high as 90 percent in the larger sizes, and for a user to purchase a pump with an efficiency of less than 70 percent would be more costly during the life of the pump than would be a pump with an efficiency of 80 percent or better, even at an increased cost, if the pump operated as much as ten hours daily