This International Standard sets the requirements for conducting and reporting the results of a pumping system energy assessment (hereafter referenced as assessment) that considers the entire pumping system, from energy inputs to the work performed as the result of these inputs. The objective of a pumping system energy assessment is to determine the current energy consumption of an existing system and identify ways to improve system efficiency. These requirements consist of organizing and conducting an assessment, analysing the data from the assessment, and reporting and documenting assessment findings. This International Standard is designed to be applied, to open and closed loop pumping systems typically used at industrial, institutional, commercial, and municipal facilities, when requested. This International Standard is focused on assessing electrically-driven pumping systems, which are dominant in most facilities, but is applicable with other types of drivers, such as steam turbines and engines, and drives such as belt.