Energy management of water distribution systems has become a tedious and expensive undertaking. This is mainly because the amount of energy required for system operation is hugely increased due to increased water usage and the requirement for a contingency plan. Although many approaches have been developed for solving these problems, there is a need to have a computer based approach to consider a combination of various problem formulations in obtaining optimum pump scheduling, minimizing pumps energy consumption and their associated costs. This paper presents a model-driven decision support tool for optimization of pump operation of water systems. Pump Scheduling Tool (PST) is a dynamic tool that can handle four different pump scheduling types (On and Off, Time control, Time-length control and Tank water level control) to generate optimum pump operation schedules for water systems. The PST has been developed as an excel-Add-in that has a user-friendly interface and it is an extension of linkage between EPANET hydraulic solver with GANetXL optimization algorithm. The user friendly interface allows easy parameters setting for a desired pump scheduling type. The tool is dynamic in that it automatically updates the problem setting and the interface for any EPANET input file. The decision variables for the four pump scheduling consist of: pump status in each time step; number of active pumps in each time step; duration in which pumps are active and upper and lower tank trigger levels. The problem has been posed as minimization of energy cost while satisfying a set of hydraulic constraints. The two main constraints are: supplying water with an adequate pressure and obtaining a full recovery of tank water levels at the end of the simulation period (i.e. water levels in tanks at the end of operation period should be equal to or higher than water levels at the beginning of operation period). The optimization problem can be set as a multi-objective (MO) or single objective optimization. Capabilities of PST have been demonstrated by application to two case studies. The application of the tool shows that PST is a powerful decision-support tool which requires no changes to the tool/interface, as the tool automatically updates all the information based on the EPANET input file. Also the dynamic nature of the tool allows four different types of pump scheduling approaches in a single framework with no changes to the tool.