This research is devote to a description of the methods available for the analysis of unsteady flows in pumping stations and their associated hydraulic systems. There are two basic approaches to the solution of unsteady internal flows: solution in the time domain and in the frequency domain. The traditional time domain methods for hydraulic systems are the most important that many unsteady hydraulic system problems can and should be treated by the time domain or “water-hammer” methods. Another approach is frequency domain method, it is sufficient to recognize that one practical advantage of this method is the capability of incorporation of experimentally obtained dynamic information and the greater simplicity of the experiments required to obtain the necessary dynamic data, the disadvantage of frequency domain is that the method are limited to small linear perturbations in the flow rate. Two types of networks are tested in this research, example (1) represents very simple network without any apparatus, and example (2) network containing some complexity and containing intakes, valves, and other apparatus. The results in example (1) identical for both methods, but in example (2) the results showing clear differences for the two approaches.