Sudden changes or the stoppage of flows in pipeline systems causes a hydraulic transient or water hammer event. A large proportion of water supply systems have traditionally been analyzed and designed without the consideration of the potential consequence of hydraulic transients. Hydraulic transient is not studying well in the period of water supply system design and the system failure is frequent because of additional pressure generated during operational problems. The hydraulic transient usually happens when a flow control component changes status (for example, pump stop), and this change flows through the system as a pressure wave. Pump run down could be planned shutdown or sudden shut down due to power failure results in column separation. The primary objective of this study is to determine the values of transient pressures that can result from shut down of pump and to avoid the resulting unwanted pressure or reduce if avoidance is not possible with surge protection device. The study also aims to provide insights for engineers how to incorporate water hammer analysis, which has been commonly neglected from hydraulic design of water supply system. A number of methods have been used to analyze hydraulic transient problem but this study employed only Bentley HAMMER v8i software to calculate and simulate transients in transmission main pipelines. Several scenarios and different time delay for shutdown of pumps were applied to the simulation without surge protection device and with surge protection device to study the transients. Analysis of transient phenomena in Gonder malt factory and Sekota town transmission main pipeline showed that there is down surge and upsurge pressures due to pump trip and this extreme pressures are additional loads for the system and the system will be fail. Because of analyzing the transmission main pipelines with hydro pneumatic tank the adverse effects of transients has been reduced by reducing pressure fluctuations. Installing also a pump which have a greater pump inertia which is a gradual closure of the check valve in a system is quiet important to control hydraulic transient problems.