It is undisputable a modern city which has active society required a water distribution infrastructure in fulfilling its basic and essential need of water during the community daily activity life. The water is distributed to residential, public facilities such as schools or universities, central business district, and small to medium industry. Unfortunately, the water infrastructure does aging respect to time, due to the complexity of urban activity or conflicting with other urban utilities, high growth of water demand, the human activity such as traffic load or construction work, or even the unfriendly environment those may damage the pipe or even deteriorating the damage. In other side, management of the water company always reports the un-accounted water loss every year about 10-30%. The water leakage flow rate is difficult to be measured in the field, often the leakage is undetected due to it is buried below the ground surface ( e.g back leak), which occur somewhere in the middle of pipe.
Fortunately, the development of computer and software can provided some way solution of the problems above. The EPANET-WaterNetGen software packages have the capability in modelling and estimation of leakages within a water distribution network. Through a robust technical approach “Pressure Driven Analysis”, the leakage especially back leak can be modelled and estimated accurately. Prior to estimate the water leakage flow rate, two leak parameter  and  is defined. Technical Performance Assessment of the hydraulic behavior is also carried out in the study, Therefore the software is used to help describing the current hydraulic behavior of pressurized pipe network within the Taichung Water Distribution Network.

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