عنوان مقاله [English]
Aging in urban water distribution networks would lead to an increased number of bursts. Beside leakage control and pressure management, the last solution in this regard is rehabilitation and replacement of main pipes in the networks. In this research the optimum time for pipe replacement in water distribution networks is obtained by an optimization model applying genetic algorithm, which minimizes the present value of the total costs. According to the obtained results, the economic constraint increases the total costs of replacement while the hydraulic constraint would decrease it. Additionally, considering the cost of water losses and grouping replacement would increase the total costs.