Determination of an optimal location for plant installation over water transmission lines leads not only to reduction in the cost of construction and energy transmission, but also to enhancement of hydrological conditions. The main objective of implementing a water supply pipelines project is not to generate power. Various economic and hydraulic attributes also play an important role during the selection of an optimal location for plant installation. Therefore, there is a need for utilising multi-attribute optimisation methods. The effective criteria include cost, maintenance and operation, and distances from both the consumption area and the main road. In this paper, six scenarios, based on the different maximum allowable pressures (in order of 10, 12·5, 15, 17·5 and 20 bar) and the current condition, were studied. The results indicated that the fourth scenario, with a maximum pressure of 17·5 bar (1750 kPa), should be regarded as the best choice for determining the optimal location. These results were in line with the ones obtained for cost analysis. Moreover, the leakage factor was mitigated by 24·1%. It is concluded that the methods of analytical hierarchy process and fuzzy analytic hierarchy process are useful tools in outlining the proper location for installation of a hydropower plant on water transmission pipelines.