Abstract
Today, one of the major problems of the water production and distribution system of water and sewage companies is the wastage of a large amount of water due to accidents, and the amount of water without revenue in developed and developing countries is less than 15% and more than 30% of production amount is water production. All over the world, the demand for water is increasing, but the resources are decreasing, therefore, the purpose of the research is to identify the effective factors in the wastage of water in the distribution networks. In general, water loss is classified into two groups: apparent and real loss. In order to obtain the effective factors in the actual water wastage, in the first stage, the values such as the volume of water losses, the number of incidents, the length of the network, the population and the pressure of the network were analyzed in the period of 1995-1999. In determining the weight of parameters in water wastage, the hierarchical analysis method (AHP) has been used. The results show that the water loss in the water distribution network with the criterion of water pressure difference in the network with a weight of 0.395 has the most importance and the accident rate criterion with a weight of 0.04 has the least importance. The results of this research can be used for planning to prevent  prevent water wastage in the urban drinking water distribution network in the future.