Water is the most valuable source for human life. Egypt is one of the driest countries facing an enormous shortage of potable water especially with the population increase and limited water resources. It is becoming aware of the need to preserve water and sustainable water management. Potable water supply pipes are important for delivering water to consumers and serving as the last process between the treatment plant and the consumer. Water demand can vary periodically over the course of the day and for the same average daily demand, the peak value of the demand pattern can vary. These variations in peak demand can have significant effect on the hydraulic behavior of pipes network, water quality, and energy consumption through it. A significant amount of cost is spent on energy consumption in the water supply pipes network. In this research, the effect of water demand pattern variation on hydraulic behavior, water quality and energy consumption in water supply pipes network is studied. EPANET2 software was used to perform the hydraulic analysis through extended period simulation through a hypothetical water supply pipes network. Five patterns of demand variation were adopted in this analysis called pattern demand for big city, village, rural area, industrial zone and hotels. It was found that the type of demand pattern has a significant effect on velocity through the different pipes and pressure head of the different nodes and chlorine decay through the network.