Water is a key element for the normal functioning of the industry and the society

which is now gravely concerned about.Though the purpose of water-using network (WUN) synthesis is to reduce the freshwater consumption and the wastewater discharge

the network reliability is worth considering for the sake of reducing the repair and maintenance cost so as to reduce the total annual cost.The WUN design has a significant impact on reliability issues.So the issue discussed in this paper is to integrate the reliability analysis into the WUN synthesis problem.The first step is to determine the reliability of the water-using system.Divide the whole system into possible subsystems

which means that the whole system maybe include one or more different subsystems.The reliability of WUN is evaluated in terms of the subsystems.For subsystem whose degree of reliability fails to meet the process specification

the dividing of the system is not accepted.Then the minimum freshwater requirement should be considered.A non-linear programming mathematical model is established to solve the problem.Take all the accepted situations into consideration.Choose the one that consumes the minimum freshwater.At last

an example is used to illustrate the application of the proposed method.The degree of reliability of the system is 0.904 which meets the process specification and the minimum freshwater is 142.88 t·h-1 with 2.27% increasing compared to the situation which takes no consideration of reliability.This result means this method is effective and could be accepted by industry.