This paper presents a new design method for regeneration recycling water-using networks with internal water mains by using the concentration potential concepts (Liu et al., 2009a. AIChE J. 55, 374-382). The precedence order of the processes is determined by the values of the Concentration Potential of the Demands (CPDs). The formation of the internal water mains is determined by the values of the Concentration Potential of the Sources (CPSs). An initial network with one regeneration unit is developed based on the concentration potential values. The final design can be obtained in a few iterations by adjusting the initial network. The results of the illustrated examples show that the designs obtained in this work are comparable to that obtained in the literature with computer programming methods. It is shown that the proposed method is simple and effective. It can be concluded that the concentration potential concepts are useful tools in design of water networks. (c) 2013 Elsevier Ltd. All rights reserved.