This paper presents a methodology for the synthesis of inter-plant heat-integrated water allocation network (IHIWAN) in industrial parks, to promote the overall level of resource conservation by exploiting the cooperative utilization among multiple plants. Based on superstructure, the proposed method introduces inter-plant integration strategies specific to industrial parks, involving the coupling scheme of water allocation and heat exchange. And a non-linear programming model (NLP) is formulated containing water allocation subsystem and heat integration subsystem. Accordingly, economically optimal IHIWAN is synthesized via two optimization routes respectively: sequential design and simultaneous design. Results of application examples indicate that inter-plant integration of the overall water-heat system in the scale of the park can bring about significant savings compared to the summation of integration within each stand-alone plant. In addition, simultaneous design presents preferable result with regard to overall economic performance, yet sequential design features more targeting flexibility and lower requirement on solution process. (C) 2017 Elsevier Ltd. All rights reserved.