Water network (called also water allocation) problem has been addressed in more than 200 papers to date - see recent reviews by Jezowski (2010) and Foo (2009). Though various solution methods have been developed they all have some limitations. This paper addresses water usage network with regeneration processes. Multiple contaminants and two types of water using processes are taken into regard. Simultaneous one stage optimization method was developed to synthesize the network. In order to solve complex MINLP formulation we propose to apply metaheuristic optimization - adaptive random search method. The paper contains detailed solution algorithm. Several examples with specific features are solved to show efficiency and flexibility of the approach. (C) 2011 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.