An efficient initialization strategy is developed in this work to solve the NLP and MINLP models for synthesizing water-using networks with multiple contaminants. A fairly good estimate of the optimal solution can be generated for any given problem according to a simple calculation procedure. Two published examples are adopted to demonstrate the effectiveness of the proposed approach. The optimum solutions obtained in this study are at least as good as those reported in the literature, while the computation time required to achieve convergence is significantly less.