The procedures introduced by Wang and Smith for the estimation of the minimum water needs for systems involving single contaminants are reviewed. A new network design procedure is then developed. This procedure is demonstrated on problems involving simple direct water re-use, water draw-off and regenerated water re-use. It is shown that in the case of regenerated wafer re-use, there are cases in which the water target can only be met by splitting operations into two parts. Where this is unacceptable, the Load Table developed in this paper can be used to determine a revised water consumption target.