In cases of limited water availability, integrated planning of potable water, reclaimed water and wastewater infrastructures can lead to economic efficiency and increased system reliability. For example, integrated planning can address the degree to which new wastewater treatment facilities should be spatially dispersed. There have been efforts to develop decision support systems to assist in siting wastewater treatment facilities - the Decision Support System (DSS) developed by Malcolm Pirnie with support from WateReuse provides a recent example. Application of a modified version of this model indicates that decentralized wastewater reclamation facilities may be a feasible option where existing infrastructure to reach areas to be served with reclaimed water is limited. Cost functions utilized by the DSS were also incorporated into an optimization routine to determine the optimal capacity at each proposed treatment facility location (could be 0) and capacities for all system pipes and pumps, including enlargements when there is existing infrastructure.