As populations grow and current water supplies become more stressed, alternative new resources must be identified. In water scare areas, such as the semi-arid southwestern United States, communities have found it necessary to shift from reliance on traditional water supplies - ground water or relatively meager surface flows - toward a combination of large, engineered water projects, water reuse and conservation measures. Examples in the southwestern United States include Las Vegas, Phoenix and Tucson, each of which faces water-related engineering challenges. In the near future, these urban centers will be forced to rely on reclaimed water to satisfy their respective needs, as it is the only remaining unexploited water resource in this region. Current practice treats the water supply infrastructure design and operation as independent from the wastewater collection and treatment system. Often these systems are managed by separate departments or by different government entities. However, as water becomes scarcer, the interdependence between water distribution and collection systems must be recognized and exploited. Distributed, dual water treatment and distribution infrastructures and management plans are recommended as the most viable ways to accommodate future water demands. The present study addresses engineering and other significant challenges relevant to dual, distributed systems in water scarce regions. Copyright ASCE 2009.