The field of water treatment is undergoing a significant transformation. The distinct boundary between "potable" water and "wastewater" is blurring. Nowhere is this transformation more advanced than in the direct reclamation of treated wastewater. The agencies charged with the stewardship of water resources in the Las Vegas, Nevada area are an excellent illustration of this transformation. Due to a combination of an arid climate, limited water resources and tremendous population pressures, both the potable water purveyors and the wastewater treatment agencies combined resources to produce the Area-Wide Reuse Study. This level of cooperation has extended into other projects and for other water resource issues. Includes tables, figures.