Water reclamation and unrestricted nonpotable reuse: a new tool in urban water management.

Growing urbanization accompanying growing population is increasing the demand for water supply in communities throughout the world. Water resources for many cities are already proving inadequate. Additional water resources are inherently more costly and are often not available because other communities and/or land owners have the water rights. Although conservation, particularly through demand management, may delay the need for additional sources for a short period, the need is inevitable. One approach that has been found to provide substantial additional water for communities is the reclamation of wastewaters produced by the communities themselves for unrestricted nonpotable purposes, such as for landscape and market crop irrigation, industry, cooling towers, air conditioning, toilet flushing, construction, vehicle washing, and environmental enhancement. This is done by providing dual distribution systems. Nonpotable reuse is already widely practiced despite the fact that the reclaimed water distribution systems needed to be installed in existing communities. Inasmuch as additional water is needed for growing populations, the costs would be substantially reduced if the two systems were to be built at the same time in the newly developing areas. Reuse of reclaimed water for potable purposes may be feasible, but it imposes added public health risks that need to be accepted only as a last resort.