The demand for drinking water in cities and the lack of new water sources have spurred water conservation and recycling measures over the last 30 years Need, coupled with advances in water treatment technology, is motivating a small but growing number of cities to use reclaimed waste water to supplement drinking-water supplies. Municipalities first must fully assess health impacts from likely contaminants and develop comprehensive systems for monitoring, testing, and treatment. Other water sources and conservation measures also should be tried to the extent practical, before turning to reclaimed waste water Because regulations for safe drinking water were not developed with reclaimed water in mind, they may not be the best standard for testing its quality, the committee said. Reclaimed water may contain sources of contamination that cannot be determined through current testing or treatment processes When considering reclaimed waste water for public water supplies, the report distinguishes between direct and indirect use. Adding highly treated waste water directly into a water supply without storing it first in a reservoir is not a viable option.
Indirect use is viable, however, and that approach was examined by the committee.
Indirect use augments the drinking-water supply by adding reclaimed treated water first to a lake, reservoir, or underground aquifer. The committee reviewed other reclaimed-water projects currently operating in the United States, including those supplying Northern Virginia, Orange County, Calif., and Phoenix. It also examined feasibility studies conducted by the cities of San Diego and Tampa. Limited data from projects and studies nationwide show that highly treated reclaimed waste water produced drinking water of excellent quality, and that no obvious health effects have been found in animal tests or in communities where reclaimed water has been used. All major sources of household, industrial, and agricultural chemical contaminants in reclaimed water should be documented and removed based on existing federal clean-water standards.