the reservoir from several small and poorly operated wastewater treatment plants. The state of Virginia regulates UOSA as a wastewater discharger rather than as a water reclamation facility, though with somewhat more stringent discharge requirements and with recognition of its connection to the water supply. Such indirect reuse may be viewed as similar to the unplanned reuse that occurs when one city discharges its waste into a river or stream used by a downstream community for its water supply.

Aside from current drinking water regulations, no enforceable federal regulations specifically address potable reuse. The Environmental Protection Agency (EPA) has developed suggested guidelines for indirect potable reuse (U.S. EPA, 1992), and a few states have developed regulatory criteria. California and Florida are in the forefront of promulgating specific criteria for planned indirect potable reuse. California has prepared draft criteria for ground water recharge, and Florida has adopted criteria for both ground water recharge and surface water augmentation. In Arizona, regulations addressing ground water recharge with treated wastewater are independent from the state's reuse criteria.

EPA's guidance manual on water reuse, though not a formal regulatory document, provides recommendations for a wide range of reuse practices, including indirect potable reuse by ground water recharge or surface water augmentation, that should be useful to state agencies in developing appropriate regulations. Table 1-2 summarizes the suggested criteria related to indirect potable reuse.

In addition to specific wastewater treatment and reclaimed water quality recommendations, the guidelines provide general recommendations to indicate the types of treatment and water quality requirements that are likely to be imposed where indirect potable reuse is contemplated. The guidelines do not include a complete list of suggested water quality limits for all constituents of concern because water quality requirements are constantly changing as new contaminants are added to the list of those regulated under the Safe Drinking Water Act. The guidelines do not advocate direct potable reuse and do not include recommendations for such use.