Expanding water reuse-the use of treated wastewater for beneficial purposes including irrigation, industrial uses, and drinking water augmentation-could significantly increase the nation's total available water resources. Water Reuse presents a portfolio of treatment options available to mitigate water quality issues in reclaimed water along with new analysis suggesting that the risk of exposure to certain microbial and chemical contaminants from drinking reclaimed water does not appear to be any higher than the risk experienced in at least some current drinking water treatment systems, and may be orders of magnitude lower. This report recommends adjustments to the federal regulatory framework that could enhance public health protection for both planned and unplanned (or de facto) reuse and increase public confidence in water reuse.

In communities all around the world, water supplies are coming under increasing pressure as population growth, climate change, pollution, and changes in land use affect water quantity and quality. To address existing and anticipated water shortages, many communities are working to increase water conservation and are seeking alternative sources of water. Water reuse- the sue of treated wastewater, or "reclaimed" water, for beneficial purposes such as drinking, irrigation, or industrial uses- is one option that has helped some communities significantly expand their water supplies. Understanding Water Reuse summarizes the main findings of the National Research Council report Water Reuse: Expanding the Nation's Water Supply Through Reuse of Municipal Wastewater. The report provides an overview of the options and outlook for water reuse in the United States, discusses water treatment technologies and potential uses of reclaimed water, and presents a new analysis that compares the risks of drinking reclaimed water to those of drinking water from traditional sources.

Reuse can be an alternative source of water for municipal water supply systems. while the demand for water continues to increase in the United States, especially in our burgeoning urban areas, the traditional alternatives for water supply planning, while useful in the past, are either inappropriate today or may no longer be practicable. Recycling renovated waste water has been shown, under specific qualifications, to be a socially acceptable and economically efficient alternative for municipal water supply planning. Two problems may be related to the low community adoption of water reuse: the unavailability of a methodology to access the relative value of reuse and the professional biases of consulting engineers and public health officials. In this report a simulation model for evaluating the economic efficiency of water reuse is formulated and applied to a single community and the nature and role of professional bias in the decision making process in water reuse planning is described.