However, the committee does not discuss building-scale reuse or greywater reuse in depth in this report.
As populations are increasing, particularly in water-limited regions, water managers are looking toward sustainable water management solutions to address shortfalls in supply from conventional water sources. Efforts to increase the efficiency of water use through enhanced conservation and improved technologies and the development of new sources of water may both be necessary to address future water demand in areas facing extreme water shortfalls. Potable and nonpotable reuse are attracting increasing attention in the search for untapped water supply sources. Out of the 32 BGD (121 million m3/d) of municipal wastewater effluent discharged nationwide, approximately 12 BGD (45 million m3/d) is discharged to an ocean or estuary (equivalent to 6 percent of the estimated total U.S. water use or 27 percent of public supply). Reuse of these coastal discharges, where feasible, in water-limited regions could directly augment available water resources. When reclaimed water is used for nonconsumptive uses, the water supply benefit of water reuse could be even greater if the water can again be captured and reused. Inland effluent discharges may also be available for water reuse, although extensive reuse has the potential to affect the water supply of downstream users and ecosystems (e.g., in-stream habitats, coastal estuaries) in water-limited settings. Municipal wastewater reuse, therefore, offers the potential to significantly increase the nation’s total available water resources. However, reuse alone cannot address all of the nation’s water supply challenges, and the potential contributions of water reuse will vary by region.