Appropriate and necessary treatment and reuse of wastewater to augment existing water resources is a rapidly expanding approach for both non-potable and potable applications. EPA recognizes that potable reuse of water can play a critical role in helping states, tribes, and c ommunities meet their future drinking water needs with a diversified portfolio of water sources. Beginning with the first pioneers in water reuse, Los Angeles County Sanitation Distric t (1962), Orange County Sanitation District (1976), and the Upper Occoquan Service Authority (1978), the practice has gained substantial momentum because of drought and the need to assure groundwater resource sustainability and a secure water supply. Long-term water scarcity is expected to increase over time in many parts of the country as a result of drought, growing water demand, and other stressors.

Across the U.S., there has been a notable increase in the deployment of technologies to augment existing water supplies through reuse of wastewater that has been treated and cleaned to be safe for the intended use. Indirect reuse usually involves passage of water through an environmental buffer (e.g., groundwater aquifer, lake, river) before the water is again treated for reuse. Direct reuse refers to those situations where treatment is followed by storage and use, but without the environmental buffer. Many drinking water systems rely on water treatment technologies to support indirect reuse of water (e.g., indirect potable reuse) and some drinking water systems now directly reuse wastewater after treatment (e.g., direc t potable reuse).

In 2012, EPA published the 2012 Guidelines for Water Reuse to serve as a reference on water reuse practices . The document provided information related to indirect potable reuse (IPR), but only briefly described direc t potable reuse (DPR). Because of increased interest in pursuing potable water reuse, EPA is is suing the 2017 Potable Reuse Compendium to outline key science, technical, and policy considerations regarding this practice. This 2017 Compendium supplements the 2012 Guidelines for Water Reuse to inform current practices and approaches in potable reuse, including those related to direct potable water reuse. EPA recognizes the recent water reuse publications from our stakeholders at the World Health Organization (WHO), the National Research Council of the National Academies of Science, the Water Environment and Reuse Foundation (WE&RF), and the Water Environment Federation (WEF). The 2017 Compendium is a compilation of technical information on potable reuse practices to provide planners and decision-makers with a summary of the current state of the practice. Specific knowledge and experience are drawn from case studies on existing reuse approaches.

EPA supports water reuse as part of an integrated water resources management approach developed at the state and local level to meet the water needs of multiple sectors including agriculture, industry, drinking water, and ecosystem protection. An integrated approach commonly involves a combination of water management strategies (e.g., water supply development, water storage, water use efficiency, and water reuse) and engages multiple stakeholders and needs, including the needs of the environment. Although EPA encourages an integrated approach to water resources management, it does not require or restrict practices such as water reuse. EPA acknowledges the primacy of states in the allocation and development of water resources. EPA, State, and local governments implement programs under the Clean Water Act and the Safe Drinking Water Act to protect the quality of source waters to ensure that source water is treated so that water provided to the tap is safe for people to drink (e.g., contaminant specific drinking water standards). The SDWA and the CWA provide a foundation from which states can further develop and support potable water reuse as they deem appropriate.

EPA will continue to engage a broad spectrum of partners and stakeholders for input on where the Agency can provide meaningful support to states, tribes, and communities as they implement potable water reuse projects. EPA will also work with stakeholders, the scientific community , and the States to monitor and evaluate performance of water treatment technologies to ensure that potable reuse projects are implemented in a manner that protects the health of communities . This document is a collaborative effort between EPA, CDM Smith, and other key stakeholders. EPA acknowledges the importance of potable water reuse and looks forward to working with our stakeholders as the practice continues to be developed and deployed as an important approach to ensure a c lean, safe, and sustainable water supply for the nation.