Water is a limiting resource, and the pressure exerted on surface and groundwater resources should be reduced or at best maintained, rather than increased, as the human population and industrial development increase. Water recycling and reuse is thus of increasing importance, not only in arid regions but also in cities and contaminated environments. This paper provides an international understanding to inform optimization of treatment under local conditions, operating efficiencies associated with chemical and energy inputs or recovery, and optimization of traditional wastewater treatment to complement water recycling. Large quantities of freshwater can be saved by industrial water reuse and recycling, lowering costs, reducing environmental pollution and improving carbon footprint. Reuse is a sustainable and cost-effective alternative water supply.As the demand for potable quality water increases, driven by increasing human populations and economic development, the drivers for indirect and direct potable reuse of water also increase in their intensity. In this paper we inspect the national situations in developed countries in the northern and southern hemispheres (the USA and Australia), and in a middle-income country (South Africa). Examples of full scale potable reuse schemes in each country are described, followed by summaries of current research focal areas and priority challenges. Finally the international research trends and commonalities are highlighted, along with the key regional differences in research objectives and application, concluding with an outline of perceived opportunities for mutual benefit by enhanced international cooperation.

Key Takeaways In 2020, AWWA Water Science published a topical collection on potable reuse that aimed to address questions raised by increasing demand for water reuse. Topics in the collection included source water management, pathogen detection and treatment, communications and outreach, and socioeconomics of potable reuse. In an interview, the collection's guest editors discuss the lessons they have learned and the future challenges for potable reuse regulation and research. Improving the feasibility and adoption of potable reuse will require additional research to ensure that it continues to be a safe and reliable water supply.