The present study highlights the evolution, progress and prospects of future practices of water reuse in the world. The objective was to produce a comprehensive timeline on the global evolution and progress of water reuse. This was achieved through the analysis of the state of the art on the subject. The present study is a qualitative research, where three aspects have been considered to highlight the global evolution of water reuse: i) Regulations, Standards, Criteria or Guidelines (RSCG); ii) Indirect Potable Reuse Projects (IPR); and iii) Direct Potable Reuse Projects (DPR). The study focused on both legal and practical aspects of water reuse and considered three timelines in the context of RSCG, IPR and DPR: 29 RSCG instruments, institutionalized from 1918 to 2020, where only four instruments were solely dedicated to drinking water reuse; 10 IPR projects; five DPR projects. To achieve good, effective results, the regulatory framework must support the objectives of a structured water reuse policy in addition to guaranteeing legitimacy and maintaining public confidence. Integrated water and wastewater management, based on technological and scientific advances, has become a relevant aspect for implementation of more adequate measures by decision makers to address future global water challenges.

The present paper carried out an evaluation of the reuse potential of the Wastewater Treatment Plants (WWTPs) effluents for irrigation in the 12 Brazilian Hydrographic Regions (BHRs). For this purpose, initially, the WWTPs were categorized and the effluent flow rate was estimated. Category 1 represents secondary effluent with an efficiency of organic matter removal greater than 80%; Category 2 represents effluent that underwent some disinfection step; and effluents that perform less than the other categories were called ‘Uncategorized’. After that, the irrigation water demands for each BHRs were compiled, and finally, the production of water for reutilization were compared with the demand for irrigation. Thus, it was observed that all the sewage flow rate generated in Brazil classified in Categories 1 and 2 represents 9% of the total irrigation water demand in the country (1,078.71 m³/s) and it stands out that only 7% of the flow treated in Brazil undergo a tertiary treatment step.

Water reuse has been practiced for more than 5,000 years with different approaches by society throughout historical periods. We developed a concept that presents evidence and artistic-cultural manifestations about episodes of valorization (V), devaluation (D), and revaluation (R) of wastewater (WW) throughout history, called ‘Historical Development VxDxR/WW’. We conclude that WW has had a long valorization period of more than 3,500 years; the WW devaluation period lasted approximately 150 years; and in the last 100 years, there has been an attempt to revalue WW, with scientific, legal, and technological advances. We believe that a broad understanding of this concept can drive a true paradigm shift to guide public policies and appropriate decision-making, in the context of efficient water management. To guarantee a safe, sustainable, and economically viable water reuse practice, it is necessary to develop and implement a regulatory framework that involves, in addition to legal aspects, regional strategic planning and the production of social education instruments for the acceptance of water reuse. In this sense, this concept can pave the way for the necessary and expected advances.

An urban–rural dichotomy currently exists in policy documentation, accessibility to resources, and human rights. In Brazil, there remains a significant deficit in water and sanitation services coverage, particularly in rural areas. To achieve universal access to water, the legal framework addresses the development of decentralization actions and co-participation in management. As a result, a community-managed water supply (CMWS) has emerged as the social tool in which the community effectively participates in decision-making and oversees the operation and maintenance of water systems. The long-term sustainability of these systems is affected by critical factors in implementation, management, and maintenance. However, no strategic plan exists to solve/mitigate the critical factors commonly associated with CMWS. We proposed an action plan with multiscale intersectoral management strategies to guarantee water security for rural populations. The strategies were separated into areas of responsibility discussed in the recent literature and evaluated by experts. The strategies at the national level were related to institutional aspects and policy formulation. At the local level, the strategies were related to supporting CMWS from project implementation to post-construction. Finally, at the community level, the strategies were related to the quality and financial recognition of the services.

No presente artigo, apresenta-se uma análise comparativa do enquadramento regulatório de reúso de água do Brasil e de Portugal, inserido nos seus cenários de gestão de saneamento ambiental e recursos hídricos. Verifica-se que os índices de atendimento em serviços de água e esgotos são bastante distintos nos dois países, sendo semelhantes, no entanto, as respetivas taxas de reúso de água em relação ao esgoto total tratado (1,5% no Brasil e 1,2% em Portugal). A água de reuso vem se tornando uma importante fonte alternativa de aumento da disponibilidade hídrica para o desenvolvimento sustentável. Apesar dos aspectos de regulamentação de ambos os países apresentarem instrumentos de gestão similares, o Brasil tende a ser mais flexível em relação aos padrões de indicadores de contaminação fecal para o reúso de água para irrigação/rega de ambientes urbanos, combate a incêndio e lavagem de ruas. No caso de reúso para irrigação/rega de ambientes agrícolas e descarga de vaso sanitário, os padrões legais são igualmente restritivos. Padrões para usos na construção civil e na desobstrução de galerias de águas residuais somente constam no documento regulador brasileiro. WATER REUSE FOR SUSTAINABLE DEVELOPMENT: REGULATORY ASPECTS IN BRAZIL AND PORTUGALABSTRACTIn this research work, a comparative analysis of the legal framework for water reuse in Brazil and Portugal within their scenarios of sanitation and water resources management is presented. It appears that the coverage in drinking water and sanitation services is quite different between the two countries. However, the respective rates of reuse of effluents in relation to the total wastewater treated are similar (1.5% in Brazil and 1.2% in Portugal). Water reuse has become an important alternative source of increasing water availability for sustainable development. Despite the legal aspects of both countries presenting similar management instruments, Brazil tends to be more flexible in relation to the standards of fecal contamination indicators for the reuse of water for irrigation of urban environments, firefighting, and street washing. In the case of reuse for irrigation of agricultural environments and flushing the toilet, legal standards are equally restrictive. Standards for use in civil construction and clearing wastewater galleries are only included in the Brazilian regulatory document.