Advances in end-user water conservation technologies: a scoping review

Introduction Water scarcity, intensified by climate change, urbanization, and increasing demand, requires sustainable strategies aimed at reducing consumption among end users. In this context, this article develops a scoping review to examine what types of sustainable technologies aimed at water conservation among end users have been investigated, how they are evaluated, and what types of evidence are reported regarding their effectiveness. Methods Studies published between 2020 and 2025 were retrieved from the Scopus, Web of Science, IEEE Xplore, Wiley Online Library, and EBSCO Engineering Source databases following PRISMA-ScR guidelines. The review integrates a bibliometric analysis of the field and a synthesis of 14 selected empirical studies addressing domestic efficiency technologies, adoption dynamics, digital monitoring systems, and resource management approaches. Results The evidence shows high methodological diversity and limited standardization of effective metrics, as only a small proportion of studies explicitly report quantified or directly measured water savings. Nevertheless, consistent patterns emerge depending on the type of intervention. Circular water management and decentralized reuse strategies report the highest potential impacts, with potable water savings ≥30% through greywater treatment and reductions of up to 80% in integrated urban scenarios. Rainwater harvesting and green infrastructure report runoff reductions between 58.3 and 94.1%, generating indirect benefits for urban water management. In contrast, informational and behavioral interventions tend to produce moderate but consistent reductions in consumption. Digital technologies based on IoT, smart metering, and advanced analytics demonstrate strong technical performance in monitoring and leak detection, although they rarely quantify post-implementation water savings. Conclusion The findings suggest that effective water conservation among end users depends on approaches that combine technological solutions, user engagement, and standardized evaluation frameworks capable of linking technological performance with verifiable reductions in water consumption.