Implications of water conservation measures on urban water cycle: A review

Water conservation measures are a means of adapting to the increasing pressures on water supply in cities. However, its widespread adoption requires knowledge of its implications at the different levels of the urban water cycle. This paper aims to provide a holistic overview and global understanding of the opportunities, challenges and implications associated with the widespread adoption of water conservation measures on the urban water cycle. A systematic search was conducted to identify water conservation case studies within the municipal sector. The analysis of studies' results highlighted that water conservation can significantly reduce buildings' water use while also providing energy savings in both buildings and water utilities. Water conservation measures were found to be economically feasible in most cases, with relatively short payback periods, although conclusions were more nuanced when adopting alternative water sources. This suggests that water conservation measures may be a better option than supply-side solutions to maintain water supply in cities. However, their performance may be undermined by design problems or user behaviour. Therefore, education and communication are key drivers for their widespread adoption. Lower water demand resulting from the implementation of conservation measures may reduce the need for water systems upgrades, delaying major investments, but this may also adversely impact these systems, causing water quality issues in distribution networks, degrading the hydraulic performances of sewers, and altering wastewater treatment efficiencies. The widespread deployment of water conservation measures requires technical, financial, social, and political considerations. Further research is still required to better understand its implications for water systems, assess its impact on water and energy use, and support decision-makers in developing water conservation programmes.