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Unlocking global rainwater harvesting potential for safe drinking water access


Abstract

Sustainable Development Goal (SDG) 6.1 aims for universal access to safely managed drinking water (SMDW) by 2030, yet progress remains off-track with 2.2 billion people lacking these services. Our comprehensive global analysis revealed a striking paradox: 88.5% of those without SMDW resided in regions with abundant rainfall, while only 1.26% used rainwater for potable use. Accordingly, a parametric framework integrating environmental and socioeconomic indicators was developed to quantify rainwater harvesting (RWH)’s potential for advancing SDG 6.1. This framework enabled a stepwise, actionable roadmap centered on two synergistic pathways: extending maximum seasonal storage potential and improving transition ratios, with simulations demonstrating that progressive optimization of RWH could increase SMDW coverage by 5.6–26%, benefiting 0.45–2.08 billion people. Socio-ecological analyses further showed that RWH supported multiple SDGs, including food security, health, gender equality, and climate action. These findings establish a systematic global assessment for unlocking vast untapped rainwater potential, providing important pathways that could fundamentally accelerate the achievement of universal SMDW access.

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Data availability

The primary data used in this study are publicly available from established databases: precipitation data from Climatic Research Unit Timeseries (CRUTS 4.05) at https://crudata.uea.ac.uk/cru/data/hrg/; surface runoff data from Geographic Remote Sensing Ecological Network at https://www.gisrs.cn; water access data from WHO/UNICEF Joint Monitoring Programme at https://washdata.org/; population data from WorldPop at https://www.worldpop.org/; health data from Institute for Health Metrics and Evaluation Global Burden of Disease at http://ghdx.healthdata.org/gbd-results-tool; socioeconomic data from World Bank at https://data.worldbank.org/. The analytical results generated in this study are provided in the Source Data file and Figshare: https://doi.org/10.6084/m9.figshare.30427318 and https://doi.org/10.6084/m9.figshare.30484844. The intermediate processed datasets generated through our analytical framework are available from the corresponding author upon request. Source data are provided with this paper.

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Acknowledgements

This research was supported by the Basic Science Center Project of the Natural Science Foundation of China (Grant no. 52388101, C.Z. Hu and F.B. Luan), and China-Sri Lanka Joint Research and Demonstration Center for Water Technology, China-Sri Lanka Joint Center for Education and Research, Chinese Academy of Sciences, China (F.B. Luan).

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Q.K. Yuan and F.B. Luan conceived and designed the study, developed the parametric framework linking rainwater harvesting potential to SDG 6.1 indicators, and prepared the initial manuscript. Y. Meng refined the parameter selection and normalization processes, constructed simulation scenarios, and assisted with data verification and quality control. Y.F. Liu and Y.K. Qie conducted data acquisition, analysis, and modeling, integrating multi-source global datasets, and created visualizations to illustrate key findings. Q.K. Yuan completed the manuscript writing. C.Z. Hu developed the transition ratio pathway within the roadmap framework, focusing on water quality requirements and quality management strategies. All authors participated in reviewing, editing, and refining the manuscript. F.B. Luan supervised the overall research, providing guidance and oversight throughout the study.

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Ying Meng or Fubo Luan.

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Nature Communications thanks Robert Bain and Ataur Rahman for their contribution to the peer review of this work. A peer review file is available.

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Yuan, Q., Liu, Y., Qie, Y. et al. Unlocking global rainwater harvesting potential for safe drinking water access.
Nat Commun (2025). https://doi.org/10.1038/s41467-025-66429-w

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