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.
Similar content being viewed by others
Assessing global drinking water potential from electricity-free solar water evaporation device
Global potential for harvesting drinking water from air using solar energy
Decision making for implementing non-traditional water sources: a review of challenges and potential solutions
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.
References
Gleick, P. H. The human right to water. Water Policy 1, 487–503 (1998).
Liu, M. J. et al. Spatial assessment of tap-water safety in China. Nat. Sustain. 5, 689–698 (2022).
Bain, R., Johnston, R. & Slaymaker, T. Drinking water quality and the SDGs. Npj Clean. Water 3, 37 (2020).
Taka, M. et al. The potential of water security in leveraging Agenda 2030. One Earth 4, 258–268 (2021).
United Nations Children’s Fund and World Health Organization. Progress on household drinking water, sanitation and hygiene 2000-2022: Special focus on gender. (World Health Organization, 2024).
World Health Organization. Progress on household drinking water, sanitation and hygiene 2000-2017: special focus on inequalities. (World Health Organization, 2019).
UN-Water. The sustainable development goal 6 global acceleration framework. Geneva: UN-Water (2020).
Segovia-Hernández, J. G., Hernández, S., Cossío-Vargas, E. & Sánchez-Ramírez, E. Challenges and opportunities in process intensification to achieve the UN’s 2030 agenda: goals 6, 7, 9, 12 and 13. Chem. Eng. Process. Process Intensif., 109507 (2023).
Naylor, K. A. Blueprint for acceleration: sustainable development goal 6 synthesis report on water and sanitation, 2023. (UN, 2023).
Hutton, G. & Varughese, M. The costs of meeting the 2030 sustainable development goal targets on drinking water, sanitation, and hygiene. World Bank, Washington, DC (2016).
Department of Economic and Social Affairs in the United Nations. Mapping and progress of the UN 2023 Water Conference Water Action Agenda, https://sdgs.un.org/sites/default/files/2024-06/WAA%20Mapping%20and%20Progress%20Report%20May%202024.pdf (2023).
Mati, B. et al. Mapping the potential of rainwater harvesting technologies in Africa. A GIS overview on development domains for the continent and ten selected countries. Tech. Man. 6, 126 (2006).
Mwenge Kahinda, J. & Taigbenu, A. E. Rainwater harvesting in South Africa: Challenges and opportunities. Phys. Chem. Earth 36, 968–976 (2011).
Wunderlich, S., St George Freeman, S., Galindo, L., Brown, C. & Kumpel, E. Optimizing household water decisions for managing intermittent water supply in Mexico City. Environ. Sci. Technol. 55, 8371–8381 (2021).
Barron, J. & Salas, J. C. Rainwater harvesting: a lifeline for human well-being. (UNEP/Earthprint, 2009).
Alim, M. A. et al. Suitability of roof harvested rainwater for potential potable water production: A scoping review. J. Clean. Prod. 248, 119226 (2020).
Lebek, K. & Krueger, T. Conventional and makeshift rainwater harvesting in rural South Africa: exploring determinants for rainwater harvesting mode. Int. J. Water Resour. Dev. 39, 113–132 (2023).
Chaplot, V., Selala, M., Thenga, H. & Jewitt, G. Comparison of the chemical quality of rainwater harvested from roof and surface run-off systems. Water SA 44, 223–231 (2018).
Ertop, H. et al. The importance of rainwater harvesting and its usage possibilities: Antalya example (Turkey). Water 15, 2194 (2023).
Dao, D. A. et al. Assessment of rainwater harvesting and maintenance practice for better drinking water quality in rural areas. Aqua Water Infrastruct. Ecosyst. Soc. 70, 202–216 (2021).
Karim, M. R. Assessment of rainwater harvesting for drinking water supply in Bangladesh. Water Sci. Technol. Water Supply 10, 243–249 (2010).
Alim, M. A. et al. Feasibility analysis of a small-scale rainwater harvesting system for drinking water production at Werrington, New South Wales, Australia. J. Clean. Prod. 270, 122437 (2020).
Kahinda, J. -mM., Taigbenu, A. E. & Boroto, J. R. Domestic rainwater harvesting to improve water supply in rural South Africa. Phys. Chem. Earth 32, 1050–1057 (2007).
Kumar, M. D. Rainwater Harvesting in India: Some Critical Issues for Basin Planning and Research. (2009).
Bhatt, S. C. Natural resources, water harvesting and drought in Central India. (Shree Publishers & Distributors, New Delhi, 2020).
Qi, Q., Marwa, J., Mwamila, T., Gwenzi, W. & Noubactep, C. Making rainwater harvesting a key solution for water management: the universality of the Kilimanjaro concept. Sustainability 11, 5606 (2019).
Imteaz, M. A., Adeboye, O. B., Rayburg, S. & Shanableh, A. Rainwater harvesting potential for southwest Nigeria using daily water balance model. Resour. Conserv Recy 62, 51–55 (2012).
Droogers, P. & van Kempen, C. Mapping the potential for rainwater harvesting under various scenarios. FutureWater Costerweg, Wageningen, the Netherlands (2014).
Harris, I., Osborn, T. J., Jones, P. & Lister, D. Version 4 of the CRU TS monthly high-resolution gridded multivariate climate dataset. Sci. Data 7, 109 (2020).
Rentschler, J., Salhab, M. & Jafino, B. A. Flood exposure and poverty in 188 countries. Nat. Commun. 13, 3527 (2022).
Fox, S., Agyemang, F., Hawker, L. & Neal, J. Integrating social vulnerability into high-resolution global flood risk mapping. Nat. Commun. 15, 3155 (2024).
Reed, B. Minimum water quantity needed for domestic uses. New Delhi: World Health Organization Regional Office for South-East Asia (2005).
Okoye, C. O., Solyalı, O. & Akıntuğ, B. Optimal sizing of storage tanks in domestic rainwater harvesting systems: A linear programming approach. Resour. Conserv. Recycl. 104, 131–140 (2015).
Kinkade-Levario, H. Design for water: rainwater harvesting, stormwater catchment, and alternate water reuse. (New Society Publishers, 2007).
Campisano, A. & Modica, C. Optimal sizing of storage tanks for domestic rainwater harvesting in Sicily. Resour. Conserv. Recycl. 63, 9–16 (2012).
Leonard, D. & Gato-Trinidad, S. Understanding the effect of household rainwater tanks on hourly residential water use. J. Sustain. Water Built Environ. 7, 05021004 (2021).
Cain, N. L. A different path: the global water crisis and rainwater harvesting. Consilience, 147–157 (2014).
Ward, S., Memon, F. & Butler, D. Performance of a large building rainwater harvesting system. Water Res 46, 5127–5134 (2012).
Zabidi, H. A., Goh, H. W., Chang, C. K., Chan, N. W. & Zakaria, N. A. A review of roof and pond rainwater harvesting systems for water security: The design, performance and way forward. Water 12, 3163 (2020).
Bain, R., Johnston, R., Khan, S., Hancioglu, A. & Slaymaker, T. Monitoring drinking water quality in nationally representative household surveys in low-and middle-income countries: cross-sectional analysis of 27 multiple indicator cluster surveys 2014–2020. Environ. Health Perspect. 129, 097010 (2021).
Manero, A. et al. Benefits, costs and enabling conditions to achieve ‘water for all’ in rural and remote Australia. Nat. Water 2, 31–40 (2024).
Nowicki, S., Koehler, J. & Charles, K. J. Including water quality monitoring in rural water services: why safe water requires challenging the quantity versus quality dichotomy. Npj Clean. Water 3, 14 (2020).
Adeyeye, K. & Bello-Dambatta, A. in Rainwater harvesting for the 21st Century 245–264 (CRC Press).
Ye, W. et al. Applicability of photovoltaic panel rainwater harvesting system in improving water-energy-food nexus performance in semi-arid areas. Sci. Total Environ. 896, 164938 (2023).
Konapala, G., Mishra, A. K., Wada, Y. & Mann, M. E. Climate change will affect global water availability through compounding changes in seasonal precipitation and evaporation. Nat. Commun. 11, 3044 (2020).
Wolf, J. et al. Burden of disease attributable to unsafe drinking water, sanitation, and hygiene in domestic settings: a global analysis for selected adverse health outcomes. Lancet 401, 2060–2071 (2023).
Organization, W. H. Burden of disease attributable to unsafe drinking-water, sanitation and hygiene, 2019 update. (World Health Organization, 2023).
De Kwaadsteniet, M., Dobrowsky, P., Van Deventer, A., Khan, W. & Cloete, T. Domestic rainwater harvesting: microbial and chemical water quality and point-of-use treatment systems. Water Air Soil Pollut. 224, 1–19 (2013).
Despins, C., Farahbakhsh, K. & Leidl, C. Assessment of rainwater quality from rainwater harvesting systems in Ontario, Canada. J. Water Supply Res. Technol. AQUA 58, 117–134 (2009).
Xiong, B. et al. Moringa oleifera f-sand filters for sustainable water purification. Environ. Sci. Technol. Lett. 5, 38–42 (2018).
Jeon, I., Ryberg, E. C., Alvarez, P. J. & Kim, J.-H. Technology assessment of solar disinfection for drinking water treatment. Nat. Sustain. 5, 801–808 (2022).
Malina, N., Millner, S. & Ojeda, A. S. “First alert” for drinking water quality: commercial water quality testing kits for community-engaged research. ACS EST Water 4, 1346–1355 (2024).
Bain, R., Johnston, R., Mitis, F., Chatterley, C. & Slaymaker, T. Establishing sustainable development goal baselines for household drinking water, sanitation and hygiene Services. Water 10 (2018).
World Health Organization (WHO) and the United Nations Children’s Fund. JMP Methodology: 2017 update and SDG baselines, https://washdata.org/reports/jmp-2017-methodology (2018).
Lord, J. et al. Global potential for harvesting drinking water from air using solar energy. Nature 598, 611–617 (2021).
FAO. Land and water digital media series, 26. Training course on RWH (CDROM). Planning of water harvesting schemes, Unit 22. Food and Agriculture Organization of the United Nations (2003).
Kuzma, S. et al. Aqueduct 4.0: Updated decision-relevant global water risk indicators. (World Resources Institute Washington, DC, USA, 2023).
Zhu, Q., Li, Y. & Tang, X. in Rainwater Harvesting for Agriculture and Water Supply (eds Qiang Zhu, John Gould, Yuanhong Li & Chengxiang Ma) 3-42 (Springer Singapore, 2015).
Our World in Data team. Water productivity, GDP per cubic meter of freshwater withdrawal, https://ourworldindata.org/grapher/water-productivity (2024).
World Bank Group. GDP per capita (current US$), https://data.worldbank.org/indicator/NY.GDP.PCAP.CD (2021).
World Bank Group. Rural population, https://data.worldbank.org/indicator/SP.RUR.TOTL (2021).
World Bank Group. Population growth (annual %), https://data.worldbank.org/indicator/SP.POP.GROW (2021).
Our World in Data team. Prevalence of moderate or severe food insecurity in total population, https://ourworldindata.org/sdgs/zero-hunger (2023).
Our World in Data team. Gender inequality index, https://ourworldindata.org/grapher/gender-inequality-index-from-the-human-development-report?time=2020 (2024).
Disaster Risk Management Knowledge Centre. DRMKC-INFORM Country Risk Profile, https://drmkc.jrc.ec.europa.eu/inform-index/INFORM-Risk/Country-Risk-Profile (2024).
Institute for health metrics and evaluation. Explore results from the 2021 Global Burden of Disease (GBD) study, https://vizhub.healthdata.org/gbd-results/ (2024).
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).
Author information
Authors and Affiliations
Contributions
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.
Corresponding authors
Ethics declarations
Competing interests
The authors declare no competing interests.
Peer review
Peer review information
Nature Communications thanks Robert Bain and Ataur Rahman for their contribution to the peer review of this work. A peer review file is available.
Additional information
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Supplementary information
Supplementary Information
Transparent Peer Review file
Source data
Source data
Rights and permissions
Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.
Reprints and permissions
About this article
Cite this article
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
Received:
Accepted:
Published:
DOI: https://doi.org/10.1038/s41467-025-66429-w
Source: Resources - nature.com

