How did the Kingdom of Saudi Arabia reduce the gap between water demand and supply: lessons for future sustainable water resource planning

The Kingdom of Saudi Arabia (KSA), one of the world’s most arid countries, has faced severe water scarcity due to limited renewable resources, rapid population growth, and high agricultural demand. This study examines KSA’s strategies over the past two decades to bridge the water demand-supply gap, analyzing data from the Ministry of Environment, Water and Agriculture (MEWA) from 2009 to 2023. Findings reveal that KSA doubled its water supply (3,968 to 8,064 MCM) through desalination expansion (119% increase), treated wastewater reuse (2,055 MCM by 2023), and optimized groundwater management. Concurrently, agricultural water demand decreased by 43% (2015–2023) due to drip irrigation, crop diversification, and reduced wheat/alfalfa cultivation, while domestic demand rose steadily (69%) with urbanization. Key lessons emerge: (1) demand management (e.g., water-saving technologies) proved as critical as supply augmentation; (2) non-conventional sources (desalination, wastewater reuse) now constitute ~ 60% of supply; (3) renewable energy integration (e.g., solar-powered desalination) enhances sustainability; and (4) policy enforcement (e.g., well licensing, subsidy reforms) curbed groundwater depletion. Challenges persist, including high per capita consumption and non-renewable groundwater reliance. Aligned with Vision 2030, KSA’s experience offers a blueprint for arid regions: prioritize circular water economies, data-driven governance, and cross-sectoral coordination. Recommendations include scaling decentralized reuse systems, mandating industrial water recycling, and regional aquifer management. This research underscores that holistic, adaptive strategies can reconcile water security with economic growth in water-scarce environments.