As droughts, extreme weather and climate change put growing pressure on global water supplies, cities are increasingly turning to “water banking” to store water underground for the future. This video explores Managed Aquifer Recharge (MAR), a technique that channels surface water into aquifers to replenish groundwater reserves. In Berlin, pilot projects and large-scale recharge basins already provide around 10% of the city’s drinking water. The report also examines MAR initiatives in California, Namibia and South Asia, highlighting both the potential and the challenges of using groundwater recharge to strengthen water security, reduce drought risks and manage increasingly erratic rainfall.