Scientists are mapping Africa’s groundwater to help millions of people find safe, reliable water hiding beneath their feet.
Mapping Africa’s groundwater has become an urgent scientific mission as rivers and lakes grow less predictable. Hotter temperatures are driving wild swings between drought and sudden downpours. Surface water sources that communities have relied on for generations are becoming harder to count on.
Around 400 million people across Africa still lack access to basic drinking water. Yet the continent holds a resource most people never see. Beneath the surface lies an estimated 660,000 cubic kilometers of groundwater, roughly 20 times the freshwater in all of Africa’s lakes combined.
A team of hydrogeologists and water policy experts is working to unlock that hidden supply. Their project, called Groundwater for Advancing Resilience in Africa, is developing a digital map that shows exactly where water can be pumped safely. Mapping Africa’s groundwater this way gives communities a clearer, science-based path to secure water, rather than guesswork.
Groundwater does not sit in one giant underground lake, as many people imagine. Instead, it fills tiny spaces in rock, such as the pores of sandstone or the cracks in stone. How much can be pumped out depends on how much water the rock holds and how easily it reaches the surface.
Africa’s aquifers vary enormously by region, which is part of why mapping Africa’s groundwater is complex. In North Africa, deep sedimentary layers beneath Libya, Algeria, and Egypt act like giant sponges, storing huge volumes of water that supply growing cities and large farms.
Much of this water is fossil water, rain that fell over 10,000 years ago when the Sahara was wetter. It cannot be refilled by today’s rainfall, so once it runs out, it is gone for good. Overdrawing these aquifers can also cause the ground above to sink, a problem already threatening cities like Jakarta and Mexico City.
South of the Sahara, the geology differs. Groundwater there sits in hard, ancient basement rock full of small cracks rather than open pores, so pumping is slower. Even so, it naturally refills during each rainy season, serving as a renewable buffer that keeps rural hand pumps and small farms running through dry spells.
The research team’s map combines data on where water is stored underground and how quickly it recharges, with data on where people live, farm, and build latrines. This layered approach is central to accurately mapping Africa’s groundwater, since the same aquifer can be a lifeline in one place and a health risk in another. Early results show about 94 million rural Africans live in areas where groundwater could provide safe drinking water, with hotspots in South Sudan, Cameroon, Liberia, Guinea, Sierra Leone, and the Democratic Republic of Congo.
By mapping Africa’s groundwater and flagging pollution risks, scientists hope to guide smarter water policy and investment across the continent. Photo by K on Pexels.
Another 333 million people live where groundwater could support sustainable irrigation, including parts of Cameroon, Congo, Gabon, Liberia, Guinea, and Tanzania. These findings could help farmers grow more food as rainfall becomes less predictable. The map also flags risk zones needing caution.
About 535 million Africans live in areas where human activity may be polluting groundwater, including large parts of Algeria and Libya, as well as sections of the DRC and Angola. This means water quality in those areas would need to be carefully tested before anyone relies on it. Once finished, the map is meant to guide real decisions rather than sit as an academic exercise.
Regional bodies like the African Ministers’ Council on Water could use the completed map to steer policy and investment toward the areas that need it most. Good data is the first step toward good water management. Maps alone cannot solve everything, though, which is why mapping Africa’s groundwater from space is only half the job.
Researchers are also doing hands-on fieldwork in West and Southeast Africa, since many aquifers cross national borders. If one country pumps too much, a neighbor could be left with a shortage or water too salty to use. Two shared aquifers are getting close attention: one under the Mono River Basin between Togo and Benin, and another beneath the Shire River Basin, shared by Malawi and Mozambique.
At both sites, teams use monitoring boreholes fitted with sensors to track water levels, temperature, and salinity. This groundwork, called a hydro-census, involves checking old records, locating existing boreholes, and repairing or drilling new ones where there are too few. A similar assessment is now underway in Uganda’s Upper Nile Water Management Zone.
The bigger aim is to build modern monitoring networks that enable neighboring countries to share data and manage shared water resources fairly. That kind of cooperation could prevent conflict over a resource that does not respect political borders.
Mapping Africa’s groundwater will not fix the climate crisis, but it offers something practical and hopeful. It gives communities and governments the information they need to plan ahead rather than react to a crisis. As rivers and lakes grow less dependable, the water stored beneath Africa’s soil may prove to be one of its steadiest defenses against a warming world.
