Scientists say a new study shows Africa sits on a huge reservoir of groundwater that could provide water for both drinking and agriculture.

The scientists estimate that 300 million people in Africa do not have access to safe drinking water and that part of the solution lies right under their feet — with over 100 times the annual renewable freshwater resource available in Africa and 20 times that stored in freshwater lakes.

Maps produced by the British Geological Survey and University College London show that the spots where groundwater is most plentiful include Libya, Algeria, Egypt and Sudan. That means that countries currently designated as “water scarce” could be sitting on groundwater supplies tens of meters deep.

One of the researchers, hydrologist Richard Taylor at University College London, told VOA that these considerable groundwater resources may help regulate soil moisture and therefore food security.

There are fears, however, of over-extraction as scientists predict the demand for water will grow rapidly with the population.