A remote region of Kenya that often suffers from drought could soon be flush with water after the discovery of underground aquifers, the government said.
Two aquifers have been identified in the Turkana region by using satellite exploration technology.
The "newly found wealth of water" opens doors to a more prosperous future for the people of Turkana and the nation, said Judi Wakhungu, the cabinet secretary for Kenya's ministry of environment, water and natural resources.
Of Kenya's 41 million people, 17 million lack access to safe water, and 28 million do not have adequate sanitation.
The discovery of at least two aquifers - and three other possibles still being investigated - was the result of a groundwater mapping project spearheaded by Unesco.
The discoveries were made near Lake Turkana, the world's largest permanent desert lake and largest alkaline lake. The region has produced a string of ancient palaeontological finds connected to humans' earliest days millions of years ago.
The underground lakes were discovered by Radar Technologies International, which said its survey found that the two confirmed aquifers hold a minimum of 250 billion cubic metres of water.
The firm said it could boost Kenya's share of available water by 17%.
RTI said the three unconfirmed aquifers could hold another 30 billion cubic metres of water. Drilling will confirm the existence of those three masses of water.
"This groundwater raises the prospect for improving the livelihoods of the Turkana people, most of whom live in poverty and have limited access to basic services and clean water," said RTI, which detects water using satellite data, oil exploration technologies and conventional hydro-geological techniques.
The finding demonstrates how "science and technology can contribute to industrialisation and economic growth, and to resolving real societal issues like access to water," said Gretchen Kalonji, Unesco's assistant director-general for natural sciences.
Ms Wakhungu said: "The news about these water reserves comes at a time when reliable water supplies are highly needed. We must now work to further explore these resources responsibly and safeguard them for future generations."