Peer-reviewed research confirms a modelled 17.3 km³ fresh/brackish groundwater body beneath southern Sicily, but it was published in 2023; the claimed September 2026 Guardian “discovery” is unverified and its supplied URL returns 404.
Sicily leaves 17.3 billion cubic metres of water untapped
Scientists confirmed a massive deep reservoir under the island, but tapping it remains uncertain as conventional supplies hold.
In a nutshell
Scientists have confirmed that a massive body of ancient water containing an estimated 17.3 billion cubic metres lies trapped deep beneath southern Sicily, but none of it is currently being pumped. Mapped from old oil exploration logs rather than direct drilling, the water is largely brackish and buried up to 2,100 metres underground. While viral posts periodically present the reservoir as a newly discovered emergency drought cure, regional authorities continue to rely on standard dams, pipe repairs, and desalination plants while extraction from the deep rock remains unproven and unfinanced.
Highlights
- Computer models estimate 17.3 billion cubic metres of water lie between 800 and 2,100 metres beneath southern Sicily.
- Researchers mapped the formation by analysing historical data from 122 onshore and offshore oil and gas wells.
- Dissolved salt levels range from 2,000 to 20,000 milligrams per litre, meaning much of the water is too brackish to drink untreated.
- A separate study identified an offshore reserve containing approximately 3 billion cubic metres in a shallower formation.
- Sicily has built no extraction facilities for the deep reservoir, relying instead on 580 million cubic metres of reservoir storage and desalination plants.
Modelled groundwater volume by formation
cubic kilometresThe findingThe inland Gela formation holds nearly six times as much modelled groundwater as the offshore Ragusa reservoir.
- The modelled volume of trapped groundwater identified in southern Sicily's two distinct rock formations.
- Gela Formation — The deep inland rock layer 800 to 2,100 metres below sea level holding ancient trapped water
- Offshore Ragusa — A separate, shallower rock layer extending up to 10 kilometres off the Sicilian coast
- It shows the relative size of Sicily's two unconventional water reserves as authorities weigh development costs.
From the Editor’s Diary
Scientific evidence can reveal immense natural resources where industry previously sought oil, but locating trapped water deep underground is entirely different from delivering drinkable water to household taps.
Who's involved
Lorenzo Lipparini and the Gela-study research team
Geologists from Italian and Maltese research institutions
goal → Map the deep water reserve using old oil industry records and evaluate its volume
OFF-GROUND and the University of Malta
European Union research project and its lead academic institution
goal → Locate hidden groundwater trapped under Mediterranean rock formations
Sicilian regional government
The island authority responsible for managing regional water supplies during dry spells
goal → Decide whether tapping deep underground aquifers is safe and economically sensible
Southern Sicily water users
Local residents, farmers, and business owners coping with water restrictions
goal → Secure steady tap water if the deep reserve proves usable and affordable
In short
Sicily holds an estimated 17.3 billion cubic metres of deep groundwater that could buffer the island against severe drought, but none of it is currently reaching taps.
The most likely next step is technical appraisal drilling to test whether the deep water can be pumped safely, cleanly, and affordably.
Whether this ever happens is uncertain, because regional authorities rely on existing reservoirs and desalination plants rather than an unproven, costly deep drilling campaign.
How it unfolded
European project starts search under Sicily
A research initiative named OFF-GROUND started on 2 May 2022 to hunt for hidden groundwater in Mediterranean rock formations using old petroleum industry logs. The team, led by geoscientist Lorenzo Lipparini, posted its first public estimate on 13 April 2023, reporting an enormous body of trapped water beneath southern Sicily.
Scientific review confirms deep water model
Formal peer review confirmed the mathematical model behind the find, which reconstructs water trapped in cracked carbonate stone rather than an open cavern. The team analysed logs from 122 oil wells to map the rocks, running calculations that yielded the headline figure of 17.3 cubic kilometres. Official announcements in December framed the find as potentially drinkable, though much of the liquid is too salty to drink straight from the ground.
Summer drought brings calls for extraction
A punishing drought across Sicily in 2024 turned the academic study into a political talking point. Observers asked whether the deep reservoir could relieve emergency shortages, but experts cautioned that pumping water requires dedicated test wells, water quality screens, and cost studies. Regional president Renato Schifani said the reserve could help over the longer term, but only if practical tests prove it usable.
Research reveals a second offshore reserve
The research team later uncovered a separate, shallower body of water stretching about 10 kilometres out to sea inside the Ragusa rock formation. Published online in late 2025, the follow-up study estimated roughly 3 cubic kilometres of offshore groundwater. That project added to evidence of Mediterranean underground water but remained distinct from the deeper 17.3-cubic-kilometre onshore formation.
Social posts revive discovery while taps rely on dams
By 2026, Sicily's official water strategy relied entirely on traditional surface reservoirs, local pipe repairs, and coastal desalination plants. In September 2026, social media posts recirculated the 17-billion-cubic-metre claim as a brand-new discovery, citing a broken link to a purported British newspaper story. While the underground water is real and verified, no commercial pumping has taken place.
Where things stand
The existence of an immense deep groundwater reserve under southern Sicily is supported by scientific modelling, but it is not an instant fix for the island's water needs. The 17.3-cubic-kilometre volume is a computer calculation based on oil well logs and an assumed 1% rock fracture rate, not a direct measurement of water in an open chamber. The water's salt content ranges from mildly brackish to very salty, meaning it cannot be piped to homes without extensive chemical testing and desalination. Geologists believe rain soaked into the rock roughly six million years ago when the Mediterranean sea level dropped sharply, but no physical age test has verified every part of the reserve. Sicily has conducted no commercial extraction, leaving the water untouched until authorities fund dedicated test wells, quality checks, and yield measurements.