Water in Yemen

Yemen is the region's groundwater emergency. A mountain nation that fed itself for millennia on terraced rain and spate floods converted, in two generations, to tubewell irrigation, much of it growing qat, and pumped its basins toward exhaustion. Sanaa's aquifer falls metres per year, and the capital has been discussed as the first that might functionally run dry. A decade of war broke what management existed. Today tankers deliver much of the water, solar pumps accelerate the drawdown, and cholera has followed the failed networks.

The numbers behind the emergency have held for decades. Highland water tables commonly fall 2–6 m a year, and in the Sanaa basin as fast as 5 m.¹⁵¹⁸ The cholera epidemic that began in 2016 passed two million suspected cases by December 2020, the largest documented in modern times.¹⁹²⁰ Researchers link it directly to the destruction of water and sanitation infrastructure since 2015.²²

A quick-reference dashboard for Yemen: headline economy and water indicators³²³³, water stress against the scarcity thresholds, non-conventional supply, and the institutions behind the sector. The commercial picture, with buyers, deal structures and the project pipeline, is in the market brief.

One interactive map of Yemen's water, built from real geodata. Climate & drought maps the aridity gradient (WorldClim) with warming projections. The WRI Aqueduct layers, covering overall water risk, water stress and flood risk (plus groundwater decline where the trend is significant), shade every river sub-basin by its 0–5 risk score. Demand shows where the population, and the water demand, concentrate. Infrastructure brings the physical system together: rivers, dams (FAO AQUASTAT), treatment plants, desalination and the major conveyors. Hover any sub-basin or marker for detail; sources are cited under each view.

Yemen covers 527,970 km² on the south-western corner of the Arabian Peninsula, with about 2,200 km of coast on the Red Sea, the Gulf of Aden and the Arabian Sea.¹⁵³ It has no perennial rivers and depends entirely on rainfall, groundwater and flash floods.¹⁷

Four landscapes

The Tihama and the southern coastal plains are flat and hot, with temperatures of 27–42 °C and less than 200 mm of rain a year.¹⁵ Behind them the mountain massif rises to 3,760 m. Its steep western and southern slopes catch 300–500 mm a year on average, and more than 1,000 mm in places.¹⁵ The eastern plateau around Hadramawt falls from 1,800 m to the desert edge and gets under 100 mm, though its floods can be devastating.¹⁵ The Ramlat as-Sab’atayn sand desert lies between the two, and the Rub’ al Khali runs north into Saudi Arabia.¹⁵

Two rainy seasons

Rain comes in two seasons. The Red Sea Convergence Zone brings it to the western highlands from March to May, and the monsoon belt reaches Yemen from July to September.¹⁵ Estimates of the national average differ by dataset, from about 150 to 190 mm a year.¹ The western highlands receive 200–600 mm, while the coastal plains and eastern deserts often get under 50 mm.¹ The national mean temperature is 25.5 °C.¹ It ranges from 10–22 °C in the highlands to the western coastal plain, where temperatures above 50 °C are common.²

A warmer, more extreme climate

Yemen warmed by 0.42 °C a decade between 1971 and 2020, fastest in Al Jawf.¹ Rainfall fell slightly, by 6.25 mm a decade, a trend the World Bank does not treat as significant.¹ Extremes are the sharper story. Cyclones Chapala and Megh struck in November 2015, and on Socotra they damaged water pipelines and wells.⁴ Floods between April and November 2024 affected more than 688,000 people, killed 240 and destroyed numerous water sources.⁵ The same year brought severe drought as well.¹ More than five million people are exposed to temperatures over 35 °C, mostly in Hodeidah, Aden and Hadramawt.¹

Projections

The World Bank projects national temperatures up to 1.69 °C higher by 2050 under a pessimistic scenario.¹ Rainfall is projected to rise in every scenario, by 15% even in the pessimistic case and by up to 43%.¹ It is expected to fall in more intense bursts between longer, hotter dry spells.¹ Under one scenario in Yemen’s second national communication, the sea at Aden rises by 0.25 m by 2050 and 0.54 m by 2100.² Demand keeps climbing regardless: total water demand is projected to reach 3.9 billion m³ by 2050.¹

Rainfall and temperature in numbers

Averaged over the whole of Yemen, ERA5 reanalysis gives about 147 mm of rain a year and a mean temperature of 25.8 °C for 1991–2020. About 45% of that rain falls in July, August and September, and 3 months average less than 5 mm. Since 1971 the country has warmed by about 0.39 °C a decade. Average rainfall in 1993–2022 was about 22% lower than in 1951–1980, and single years swing widely around that.

Projected change

Source: World Bank Climate Change Knowledge Portal, retrieved September 2026. ERA5 0.25° reanalysis for the annual series (1950–2022) and the monthly climatology (1991–2020); CMIP6 0.25° multi-model ensemble median for the projections, as change against 1995–2014. These are national averages, which hide the gap between wet highlands and dry interiors, and reanalysis rainfall over deserts carries wide uncertainty.

Yemen receives 67–93 km³ of rain a year, concentrated on the western and south-western highlands.¹⁵ Renewable resources of about 2,100 million m³ a year are topped up by mining deep aquifers.¹⁷ The World Bank’s 2024 water balance puts total runoff at 2.5 billion m³, of which 1.0 billion m³ is available for spate diversion. It puts average groundwater recharge at around 316 million m³.¹ Other estimates differ widely: FAO put renewable groundwater at about 1.5 km³ a year.¹⁵

The aquifers are layered. In the Sanaa basin, a shallow alluvial aquifer lies above the deep Tawilah sandstone, which policy aimed to keep for the city’s drinking water.¹⁸ In the Tihama, Wadi Surdud crosses a mountain aquifer, a shallow wadi aquifer and a coastal aquifer.² Surface runoff of about 270 million m³ a year still reaches the sea.¹⁵ Desalination and reclaimed wastewater remain negligible.¹⁷

Yemen began mining its groundwater in the mid-1980s, when use first exceeded recharge.¹⁷ Total withdrawal rose from 2.9 km³ in 1990 to 3.4 km³ in 2000. That year agriculture took 90%, municipal use 8% and industry 2%.¹⁵ In 2005 renewable resources of about 2,100 million m³ a year were topped up by about 1,300 million m³ mined from deep aquifers.¹⁷ Irrigation alone consumed 130% of renewable resources by 1990 and more than 150% by 2005.¹⁷

The tubewell boom

Private drilling did the damage. FAO counted 52,000–55,000 active wells and about 800 drilling rigs, mostly unpermitted. In May 2005 only 70 rigs and 1,000 wells were licensed.¹⁵ Highland water tables commonly fall 2–6 m a year, and over-pumping on the coasts draws in seawater.¹⁵ Regulation came late. The Water Law was enacted in August 2002, and that November the cabinet declared Sadah, Sanaa and Taiz protected areas.¹⁵ Diesel price rises were tried as a brake, but the World Bank found no measured effect on groundwater overdraft.¹⁷

Qat

Qat covered 122,844 ha in 2004, 10% of the cultivated area, and 99,504 ha of it was irrigated.¹⁵ Its area more than tripled in 25 years.¹⁵ The World Bank did not consider qat a heavy water user. But its area was growing 9% a year, so it took a rising share of the water, and in some areas half of irrigation abstraction went to it.¹⁷ By the 2009 census qat covered 11.3% of cultivated land and made up 41% of the value of farm output.²³ A national debate on qat, launched in 1999, had no discernible effect on behaviour.¹⁷

The Sanaa basin

Irrigated land in the Sanaa basin grew from under 3,000 ha in 1985 to about 23,400 ha in 2000. About 13,000 wells were drilled without regulation, helped by a 90% subsidy on pump diesel.¹⁶ By 2005 abstraction of about 250 million m³ a year was more than four times the nominal recharge of 42 million m³.¹⁷ The World Bank warned that the deep fossil water could be exhausted within twenty years if nothing changed.¹⁷ Between 2005 and 2009, 614 wells were dug illegally in the basin, against 106 licensed.¹⁸

Spate floods and dams

All 454,310 ha of fully or partly controlled irrigation drew on groundwater in 2004, most of it from tubewells.¹⁵ Spate irrigation swings with the floods. Its command area of 217,541 ha was fully irrigated in 2001, but only 89,363 ha were watered in 2004.¹⁵ The rebuilt Marib Dam, financed by the UAE, holds 400 million m³. Irrigation efficiency runs at only 35–45%.¹⁵

Cities and war

Aden’s Bir Nasr well field fell more than 8 m between 1998 and 2003. By mid-2004 the city’s 24-hour supply had been cut to 12 hours.¹⁷ Since 2015 private tankers have supplied about 40% of the urban population.²² Solar panel sales rose more than 2,000% between 2015 and 2016. Solar power increasingly pumps the private wells of powerful elites, for farming and for sale to tankers.²² In August 2026 Aden began preparing a Saudi-financed seawater desalination plant with a first phase of about 10,000 m³ a day.²⁶ Rising fuel and freight costs were pushing up the cost of trucked water in mid-2026.²⁷

Withdrawals over time

FAO’s AQUASTAT estimates put Yemen’s freshwater withdrawals at 2,922 million m³ in 1990 and 3,565 million m³ in 2022. Agriculture’s share of the total moved from 91% in 1994 to 91% in 2022.

Source: FAO AQUASTAT via the World Bank World Development Indicators, retrieved September 2026. AQUASTAT revises national figures irregularly and fills the years between surveys, so a jump between two adjacent years usually marks a new national estimate rather than a change on the ground.

Yemen’s water infrastructure is small-scale, ageing and badly damaged. Most of its dams are small: FAO counted 347 storage dams, and the rebuilt Marib Dam holds 400 million m³.¹⁵ Displacement to Marib has increased the population at risk downstream of that dam.¹ In 2005 the World Bank judged spending on watershed dams poor and called for an overhaul of the dams programme.¹⁷

Spate and groundwater schemes

Donor projects rebuilt traditional flood irrigation. The Irrigation Improvement Project improved irrigation and flood control on 26,000 ha in Wadi Tuban and Wadi Zabid.⁶ A groundwater and soil conservation project delivered 62 small and medium spate schemes and equipped 50,868 ha with modern irrigation by 2012.⁷ Around Sanaa, 11 recharge dams were rehabilitated by 2010.¹⁸ Monitoring has since collapsed. Of the 354 stations the water resources authority ran in 2010, 70% are out of service, destroyed or stolen.¹

Networks and the war

In 2008, 56% of urban residents had piped water and 31% had sewerage.⁸ By 2021 public networks covered only a third of city dwellers, down from half before the war.⁹ A World Bank assessment of 16 cities in 2020 found 38% of water and sanitation assets damaged or destroyed.¹² Both desalination plants assessed had been destroyed. Of 493 wells, 172 were damaged or destroyed, as were 45% of the primary and transmission mains.¹² Damage to the sector was put at US$421–515 million.¹²

Rebuilding runs through the UN. The first World Bank urban services emergency project reached more than 1.2 million people and put solar power on municipal and rural wells.¹⁰ Its successor, approved in June 2021, had restored water to 924,103 people by April 2026, 92% of its target.¹¹

The asset base in numbers

Sources: FAO AQUASTAT regional dam inventories (CC BY 4.0), which list large dams with a published capacity and can lag recent construction; the MENA Water Review major projects register, where each record cites its source on the project page. The database follows large contracted projects, not the whole asset base.

Over-pumping has turned coastal groundwater salty. At Al-Jar in the Tihama, 8 km from the Red Sea, conductivity rose from 225 to 3,480 µS/cm after about 2,000 wells were drilled for mango orchards.¹⁵ The Red Sea and western Gulf of Aden coastal aquifers face rapid depletion and seawater intrusion.¹⁷ In the Sanaa basin, groundwater has deteriorated mainly downstream of land irrigated with wastewater.¹⁶

Treatment plants were overloaded long before the war. Sanaa’s plant, designed for 25,000 m³ a day, received more than 50,000 m³.¹⁵ Of 74 million m³ of wastewater produced in 2000, only 6 million m³ a year was reused in farming. Uncontrolled reuse watered vegetables and fruit around Sanaa.¹⁵

Cholera

Before the war, Yemen reported cholera in 10 of the 40 years from 1971 to 2010. An outbreak in 2011 caused 31,789 cases and 45 deaths.¹⁹ Between April 2015 and December 2017, the Yemen Data Project documented 74 airstrikes on water infrastructure, including desalination and bottling plants.²¹ From 28 September 2016 to 12 March 2018, 1,103,683 suspected cholera cases and 2,385 deaths were reported.¹⁹ By December 2020 suspected cases had passed two million, with more than 3,500 deaths.²⁰ Cholera surged again in 2024, with 260,552 cases and 879 deaths reported.²⁰ In 2026 cases fell sharply, to 6,625 suspected by 9 August.²⁸

The need remains vast. In June 2026, 14.4 million people required humanitarian water and sanitation assistance, and only 14% of the US$178.7 million appeal was funded.²⁹ Water scarcity affects 301 of Yemen’s 333 districts.²⁹

The reported indicators

Sources: WHO/UNICEF Joint Monitoring Programme via the World Bank; SDG 6.3.1 and 6.3.2 from the UN Statistics Division SDG database, retrieved September 2026. Safely managed means an improved source on the premises, available when needed and free from priority contamination. SDG 6.3.2 rests on each country’s own monitoring network, so a high share can mean few water bodies were assessed, and values move when methods change between reporting rounds.

Yemen has no perennial transboundary river. Some groundwater and surface drainage may cross into Saudi Arabia, but FAO found no data on it.¹⁵ Its shared waters are deep aquifers with Saudi Arabia and Oman, and none is covered by a water agreement.²⁴²⁵

The aquifers

The Wasia–Biyadh–Aruma system, shared with Saudi Arabia, covers about 157,000 km² and holds fresh water. Its maximum extraction potential is estimated at about 500 billion m³.²⁴ Use is limited to nomads and the Sharurah–Al Abr border posts. ESCWA sees the aquifer as a possible future source for Najran and Sa’dah.²⁴ Natural uranium in the sandstone may pose a radionuclide risk, and no cooperation between the two states has been reported.²⁴

The southern Umm er Radhuma–Dammam system is shared by Oman, Saudi Arabia, the UAE and Yemen. It covers 678,000 km², of which 72,000 km² lie under Yemen’s Hadhramaut–Al Mahra plateau.²⁵ ESCWA flags the border area where Oman, Saudi Arabia and Yemen meet as a candidate for joint management.²⁵

War across the border

The war has put water infrastructure in the line of fire beyond Yemen too. The Houthis attacked desalination plants in Saudi Arabia in 2022.³⁰ On 20 July 2026 the Sanaa-based authorities declared a maritime blockade of Saudi ports, and Saudi Arabia struck Houthi-held Al-Hudaydah.²⁷

The record

Shared aquifers

• Umm er Radhuma-Dammam Aquifer System (South): Rub' al KhaliOman, Saudi Arabia, UAE · data moderate
• Wajid Aquifer SystemSaudi Arabia · data good
• Wasia-Biyadh-Aruma Aquifer System (South): Tawila-Mahra/Cretaceous SandsSaudi Arabia · data moderate

Source: IGRAC and UNESCO, Transboundary Aquifers of the World. Data reliability is IGRAC’s own assessment of the information behind each outline.

Yemen built its water institutions in layers. A national urban utility was set up in the 1980s and a rural water authority in the early 1990s.¹⁷ The National Water Resources Authority followed in 1996.⁸ The Ministry of Water and Environment was created in 2003.¹⁵ A 1997 reform plan began handing urban water to local corporations.⁸ The Water Law of 2002, amended in 2006, remains the legal base.¹⁵

Reform stalled before the war. By 2009 tariff increases were mired in local and national politics, and little progress had been made on private participation.⁸ Tariffs are set locally. In 2005 the World Bank judged Sanaa’s structure neither pro-poor nor water-conserving.¹⁷ The update of the national water strategy aimed for full urban cost recovery by 2015.⁸

The war split the state. The internationally recognised government sits in Aden, while the Houthi authorities in Sanaa control areas holding about 70% of the population.¹ Agricultural services now run through separate ministries on each side.¹ By 2021 line ministries and local authorities could no longer deliver urban services, so donor projects worked through the UN with the local water corporations.⁹ Civil society fills part of the gap: a 2026 mapping examined 53 organisations working in water.¹³

Any Yemeni recovery is a water programme first. The immediate task is repair: networks, wells and treatment plants damaged in the war, and a monitoring network that has largely gone dark.¹²¹ The longer task is groundwater. The World Bank’s warning that Sanaa’s deep fossil water could run out within twenty years dates from 2005, and pumping has since shifted to solar power.¹⁷¹⁴

Climate adds a twist. Rainfall is projected to rise, but in more intense bursts, so spate systems, terraces and flood protection matter as much as new supply.¹ Long-term security of municipal supply may require desalination, but only with a better enabling environment.¹ The engineering is modest by Gulf standards. The state-building is not.