Water in Tunisia

Tunisia manages Mediterranean scarcity with North Africa's most established institutions, and it has spent recent years discovering their limits. A long drought cut national dam storage to 23% by September 2024,³⁰ forced night-time cuts in Tunis and other cities, and pushed the state into emergency mode. Quotas hit irrigation, desalination was fast-tracked at Sousse, Sfax and Zarat, and the reuse push built on decades of experience. A politically fragile state is now testing whether competence survives austerity.

In March 2023 the drought forced the first government rationing in Tunisia's history, with nightly cuts and bans on using drinking water for farms and car-washing.³¹³³ The response since has followed the regional playbook: desalination at Sfax, Zarat and Sousse, reuse expansion, and tariff reform that keeps the social block almost free while charging heavy users more.

A quick-reference dashboard for Tunisia: headline economy and water indicators⁵⁵⁵⁶, 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 Tunisia'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.

Tunisia covers 163,610 km², including 11,160 km² of lakes and chotts.²⁴ The Dorsal, an extension of the Atlas, runs diagonally across the country from Algeria. North of it lie fertile plains; to the south come hot, dry central steppes and then the Sahara.¹ The Medjerda, the longest river, flows from Algeria through the northern plains to the Gulf of Tunis.¹ Chott el Djerid, a vast salt lake, lies below sea level in the south.¹

A steep rainfall gradient

Average rainfall is 594 mm a year in the north, 296 mm in the centre and 156 mm in the south, and below 100 mm in the far south-west.²⁴ The north-west is wettest: Jendouba gets more than 900 mm, and Beja, Bizerte and Le Kef more than 700 mm.¹ National averages range from about 207 to 281 mm a year, depending on the dataset.²⁴¹ Single years swing from a third of the average to three times it.²⁴ Potential evapotranspiration of 1,200–1,800 mm a year far exceeds the rain.²⁴

Heat and drought

The mean annual temperature is 20.5 °C.¹ Tunisia has warmed by 0.46 °C a decade since 1971. Rainfall fell by 8.91 mm a decade between 1970 and 2020, a decline that is not statistically significant nationally.¹ Drought was officially declared in ten years between 1994 and 2016, and 2000–2002 was the worst in 50 years.²⁶ The national temperature record of 50.3 °C was set in August 2021.⁵ In 2024 the mean annual temperature reached 21.5 °C for the first time, 1.6 °C above the 1991–2020 average.³ August 2026 was the hottest August on record since 1950.⁴

Projections

Under a high-emissions pathway (SSP3-7.0), days above 35 °C rise from 57 a year to 84 by 2040–2059.¹ Rainfall is projected to fall by 7.9% over the same period, most in the rainier north-west. The heaviest 100-year rainfall events are projected to rise by 20% by 2050.¹ Sea level is projected to rise by 0.23 m by 2050 and 0.68 m by 2100.¹ Tunisia’s updated climate pledge rates 440 km of coastline, 26.6% of the total, as very highly vulnerable to marine submersion.²

Rainfall and temperature in numbers

Averaged over the whole of Tunisia, ERA5 reanalysis gives about 204 mm of rain a year and a mean temperature of 20.3 °C for 1991–2020. About 35% of that rain falls in October, January and March. Since 1971 the country has warmed by about 0.48 °C a decade. Average rainfall in 1993–2022 was about 10% 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.

Dams capture the north's surface water, interconnected by canals to supply Tunis and the Sahel. Central and southern groundwater, much of it fossil, irrigates dates and greenhouse crops and is overdrawn in the oases. Treated wastewater, a pioneer programme running since the 1980s, irrigates fodder, golf courses and orchards. Perception of its quality limits uptake. Desalination, long confined to Djerba in the south, is now scaling on the eastern seaboard.

The main rivers

The table ranks the rivers of Tunisia by the largest natural flow they reach inside the country. Natural flow is the modelled long-term average before any withdrawals. For a heavily used river it measures what the river could carry, not what arrives today.

Sources: Grill, Lehner, Thieme et al. (2019), Mapping the world’s free-flowing rivers, Nature 569, dataset under CC BY 4.0, for length, natural flow (WaterGAP, 1971–2000) and free-flowing status, meaning the share of the river’s length inside Tunisia still classed as free-flowing. No flow figure is given below 20 m³/s, where a global model is too coarse to rank small rivers. Dams from the FAO AQUASTAT regional inventories, matched to the nearest river reach, so a dam on a tributary close to a main stem can be counted against the main stem. The same rivers are drawn on the water map above under Rivers & lakes.

Tunisia already uses almost all the water it can capture. It mobilised 92% of its renewable resources in 2018.²⁷ Withdrawals rose from 2,640 million m³ in 2000 to 2,971 million m³ in 2007–08, and reached 3,305 million m³ in 2011.²⁴ In 2010 agriculture took 80%, municipalities 14%, industry 5% and tourism 1%. Dams supplied 35% of the water, deep groundwater 40% and shallow wells 22%.²⁴ Surface withdrawals swing with the rain, from 3,785 million m³ in 2004–05 to 1,151 million m³ in 2010–11.²⁴

From springs to drip

About 65,000 ha were irrigated at independence in 1956, mostly from springs and artesian wells.²⁴ Major works on the lower Medjerda were completed in 1960 and at Nebhana in 1970.²⁸ Equipped land reached 385,000 ha in 1991 and 459,570 ha in 2011. Private farmers equipped 216,400 ha of that, 150,000 ha of it on shallow groundwater.²⁴ Irrigated farming produced about 37% of agricultural output on 8% of farmland in 2018.²⁷

A national water-saving strategy began subsidising efficient irrigation in 1995, with support stepped up from 2006. Drip and other localised systems spread from 6,000 ha in 1991 to 62,000 ha in 2001 and 155,000 ha in 2012.²⁴ Much public equipment has aged. The Court of Audit found 61% of irrigation equipment obsolete across 156,000 ha of public schemes, where networks lose 43% of the water.³⁴

The northern system

The Medjerda is Tunisia’s only perennial river, and the northern basins supply 82% of its surface water.²⁴ A 1977 World Bank loan financed the Sidi Salem dam on the Medjerda and the canal to Cap Bon, to supply Greater Tunis and the Sahel.²⁸ Sidi Salem entered service in 1981 with an initial capacity of 814 million m³. By the 2018 survey, silt had taken 28.7% of it.³⁰

The long drought

Dam storage fell in steps through a run of dry years. On 1 September it stood at 64% in 2019, 44% in 2020, 33% in 2021 and 23% in 2024.³⁰ Sidi Salem, which serves Tunis, was 16.7% full on 28 March 2023.³⁰ Three days later SONEDE, the water utility, began cutting supply every night from 9pm to 4am. Using drinking water on farmland, green spaces and cars was banned.³¹ The 2023 grain crop was forecast at 200,000–250,000 tonnes, against 750,000 tonnes in 2022.³² The Tunisian Water Observatory recorded 2,153 unannounced cuts and 186 water protests in 2024.³⁴

Rain returned in 2025–26. Northern dams were close to 68% full in April 2026, and national storage reached about 60% in June.³⁵³⁶ Central dams such as Nebhana still had no inflows.³⁶

Aquifers under strain

Of 273 identified aquifers, 71 are overexploited, with use nearly 50% above renewal.²⁶ Shallow aquifers yielded 807 million m³ in 2007, against a potential of 745 million m³.²⁴ Counting illegal wells, the Court of Audit put groundwater use at 126% of available reserves.³⁴ In the Saharan oases of Djerid and Nefzaoua, deep fossil aquifers have been used intensively for farming.⁴⁴ Around Kebili the Continental Intercalaire has been heavily overexploited since 2000.⁴³ On Cap Bon, pumping since 1965 draws about 5.15 million m³ of seawater a year into the Korba aquifer.⁴⁵

Withdrawals over time

FAO’s AQUASTAT estimates put Tunisia’s freshwater withdrawals at 1,070 million m³ in 1975 and 3,864 million m³ in 2022. Agriculture’s share of the total moved from 86% in 1994 to 76% 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.

Tunisia has one of North Africa’s densest dam networks. The dams directorate’s bulletin of 1 September 2025 lists 36 dams with an initial capacity of 3,021 million m³.⁶ Silt has cut that to 2,368 million m³, and the loss grows by about 13 million m³ a year.⁶ Sidi Salem, commissioned in 1981, is the largest.³⁰ Sidi El Barrak, finished in 1999, holds 287 million m³.⁶ The old Mellègue dam shows the problem at its worst, with 81% of its capacity lost to silt.⁶

New dams and transfers

The Upper Mellègue dam in Le Kef was about 90% complete in August 2026, with around 200 million m³ of storage and a cost of TND 276 million.⁷ The 45 million m³ Douimis dam near Bizerte is to feed the Sejnane reservoir in the northern transfer system by the end of 2026.⁷ In February 2025 a ministerial council ordered work finished on four dams and reservoirs holding 318 million m³ in total.⁸ SONEDE is also laying about 28 km of large pipes to secure transfers of northern water to Cap Bon, the Sahel and Sfax.¹²

Desalination

SONEDE built its first desalination plant in 1983.¹³ Seawater plants now anchor supply in the south and east. Djerba’s 50,000 m³/day plant opened in 2018, and a plant of the same size at Zarat, near Gabès, followed in 2024.¹⁴¹⁵ The Sfax plant started its first unit in July 2024 with 100,000 m³/day, expandable to 250,000. JICA financed it at about TND 1 billion.¹⁶ A 50,000 m³/day plant at Sousse, paid for from the state budget, is linked to the northern water system.¹⁷

Networks and sanitation

SONEDE distributes water through 48,241 km of pipes and 1,412 reservoirs, and it supplied 667.9 million m³ in 2023.¹⁸ Rural coverage reached 95.5% in 2022: SONEDE served 54.1% of rural people and user-group systems 41.3%.¹⁹ Estimates of network losses vary widely, and one expert put them at about 50% in March 2026.²¹ ONAS runs 127 treatment plants and 18,437 km of sewers, and it treated 295.7 million m³ in 2024.²² Electricity is a weak link. In summer 2026, rotating power cuts stopped electric pumping stations and disrupted water distribution.⁵

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.

Rising salinity in coastal aquifers is Tunisia’s main water-quality problem, driven by irrigation demand and seawater intrusion.²⁴ At Korba, monitoring from 2006 to 2020 found a 5 m depression in the water table 4 km from the shore.⁴⁶ Elsewhere on Cap Bon, seawater contamination forced farmers to abandon plots and wells.³³ In the Sidi Bouzid basin, 76% of groundwater samples exceeded 30 mg/L of nitrate.⁴⁷ Near Kebili, oil and brine have contaminated wells, and one well carries water at 20 g/L of salt.⁴³

River water turns saltier in summer. In the lower Medjerda, salt content ran at 1–1.5 g/L in winter and 3–3.5 g/L in summer.²⁸ Monitoring at 12 sites in 2013 linked salinity to intensive farming, and ammonium, phosphate and organic load to towns.⁴⁸ Only 19% of Tunisians were satisfied with local water quality in 2022, a Gallup poll found.³³ Drinking-water networks lose about a quarter of their water.³⁴

Wastewater

ONAS, the sanitation office, served about 63% of the population in 2020. That year 24% of its treatment plants ran above hydraulic capacity, and 27% of effluent did not conform to standards.²⁹ Of 287 million m³ treated, 21 million m³ were reused directly and 41 million m³ indirectly.²⁹ Only 9,500 of 487,000 irrigated hectares can use treated wastewater.²⁹ In the south-east, 71% of plants failed to meet discharge standards consistently in 2019. A 2022 World Bank project lends €113.6 million to bring private operators into plants in northern Tunis and the south-east.²⁹

Gabès

The phosphate complex at Gabès is the main pollution source in its gulf, because most of its waste goes straight to sea untreated.⁵¹ About a hundred million tonnes of untreated phosphogypsum have been discharged since the complex was built.⁴⁹ Seawater near the plant is strongly to seriously affected.⁵⁰ The plant opened in 1972, and a 2017 government pledge to phase it out was not carried out.³⁷ In October 2025 a general strike shut the city after more than 200 people were hospitalised with breathing problems.³⁷ About 2,500 people marched again in December.³⁸ President Saied received a working group’s final report in January 2026 and visited Gabès in August.³⁹

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.

Tunisia shares the Medjerda with Algeria and its deep Saharan aquifers with Algeria and Libya. About 320 million m³ a year flows in from Algeria, 168 million m³ of it through the Medjerda basin.²⁴ A joint technical commission on water and the environment has served since 1984 as a forum for consultation and data exchange.²⁴ Formal frameworks for managing the Medjerda basin with Algeria were still to be defined in 2025, IUCN noted.⁴⁰

The North-Western Sahara Aquifer System

The system covers about 1.19 million km². Algeria holds 68%, Libya 24% and Tunisia 8%.²⁵ Pumping across the basin rose from about 0.6 billion m³ in 1970 to 3.2 billion m³ in 2018, against recharge of about 1 billion m³ a year.⁴¹ Scientists regard these waters as fossil and effectively non-renewable.⁵²

Cooperation has grown slowly. The Sahara and Sahel Observatory has hosted a light management structure since 2002. A permanent technical committee of the three water authorities has operated since 2008.²⁵ On 24 April 2024 the three governments signed an agreement in Algiers on consultation over the shared groundwater. Tunisia ratified it in January 2025.⁴²

The record

Shared river basins

Cooperation and conflict on the record, 1948 to 2008

The International Water Events Database scores every reported interaction between riparian states on the Basins at Risk scale, from formal war over water to voluntary unification. Cooperative and conflictive events add up to less than 100% because neutral events are counted too.

Source: Transboundary Freshwater Dispute Database, International Water Events Database, Oregon State University, as compiled by the Transboundary Waters Atlas. The series ends in 2008; every later dispute and agreement is outside it and is covered in the text above.

Shared aquifers

• Coastal Aquifer System of the Jeffara Plain / Système Aquifère Côtier de la Plaine de la DjeffaraLibya · data moderate
• Kasserine Aquifer SystemAlgeria · data moderate
• North-Western Sahara Aquifer System / Système Aquifère du Sahara SeptentrionalAlgeria, Libya · data good

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

Water sits under the Ministry of Agriculture. Its directorates-general assess resources, build and run large dams, manage irrigation and rural drinking water, and protect watersheds.²⁴ In each governorate, a regional agricultural development commission manages water resources and public irrigation schemes.²⁴ SONEDE, created in 1968, supplies drinking water.¹³ ONAS, created in 1974, runs sanitation.²³ More than 2,800 user groups managed small schemes in 2009, and a consultative National Water Council has advised the ministry since 2010.²⁴

A water code still in revision

The Water Code dates from 1975 and was amended in 1987, 1988 and 2001.²⁴ A 2015 attempt at a new code met trade-union resistance over fears of privatisation.³³ A parliamentary committee adopted draft law 66/2019 in June 2021. It would have handed rural water to SONEDE and ended the user-group system.⁹ A redraft went to the prime minister’s office in January 2023.¹⁰ In February 2025 the government ordered a final version, and by April 2026 the code was still under revision.⁸³⁵ The Eau 2050 strategy aims to cut agriculture’s share of water from 80% to 70% and raise network efficiency from 67% to 85%.³⁴

Tariffs and private operators

Drinking-water tariffs follow one national scale of six quarterly bands, set by ministerial order.²⁰ Under a five-year plan to rescue SONEDE’s finances, prices rise by about 150 millimes a year. The fourth increase came in March 2024, while the lowest band stayed at 200 millimes per m³.¹¹ Irrigation tariffs were frozen from 2002 and covered only 50–60% of operating costs in 2018.²⁷ ONAS has used private operators since a 1997 pilot on 185 km of Greater Tunis sewers. Under the 2015 PPP law its new performance contracts run for ten years.²⁹

Tunisia’s water future rides on its fiscal one. The next drought will test three weak points at once: dams losing capacity to silt, networks losing water to leaks, and a power grid that can stop the pumps.⁶²¹⁵ Desalination at Djerba, Zarat, Sfax and Sousse eases the coast, but the northern dam system still decides whether Tunis faces rationing again.

The institutional agenda is overdue. A new Water Code has been in draft since 2019, and the action plans for Eau 2050 are still being prepared.³⁵³⁴ Projections point to less rain in the wetter north-west and heavier downpours.¹ That puts storage, flood protection and demand reform in agriculture at the centre of any plan, and all three need finance the state struggles to raise.