Water in Tunisia

Tunisia receives most of its rain in the north, where dams capture it and canals carry it to Tunis and the SahelSahel (Tunisia) Al-Sāḥil, one of the large plains on Tunisia’s eastern coast, lying south of Sousse. Source: Tunisia, Encyclopædia Britannica. The centre and south rely on groundwater; in the south, much of it is fossil waterFossil water Groundwater held in deep aquifers that renew very slowly, by less than 1% a year, so it is treated as non-renewable. Source: Fossil groundwater: abstraction, UN ESCWA Sustainable Development Glossary (FAO AQUASTAT definition).¹ The country already uses almost all the water it can capture.² Recent droughts brought rationing, and seawater desalination plants have since entered service along the eastern coast.^3 4 5 Silting dams, leaking networks and a water code still under revision will all shape what comes next.^6 7 8

Tunisia’s cities have long drawn their water from far away. In the 2nd century AD, a Roman aqueduct system, about 132 km in all, carried spring water from Mount Zaghouan to Carthage.^9 10 It was destroyed and rebuilt in sections several times. Restored and brought back into service in 1862, it still supplies Tunis.¹⁰ In Kairouan, the AghlabidAghlabids An Arab Muslim dynasty that ruled Ifrīqīyah (Tunisia and eastern Algeria) from 800 to 909, with its capital at Kairouan. Its public works for storing and distributing water helped the country prosper. Source: Aghlabid dynasty, Encyclopædia Britannica basins, built in the 860s, stored water for the town; the larger pool holds more than 57,000 m³.^11 12 At independence in 1956, about 65,000 ha were irrigated, mostly from springs and artesian wells.¹ The state then turned to dams. The Sidi Salem dam on the Medjerda, the country’s longest river, entered service in 1981 to supply Greater Tunis and the Sahel,^13 14 and water from the north now reaches as far as Sfax.¹⁵

Drought has exposed the limits of that system. A run of dry years drew down the dams, and in March 2023 the water utility began cutting supply every night, the first government rationing in Tunisia’s history.^3 16 Groundwater offers little reserve: 71 of 273 identified aquifers are overexploited.¹⁷ Tunisia has turned to the sea, with desalination plants entering service at Sfax in 2024 and at Sousse in 2026.^4 5 Rain returned in 2025 and 2026, and national storage reached about 60% in June 2026,¹⁸ but silt keeps reducing what the dams can hold.⁶

One interactive map of Tunisia's water, built from real geodata. Climate & drought maps the aridity gradient (WorldClim) with warming projections. The Water risk layer's WRI Aqueduct indicators, 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. Shared waters outlines the transboundary river basins and aquifers that Tunisia shares with other countries, each drawn in full across the border; hover an outline for the countries that share it. 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.¹ 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.²³ The Medjerda, the longest river, flows from Algeria through the northern plains to the Gulf of Tunis.²³ Chott el Djerid, a vast salt lake, lies below sea level in the south.²³

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.¹ The north-west is wettest: Jendouba gets more than 900 mm, and Beja, Bizerte and Le Kef more than 700 mm.²³ National averages range from about 207 to 281 mm a year, depending on the dataset.^1 23 Single years swing from a third of the average to three times it.¹ Potential evapotranspiration of 1,200–1,800 mm a year far exceeds the rain.¹

In the World Bank Climate Change Knowledge Portal’s ERA5 reanalysis, averaged over the whole of Tunisia, about 204 mm of rain falls in a year (1991–2020). Station records and national averages use other sources and baselines, so their figures can differ (the text cites national averages of about 207 mm from FAO and 281 mm for 1991–2020 in the World Bank profile). About 35% of the rain falls in October, January and March. Average rainfall in 1993–2022 was about 10% lower than in 1951–1980, and single years swing widely around that.

Heat and drought

The mean annual temperature is 20.5 °C.²³ Tunisia warmed by 0.46 °C a decade over 1971–2020. Rainfall fell by 8.91 mm a decade between 1970 and 2020, a decline that is not statistically significant nationally.²³ Drought was officially declared in ten years between 1994 and 2016, and 2000–2002 was the worst in 50 years.¹⁷ The national temperature record of 50.3 °C was set in August 2021.²⁴ In 2024 the mean annual temperature reached 21.5 °C for the first time, 1.6 °C above the 1991–2020 average.²⁵ August 2026 was the hottest August on record since 1950.²⁶

The same reanalysis gives a mean temperature of 20.3 °C for 1991–2020 and a warming of about 0.48 °C a decade over 1971–2022. Station records and national reports use other sources and periods, so their warming rates can differ (the text cites 0.46 °C a decade over 1971–2020 in the World Bank profile).

Projections

Under a high-emissions pathway (SSP3-7.0), days above 35 °C rise from 57 a year to 84 by 2040–2059.²³ Rainfall is projected to fall by 7.9% over the same period, most in the rainier north-west. Rainfall events now expected once a century are projected to become 20% more frequent by 2050.²³ Sea level is projected to rise by 0.23 m by 2050 and 0.68 m by 2100.²³ Tunisia’s updated climate pledge rates 440 km of coastline, 26.6% of the total, as very highly vulnerable to marine submersion and erosion.²⁷

Projected change for Tunisia

The table gives the CMIP6 multi-model median from the same World Bank portal, as change against 1995–2014. Projections cited in the text may use other models, scenarios or baselines, so their figures can differ.

Dams capture the north's surface water, interconnected by canals to supply Tunis and the Sahel. Southern groundwater, much of it fossil, irrigates the date-palm oases and is overdrawn there; the centre draws on deep and shallow aquifers of medium to poor quality.¹ Treated wastewater, reused in Tunisia since 1965, irrigates fodder, fruit trees and golf courses.^28 29 Uneven effluent quality and unreliable supply limit uptake.²⁹ Desalination, long established at brackish-water plants in Kerkennah, Gabès, Zarzis and Djerba, is now expanding along the eastern coast.^{1 4 30 5}

The Medjerda is Tunisia’s only perennial river, and the northern basins supply 82% of the country’s surface water.¹ In 2011 dams supplied 35% of the water, deep groundwater 40% and shallow wells 22%, in FAO’s 2015 profile; AQUASTAT’s split for 2023 is charted below. Surface withdrawals swing with the rain, from 3,785 million m³ in 2004–05 to 1,151 million m³ in 2010–11.¹ Dam storage and its swings through the drought are covered under Infrastructure.

Aquifers under strain

Of 273 identified aquifers, 71 are overexploited, with use nearly 50% above renewal.¹⁷ Shallow aquifers yielded 807 million m³ in 2007, against a potential of 745 million m³.¹ Counting illegal wells, the Court of Audit put groundwater use at 126% of available reserves.⁷ In the Saharan oases of Nefzaoua, deep fossil aquifers have been used intensively for farming.³¹ Around Kebili the Continental Intercalaire has been heavily overexploited since 2000.³² On Cap Bon, a model study found that overexploitation since 1965 has induced a seawater inflow of about 5.15 million m³ a year into the Korba aquifer.³³ At Korba, monitoring from 2006 to 2020 found a 5 m depression in the water table 4 km from the shore.³⁴

Supply by source

The main river

The main river of Tunisia in the dataset is the Medjerda, which also flows through Algeria. It runs 303 km in Tunisia; its modelled natural flow, the long-term average before any withdrawals, reaches 75 m³/s inside the country, and 0% of that length is still classed as free-flowing.

The dams on it, from the FAO AQUASTAT inventory, are listed river by river under Infrastructure.

Tunisia already uses almost all the water it can capture. It mobilised 92% of its renewable resources in 2018.² Withdrawals rose from 2,640 million m³ in 2000 to 2,971 million m³ in 2007–08, and reached 3,305 million m³ in 2011.¹ In 2010 agriculture took 80%, municipalities 14%, industry 5% and tourism 1%.¹

From springs to drip

About 65,000 ha were irrigated at independence in 1956, mostly from springs and artesian wells.¹ Major works on the lower Medjerda were completed in 1960 and at Nebhana in 1970.¹³ 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.¹ Irrigated farming produced about 37% of agricultural output on 8% of farmland in 2018.²

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 2012.¹ Much public equipment has aged. The Court of Audit, in its report published in 2021, found about 61% of the equipment of irrigated areas covering 156,160 ha obsolete and more than 25 years old. It put water losses in the networks that convey and distribute irrigation water at 43% of all the water conveyed and distributed between 2013 and October 2019, a figure that includes losses within farms.³⁵

The long drought

In late March 2023, as the reservoirs ran low (see Infrastructure), SONEDE, the water utility, began cutting supply every night from 9pm to 4am. Using drinking water on farmland, green spaces and cars was banned.³ The 2023 grain crop was forecast at 200,000–250,000 tonnes, against 750,000 tonnes in 2022.³⁶ The Tunisian Water Observatory recorded 2,153 unannounced cuts and 186 water protests in 2024.⁷

Use by sector

Withdrawals over time

The World Bank series charted below carries FAO AQUASTAT’s estimate of Tunisia’s freshwater withdrawals at 1,070 million m³ in 1975 and 3,864 million m³ in 2020; AQUASTAT’s newer estimate is 3,822 million m³ in 2023. Agriculture’s share of total withdrawals fell from 86% in 1994 to 76% in 2020 in the World Bank series; AQUASTAT’s 2023 share is in the split above.²⁰

The ministry counts irrigated perimeters of about 445,000 ha in 2025: 253,000 ha of public perimeters and, on its earlier estimates, around 192,000 ha of private ones, irrigated mainly with groundwater.³⁹ Of the public perimeters, 157,000 ha are served by large dams, 82,280 ha by groundwater, mostly in the south and centre, 5,900 ha by hillside dams and lakes and 1,179 ha by treated wastewater.³⁹ In 2025 the agriculture quota from the dams was 70 million m³, of which almost 48 million m³ was used.³⁹ Agriculture takes about 86% of the 3,217 million m³ of groundwater withdrawn in 2024, a rate of exploitation of 133%, with about 827 million m³ from unauthorised boreholes.³⁹ The national supply mix is under Water resources, and the equipped area since independence under Water use.

Methods and programmes

Water-saving equipment covered 428,500 ha in 2024, or 96.9% of irrigated perimeters; the national programme has invested 1,727 million dinars since 1995, 782.5 million of it as subsidies to farmers.^44 39

The Bank-financed Irrigated Agriculture Intensification Project, which was due to close on 30 June 2026, reported 16,832 ha with new or improved irrigation services on 5 June 2026 against a target of 24,371 ha, 69%, and efficiency of 62% in the two schemes that had finished modernising.⁴⁵ Of 1,318 user groups for public irrigation perimeters in 2025, 46% had a signed management contract with the regional commission and 16% an audited financial report.³⁹ In 2025 the commissions charged the groups 47 to 205 millimes per m³, and the directorate-general put average cost recovery at 79%.³⁹ The Bank approved a follow-on project of US$124 million in March 2026 for four northern governorates.⁴⁶ Governance and the draft Water Code are under Governance & institutions.

Treated wastewater

The ministry counts 7,819 ha of perimeters equipped for treated wastewater in 2025, of which 1,817 ha were irrigated. Irrigation took 4.4 million m³ in 2024/25, against 11.3 million in 2023/24.³⁹ It put the fall down to poorer effluent: 15 plants feeding perimeters had salmonella or non-cholera vibrios and irrigation stopped.³⁹ Wider reuse of all kinds reached 64.9 million m³ in 2024, about 22% of treated wastewater.³⁹ Tunisian rules since 1994 limit treated wastewater to industrial and fodder crops, forests and fruit trees, and bar crops eaten raw.²⁹ The TANIT project, launched with Italy on 3 November 2025, is to bring treated water from five plants to farms of the state land office, about 11,500 ha in all; the ministry reports that financing is approved and the agreement still under negotiation.^47 39 The ministry says reuse in irrigation remains far below the goals of its Eau 2050 plan, which sees treated water irrigating about 40,000 ha by 2050.³⁹ Plants are under Infrastructure; reuse and irrigation projects across the region are on the Agriculture & Food hub.

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, on the Medjerda, is the largest. A 1977 World Bank loan partly financed it and the canal to Cap Bon, to supply Greater Tunis and the Sahel.¹³ It entered service in 1981 with an initial capacity of 814 million m³; by the 2018 survey, silt had taken 28.7% of it.¹⁴ Sidi El Barrak, finished in 1999, holds 286.5 million m³.⁶ The old Mellègue dam shows the problem at its worst, with 81% of its capacity lost to silt.⁶

Tracked projects

Open the project database for Tunisia

Storage through the 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 2024.¹⁴ Sidi Salem, which serves Tunis, was 16.7% full on 28 March 2023.¹⁴

Rain returned in 2025–26. Northern dams were close to 68% full in April 2026, and national storage reached about 60% in June.^8 18 Central dams such as Nebhana still had no inflows.¹⁸

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.⁴⁸ The 45 million m³ Douimis dam near Bizerte is to feed the Sejnane reservoir in the northern transfer system by the end of 2026.⁴⁸ In February 2025 a ministerial council ordered work finished on four dams and reservoirs holding 318 million m³ in total.⁴⁹ SONEDE also plans about 28 km of large mains, financed by an AFD loan, to secure transfers of northern water to Cap Bon, the Sahel and Sfax.¹⁵

Desalination

SONEDE built its first desalination plant in 1983.⁵⁰ 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.^51 30 The Sfax plant, built for 100,000 m³/day and expandable to 250,000, started its first unit in July 2024 and reached full output in September 2024.⁴ Its updated estimated cost is about TND 1.18 billion,⁵² including a JICA loan of about TND 800 million.⁵³ A 50,000 m³/day plant at Sousse, paid for from the state budget and linked to the Northern Waters system, entered service in September 2026.^54 5

Networks and sanitation

SONEDE distributes water through 48,241 km of pipes and 1,412 reservoirs, and it supplied 667.9 million m³ in 2023.⁵⁵ Rural coverage reached 95.5% in 2022: 54.1% of rural people were supplied by SONEDE and 41.3% by the Génie Rural, the rural engineering service.⁵⁶ Estimates of drinking-water network losses range from about a quarter to about half: the coordinator of the Tunisian Water Observatory puts them at about 25% of the country’s potable water,⁷ and one expert put them at about 50% of SONEDE’s water in March 2026.⁵⁷ The Eau 2050 strategy aims to raise the efficiency of drinking-water and irrigation networks together from 67% to 85% by 2050.⁷ For public irrigation networks alone, the ministry’s 2025 water report gives an average efficiency of about 60% and an aim of 80%.³⁹ ONAS runs 127 treatment plants and 18,437 km of sewers, and it treated 295.7 million m³ in 2024.⁵⁸ Of 287 million m³ treated in 2020, 21 million m³ were reused directly and 41 million m³ indirectly, and that year 24% of the treatment plants ran above hydraulic capacity. ONAS served about 63% of the population when the World Bank appraised its 2022 project, which lends €113.6 million to bring private operators into plants in northern Tunis and the south-east. Only 9,500 of the 487,000 hectares equipped for irrigation it counts can be irrigated directly with treated wastewater.⁵⁹ Electricity is a weak link. In summer 2026, rotating power cuts stopped electric pumping stations and disrupted water distribution.²⁴

Dams and reservoirs

Rising salinity in coastal aquifers is Tunisia’s main water-quality problem, driven by irrigation demand and seawater intrusion.¹ On Cap Bon, seawater contamination forced farmers to abandon plots and wells.¹⁶ In the Sidi Bouzid basin, 76% of groundwater samples exceeded 30 mg/L of nitrate.⁶⁰ Near Kebili, oil and brine have contaminated wells, and one well carries water at 20 g/L of salt.³²

River water turns saltier in summer. In the lower Medjerda, a World Bank appraisal of 1982 reported salt content of 1–1.5 g/L in winter and 3–3.5 g/L in summer.¹³ Monthly monitoring at 12 sites during 2013 linked salinity to intensive farming, and ammonium, phosphate and organic load to urban sites.⁶¹ In 2022 only 19% of Tunisians said they were satisfied with the quality of water in their city or area, according to a Gallup poll.¹⁶

Wastewater

In 2020, 27% of the effluent of ONAS, the sanitation office, did not conform to standards. In the two areas of the World Bank’s 2022 project (see Infrastructure), northern Tunis and the south-east, 71% of plants failed to meet discharge standards consistently in 2019.⁵⁹

Gabès

The phosphate complex at Gabès is the main pollution source in its gulf, because most of its waste goes straight to sea untreated.⁶² About a hundred million tonnes of untreated phosphogypsum have been discharged since the complex was built.⁶³ Seawater near the plant is strongly to seriously affected.⁶⁴ The plant opened in 1972, and a 2017 government pledge to phase it out was not carried out.⁶⁵ In October 2025 a general strike shut the city after more than 200 people were hospitalised with breathing problems.⁶⁵ About 2,500 people marched again in December.⁶⁶ President Saied received a working group’s final report in January 2026 and visited Gabès in August.⁶⁷

The reported indicators

On the latest values each country reports for SDG indicator 6.3.1, Tunisia’s 76% (2024) ranks joint 7th of the 17 countries covered here that report it; years differ by country. The regional comparison is in the wastewater and reuse dashboard.

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.¹ A joint technical commission on water and the environment has served since 1984 as a forum for consultation and data exchange.¹ Formal frameworks for managing the Medjerda basin with Algeria were still to be defined in 2025, IUCN noted.⁶⁸

The North-Western Sahara Aquifer System

The system covers about 1.19 million km². Algeria holds 68%, Libya 24% and Tunisia 8%.⁶⁹ 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.⁷⁰ Scientists regard these waters as fossil and effectively non-renewable.⁷¹

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 2008.⁶⁹ On 24 April 2024 the three governments signed an agreement in Algiers on consultation over the shared groundwater. Tunisia ratified it in January 2025.⁷²

The record

Shared river basin

The register also lists Tunisia as a riparian of the Oued Bou Namoussa basin (2,763 km² in all), with no area, modelled flow or agreement recorded for Tunisia there.

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

Water resources, irrigation and drinking water are overseen by the Ministry of Agriculture, Water Resources and Fisheries; sanitation is overseen by the Ministry of Environment.⁵⁹ The agriculture ministry’s directorates-general assess resources, build and run large dams, manage irrigation and rural drinking water, and protect watersheds.¹ In each governorate, a regional agricultural development commission manages water resources and public irrigation schemes.¹ SONEDE, created in 1968, supplies drinking water.⁵⁰ ONAS, created in 1974, runs sanitation.⁷³ More than 2,800 user groups managed small schemes in 2009, and a consultative National Water Council has advised the ministry since 2010.¹

A water code still in revision

The Water Code dates from 1975 and was amended in 1987, 1988 and 2001.¹ A 2015 attempt at a new code met trade-union resistance over fears of privatisation.¹⁶ 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.⁷⁴ A redraft went to the prime minister’s office in January 2023.⁷⁵ In February 2025 the government ordered a final version, and by April 2026 the code was still under revision.^49 8 The Eau 2050 strategy aims to cut agriculture’s share of water from 80% to 70%; its network-efficiency target is under Infrastructure.⁷

Tariffs and private operators

Drinking-water tariffs follow one national scale of six quarterly bands, set by ministerial order.⁷⁶ 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 m³.⁷⁷ Irrigation tariffs were frozen from 2002 and covered only 50–60% of operating costs in 2018.² A ministry circular of March 2021 provided for annual increases, and in 2025 the regional agricultural commissions charged water user groups 47 to 205 millimes per m³, with average cost recovery put at 79%.³⁹ ONAS has used private operators since a 1997 pilot on 185 km of Greater Tunis sewers. Under the 2008 concessions law and the 2015 PPP law, its new concession contracts run for ten years.⁵⁹

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.^6 57 24 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 2019,⁸ and the Eau 2050 strategy comprises 43 programmes and about 1,200 measures.⁷⁸ The projections under Geography & climate point to less rain in the wetter north-west and more frequent extreme rainfall.²³