Desalination is used in more than 150 countries, but the scale varies enormously, from massive national programs that supply most of a country’s drinking water to small portable units that serve a single coastal town. Saudi Arabia, the United Arab Emirates, Kuwait, Israel, and Spain operate some of the world’s largest desalination networks, and the United States, Australia, China, and several island nations depend on the technology in water-scarce regions. What makes the global picture interesting is not just who desalinates but why, since the reasons range from extreme aridity to mining operations to diplomatic strategy.
The Middle East and North Africa
No region is more synonymous with desalination than the Persian Gulf. Saudi Arabia, the UAE, Kuwait, Bahrain, Qatar, and Oman all draw a significant share of their municipal water from the sea. Saudi Arabia alone operates dozens of large plants along its Red Sea and Gulf coastlines, and the country treats desalination not as a backup supply but as its primary source of drinking water. In arid regions like these, where rainfall is minimal and aquifer recharge is slow, turning seawater into freshwater is the only realistic way to supply rapidly growing cities.1Water. Comprehensive Evaluation of Drinking Water Quality and the Effect of the Distribution Network in Madinah City, Saudi Arabia
Kuwait is an extreme case: it has almost no natural freshwater and has relied on desalination since the 1950s. The UAE has similarly scaled up, with Abu Dhabi’s massive thermal and membrane plants feeding a population that has grown tenfold in half a century. Across the Gulf states, desalination capacity has historically been tied to oil wealth, since the energy-intensive process is cheaper to run where fuel costs are low. That dynamic is slowly shifting as these countries invest in solar-powered plants, but the Gulf remains the world’s most concentrated hub of desalination infrastructure.
North Africa is catching up. Algeria operates one of the continent’s largest reverse-osmosis plants, and Libya and Egypt have expanded capacity along their Mediterranean coasts. Egypt is particularly active, with proposals to pair desalination with hybrid solar and wind power systems at port cities along both the Mediterranean and Red Sea.2Heliyon. Feasibility and optimal sizing analysis of hybrid PV/Wind powered seawater desalination system: A case study of four ports, Egypt
Spain and Israel
In the Mediterranean, Spain and Israel stand out as countries that have woven desalination deeply into their water systems. Both face the combination of semi-arid climates, growing populations, and agricultural sectors that consume enormous volumes of water. Spain’s southeastern coast, including the Murcia and AlmerÃa regions, hosts multiple large reverse-osmosis plants, and desalinated seawater there has moved beyond municipal taps into irrigation for high-value crops like tomatoes and peppers.3Desalination. Seawater desalination for crop irrigation — A review of current experiences and revealed key issues
Israel has arguably gone further. After severe droughts in the early 2000s threatened national water security, Israel built a string of large coastal plants that now supply a substantial share of the country’s total freshwater. Like Spain, Israel has also explored using desalinated water for farming, and both countries rely primarily on reverse-osmosis technology for these applications.3Desalination. Seawater desalination for crop irrigation — A review of current experiences and revealed key issues The Israeli model is often cited as a success story for water-scarce nations, in part because it combined desalination with aggressive water recycling and conservation to transform the country from chronic water deficit to relative surplus within about a decade.
The United States
Desalination in the United States has been growing since the 1950s, driven by droughts, population growth, and dwindling conventional supplies. By 2013, American facilities were producing roughly two billion gallons of desalinated water per day.4ScienceDirect. Competition for Water Resources – Section: Prospects for Desalination in the United States That number has continued to climb, and the hotspots are concentrated in three states: California, Florida, and Texas.
California’s Carlsbad plant, near San Diego, is the largest seawater desalination facility in the Western Hemisphere. It came online in 2015 after years of debate and produces enough water for roughly 400,000 people. A proposed second large plant in Huntington Beach was ultimately rejected due to environmental concerns, illustrating the tension between water need and coastal ecosystem protection that plays out in permitting across the country.
Florida takes a different approach. Most of its desalination plants treat brackish groundwater rather than ocean water, which is cheaper and less energy-intensive. Tampa Bay Water’s facility is one of the largest brackish-water plants in the country. Texas, meanwhile, has looked at both brackish and seawater options as the state’s western and southern regions contend with chronic drought and a booming population.
The U.S. also illustrates how desalination fits into a broader water portfolio. When researchers compare the cost and energy footprint of seawater desalination against alternatives like municipal water reuse and brackish-water treatment, seawater consistently comes in as the most expensive option, while brackish-water desalination is the cheapest of the three.5ACS ES&T Engineering. Cost and Energy Metrics for Municipal Water Reuse That cost hierarchy is why most U.S. utilities treat desalination as a drought-proof supplement rather than a primary supply.
Island Nations and Remote Coastlines
For small island nations, desalination is often less of a policy choice and more of a geographic necessity. Islands in the Caribbean, the Pacific, and the Indian Ocean frequently lack the land area to capture and store enough rainwater or the geology to tap meaningful aquifer reserves. Reverse osmosis has become a standard solution in these settings, converting surrounding ocean water into drinking water for communities that would otherwise face chronic shortages.6Frontiers in Water. Interventions and solutions for water supply on small islands: The case of New Providence, The Bahamas
The Bahamas is a well-documented example. New Providence, the island that contains the capital Nassau, depends heavily on desalination to meet demand from both residents and tourists. Similar setups exist across the Cayman Islands, Aruba, Curaçao, and dozens of Pacific island states. In the Maldives, where freshwater lenses are thin and vulnerable to saltwater intrusion, desalination has become critical infrastructure.
Australia fits a slightly different version of this pattern. Though it is a continent rather than a small island, much of its population clusters along arid coastlines. During the “Millennium Drought” of the 2000s, several major cities built large seawater desalination plants. Sydney, Melbourne, Perth, Adelaide, and the Gold Coast all brought facilities online. Perth’s plant was one of the first in the world to be powered entirely by a dedicated wind farm, setting a template for renewable-energy-linked desalination that other countries have since followed.
Mining the Desert in Chile and Peru
One of the less widely known drivers of desalination is mining. Northern Chile and southern Peru sit atop vast copper and lithium deposits, but the Atacama Desert that covers much of the region is the driest place on Earth. Mining operations need water, sometimes enormous quantities of it, for mineral processing, dust suppression, and worker camps. For decades, mines drew from underground aquifers, but overexploitation has depleted those reserves and created intense pressure to find other sources.7Desalination and Water Treatment. Northern Chile and Peru: a hotspot for desalination
The result has been a wave of coastal desalination plants built specifically to feed mining operations located at high elevations far inland. These projects involve not just reverse-osmosis plants but hundreds of millions of dollars’ worth of pipelines, pumping stations, and power infrastructure to move desalinated water from sea level up into the mountains.7Desalination and Water Treatment. Northern Chile and Peru: a hotspot for desalination Chile’s mining industry has framed this shift as both an operational necessity and an act of environmental responsibility, arguing that taking water from the ocean relieves pressure on scarce inland freshwater that communities also depend on.8Human Geography. Repairing harm: Desalination in copper mining and claims for responsibility in Chile’s Atacama Desert
Whether that framing holds up is debated. On the one hand, desalination does allow mining companies to operate independently of freshwater availability, and the infrastructure could in theory serve broader community water needs.9The Extractive Industries and Society. Desalination investment for copper mining: Barriers and opportunities in Chile On the other hand, the plants are privately owned, the pipelines go to mine sites rather than towns, and local communities remain skeptical that they will see real benefits. The Chilean model matters beyond South America because it shows how industrial demand can drive desalination buildout in places where municipal needs alone might never justify the cost.
How Brine Discharge Affects the Ocean
Every liter of desalinated seawater leaves behind a concentrated stream of brine, typically about one and a half to two times saltier than the ocean water that went in. That brine, along with chemical additives like antiscalants and coagulants used to protect plant membranes, gets discharged back into the sea.10PubMed. Impacts of Desalination Brine Discharge on Benthic Ecosystems Because the brine is denser than seawater, it tends to sink and creep along the seafloor, sometimes spreading several kilometers from the discharge point.
Research has documented a range of effects on bottom-dwelling organisms. Bacteria, seagrasses, worms, and corals living within the mixing zone can experience impaired activity, physical deformities, and shifts in community composition. Modeling work suggests the brine plume can spread across the seabed for tens of kilometers, potentially disrupting nutrient cycling from sediments into the water column.10PubMed. Impacts of Desalination Brine Discharge on Benthic Ecosystems Antiscalant chemicals in the discharge have been shown to affect coral physiology even at low concentrations.11PubMed. Antiscalants used in the desalination industry impact the physiology of the coral Montipora capricornis
The picture is not uniformly grim, though. A study of brine discharge in the northwestern Mediterranean found no significant impact on bottom-dwelling communities, largely because the local environment was already highly variable and the brine diluted rapidly after leaving the discharge pipe.12PubMed. Effect of brine discharge from a desalination plant on macrobenthic communities in the NW Mediterranean Location matters: discharge into shallow, low-energy coastlines near coral reefs or seagrass beds carries far more risk than discharge into deep, high-current waters. Plant design, outfall engineering, and dilution strategies all influence the outcome.
Beyond brine salinity itself, the chemical load of discharge is a separate concern. Pretreatment chemicals are added to intake water regardless of whether the plant uses thermal or membrane technology, and corrosion from plant infrastructure contributes heavy metals to the discharge stream.13Desalination. Chemical impacts from seawater desalination plants — a case study of the northern Red Sea In ecologically sensitive areas like the Red Sea and the Persian Gulf, where many of the world’s largest plants are clustered, managing cumulative chemical impacts is a growing regulatory challenge.
The Energy and Cost Equation
Desalination has long been expensive relative to conventional water treatment, but costs have fallen substantially. Improvements in membrane technology, energy recovery devices, and plant design brought the total cost of seawater desalination down significantly between the early 1990s and the mid-2000s.14Desalination. Technical review and evaluation of the economics of water desalination: Current and future challenges for better water supply sustainability Researchers have estimated that a cost of roughly a dollar per cubic meter for seawater desalination and about sixty cents per cubic meter for brackish water is feasible with current technology, and the trajectory continues downward.15Water Resources Research. Evaluating the costs of desalination and water transport
Energy remains the dominant operating expense. Pushing water through a reverse-osmosis membrane at high pressure takes electricity, and the saltier the source water, the more energy you need. Moving from brackish water at about 15 parts per thousand to full-strength seawater at 40 parts per thousand increases energy demand by roughly 74 percent.16Water Research. Global energy, costs, and emissions from reverse osmosis desalination under future water scarcity That salinity sensitivity is why brackish-water plants are so much cheaper to operate than seawater plants, and why landlocked regions with salty groundwater can sometimes desalinate more affordably than coastal ones dealing with ocean-strength brine.
Looking ahead, the energy question becomes a climate question. Under a scenario of three degrees of warming, addressing global water scarcity through desalination could require up to about 1,670 terawatt-hours of electricity per year and produce roughly a billion tons of carbon dioxide annually, accounting for around one percent of global energy use and two and a half percent of emissions, at costs exceeding 130 billion dollars.16Water Research. Global energy, costs, and emissions from reverse osmosis desalination under future water scarcity Those numbers are large in absolute terms, but they also show that desalination is not the energy apocalypse it is sometimes painted as. The footprint is manageable if it is powered cleanly, which is why countries like Egypt, Saudi Arabia, and Australia are pairing new plants with dedicated solar and wind capacity.
When Desalination Reshapes Diplomacy
Water scarcity has fueled political tension between neighboring countries for centuries. Rivers that cross borders, aquifers that underlie multiple nations, and upstream dams that control downstream flow are all flashpoints. Desalination introduces a genuinely new variable into these dynamics. By giving a country access to water that does not depend on shared rivers or rainfall, it can ease the urgency of transboundary disputes and make governments more flexible in negotiations.17Environmental Science & Policy. Desalination and hydrodiplomacy: Refreshening transboundary water negotiations or adding salt to the wounds?
The flipside is less often discussed. When a country builds enough desalination capacity to reduce its dependence on shared water, it may also lose motivation to cooperate with neighbors on joint water management. If you can produce your own water, the diplomatic cost of walking away from a negotiating table drops. Desalination can also create new disputes: a country that previously had no use for a stretch of coastline or an adjacent body of brackish water might suddenly claim rights to it, generating friction where none existed before.17Environmental Science & Policy. Desalination and hydrodiplomacy: Refreshening transboundary water negotiations or adding salt to the wounds?
Israel’s relationship with its neighbors is the most studied example. As Israeli desalination capacity grew, the country’s dependence on the Jordan River and the Mountain Aquifer shared with the Palestinian territories shifted. Scholars have argued that desalination both relieved some pressure and reduced Israel’s incentive to negotiate water-sharing agreements on terms favorable to less-resourced neighbors.18Desalination and Water Treatment. Desalination, transboundary water desecuritization and cooperation The pattern is not unique to the Middle East. Any region where one country has the capital and coastline to desalinate and its neighbor does not faces a potential imbalance.
Mining Minerals from Brine
The roughly 142 million cubic meters of waste brine generated daily by the world’s desalination plants represent an environmental liability, but they also represent a concentrated soup of dissolved minerals. Desalination brine holds higher concentrations of valuable elements than most natural water sources, and researchers have been working to turn that waste stream into a revenue stream.19Desalination. Lithium recovery from brine: Recent developments and challenges
Lithium has attracted the most commercial interest, for obvious reasons. Demand for lithium-ion batteries is surging, and conventional mining is geographically concentrated and environmentally contentious. Extracting lithium from desalination brine would diversify supply chains and reduce the volume of waste that ends up in the ocean. Magnesium, potassium, and various trace metals are also potential targets. The technology is still largely in pilot stages, but investment has picked up as both mineral prices and brine volumes climb.
The economics of brine mining depend on two things: how concentrated the target mineral is in a given plant’s waste stream and how cheaply it can be separated. Seawater brine, which comes out at high salt concentrations, tends to offer better mineral recovery potential than brackish-water brine. A future in which desalination plants function as both water factories and mineral-harvesting operations would transform the cost calculus of the technology, potentially offsetting a meaningful fraction of operating expenses while reducing the ecological damage of ocean discharge.19Desalination. Lithium recovery from brine: Recent developments and challenges
Countries Often Overlooked
The usual list of desalinating countries focuses on the Middle East, the Mediterranean, and Australia, but the technology has spread far more widely than most people realize. Singapore operates a large-scale plant as part of its “Four National Taps” strategy, which treats desalination alongside imported water, recycled water, and local catchment. India has plants along its southeastern coast, with Chennai’s facility serving as a lifeline during acute drought periods. China has invested heavily in desalination around the Bohai Sea, where industrial and municipal demand outstrips freshwater availability. South Korea, Japan, and several Central Asian countries desalinate brackish groundwater for agriculture and drinking.
Sub-Saharan Africa has been slower to adopt desalination at scale, largely because the capital costs are prohibitive relative to national budgets, and many coastal African cities still have untapped conventional freshwater options that are cheaper to develop first. That said, South Africa built an emergency desalination plant during the Cape Town “Day Zero” crisis of 2017-2018, and Namibia has explored the technology for its hyper-arid coast. As conventional water sources become less reliable across more of the continent, desalination is likely to grow there as well.
The global trend is toward wider adoption, with falling membrane costs and renewable-energy integration making the technology viable in places that would have dismissed it a decade ago. The question for most water-stressed countries is no longer whether to desalinate but how much and at what cost relative to conservation, recycling, and more efficient use of existing supplies.