Desalination Plants Market

Desalination is the water supply of last resort, bought when a city has run out of cheaper options rather than when it wants to. Douglas Insights values the desalination plants market at USD 6.44 billion in 2025 and expects USD 12.9 billion by 2035, compounding at 7.23%. The estimate is built from the bottom up: roughly 5.6 million cubic metres per day of new desalination capacity contracted in 2025 across seawater reverse osmosis plants, brackish water reverse osmosis plants, thermal desalination plants, and pretreatment, energy recovery and brine management systems, at an average realised capital value of USD 1,150 per cubic metre per day of capacity, triangulated against project awards, water authority programmes and contractor disclosures. Capacity contracted grows 6.8% a year as water scarcity spreads (the same pressure behind the smart water metering infrastructure market), while value per unit of capacity rises 0.4% a year as tighter environmental rules on brine offset falling membrane costs. Plant operation and water sales, industrial zero liquid discharge, sized separately in our Industrial Wastewater Zero Liquid Discharge Systems Market report, and treatment chemicals are excluded; industrial users’ treatment chemistry is sized in our Industrial Water Treatment Chemicals Market report. This study sits within our water and wastewater treatment coverage and follows the published Douglas Insights methodology.

How did reverse osmosis make desalination affordable?

By cutting the energy needed to turn seawater into drinking water to a fraction of what older thermal plants used. For decades, desalination in the Gulf relied mainly on thermal plants that boiled seawater and condensed the vapour, which worked but consumed enormous amounts of energy, usually supplied by burning oil or gas. Reverse osmosis instead pushes seawater at high pressure through membranes that let water pass but hold back salt. Improvements in membranes and, above all, energy recovery devices that capture the pressure from the concentrated brine and reuse it, have reduced the energy needed per cubic metre dramatically. As a result, reverse osmosis has become the default technology for new plants almost everywhere, including in the Gulf states that once relied on thermal desalination, and the cost of desalinated water has fallen to levels that make it a practical supply for cities in water stressed regions. The exclusive chapter of this report tracks the cost of desalinated water by region and technology, since cost determines where desalination competes with other water sources.

What does this market include?

This study covers the construction and equipment of new desalination plants. Seawater reverse osmosis plants cover plants that desalinate seawater using membranes, the largest category. Brackish water reverse osmosis plants cover plants treating less salty groundwater and surface water. Thermal desalination plants cover multi stage flash and multi effect distillation plants. Pretreatment, energy recovery and brine management systems cover intake and pretreatment systems, energy recovery devices and systems that manage or treat brine discharge. Plant operation and water sales, industrial zero liquid discharge systems, on-site wash-water reuse covered in the Washing Water Recycling System Market report, water treatment chemicals, covered in our separate water treatment chemicals coverage, and small point of use desalination units sit outside the boundary. Value is measured at capital value of plants contracted.

Why is brine the environmental challenge?

Because every desalination plant produces a concentrated salt water stream that must go somewhere, and discharging it carelessly can harm marine life. For every cubic metre of fresh water produced, a seawater reverse osmosis plant typically returns more than a cubic metre of brine roughly twice as salty as seawater, often carrying traces of treatment chemicals. Discharged near the shore, especially in enclosed seas such as the Gulf, dense brine can sink and spread along the seabed, affecting marine ecosystems. Regulators increasingly require diffusers that dilute brine quickly, monitoring, and in some cases minimising or treating brine, and researchers are working to recover valuable minerals from it. These requirements add cost to plants and create demand for brine management systems. The model reflects stricter brine rules as a factor supporting value per unit of capacity.

What drives demand?

The first driver is water scarcity. Population growth, urbanisation and depleted groundwater leave many regions without enough fresh water, making desalination a necessary supply.

The second driver is climate change. Droughts and changing rainfall patterns make conventional water supplies less reliable, pushing governments toward climate independent sources such as desalination.

The third driver is industrial and mining demand. Mines, refineries and industrial zones in arid regions need water supplies that do not compete with communities.

The fourth driver is falling costs. Cheaper reverse osmosis and the use of renewable electricity make desalination more affordable.

What restrains the market?

Three restraints are modelled. Cost and energy are the first: desalinated water remains more expensive than most conventional supplies, and energy is a major operating cost. Environmental concerns are second: brine discharge, intake effects on marine life and carbon emissions from fossil powered plants attract opposition and regulation. Financing is third: large plants require substantial investment, often through public private partnerships, and project development can be slow.

Which categories carry the value?

Seawater reverse osmosis plants lead with 62% of 2025 value, USD 3,992.8 million, and grow 7.33% a year to USD 8,105.5 million, the dominant technology for new capacity. Brackish water reverse osmosis plants hold 16%, USD 1,030.4 million, and grow 7.74% to USD 2,170.9 million. Pretreatment, energy recovery and brine management systems account for 12%, USD 772.8 million, and grow fastest at 9.53% to USD 1,921.0 million as brine rules tighten. Thermal desalination plants contribute 10%, USD 644.0 million, and grow just 1.44% to USD 743.0 million, a declining share as reverse osmosis replaces them. Each category is modelled through 2035 by region.

Which desalination plants segment grows fastest?

Pretreatment, energy recovery and brine management systems grow fastest, at 9.53% a year against the market’s 7.23%, because they are the part of a desalination plant that regulation keeps adding to. A plant contracted in 2015 could discharge brine through a simple outfall; one contracted now is more likely to need diffusers that dilute it quickly, discharge monitoring, and in enclosed seas such as the Gulf a brine minimisation or treatment step, while energy recovery devices have gone from optional to standard on every seawater train. Each requirement is bought as equipment rather than saved on membranes, so this category grows faster than the capacity it is attached to. Brackish water reverse osmosis is second at 7.74%, seawater reverse osmosis third at 7.33%, and thermal desalination close to flat at 1.44% as no significant new thermal capacity is contracted outside a few Gulf retrofits.

Where are desalination plants built?

The Middle East dominates with 46% of 2025 value, USD 2,962.4 million, growing 6.19% a year, reflecting very large plants in Saudi Arabia, the United Arab Emirates and other Gulf states that depend on desalination for most drinking water. Asia Pacific holds 20%, USD 1,288.0 million, at 8.2%, with capacity in China, India, Australia and Singapore. Africa holds 10%, USD 644.0 million, at 9.2%, led by North African countries such as Egypt, Morocco and Algeria. North America contributes USD 515.2 million at 7.0%, Europe USD 515.2 million at 6.0%, led by Spain, and Latin America USD 515.2 million at 9.0%, driven by mining and municipal demand in Chile and Peru. Six regional models sum to the global figure, with country tables in the Excel model.

Who builds desalination plants?

Specialist engineering contractors and water companies build most large plants. Acciona, Veolia, IDE Technologies, Doosan Enerbility, Suez, Metito, Abengoa’s successors and Chinese contractors are among the leading builders, often in partnership with developers under public private partnership contracts. Membranes are supplied by companies including DuPont, Toray, LG Chem and Nitto Hydranautics, and energy recovery devices by Energy Recovery and others. The competitive chapter profiles each contractor’s project record, technology and regional presence.

How are desalination plants priced?

Average realised capital value is USD 1,150 per cubic metre per day of capacity in 2025, varying with plant size, water quality, intake and outfall design, and local conditions. Very large seawater plants benefit from economies of scale, while smaller plants and those with complex intakes or strict brine rules cost more per unit of capacity. Many plants are procured as build, own, operate or similar contracts, where the developer is paid through long term water purchase agreements. Falling membrane costs are offset by stricter environmental requirements, keeping value per unit of capacity roughly stable. The pricing chapter publishes value bands by plant type and size.

How do the scenarios diverge by 2035?

The base case carries 6.8% growth in capacity contracted and 0.4% growth in value per unit of capacity for a 7.23% revenue CAGR and USD 12,940.5 million in 2035. The slower-build scenario, in which financing constraints and alternative water sources such as reuse slow new plants, sets the legs at 4.0% and minus 0.6%, landing near USD 8,980 million. The scarcity-driven scenario, in which droughts and growing demand accelerate construction, sets them at 9.0% and 1.2%, carrying the market past USD 17,170 million. Each 1-point change in capacity growth moves the 2035 figure by roughly USD 1,210 million.

Which rules and standards apply?

Three layers matter. Environmental regulation comes first: rules on brine discharge, seawater intake and energy use determine plant design and cost. Drinking water standards are second: desalinated water must meet drinking water quality standards, including requirements on minerals and boron. Procurement and concession rules are third: water authorities procure plants through public tenders and public private partnerships, which shape project structures. The regulatory chapter maps these requirements by country.

Can renewables power desalination?

Pairing desalination with solar and wind power addresses its biggest environmental drawback, the carbon emissions from the electricity it uses, and falling renewable costs make this increasingly practical. Reverse osmosis plants run best continuously, while solar power varies through the day, so projects combine renewables with grid power, battery storage or water storage that lets plants produce more water when power is cheap. Several large plants in the Gulf and elsewhere are being built with dedicated solar power or renewable power purchase agreements. Water utilities that run both supply and sewage treatment can offset part of the same electricity load with biogas from sludge digestion, the capacity sized in our Anaerobic Digestion Biogas Plants Market report. This reduces the carbon footprint and can lower long term costs. The model treats renewable powered desalination as supporting growth, particularly in sunny, water scarce regions.

Douglas Exclusive: the desalinated water cost tracker

This report tracks, by region and technology, the capital and operating cost of desalinated water, energy use, brine management requirements, and comparison with alternative water sources, converting water demand into new desalination capacity and value by category and region. Licence holders receive it as a maintained tab in the Excel model.

Methodology and receipts

The model is built bottom-up from capacity: desalination project awards and pipelines by region and technology, water authority programmes, industrial and mining demand, and realised capital values from contract and contractor disclosures, with plant operation and water sales, industrial zero liquid discharge, treatment chemicals and point of use units excluded. Every figure carries a numbered source and a confidence grade in the fact sheet above, and the working model ships with every licence. The next scheduled review of this study is September 2027.