Regional spotlight: Desalination & advanced water treatment in US — what's different and why it matters

The United States desalination sector stands at a peculiar inflection point. While the Middle East and Mediterranean nations have operated large-scale seawater desalination for decades, the US has historically relied on surface and groundwater supplies that are now failing under combined pressures of climate change, population growth, and aquifer depletion. California alone lost an estimated 4.3 trillion gallons of stored groundwater between 2012 and 2025 according to NASA's GRACE satellite data, and the Colorado River basin continues to supply less than its allocated volume to the 40 million people who depend on it. Yet despite this intensifying crisis, the US operates only about 2,300 desalination facilities with a combined capacity of approximately 2.1 billion gallons per day, the vast majority treating brackish groundwater rather than seawater. Understanding why US desalination development follows a fundamentally different trajectory than global peers, and where the sector is heading, is essential for engineers, utilities, and investors evaluating water infrastructure opportunities.

Why the US Market Is Different

Regulatory Complexity Creates Longer Timelines

The US permitting environment for desalination plants is among the most complex globally. The Carlsbad Desalination Plant in San Diego County, which began producing 50 million gallons per day of drinking water in 2015, required 14 years of regulatory review before construction began. By contrast, comparable facilities in Israel and Saudi Arabia have moved from concept to commissioning in 4 to 6 years. The difference stems from layered federal and state requirements that have no parallel in most international markets.

At the federal level, desalination intake and discharge structures must comply with the Clean Water Act Section 316(b), which requires the use of best technology available to minimize impingement and entrainment of aquatic organisms. The National Environmental Policy Act (NEPA) mandates environmental impact assessments for projects requiring federal permits or funding. The Endangered Species Act adds consultation requirements whenever threatened or endangered species inhabit intake or discharge zones. California's supplementary regulations under the State Water Resources Control Board's 2015 Ocean Plan Amendment impose some of the most stringent intake and concentrate discharge requirements in the world, mandating subsurface intakes for new facilities where feasible and requiring dilution ratios for brine discharge that significantly increase capital costs.

Texas and Florida, by contrast, have adopted more streamlined permitting frameworks. The Texas Water Development Board has actively supported desalination through its State Water Plan, identifying brackish groundwater desalination as a key strategy for meeting the state's projected 18 million acre-feet annual shortfall by 2070. Florida's Southwest Florida Water Management District has funded over $100 million in alternative water supply development, with the Tampa Bay Seawater Desalination Plant serving as a template for public utility ownership models.

Energy Costs Shape Plant Economics Differently

US electricity prices vary enormously by region, creating disparate economic conditions for energy-intensive desalination. Industrial electricity rates in California averaged $0.19 per kWh in 2025, compared to $0.08 per kWh in Texas and $0.10 per kWh in Florida. Since energy consumption accounts for 30 to 50 percent of seawater desalination operating costs, these differentials translate directly into water production costs. The Carlsbad plant produces water at approximately $2,100 to $2,500 per acre-foot, while comparable technology deployed in Texas would produce water at $1,400 to $1,800 per acre-foot.

This regional energy cost variation is driving innovation in energy recovery and renewable energy integration that distinguishes US projects from international counterparts. The proposed Doheny Ocean Desalination Project in Dana Point, California, has designed its facility around co-located solar generation and battery storage to reduce grid electricity dependence by an estimated 40 percent. El Paso Water's Kay Bailey Hutchison Desalination Plant, the largest inland desalination facility in the world, has achieved energy consumption of 1.2 kWh per cubic meter for brackish water treatment, roughly one-third the energy required for seawater reverse osmosis.

Brackish Groundwater Dominance

Unlike global markets where seawater desalination dominates investment and capacity, the US market is overwhelmingly oriented toward brackish groundwater treatment. Approximately 75 percent of US desalination capacity treats brackish water with total dissolved solids (TDS) ranging from 1,000 to 10,000 mg/L, compared to seawater at 35,000 mg/L. This distinction matters enormously for engineers because brackish desalination operates at lower pressures (150 to 400 psi versus 800 to 1,000 psi for seawater), uses less energy (0.5 to 2.5 kWh per cubic meter versus 3.0 to 4.5 kWh per cubic meter), and costs substantially less per unit of production.

The Brackish Groundwater National Desalination Research Facility in Alamogordo, New Mexico, operated by the Bureau of Reclamation, has served as the primary federal research platform for advancing brackish treatment technologies since 2007. Research programs there have demonstrated concentrate minimization approaches, including high-recovery reverse osmosis systems achieving 90 to 95 percent recovery rates compared to the 40 to 50 percent typical of conventional seawater systems. These high-recovery systems are critical for inland applications where brine disposal options are limited and deep-well injection costs can exceed $10 per thousand gallons of concentrate.

What's Working

Direct Potable Reuse Is Overtaking Desalination in Some Markets

Advanced water treatment for direct potable reuse (DPR) has emerged as a competitive alternative to desalination in several US markets. The Pure Water San Diego program, which will produce 83 million gallons per day of purified recycled water by 2035, uses a treatment train of ozonation, biologically active filtration, membrane filtration, reverse osmosis, and ultraviolet disinfection with advanced oxidation. The estimated cost of $1,600 to $2,000 per acre-foot undercuts seawater desalination by 20 to 30 percent while avoiding the marine environmental impacts that complicate coastal permitting.

Texas has taken an equally aggressive posture. The Texas Commission on Environmental Quality approved rules for direct potable reuse in 2023, making Texas one of the first states to establish a comprehensive DPR regulatory framework. The Colorado River Municipal Water District's Big Spring facility, operational since 2013, demonstrated that advanced treatment produces water meeting or exceeding all Safe Drinking Water Act standards, with some constituents measured at levels ten times lower than required limits.

Membrane Technology Advances From US Research Institutions

US-based research has driven significant membrane performance improvements that benefit both domestic and global markets. The National Alliance for Water Innovation (NAWI), a Department of Energy consortium headquartered at Lawrence Berkeley National Laboratory, has coordinated research across national laboratories and universities targeting a pipe-parity desalination cost of $0.50 per cubic meter. Key technical advances include thin-film nanocomposite membranes incorporating graphene oxide and metal-organic frameworks that demonstrate 30 to 40 percent higher water permeability than conventional polyamide thin-film composite membranes in laboratory testing.

The Environmental Protection Agency's Water Research Foundation has funded pilot-scale testing of forward osmosis and membrane distillation hybrid systems that can utilize low-grade waste heat from industrial processes or solar thermal collectors, potentially reducing electrical energy consumption by 50 to 70 percent for brackish water applications. The Massachusetts Institute of Technology's Global Engineering and Research Center has developed solar-powered electrodialysis systems specifically designed for community-scale brackish water treatment in regions where grid electricity is expensive or unreliable.

Innovative Financing Models

US water utilities have pioneered public-private partnership structures that reduce ratepayer risk while attracting private capital to desalination infrastructure. The Carlsbad plant operates under a 30-year water purchase agreement between Poseidon Water (now owned by Brookfield Infrastructure Partners) and the San Diego County Water Authority, with a fixed-price escalation structure that shields the utility from construction cost overruns. The Santa Cruz Mid-County Groundwater Agency's desalination feasibility study evaluated a design-build-operate-maintain model that transfers technology risk to the private partner while maintaining public ownership of the water supply.

The Water Infrastructure Finance and Innovation Act (WIFIA) program has provided over $16 billion in low-interest federal loans for water infrastructure since 2014, with desalination and advanced water treatment projects representing a growing share of the portfolio. WIFIA loans offer interest rates at or below Treasury rates with repayment terms up to 35 years, substantially improving project economics for capital-intensive desalination facilities. The Pure Water Southern California project secured a $700 million WIFIA loan in 2023, one of the largest single water infrastructure loans in program history.

What's Not Working

Concentrate Management Remains the Binding Constraint

Brine disposal is the single most challenging technical and regulatory issue facing US desalination expansion, particularly for inland applications. Coastal plants can discharge concentrate to the ocean with appropriate dilution, but inland facilities face disposal costs that can represent 20 to 40 percent of total operating expenses. Deep-well injection, the most common inland disposal method, requires permits under the Underground Injection Control program and encounters growing regulatory scrutiny due to concerns about induced seismicity and aquifer contamination. In the Permian Basin, where brackish water desalination supports oil and gas operations, injection capacity is approaching regulatory limits.

Zero-liquid discharge (ZLD) systems, which evaporate all concentrate to produce solid salt residuals, consume 20 to 30 kWh per cubic meter, making them economically prohibitive for most municipal applications. The Bureau of Reclamation's Desalination and Water Purification Research Program has identified concentrate management as its top research priority, with ongoing pilot projects evaluating selective salt recovery systems that extract marketable mineral products (lithium carbonate, gypsum, sodium chloride) from desalination brine to offset disposal costs.

Public Perception and Environmental Opposition

Every major seawater desalination proposal in California has faced organized environmental opposition. The Huntington Beach Desalination Project, which Poseidon Water pursued for over two decades, was ultimately denied by the California Coastal Commission in 2022 on grounds including marine life impacts, environmental justice concerns related to facility siting, greenhouse gas emissions, and inconsistency with the state's emphasis on water recycling and conservation. The denial sent a signal that seawater desalination faces structural political obstacles in California that engineering solutions alone cannot resolve.

Environmental groups including the Surfrider Foundation and the Natural Resources Defense Council have consistently argued that desalination should be pursued only after conservation, efficiency, stormwater capture, and water recycling options are fully exhausted. This "last resort" framing has influenced state water policy and creates an investment climate where desalination projects carry significant permitting and political risk that increases the cost of capital.

Aging Infrastructure and Workforce Gaps

Many existing US desalination facilities, particularly smaller brackish water plants operated by municipal utilities, are approaching end-of-life for their membrane systems and high-pressure pumps. A 2024 American Water Works Association survey found that 35 percent of operating desalination facilities had not replaced membranes within manufacturer-recommended intervals, resulting in 15 to 25 percent declines in water quality and production efficiency. The same survey identified workforce shortages as a compounding factor, with 40 percent of utilities reporting difficulty hiring operators with membrane treatment certifications.

Key Players

Established Leaders

IDE Technologies operates the Carlsbad facility and maintains the largest US desalination services footprint, with engineering and operations contracts spanning municipal and industrial markets across multiple states.

Veolia Water Technologies provides membrane systems, chemicals, and operations services for over 200 US water treatment facilities, including several of the largest brackish desalination plants in Texas and Florida.

Xylem supplies pumps, energy recovery devices, and monitoring systems for desalination applications, with their PX Pressure Exchanger technology deployed in over 25,000 installations globally.

Emerging Innovators

Gradiant has developed counter-flow reverse osmosis and selective contaminant extraction systems that achieve 98 percent recovery rates for industrial brine treatment, targeting zero-liquid discharge at significantly lower energy consumption than thermal alternatives.

Trevi Systems has commercialized forward osmosis systems utilizing low-grade heat sources for desalination, with pilot deployments at US military installations demonstrating 60 percent energy reduction compared to conventional reverse osmosis.

Epic Cleantec focuses on building-scale water recycling and treatment systems, deploying advanced treatment in commercial buildings to reduce municipal water demand by 70 to 90 percent.

Action Checklist

• Evaluate source water chemistry comprehensively, including seasonal TDS variation, silica, barium, and strontium concentrations that affect membrane selection and antiscalant requirements
• Engage regulatory agencies early in project development to identify permitting pathways and timeline expectations for intake and discharge structures
• Assess concentrate disposal options and costs before finalizing plant design, particularly for inland applications where disposal may dominate operating budgets
• Investigate WIFIA and state revolving fund financing to reduce capital costs by 15 to 25 percent compared to conventional municipal bond financing
• Compare desalination costs against advanced water treatment for potable reuse, which may offer lower costs and simpler permitting in some jurisdictions
• Design for energy flexibility by incorporating variable-speed drives, energy recovery devices, and renewable energy integration to manage operating cost volatility
• Plan for membrane replacement cycles of 5 to 7 years and budget accordingly in long-term financial models
• Develop public engagement strategies early, particularly for seawater desalination projects where environmental opposition has delayed or blocked comparable facilities

FAQ

Q: What is the current cost range for desalinated water in the US? A: Costs vary substantially by source water and region. Brackish groundwater desalination produces water at $500 to $1,200 per acre-foot depending on source water salinity, energy costs, and concentrate disposal requirements. Seawater desalination ranges from $1,800 to $2,800 per acre-foot on the Pacific Coast and $1,400 to $2,000 per acre-foot on the Gulf Coast and Atlantic seaboard. For context, imported water from the Colorado River currently costs Southern California agencies $1,000 to $1,400 per acre-foot, a price that has doubled in the past decade.

Q: How does the US regulatory environment compare to international markets for permitting desalination? A: The US has the most complex multi-jurisdictional permitting process for desalination globally. Projects typically require 6 to 14 years from initial proposal to operations, compared to 3 to 6 years in Israel, Saudi Arabia, and Australia. The primary differentiator is the combination of federal environmental review (NEPA, ESA, Clean Water Act), state coastal and environmental regulations, and local land use approvals. States like Texas and Florida have shorter timelines (3 to 5 years) due to more consolidated permitting authority and fewer marine environmental constraints.

Q: Is direct potable reuse a better investment than desalination for US utilities? A: In most inland and many coastal markets, advanced water treatment for direct potable reuse offers lower capital costs, lower energy consumption (1.0 to 1.5 kWh per cubic meter versus 3.0 to 4.5 kWh for seawater RO), and simpler permitting than seawater desalination. However, potable reuse requires reliable wastewater influent volumes and may face public acceptance challenges. Desalination remains the preferred option where groundwater sources are brackish but abundant, where wastewater volumes are insufficient for reuse programs, or where supply diversification is the primary objective.

Q: What role will federal funding play in US desalination expansion? A: The Bipartisan Infrastructure Law allocated $8.3 billion for Bureau of Reclamation water infrastructure, including desalination research and implementation. WIFIA has grown to authorize over $6 billion annually in low-interest loans. The Inflation Reduction Act's environmental justice provisions direct additional funding toward water infrastructure in disadvantaged communities. Collectively, federal programs are expected to support $15 to $20 billion in desalination and advanced water treatment investment through 2030, representing the largest federal commitment to alternative water supply development in US history.

Q: What are the most promising technology developments for reducing US desalination costs? A: Three technology pathways are likely to deliver meaningful cost reductions within the next five years. First, high-permeability membranes incorporating nanomaterials could reduce operating pressures by 20 to 30 percent and energy consumption proportionally. Second, closed-circuit desalination and batch processing configurations achieve 85 to 92 percent recovery rates for brackish water, reducing concentrate volumes and disposal costs. Third, integration of renewable energy with flexible desalination operations, producing and storing water during periods of low electricity prices, could reduce effective energy costs by 30 to 50 percent in markets with high solar penetration.

Sources

• Bureau of Reclamation. (2025). Desalination and Water Purification Research Program: Annual Report 2024. Washington, DC: US Department of the Interior.
• California State Water Resources Control Board. (2024). Ocean Plan Amendment Implementation: Desalination Facility Compliance Report. Sacramento, CA: SWRCB.
• National Alliance for Water Innovation. (2025). NAWI Master Technology Roadmap: 2025 Update. Berkeley, CA: Lawrence Berkeley National Laboratory.
• American Water Works Association. (2024). State of the Desalination Industry: US Market Assessment and Workforce Survey. Denver, CO: AWWA.
• Texas Water Development Board. (2025). 2027 State Water Plan: Desalination Strategy Chapter. Austin, TX: TWDB.
• Water Research Foundation. (2025). Advanced Water Treatment for Direct Potable Reuse: Cost and Performance Benchmarking. Denver, CO: WRF.
• US Environmental Protection Agency. (2024). Water Infrastructure Finance and Innovation Act: Program Status Report. Washington, DC: EPA.