To avoid a water crisis, Texas may bet big on desalination. Here’s how it works in El Paso.

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This article is part of Running Out, an occasional series about Texas’ water crisis. Read more stories about the threats facing Texas’ water supply here.

EL PASO — The wind swept through El Paso one day in March, lifting a fine layer of dust that settled onto windshields, clothes and skin. The air was thick with haze from a dust storm. This border city, perched on the edge of the Chihuahuan Desert, receives on average less than 9 inches of rain each year.

Water in the city of 679,000 people is a challenge.

Inside El Paso’s Kay Bailey Hutchison Desalination Plant, Hector Sepúlveda, the plant’s superintendent, walks through rows of towering steel tubes as a loud hum vibrates through the air. This machinery is essential to providing thousands in the city with clean water.

“This is a desert community,” Sepúlveda said. “So the water utilities have to always think ahead and be very resourceful and very smart and find resources to take the water that we do have here and provide for a desert community.”

Sepúlveda says the city’s dry climate, compounded by dwindling ground and surface water supplies and climate change has made innovation essential. A key piece of that strategy is desalination — the process of removing salt and other minerals from seawater or salty groundwater so people can drink it.

When it opened in 2007, El Paso’s desalination plant was the largest inland desalination facility in the world. It was built through a partnership between El Paso Water and Fort Bliss, one of the nation’s largest military bases, when water shortages threatened the base’s operations. Today, at max capacity the plant can supply up to 27.5 million gallons per day — helping stretch the city’s supply by making use of the region’s abundance of brackish groundwater, salty groundwater with salinity levels higher than freshwater, but lower than seawater.

The city wants to expand the plant’s capacity to 33.5 million gallons per day by 2028. El Pasoans used about 105 million gallons per day last year.

As Texas faces twin pressures of population growth and prolonged drought, lawmakers are looking to desalination as a way forward. The Texas Legislature took a major step in 2023, creating the New Water Supply for Texas Fund, to support desalination projects — including both brackish and seawater. This legislative session, lawmakers are pushing to accelerate that effort with a bill by state Sen. Charles Perry, a Lubbock Republican, that could dedicate millions for new water projects, including desalination. Senate Bill 7 cleared the upper chamber earlier this month and is now awaiting a House committee’s consideration.

“We've developed all the cheap water, and all the low-hanging fruit has been obtained. There is no more of it, and it's depleting what's left. We're going into the second phase of water development through brackish marine, brackish produced water and brackish aquifers,” Perry said on the Senate floor before his colleagues gave the legislation unanimous approval.

Sixty municipal water desalination facilities are already online, according to the Texas Water Development Board, the state agency that helps manage and finance water supply projects. Of those, 43 desalinate brackish groundwater. El Paso’s is the largest.

As of December 2024, the agency had designated 31 brackish groundwater sites as production zones, meaning they have moderate to high availability of brackish groundwater to treat. The board’s 2022 state water plan proposes implementing an additional 37 brackish groundwater desalination projects in South Texas cities like McAllen, Mission, San Benito; and West Texas towns like Abilene and Midland.

The plan states that if all recommended strategies are used, groundwater desalination could make up about 2.1% of the state’s projected water needs by producing 157,000 acre-feet per year by 2070 — enough to support 942,000 Texans for one year.

Still, desalination isn’t without tradeoffs. The technology takes a lot of energy, and construction costs can be steep. There are also several factors to consider that affect the final price tag: How deep the water lies, how salty it is, how far it needs to travel, and how to dispose of the leftover salty waste.

The water board estimates treating brackish groundwater can run anywhere from $357 to $782 per acre-foot, while seawater desalination ranges from $800 to $1,400. Lawmakers say water funding at a state-level is critical to help communities shoulder the upfront costs of these alternative water supplies.

How brackish groundwater desalination works

Sepúlveda, who has spent more than 30 years with El Paso Water, says the process at the desalination plant begins with brackish groundwater drawn from 15 wells near the El Paso International Airport. The salty water is transported to the plant where it is first filtered through strainers to remove sand particles. Then it is transported through cartridge filters. This process is similar to how household water filters work, but far more efficient.

The cartridge filters trap fine sediments smaller than a strand of hair, further filtering the water before it reaches the heart of the system: reverse osmosis, often referred to as RO membranes.

Sepúlveda, who wears a blue construction hat and highlighter yellow vest, stands amid a room full of long rows of stacked steel tubes, or RO membrane units. Here, brackish groundwater gets turned into fresh, drinkable water. It’s pumped through these tubes — each with 72 vessels — at extremely high pressure, leaving behind salt and bacteria.

“We’re separating the undesirable stuff from the potable water,” he said, as he opened a faucet and sipped the water. “At the end you end up with safe drinking water. The process is just amazing.”

Once cleaned, the water is divided between El Paso Water customers and Fort Bliss. Sepúlveda said they will soon expand the plant to produce 33.5 million gallons per day by adding a sixth row of RO membranes.

The brine, or concentrated salty water left over from the process, is pumped 22 miles to deep well injection sites. The desal plant can separate up to 3 million gallons of brine a day. At the site, the concentrate is sent 3,500 feet underground into a fractured rock formation.

Concerns of desalination

While brackish groundwater desalination has proven to be a viable solution for inland communities like El Paso, environmentalists are raising concerns about the potential consequences of scaling up the water strategy.

Seawater desalination is gaining attention as Gulf Coast cities like Corpus Christi start developing their own seawater desalination facility.

For seawater desalination, Shane Walker, professor and director of a water research center at Texas Tech University, says the main concern is removing the excess salt. While most of the salinity comes from dissolved minerals that aren’t harmful, Walker says, high concentrations — think of over-salted French fries — can harm marine life and disrupt coastal ecosystems.

Seawater is much saltier than brackish water and salt levels vary widely depending on the source.

In seawater desalination, the brine byproduct — which can be twice as salty as seawater — is often discharged back into the ocean. If not properly managed, this can increase salinity in bays and estuaries, threatening species like oysters, crabs and shrimp that are critical to local fisheries and ecosystems.

Myron Hess, an environmental consultant for the nonprofit National Wildlife Federation, said that when plants take in water it could potentially suck in marine creatures with the ocean water.

“As you're diverting particularly massive amounts of water, you can be pulling in lots of organisms,” Hess said.

For inland facilities like the Kay Bailey Hutchison plant, the environmental concerns are different. They don’t kill marine life, but disposal is still a concern.

In El Paso, Art Ruiz, chief plant manager for El Paso Water and the former superintendent of the utility’s desalination plant, calls this disposal “chemistry salts” and says that disposal is handled through deep well injection into an isolated part of the aquifer. Ruiz said El Paso is blessed with a geological formation that has a natural fault that prevents the concentrate from migrating and contaminating the freshwater supply. In regions where this is not feasible, evaporation ponds are used, but they require large amounts of land and careful management to prevent environmental hazards.

“Deep well injection is a common method used for larger desalination facilities, but the geology has to be right,” Walker said. “You have to ensure that the injection site is isolated and won’t contaminate freshwater aquifers.”

Another concern raised by water experts is how Texas manages brackish groundwater and whether the state is doing enough to protect nearby freshwater sources. Senate Bill 2658 proposes to exempt certain brackish groundwater wells located within state-designated production zones from needing a permit. Experts say the move would bypass a permitting process in the state's water code that was specifically designed to safeguard freshwater aquifers.

The central worry is that brackish and fresh groundwater are often hydrologically connected. While brackish groundwater can be an important part of the state's water portfolio, Vanessa Puig-Williams, a water expert with the Environmental Defense Fund, says there’s a real risk that pumping brackish water could unintentionally start drawing in and depleting nearby fresh water if oversight is not required from local groundwater conservation districts.

Experts also caution that the production zones identified by the water board weren’t designed to guide site-specific decisions, such as how much a well can safely pump or whether it could affect nearby freshwater supplies.

Hess, consulting for the National Wildlife Federation, authored a paper on the impacts of desalination, including the price tag. Constructing a facility is costly, as is the energy it takes to run it. El Paso’s desalination facility cost $98.3 million, including the production and injection wells construction, $26 million of which it received in federal funding.

The technology to clean the water is energy intensive. Desalinating water in El Paso costs about $500 per acre-foot of water — 46% more than treating surface water from a river. Seawater facilities require even more energy, which adds to the costs in producing or cleaning the water. TWDB estimates those range from $800 to $1,400 per acre-foot.

Texas has no operating seawater desalination plants for municipal use, but the state’s environmental agency, Texas Commission on Environmental Quality, has authorized permits for two marine desalination facilities and has four pending applications for seawater desalination facilities, three in Corpus Christi and one in Port Isabel.

“The first seawater plant in Texas is going to be expensive,” Walker said. “The first time somebody does something, it’s going to cost way more than the other ones that come along behind it, because we're having to figure out all the processes and procedures to do it the first time.”

Lessons from El Paso and the path forward

Back at the Kay Bailey Hutchison plant in El Paso, Sepúlveda, the plant’s superintendent, walks into a lab opened to students and professors from the University of Texas at El Paso, New Mexico State University, and Rice University to test new technologies to help refine the desalination processes or extend the lifespan of RO membranes.

Sepúlveda said water utility employees have learned a lot since 2007 when the plant first opened. RO membranes, used to clean the salty water, cost anywhere from $600 to $800. El Paso uses 360 RO membranes to run its plant. To extend the life from five to 12 years, utility employees figured out a system by checking salinity levels before extracting from a certain well.

“When we first bring water in from the brackish wells, we know how salty each well is, so we try to bring in the wells that are less salty to not put the membranes under such stress,” he said. “It almost doubled the life of the membrane.”

He added that this technique is also helping plant operators reduce energy consumption. Plant operators have adjusted salinity levels by blending the brackish groundwater with less salty water, which helps prevent pipe corrosion and clogging.

Their pipes are also now winterized. After the 2011 freeze, El Paso upgraded insulation and installed heat tape to protect equipment.

As Texas moves forward with more desalination projects, Sepúlveda said the lessons from El Paso will be critical as more plants go online.

“You always have to be forward-thinking. Always have to be innovative,” he said, as the machines buzzed in the background. “You always have to be on top of the latest technological improvements to be able to extract water from whatever scant resources you have.”

Disclosure: The city of Corpus Christi, Environmental Defense Fund, Rice University, Texas Tech University and University of Texas at El Paso have been financial supporters of The Texas Tribune, a nonprofit, nonpartisan news organization that is funded in part by donations from members, foundations and corporate sponsors. Financial supporters play no role in the Tribune's journalism. Find a complete list of them here.

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