El Paso Is Going to Turn Wastewater Into Drinking Water. Other Cities Will Soon Follow

El Paso Water broke ground on the first U.S. facility that will treat wastewater for direct re-use in a city water supply, using a four-step process to transform wastewater into clean, potable drinking water.

This desert city gets less than nine inches of rain a year and experienced the two hottest years in its recorded history in 2023 and 2024. 

But El Paso Water started planning decades ago for this hotter, drier climate. On Thursday the utility broke ground on its latest project to secure water for the city of 700,000: an advanced water purification facility that will deliver 10 million gallons per day of purified water from the city’s wastewater stream directly into its drinking water supply. 

El Paso’s Pure Water Center, which will go online by 2028, is the first direct-to-distribution reuse facility in the country. Treating wastewater for reuse as drinking water has long been controversial. But as the technology has advanced and water resources dwindle, more cities are exploring direct reuse.

El Paso is the first out of the gate, but Phoenix and Tucson are expected to follow suit. Elsewhere in Texas, communities from the Panhandle to the Hill Country are considering their own facilities. Colorado and California recently adopted rules to regulate the treatment technology.

“El Paso, Texas, is the center of the universe in water recycling right now,” said Gilbert Trejo, vice president of operations at the utility during the groundbreaking Thursday. 

Growing Acceptance of Direct Reuse

El Paso Water began a pilot study in 2016 to test direct potable reuse of sewage and other wastewater with a four-step treatment process. The utility sent water samples to state-certified laboratories for testing and found that the water met all drinking water standards. The Texas Commission on Environmental Quality (TCEQ) reviewed the pilot data and authorized El Paso Water to move forward with the design of a full facility. 

After nearly a decade of work, TCEQ approved construction of the facility in October 2024. The advanced purification process begins with treated wastewater from the Roberto Bustamante Wastewater Treatment Plant in El Paso. This source water then goes through a multiple barrier system, first going through reverse osmosis, in which a membrane separates water molecules from other substances. Then hydrogen peroxide and ultraviolet light are used to kill bacteria in the water. Next, activated carbon absorbs chemicals or compounds in the water. Lastly, chlorine is added for disinfection. 

TCEQ requires an online monitoring system with alarms and automatic shut-down capability. Trejo said this real-time monitoring will detect constituents breaking through the treatment process. 

“Before we start to break any type of threshold that would worry us, we will know well in advance so that we can take action,” he said.

The utility will also work to educate residents and businesses in El Paso to discourage them from putting chemicals and pharmaceuticals down the drain. Trejo acknowledged that unwanted material will inevitably enter the sewer system, so the treatment process is designed to remove these potential contaminants.

Environmental advocates have raised concerns about contaminants of emerging concern in the purified water, like per- and polyfluoroalkyl substances (PFAS), which aren’t yet regulated in drinking water. The environmental nonprofit Food and Water Watch warns that, “It’s impossible to monitor every potential toxin in a direct potable reuse system.” 

Trejo said that the treatment process was designed to remove pharmaceuticals, emerging contaminants of concerns and future contaminants. The first step was understanding the baseline quality of the source water. To that end the utility began collecting data from its sewer system in 2016. The utility commissioned an independent panel of experts through the National Water Research Institute to review its designs for the plant. 

“The good thing is that our multiple barrier approach to remove viruses, pathogens and any of these emerging constituents of concern is in place,” Trejo said. “It’s a very robust system.”

TCEQ spokesperson Richard Richter said that the agency has met with El Paso Water since 2014 to review the project. TCEQ issued an authorization for the facility under Chapter 210 of Texas administrative code, which governs reclaimed water. Richter said each authorization is tailored to the specific plant design and source water quality. While TCEQ and the Environmental Protection Agency do not have specific design standards for direct potable reuse facilities, the Clean Water Act and the Safe Drinking Water Act are the foundation for design choices. 

“Once the facility is constructed, there are multiple steps still required in the TCEQ review process before approval can be given for the facility to send water to customers,” he said.

El Paso Focuses on Reuse 

El Paso Water CEO John Balliew said Thursday that the Pure Water Center “is the culmination of our efforts so far to diversify the water supply of El Paso.”

The utility has spent decades securing a diverse water portfolio in the Chihuahuan Desert. El Paso historically relied on the Rio Grande, whose flows have diminished, and groundwater pumped from the Hueco Bolson, an aquifer shared with Ciudad Juárez across the border. 

Alex Mayer, a civil engineer and director of the University of Texas at El Paso’s Center for Environmental Resource Management, said El Paso has been a leader in “drought-proofing” water supplies. “The utility has been very effective in putting together plans that make sure the water availability is there,” he said.

In the 1960s, El Paso began its water reclamation program, which distributes treated wastewater to irrigate outdoor areas. El Paso Water has also treated wastewater to drinking water standards to recharge the aquifer since the 1980s. 

In the 1990s, El Paso Water undertook an educational campaign to encourage residents to conserve water, which successfully brought down average consumption. Green lawns were replaced with native desert landscaping. Meanwhile the utility set in motion plans to diversify its water supply. 

El Paso Water brought the Kay Bailey Hutchison Desalination Plant online in 2017. The plant, the largest inland desalination facility in the U.S., treats brackish groundwater from the Hueco Bolson. The utility also acquired land in Dell City, Texas, from which it will import groundwater in the future.

Federal funding has aided El Paso Water’s projects. The U.S. Bureau of Reclamation provided $3.5 million for design of the advanced water purification facility in 2019 and provided another $20 million in 2022 for construction. Utility officials have estimated the total project cost to be $295 million. Balliew said that the utility will seek additional state and federal funding to complete the facility.

Balliew said that the cost of water from the Pure Water Center will be about $500 per acre foot, which is comparable to the cost of water from the desalination plant. However this is several times more expensive than the fresh water pumped from the aquifers and the Rio Grande. 

Cover photo:  A rendering of the Pure Water Center, which broke ground on Feb. 27 and is expected to be operational by 2028. Credit: Courtesy of El Paso Water