Hundreds of feet below Bexar County lie billions of gallons of salty Wilcox Aquifer groundwater that were, until now, unusable.

San Antonio Water System‘s newest water desalination plant, H2Oaks, officially opened to the public on Friday, although most San Antonians have been drinking and using its water since the facility in Elmendorf came online in November.

“Just 17 years ago, if you can believe it, our city was 100% dependent on Edwards Aquifer water,” Mayor Ivy Taylor told the large crowd that gathered at the grand opening ceremony in southeast Bexar County. H2Oaks represents the ninth water source San Antonio has developed since. The controversial Vista Ridge water pipeline will be the 10th water source.

“San Antonio has truly demonstrated that we are an innovative, collaborative community of problem solvers that can successfully address one of the most challenging global problems of the 21st century – ensuring that we’re ‘waterful,’” Taylor said, using a promotional catch phrase developed by SAWS.

SAWS officials estimate that the $192 million first phase of the plant will produce about 12 million gallons of finished water per day, enough to supply up to 53,000 households.

SAWS pumps an average of 225,000 acre-feet of water to more than 1.6 million customers per year, and H2Oaks’ first phase will contribute 13,441 acre-feet, almost 6%. Once the third phase of the plant is complete, it would contribute 30,000 acre-feet per year, almost 13%, though total use will likely increase as the San Antonio area stands to gain more than one million people by 2040.

At the entrance of the H2Oaks facility is a mural of a composite of photographs from SAWS sites around the city. The photos were taken by SAWS photographer Paul Robinson.
At the entrance of the H2Oaks facility is a mural of a composite of photographs from SAWS sites around the city. The photos were taken by SAWS photographer Paul Robinson. Credit: Kathryn Boyd-Batstone / Rivard Report

“But the true importance of [desalinated water use] is …. we’re using a water resource that up until now is unusable by anyone. It’s just there,” SAWS President and CEO Robert Puente told the Rivard Report during a phone interview Thursday. “There is an ocean of brackish water under our feet unaffected by drought.”

The H2Oaks facility will be one of the largest inland desalination plants in the country; most U.S. plants are coastal. El Paso’s facility, which opened in 2007, produces 27.5 million gallons of fresh water daily.

H2Oaks looks more like a visitor center or administrative building than a water treatment plant, and that’s entirely on purpose.

The center will function as an educational, research, and meeting facility for SAWS, local universities, and school districts, Puente said. And because it’s adjacent to SAWS’ Carrizo Aquifer pumps and Aquifer Storage and Recovery, the center consolidates maintenance and monitoring processes for three different water sources.

After reviewing three undesirable pipeline proposals that would have piped in billions of gallons of water from surrounding counties, SAWS shifted its focus in early 2014 to expanding plans for the desalination plant. Original timelines set completion of the second phase, which would double production to 24 million gallons per day, in 2021. The final third phase, which would add 5 million more gallons, had been slated for completion in 2026.

The new H2Oaks San Antonio Water System building.
The new H2Oaks San Antonio Water System building. Credit: Kathryn Boyd-Batstone / Rivard Report

Funding for H2Oaks phase one was approved by City Council in 2014. Later that year, a contract proposal for the 142-mile Vista Ridge pipeline that came before the SAWS board was too good to pass up, as board Chairman Berto Guerra Jr. often says.

Now the timeline for the second and third phases of the desalination plant await review as part of SAWS’ next Water Management Plan, slated to come out this spring, Puente said.

“Being successful so far with Vista Ridge, we now have the luxury to see what kind of timeframe we’re talking about [for the next desalination plant phases],” he said.

The full build-out of the center will still cost about $411.4 million, Puente said. The cost per acre-foot for the H2Oaks water is $1,177, compared to an estimated $1,645 per acre-foot from Vista Ridge. Once the center is completed, the acre-foot cost is estimated to average out at $1,138.

H2Oaks was funded almost entirely by water supply fees collected from SAWS customers. The Texas Water Development Board assisted SAWS with a $110 million low-interest loan for the project.

Puente, Taylor, Guerra, and water development board Chair Bech Bruun gave remarks Friday after a rousing performance from a Southside Cardinals percussion ensemble. Dignitaries then lined up to pull down large sheets unveiling the main entrance to H2Oaks and a mariachi band.

Elected officials, business members, news outlets, and other curious community members took a tour of the center Friday afternoon. The reverse osmosis process is extremely loud, but large groups were able to walk through, observe the various processes, and hear tour guides with ease, thanks to corridors designed to dampen noise and allow for video explanations of each step of the process.

The water is treated with calcium carbonate crystals to re-mineralize the water to closely match the composition and flavor of water pumped from the Edwards Aquifer. Visitors were invited to taste bottles of desalinated water.

“It tastes like water,” one man said to laughter.

It requires a lot of energy to pump water 1,500 feet up from the aquifer, cool it down, and push it through ultra-fine filters. For every 10 gallons that comes out of the aquifer, about nine is converted into drinkable water. The remaining brine, also called concentrate, is then injected into wells more than a mile deep.

Two Energy Recovery Turbochargers have been installed on reverse osmosis as a kind of pilot program to find ways to reduce energy usage.

“If it does well, then we can use it more in future as we build out phases,” SAWS spokeswoman Anne Hayden told the Rivard Report.

Iris Dimmick

Iris Dimmick

Senior reporter Iris Dimmick covers City Hall, politics, development, and more. Contact her at iris@rivardreport.com