Mayor Ron Nirenberg plans to propose using future borrowing to help preserve land over the Edwards Aquifer while shifting the sales tax that currently funds that preservation over to San Antonio’s transit system.
In an interview Thursday, Nirenberg laid out more specifics for his plan to continue funding the Edwards Aquifer Protection Program (EAPP). He proposed using an unspecified annual amount of San Antonio Water System funds, which could allow SAWS to pay for preserving more aquifer land over 10 years. The effort to leverage SAWS funding comes after a failed attempt to fund the program through the San Antonio River Authority.
Nirenberg said the SAWS funding could preserve an additional 56,000 acres of land over the aquifer’s recharge and contributing zones in Bexar, Medina, and Uvalde counties, taking the total amount of preserved land over sensitive zones of the aquifer from 239,000 acres to 295,000 acres by the early 2040s. That’s based on an analysis by City staff that shows the amount of land necessary to protect San Antonio’s main water supply through 2070.
Nirenberg wouldn’t say how much SAWS would have to contribute from its annual budget so that the utility could borrow enough to pay for the program. He only said it could low enough for SAWS to avoid rate increases to pay for the program.
“I want to ensure that the annual cost to SAWS and continuing the aquifer protection program is offset within the SAWS budget so that we reduce the impact to both SAWS and the ratepayer,” Nirenberg told the Rivard Report. “My goal is to ensure that SAWS taking over the aquifer protection program involves no rate increase to the SAWS customer.”
Around 20 SAWS officials were briefed on the details this week, according to Nirenberg staffers. The municipally owned water and sewer utility’s board could vote as soon as February or March on whether to take on funding for the EAPP.
To ensure enough clean water remains in the Edwards to help meet an annual water demand estimated to reach 105 billion gallons by 2070, another 56,000 acres would have to be preserved, according to City staff estimates obtained by the Rivard Report.
It’s not clear how exactly the City’s staff derived these numbers. However, the City has access to a GIS program that ranks acreage over the aquifer by how easy it is for water to infiltrate the aquifer, the presence of rare plants and animals, whether it’s next to other open space, and the size of the property.
Aquifer Issues Coming To a Head
The Edwards Aquifer, a vast, water-bearing limestone rock layer that stretches from Del Rio to north of Austin, is the most important drinking water supply for roughly 2 million people in the San Antonio area. It supplies most of San Antonio’s drinking water, though the exact percentage varies from year to year.
Because of the sinkholes, caves, and cracks that allow water to flow directly into the Edwards, the aquifer drinks in water during rainy times, but is also vulnerable to pollution. In urban Bexar County, small parts of the aquifer have already become contaminated because of harmful runoff and abandoned wells.
That’s why the City has for two decades been paying ranch owners whose property covers areas where water flows into the aquifer not to build on their land. In some cases, the program has purchased land outright, but the vast majority of the 160,000 acres protected so far have been put under conservation easements.

These easements are permanent contracts that prevent any future owners from developing the land. The program has mostly focused on preserving land over the recharge zone, where the aquifer’s rock layer touches the surface and water can easily infiltrate through cracks and crevices. However, many say it should focus more on the Edwards Aquifer Contributing Zone, the land directly upstream of the recharge zone.
Since 2000, money to pay landowners has come from a one-eighth-cent portion of local sales tax on purchases within San Antonio city limits. Voters have approved sales tax for the aquifer four times in five-year increments, with the latest in 2015 for up to $100 million in revenue. Over two decades, San Antonio residents have voted to tax themselves $325 million to preserve the aquifer.
However, aquifer experts and environmentalists who champion the program say there’s never been a firm target for how much land needs to be preserved.
“I don’t know that we – the collective we – have done a really good job of explaining over time the merits of the [EAPP],” said Roland Ruiz, general manager of the Edwards Aquifer Authority, which regulates pumping from the aquifer. “I think it’s been mom and apple pie – we just know it’s good for the aquifer. It’s been renewed every time, and it’s gotten momentum, and it’s been popular, and nobody’s questioned it.”
Nirenberg and his allies, including Bexar County Judge Nelson Wolff, say the one-eighth-cent sales tax, originally part of a 1-cent percent sales tax created by the Texas Legislature in the 1970s for cities to use for transportation, should go towards VIA Metropolitan Transit. Unlike Dallas, Houston, and Austin, which put the full cent towards transportation, San Antonio only claimed a half-cent. Over decades, the remaining half-cent was divided among VIA, the City, transportation initiatives, Pre-K 4 SA, and the EAPP.
For the mayor, shifting the sales tax to VIA is a vital next step in accomplishing his biggest economic and environmental initiatives – creating functional public transit, reining in sprawl, and improving air quality.
“We have for more than a generation longed for a transportation system that was ready for the future,” Nirenberg said. “The strategy that we’ve laid out allows us to continue these valuable programs while building a modern, multimodal transportation system that will keep our economy viable, that will make a huge leap in our fight against poverty, and help us reach our climate action goals.”
Last year, Nirenberg and his allies had hoped a San Antonio River Authority tax could shore up the aquifer program, but that strategy failed when the river authority’s board voted against pursuing the tax. That led to a shift in focus to SAWS as a funding source.

Nirenberg’s challenge is to put forth a new version of the EAPP that SAWS board members can accept without fear of spiking bills. For years, SAWS customers have experienced annual rate increases to pay for water supply projects and sewer upgrades and repairs. Rate increases have raised the average customer’s bill 50 percent since 2015. In December, SAWS trustees expressed caution about taking on the aquifer protection program if it would lead to a bill increase.
This year, SAWS’ annual revenue contribution to the City’s coffers is rising from 2.7 percent to 4 percent, an increase of about $10 million that will bring the utility’s total contribution to the City to $29 million. SAWS officials have said their budget can absorb that additional amount in the short term, though they will likely have to raise rates in the future to keep payments at that level.
How Much Preservation Is Enough?
Even as he tries to ease SAWS’ budget concerns, Nirenberg is trying to ensure a version of the program continues in some form. Many of his longtime supporters are environmentalists who worked to build the EAPP more than 20 years ago. Some of the mayor’s longtime allies are upset Nirenberg would even consider changing the program.

The 56,000 acres Nirenberg proposes is far less land than what some aquifer advocates say is necessary to protect the aquifer. Francine Romero, chair of the Conservation Advisory Board that vets properties for participation in the EAPP, says the program should preserve 200,000 acres of the recharge zone and 118,000 acres of the most important parts of the contributing zone.
Other EAPP advocates have not determined exactly how much land it needs to preserve.
“It’s a legitimate question,” said Bonnie Conner, a former District 8 councilwoman and part of the group that formed the EAPP. “I don’t think the group I’m with has come up with an answer to that.”
Neither have aquifer scientists, who say there’s simply not enough data out there to know what the program’s parameters ought to be.
“It’s difficult to answer on a scientific basis,” said Mark Hamilton, the Edwards Aquifer Authority’s director of aquifer management.
In a December 2018 whitepaper, Hamilton and his team looked at how much of the aquifer’s watershed has been protected: only 6 percent, counting all of the 2.5 million to 2.8 million acres in the aquifer’s watershed in Bandera, Bexar, Edwards, Gillespie, Kendall, Kerr, Medina, Real, and Uvalde counties. But they’re unable to say how much land would be enough or how best to preserve the aquifer without studies that could take years to complete.
Romero said her estimate is based on that EAA whitepaper. Yet EAA officials said there’s no reliable scientific answer for how much land needs to be protected to ensure good water quality.
“One of the questions that keeps coming up is, ‘How much is enough?’” Ruiz said. “I don’t know that there’s a clear-cut answer to that. Maybe the more appropriate is, if you have a limited amount of funding, how should it be prioritized?”
The Edwards Aquifer Protection Program came out of the water battles of the 1990s, a time of intense scrutiny of San Antonio water issues. A group of environmentalists, civic leaders, and businesspeople began convening to find a way to preserve land over the recharge zone.
“We knew it [there] had to be some way to obtain the funds to buy land or put conservation easements on it,” said Conner, a former Nirenberg advisor who remains an influential voice in the mayor’s former City Council district.
Many of the EAPP’s advocates see the program as one of the city’s great accomplishments, a model that’s drawn attention from around the world for using financial incentives instead of regulation to protect drinking water.
“What has resulted from it is more than providing clean water,” Conner said. “It has, in my opinion, provided a buffer” to development on the city’s fringes.
Romero said EAPP advocates are “shocked at the mayor not wanting to extend” the sales tax.
“That’s why everybody sprung into action,” Romero said. “People thought there would be so much support for this, because there’s been so much support from the citizens.”