Growing the state’s water supply
As the reality of a drying climate becomes increasingly difficult to ignore across Texas — with reservoirs at record lows and beloved springs no longer flowing — many are wondering how the state can cope with a more arid future coupled with ongoing unprecedented growth. A new publication by Texas Water Trade (TWT) called the “Net Zero Water Toolkit — A guide to non-potable onsite water reuse for Texas developers and owner/operators” poses the question as follows: “How do we grow our water supply and ensure water security for Texas? The answer is in the problem — we have to look at growth as a source of water, not just a source of demand.” According to TWT CEO Sharlene Leurig, “With around 1,000 new Texans arriving each day, there is no question that we need to grow our state’s water supplies. Texas Water Trade believes that water reuse is one of our biggest opportunities.”
Since the vast majority of the water needed for municipal uses, such as toilets, irrigation and cooling towers, doesn’t have to be potable, the goal of Net Zero Water is to “help a development provide for its own water needs through the capture, storage, and treatment of compatible water sources found onsite.” These sources can include the accumulating moisture that drains from a structure’s foundation, condensate from air conditioners, and rainwater captured off buildings and parking lots.
According to the Toolkit, Net Zero Water systems “copy nature’s water cycle — after all, every drop of water we’ve ever consumed, cooked with, or bathed in has been used and recycled countless times through millennia.” Instead of relying on the old model of using water one time and sending it back to the central utility for treatment, Net Zero systems diversify the water portfolio by reusing the same water multiple times for a cascading range of uses.
One of the most impressive aspects of the toolkit is that it doesn’t just wag an accusatory finger at the status quo, but instead highlights the cost efficiencies, available incentives and wide-ranging benefits of adopting a Net Zero Water approach to new buildings and developments. By speaking the language of developers, Leurig is hoping “that Net Zero designs can become the new normal for Texas … making the Lone Star State’s water systems more independent and resilient.”
The Net Zero Water Toolkit provides many examples of how non-potable reuse can actually benefit a developer’s bottom line. “Development permits require evidence of sufficient water to support the number of planned units. Those calculations assume that all water demands will be met with potable water and then discharged as wastewater. Water reuse can be used to negotiate greater intensity of development by stretching water supplies further.” The toolkit authors also point out that “land application of wastewater and stormwater detention occupy valuable acreage. Water reuse can reduce the amount of land that must be dedicated to these purposes,” freeing up more land for development. And as “water and sewer rates have increased by 2.5 times the Consumer Price Index over the last 20 years,” Net Zero Water developments will become increasingly cost effective over time because they only use “10-30% of the potable water required by status quo developments.”
Perhaps the most compelling argument for developers to adopt a Net Zero Water approach involves the very real prospect of construction moratoriums in extremely water-constrained regions. Dripping Springs, Texas, enacted a year-long moratorium on new construction in 2021 largely due to the city’s limited wastewater capacity. And in 2023, Magnolia, Texas, extended its moratorium on new building permits for a third time as the city struggled to address a water supply shortage. By adopting Net Zero Water principles in all new construction, developers can ensure that their businesses will thrive in a drying, warming climate.
The toolkit includes many inspiring descriptions of Net Zero Water in action, including the University of Texas at Austin, which “uses 50-60 million gallons of AC condensate water to fill its cooling towers all across campus … Onsite water reuse saves the university more than 100 million gallons of potable water each year.” The Credit Human Headquarters in San Antonio uses “captured water … to flush all toilets, provide irrigation, and supply makeup water for the cooling towers, resulting in an estimated savings of 4 million gallons of water per year.” And the Austin Central Library reuses rainfall and air conditioner condensate, enabling “85% less potable water use” and saving “1.5 million gallons of potable water a year.”
“One barrier to the widespread implementation of these emerging Net Zero Water technologies … is a lack of educational resources available to developers … municipalities and school districts,” said Leurig. “That lack of resources leads to the belief that implementing these tools is too costly and slows down the development timeline. To overcome this knowledge gap and speed the adoption of onsite water reuse strategies, Texas Water Trade created the Net Zero Water Toolkit.” She and her team at TWT are confident that “onsite water reuse is not a fad but a much-needed supply resource … With onsite water reuse, growth can actually help Texas grow its water supplies — a win for developers and for Texas.”
Visit texaswatertrade.org/net-zero-water to learn more.
Trey Gerfers is a San Antonio native and serves as general manager of the Presidio County Underground Water Conservation District. He has lived in Marfa since 2013. He can be reached at tgerfers@pcuwcd.org.