San Antonio Water System — SAWS — operates one of the largest water utilities in Texas, managing roughly 9,000 miles of water and sewer mains serving about 2 million people across the service area.
And here’s something that sets it apart from most major US cities: SAWS reports no known lead service lines in its system.
Like Phoenix, San Antonio’s water infrastructure was largely built after lead pipe installation was discontinued. That’s a significant advantage when cities like Milwaukee and Philadelphia are spending billions to dig up and replace lead lines that were standard practice a century ago.
But San Antonio’s water story is about different challenges — groundwater dependence, drought vulnerability, and what happens when a winter storm brings one of the nation’s largest water systems to its knees.
The Edwards Aquifer and Beyond
San Antonio has historically depended on the Edwards Aquifer as its primary water source — one of the most productive artesian aquifers in the world. The Edwards supplies drinking water to roughly 2 million people in south-central Texas and feeds the springs that sustain endangered species habitat.
But relying on a single source, even a prolific one, is a risk. SAWS recognized this and has spent decades diversifying. Today the utility draws from multiple aquifers — the Edwards, Carrizo, Trinity, and Wilcox — reducing its dependence on any single source.
The crown jewel of that diversification effort is the Vista Ridge Pipeline: a 142-mile pipeline from Burleson County to San Antonio that became operational in 2020. Vista Ridge taps the Carrizo-Wilcox Aquifer and can deliver up to 16.3 billion gallons annually — a massive addition to the city’s water portfolio.
SAWS also operates one of the largest Aquifer Storage and Recovery (ASR) programs in the United States. During wet years, the utility banks water underground in the Edwards Aquifer. During droughts, it recovers that stored water. It’s essentially a savings account for water — and in a state that cycles between floods and droughts, it’s smart planning.
Winter Storm Uri: The Wake-Up Call
In February 2021, Winter Storm Uri hit Texas with temperatures and conditions the state’s infrastructure was never designed to handle. Power grids failed. Pipes froze and burst. Water treatment plants lost power and pressure.
SAWS experienced significant service disruptions — main breaks, loss of system pressure, and boil water notices affecting hundreds of thousands of customers. The storm laid bare how interconnected infrastructure systems are: when the power grid fails, water treatment fails, and when water pressure drops, hospitals, fire departments, and households all suffer simultaneously.
To its credit, SAWS has invested heavily in hardening its system since Uri. Generator backup systems, pipe insulation, and redundancy improvements have all been part of a post-storm capital investment program designed to ensure the system can survive the next extreme weather event.
The American Society of Civil Engineers gave Texas a C grade on its 2025 infrastructure report card, with Winter Storms Viola and Uri specifically cited as events that “revealed interdependence of infrastructure systems.”
A Smarter Way to Replace Pipes
Here’s where San Antonio is doing something genuinely interesting. Rather than replacing pipes based solely on age — the traditional approach — SAWS is shifting to condition-based replacement.
The concept is straightforward: not every old pipe is a bad pipe, and not every new-ish pipe is in good shape. Soil conditions, water chemistry, installation quality, and operating pressure all affect how fast a pipe deteriorates. A 60-year-old pipe in stable soil might have decades of life left, while a 30-year-old pipe in corrosive soil might be failing.
SAWS is using data-driven assessment tools — acoustic monitoring, pressure sensors, and break history analysis — to identify which pipes actually need replacement versus which ones can safely continue operating. It’s a more efficient use of capital dollars and avoids the disruption of replacing pipes that don’t need it.
This approach requires good data, and SAWS has been building that database across its 9,000-mile network. As other cities face their own infrastructure backlogs, San Antonio’s model could become a template.
Water Quality
The Texas Commission on Environmental Quality has rated SAWS water quality as “superior” since 1936. That’s not a typo — nearly 90 years of consistent quality from a groundwater-dependent system.
Groundwater generally presents fewer treatment challenges than surface water. There’s no seasonal variation in organic matter, no algae blooms to manage, and lower risk of the contamination events that plague river-sourced systems. Natural filtration through rock and soil does much of the work before the water ever reaches a treatment plant.
That said, Texas aquifers can contain naturally occurring contaminants. Radium, arsenic, and fluoride are all found at varying levels in groundwater throughout the state. SAWS treats for these and conducts extensive monitoring to maintain compliance with EPA and TCEQ standards.
SAWS has also conducted PFAS sampling under the EPA’s Fifth Unregulated Contaminant Monitoring Rule (UCMR 5). Groundwater sources are generally less susceptible to PFAS contamination than surface water, though localized sources near industrial or military sites can occur.
Detailed contaminant data for the San Antonio Water System is available through the EWG Tap Water Database.
Water Costs
SAWS water rates have been increasing modestly — in line with most major utilities nationwide. The rate structure uses conservation-oriented tiered pricing: use more, pay more per gallon. In a region where drought is a recurring reality, that pricing structure serves double duty as both a revenue tool and a conservation incentive.
For customers who need help with bills, SAWS offers the Uplift program — a payment assistance program for qualifying households.
What San Antonio Residents Should Do
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Read your annual water quality report. SAWS publishes detailed water quality reports annually. These reports show exactly what’s been tested, what’s been detected, and how levels compare to federal and state limits.
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Test if you’re on a private well. If you’re outside the SAWS service area and rely on a private well, test for the contaminants common in Texas aquifers: arsenic, radium, fluoride, and nitrates. Municipal customers benefit from continuous monitoring; private well owners are on their own.
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Winterize your plumbing. Uri was a painful lesson. Insulate exposed pipes, know where your main shutoff valve is, and have a plan for extended cold weather events — even in Texas.
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Conserve water. San Antonio has made conservation part of its identity, but there’s always room to do more. The city’s aquifer storage program only works if there’s surplus water to bank during wet years.
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Consider point-of-use filtration. Even with excellent municipal treatment, an additional layer of filtration at the tap — particularly reverse osmosis for drinking water — can provide peace of mind, especially regarding naturally occurring contaminants like radium and arsenic.
San Antonio’s water system is a model of forward thinking in many ways: diversified supply, no lead pipes, data-driven maintenance, and lessons learned from disaster. It’s not perfect — no system managing 9,000 miles of pipe can be — but it’s a city that takes its water seriously.
If you’re concerned about your water quality, a certified water treatment professional can test your water and help you choose the right treatment system for your home.