San Antonio Water Hardness & Quality Report (2026)
Water Hardness
180+ mg/L
Very Hardestimated · not lab-verified
Source
reservoir
pH Level
7.8
neutral = 7.0
Lead
0.002 mg/L
✓ Below action level
TDS
295 mg/L
Est. Daily Cost
$0.91
energy & soap waste
Source: See methodology section below · Updated 2026
0–60
mg/L
Soft
61–120
mg/L
Moderately Hard
121–180
mg/L
Hard
180+
mg/L
Very Hard
Appliance Damage Report
In San Antonio, your appliances are currently losing 45% efficiency due to mineral buildup.
| Appliance | In San Antonio | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 4.7 yrs | 8.5 yrs | -45% |
| Washing Machine | 6.6 yrs | 12 yrs | -45% |
| Water Heater | 8.3 yrs | 15 yrs | -45% |
Regional Water Comparison
How San Antonio compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ San Antonio, Texas | ≈ 180+ mg/L | 3.8 ppt | 🔴 Very Hard | reservoir |
| Leon Valley, Texas | ≈ 180+ mg/L | 3.1 ppt | 🔴 Very Hard | groundwater |
| Converse, Texas | ≈ 180+ mg/L | 0 ppt | 🔴 Very Hard | reservoir |
| Live Oak, Texas | ≈ 180+ mg/L | 0 ppt | 🔴 Very Hard | groundwater |
| Universal City, Texas | 251 mg/L | 0 ppt | 🔴 Very Hard | groundwater |
National Benchmark
How San Antonio compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ San Antonio | ≈ 180+ mg/L | 🔴 High |
| USA National Avg | 151 mg/L | 🟠 Moderate |
| Scarsdale Top Rated | 0.02 mg/L | 🟢 None |
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What Makes San Antonio's Water Unique?
Local geology and source profile
The San Antonio Water System (SAWS) is the primary municipal utility serving San Antonio, Texas, and surrounding areas in Bexar County, including Alamo Ranch, Stone Oak, and Leon Valley. SAWS draws predominantly from the Edwards Aquifer, with supplemental supplies from the Trinity Aquifer and surface water reservoirs including Canyon Lake and Medina Lake. Key treatment facilities include the 223 million-gallon-per-day Edwards Aquifer facility and plants including Dos Rios and King William purification plants, delivering water to over 1.3 million customers across a 360-square-mile service area.
The Edwards Aquifer recharge zone spans the Balcones Fault Zone in Central Texas, where rainwater percolates through thin soils into underlying Cretaceous limestone formations, including the Edwards Group limestones and Georgetown Formation. This karst aquifer system—characterized by solution-enlarged fractures and caves—facilitates rapid mineral dissolution from carbonate rocks rich in calcium and magnesium. The Trinity Aquifer provides deeper groundwater from similar Cretaceous strata, reinforcing the naturally hard, high-mineral character of the supply with elevated dissolved solids.
Very hard water in San Antonio causes significant scale buildup in pipes, fixtures, water heaters, dishwashers, washing machines, and coffee makers, shortening appliance lifespan by years and increasing energy costs. White mineral deposits appear on glassware, faucets, and showerheads; laundry feels stiff and skin and hair dry out. Regular vinegar descaling, drain screens, and annual water heater flushing help manage deposits. A whole-home water softener is strongly recommended. SAWS water maintains pH 7.2–8.0; lead and copper rules are met through corrosion control. PFAS monitoring shows no highlighted concerns; chloramines provide residual disinfection protection. All parameters meet Safe Drinking Water Act standards per annual reports.
Geology & Source: Edwards Aquifer - Cretaceous karst limestone; Edwards Formation limestones highly permeable, rich in calcium and magnesium; Trinity Aquifer - Cretaceous sandstone and limestone; carbonate dissolution through recharge zone yields characteristically
Hardness Varies Across San Antonio — Find Your Area
City average is ≈ 180+ mg/L. Individual ZIP areas differ.
* ZIP code estimates are derived from the city-wide measurement. Actual readings may vary slightly by neighbourhood.
| ZIP Code | Neighbourhood | Hardness (mg/L) | Risk Level |
|---|---|---|---|
| 78212 | Olmos Park area | ≈ 337 | 🔴 Very Hard |
| 78205 | Downtown | ≈ 338 | 🔴 Very Hard |
| 78201 | Prospect Hill | ≈ 339 | 🔴 Very Hard |
| 78204 | King William | ≈ 339 | 🔴 Very Hard |
| 78209 | Alamo Heights | ≈ 339 | 🔴 Very Hard |
| 78203 | Government Hill | ≈ 341 | 🔴 Very Hard |
| 78216 | Airport area | ≈ 341 | 🔴 Very Hard |
| 78240 | Leon Valley | ≈ 341 | 🔴 Very Hard |
| 78202 | Denver Heights | ≈ 343 | 🔴 Very Hard |
| 78207 | West Side | ≈ 343 | 🔴 Very Hard |
| 78213 | North Central | ≈ 343 | 🔴 Very Hard |
| 78228 | West | ≈ 343 | 🔴 Very Hard |
Other Texas Water Reports
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Frequently Asked Questions
Is San Antonio's water safe to drink?
Do I need a water softener in San Antonio?
How does San Antonio compare to the USA average?
Data Sources & Methodology
Water quality data for San Antonio is derived from geographic and geological modelling of the surrounding region. No federal monitoring station data was available for this location.
Water Hardness
Modelled estimate based on state-level USGS geological survey data for this region. No direct USGS Water Quality Portal measurement was matched to this city — the value reflects a statistical range calibrated to the state's dominant rock types and typical source water characteristics.
pH
Estimated from regional geology and source water characteristics. pH is correlated with water hardness and local bedrock — values may differ from utility-reported figures.
TDS — Total Dissolved Solids
Estimated using a derived ratio from water hardness and regional conductance profiles. TDS in natural water correlates strongly with total mineral content including hardness ions.
PFAS — Perfluoroalkyl and Polyfluoroalkyl Substances
EPA UCMR5 (5th Unregulated Contaminant Monitoring Rule, 2023–2025) — sum of PFAS compounds detected at the public water system serving this city. A value of 0 indicates the system was sampled with no detection above reporting limits.
Lead
Modelled estimate based on the EPA Lead and Copper Rule 90th-percentile tap-sample methodology. No publicly available per-city lead dataset with sufficient national coverage exists. Values are a conservative baseline derived from city population tier and infrastructure age — all estimates are maintained below the EPA action level of 0.015 mg/L.
Appliance Lifespan
Calculated from water hardness using a linear degradation model. Baseline lifespans represent soft-water performance (kettle: 8.5 yrs, washing machine: 12.0 yrs, water heater: 15.0 yrs). Hard water mineral scale progressively reduces operational life in direct proportion to hardness concentration.