Robstown Water Hardness & Quality Report (2026)
Water Hardness
~120–179 mg/L
Hardestimated · not lab-verified
Source
reservoir
pH Level
7.9
neutral = 7.0
Lead
0.007 mg/L
✓ Below action level
TDS
976.4 mg/L
Est. Daily Cost
$0.40
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 Robstown, your appliances are currently losing 20% efficiency due to mineral buildup.
| Appliance | In Robstown | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 6.8 yrs | 8.5 yrs | -20% |
| Washing Machine | 9.6 yrs | 12 yrs | -20% |
| Water Heater | 12 yrs | 15 yrs | -20% |
Regional Water Comparison
How Robstown compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Robstown, Texas | ≈ 120–179 mg/L | 27.4 ppt | 🟠 Hard | reservoir |
| Corpus Christi, Texas | ≈ 180+ mg/L | 0 ppt | 🔴 Very Hard | reservoir |
| Kingsville, Texas | ≈ 120–179 mg/L | 51.3 ppt | 🟠 Hard | reservoir |
| Portland, Texas | ≈ 180+ mg/L | 35.8 ppt | 🔴 Very Hard | reservoir |
| Alice, Texas | ≈ 180+ mg/L | 39.2 ppt | 🔴 Very Hard | reservoir |
National Benchmark
How Robstown compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Robstown | ≈ 120–179 mg/L | 🟠 Moderate |
| USA National Avg | 151 mg/L | 🟠 Moderate |
| Scarsdale Top Rated | 0.02 mg/L | 🟢 None |
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What Makes Robstown's Water Unique?
Local geology and source profile
Nueces County Water Control and Improvement District #3 (WCID #3) supplies water to Robstown and nearby areas in Nueces County, Texas, serving around 12,000 people. Their main source is groundwater from the Carrizo-Wilcox Aquifer, which is then blended with surface water obtained through a new connection to Corpus Christi's O.N. Stevens Water Treatment Plant. This blending helps manage local water quality. Treatment takes place at the district's own facilities before the water is sent out through the local distribution network. The utility is committed to meeting all state and federal water quality regulations, even as they work on improving their infrastructure.
The Carrizo-Wilcox Aquifer, a significant groundwater source for South Texas, is composed of Eocene-age sands and clays. Interspersed within these are zones rich in minerals like calcium and magnesium, which dissolve into the water, contributing to its hardness. Additionally, surface water sourced from the Nueces River watershed is influenced by Cretaceous limestone formations, such as the Edwards Group. These limestones can add bicarbonates to the water. This combination of mineral-rich aquifers and limestone geology is typical for the Coastal Bend region, resulting in groundwater that carries a noticeable mineral content.
This moderately hard water can lead to scale buildup within appliances like water heaters and dishwashers, potentially reducing their efficiency by up to 30% and increasing energy costs. You might also notice that laundry feels stiffer, and soaps don't lather as easily, often requiring more detergent. Annual descaling of fixtures and the installation of sediment filters are good maintenance practices. For households experiencing issues like spots on dishes or dry skin, installing a whole-home water softener is often recommended to extend appliance life and improve water feel. Despite recent reports concerning elevated TDS and arsenic, officials confirm the water is safe to drink, with treatment processes in place to manage naturally occurring contaminants from the local geology.
Geology & Source: Carrizo-Wilcox Aquifer (Eocene sands/clays) and Cretaceous limestone; calcium/magnesium in sands and bicarbonates in limestone create hard water.
Other Texas Water Reports
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Frequently Asked Questions
Is Robstown's water safe to drink?
Do I need a water softener in Robstown?
How does Robstown compare to the USA average?
Data Sources & Methodology
Water quality data for Robstown 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.