Well owners in San Patricio County should be aware of arsenic, chloride, uranium, and fluoride in their groundwater. Several of these contaminants exceed EPA health standards, including arsenic, chloride, fluoride, iron, manganese, and uranium, so testing your well is important.
These contaminants come from the coastal geology of this region. The rock layers here contain naturally occurring minerals and salts that dissolve into groundwater. Uranium and arsenic occur naturally in the rock, while chloride concentrations are elevated because of the county's proximity to the Gulf Coast, where salt water can influence underground water supplies.
Groundwater in San Patricio County is very hard, driven by elevated calcium and magnesium from the rock layers below, combined with very high sodium that adds to the mineral load. The coastal location and the composition of the underground rock layers concentrate these minerals in the water as it flows through. These characteristics are widespread across wells throughout the county.
Wells in San Patricio County commonly have arsenic, uranium, fluoride, chloride, and manganese at levels above EPA health standards. Arsenic and uranium are radioactive elements that can damage your kidneys and bones with long-term exposure. Fluoride at high levels can affect tooth and bone health. Manganese can harm your nervous system if you drink it over many years. Chloride itself isn't toxic, but very high levels signal other contaminants in the water.
County wells also tend to be very hard, with high sodium content. The hardness means you'll see white scale buildup in your pipes, on faucets, and inside appliances like your water heater and dishwasher. This scale can shorten how long these appliances last. The high sodium will give your water a slightly salty taste. Iron in the water can leave rust-colored stains on sinks, toilets, and laundry.
We recommend testing your well water since every well is different and your water could have higher or lower levels than what's common here. A comprehensive metals and minerals panel costs between $200 and $400 and is the only way to know exactly what you're dealing with. Once you know your results, you can install the right treatment system, such as a reverse osmosis filter for arsenic removal or a water softener for hardness.
Not sure if your well is affected? Get certified results in 5–7 days.
Test Your Well Water with Tap Score →| Contaminant | Samples ⓘ | % Above MCL ⓘ | Distribution ⓘ | Confidence ⓘ | Risk ⓘ |
|---|---|---|---|---|---|
| Chloride | 61 | 75% | Moderate | High | |
| Uranium | 18 | 22% | Moderate | High | |
| Arsenic | 51 | 18% | Moderate | High | |
| Iron | 68 | 15% | Moderate | Moderate | |
| Manganese | 53 | 6% | Moderate | Moderate | |
| Sulfate | 60 | 5% | Moderate | Moderate | |
| Fluoride | 212 | 0% | High | Low | |
| HFPO-DA (GenX) ⓘ municipal | 34 | 0% | Moderate | Safe | |
| Lead | 50 | 0% | Moderate | Low | |
| Nitrate | 65 | 0% | Moderate | Low | |
| PFHxS ⓘ municipal | 34 | 0% | Moderate | Safe | |
| PFNA ⓘ municipal | 34 | 0% | Moderate | Safe | |
| PFOA ⓘ municipal | 34 | 0% | Moderate | Safe | |
| PFOS ⓘ municipal | 34 | 0% | Moderate | Safe | |
| Hardness | 61 | — | Moderate | Low | |
| PFBS ⓘ municipal | 34 | — | Moderate | Low | |
| pH | 56 | — | Moderate | Low | |
| Sodium | 11 | — | Low | Low |
MCL = Maximum Contaminant Level (EPA limit for public water; used as benchmark for private wells). Distribution shows % of sampled wells in each concentration band. Methodology.
* Microbial contaminants (E. coli, coliform) reflect only samples from the last 10 years.
Data shows potential risk — a certified test confirms whether your water is affected.
Order a Tap Score Test →Population-level CDC data. Not individual risk prediction.
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