Groundwater in Zavala County contains radon, iron, chloride, manganese, nitrate, sulfate, and uranium at levels that exceed EPA health standards. These contaminants appear in moderate to high amounts, making them a concern for well owners in this area.
The rocks beneath Zavala County naturally contain minerals and radioactive elements that dissolve into groundwater as water moves through them. Chloride and sulfate come from the mineral composition of the local rock layers. Nitrate enters from agricultural and land activities on the surface. Radon is produced by the natural decay of uranium in the bedrock itself.
Groundwater in this county is very hard, driven by elevated calcium and magnesium from the surrounding rock, combined with high sodium and moderate sulfate. These minerals dissolve naturally as water passes through the local geology. Hard, mineral-rich water with elevated sodium is widespread across wells throughout the county.
Wells in Zavala County commonly exceed EPA health standards for several contaminants including uranium, radon, nitrate, and some mineral salts like chloride and sulfate. Uranium and radon are radioactive elements that can increase cancer risk with long-term exposure. Nitrate is especially dangerous for infants and can cause serious illness. Chloride and sulfate at high levels can cause digestive issues and contribute to other health problems over time.
The very hard water in county wells creates noticeable quality-of-life problems for many families. Hard water leaves white scale buildup on faucets, showerheads, and inside pipes. It makes soap less effective for cleaning and leaves spots on dishes and glass. The high sodium content can affect the taste of water and food. Over time, very hard water can shorten the lifespan of water heaters, dishwashers, and washing machines.
We recommend testing your well water with a comprehensive panel since several analytes exceed standards in this county. Every well is different--yours could have higher or lower levels than what is common here. Testing is the only way to know what is actually in your water so you can treat it properly. A comprehensive metals and minerals panel typically costs between $200 and $400. Water softeners and filters designed for uranium and radon removal are available treatment options.
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 ⓘ |
|---|---|---|---|---|---|
| Radon | 3 | 33% | Low | High ⓘ | |
| Iron | 258 | 32% | High | High | |
| Chloride | 8 | 25% | Low | High ⓘ | |
| Sulfate | 8 | 25% | Low | High ⓘ | |
| Manganese | 224 | 12% | High | Moderate | |
| Nitrate | 28 | 4% | Moderate |
Moderate
Elevated concentration, not % above limit
|
|
| Uranium | 61 | 2% | Moderate | Low | |
| Arsenic | 148 | 0% | High | Low | |
| Fluoride | 562 | 0% | High | Low | |
| HFPO-DA (GenX) ⓘ municipal | 8 | 0% | Low | Safe ⓘ | |
| Lead | 148 | 0% | High | Low | |
| Nitrite | 6 | 0% | Low | Safe ⓘ | |
| PFHxS ⓘ municipal | 8 | 0% | Low | Safe ⓘ | |
| PFNA ⓘ municipal | 8 | 0% | Low | Safe ⓘ | |
| PFOA ⓘ municipal | 8 | 0% | Low | Safe ⓘ | |
| PFOS ⓘ municipal | 8 | 0% | Low | Safe ⓘ | |
| PFBS ⓘ municipal | 8 | — | Low | Safe ⓘ | |
| Sodium | 8 | — | Low | Low ⓘ | |
| Hardness | 8 | — | Low | Low ⓘ | |
| pH | 8 | — | 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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