Groundwater in Tom Green County contains radon, nitrate, and chloride along with several other contaminants that exceed EPA health standards, including fluoride, iron, lead, manganese, and sulfate. These levels are concerning enough to warrant attention and testing.
Radon seeps naturally from radioactive minerals in the bedrock below the county. Nitrate can come from fertilizer use on agricultural land as well as natural soil sources. Chloride and sulfate accumulate because water moving slowly through the underlying rock dissolves these minerals over time. Lead may enter from pipes or well construction materials rather than the geology itself.
Groundwater in this county is very hard, driven primarily by dissolved calcium and magnesium from the rock below. The water also contains elevated sodium and moderate sulfate. These mineral concentrations are common across wells throughout Tom Green County because the local rock naturally releases these substances into the water as it percolates downward.
Wells in Tom Green County commonly contain chloride, fluoride, iron, lead, manganese, nitrate, radon, and sulfate at levels above EPA health standards. Lead can harm children's brain development and cause learning problems. Nitrate is especially dangerous for infants and can reduce oxygen in the blood. Radon is a radioactive gas that increases lung cancer risk. Fluoride, manganese, and the other metals at elevated levels can affect your nervous system and organs over time.
County well water is very hard, which causes stubborn white scale buildup on faucets, shower heads, and inside pipes. The high mineral content shortens the lifespan of water heaters, dishwashers, and other appliances. You may notice a salty taste from sodium, a rotten egg smell from sulfate, or reddish staining from iron. Soap and shampoo will not lather well, and your laundry may feel stiff and dingy.
We recommend testing your well with a comprehensive metals and minerals panel, which typically costs $200-400. Every well is different, and your water may have higher or lower levels than what is common in the county. Testing is the only way to know what is actually in your well so it can be properly treated. A water softener can help with hardness, while reverse osmosis or other filtration may address specific contaminants.
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 | 1 | 100% | Low | High ⓘ | |
| Nitrate | 59 | 64% | Moderate | High | |
| Chloride | 35 | 54% | Moderate | High | |
| Sulfate | 33 | 27% | Moderate | High | |
| Iron | 141 | 1% | High | Low | |
| Manganese | 144 | 1% | High | Low | |
| Lead | 125 | 1% | High | Low | |
| Fluoride | 380 | 0% | High | Low | |
| Arsenic | 143 | 0% | High | Low | |
| HFPO-DA (GenX) ⓘ municipal | 31 | 0% | Moderate | Safe | |
| Nitrite | 9 | 0% | Low | Low ⓘ | |
| PFHxS ⓘ municipal | 31 | 0% | Moderate | Low | |
| PFNA ⓘ municipal | 31 | 0% | Moderate | Safe | |
| PFOA ⓘ municipal | 31 | 0% | Moderate | Safe | |
| PFOS ⓘ municipal | 31 | 0% | Moderate | Safe | |
| Uranium | 41 | 0% | Moderate | Low | |
| PFBS ⓘ municipal | 31 | — | Moderate | Low | |
| pH | 33 | — | Moderate | Low | |
| Sodium | 33 | — | Moderate | Low | |
| Total Coliform | 1* | 0% | Low | Safe ⓘ | |
| E. coli | 1* | 0% | Low | Safe ⓘ | |
| Hardness | 33 | — | Moderate | 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.
Loading recent water news…