Groundwater in Bexar County contains arsenic, chloride, fluoride, iron, lead, manganese, nitrate, radon, and sulfate. Several of these contaminants exceed EPA health standards and warrant attention from well owners.
These contaminants come from both natural and human sources. The rock beneath Bexar County naturally releases arsenic, iron, and manganese as water moves through it over time. Chloride and sulfate also occur naturally in the local geology. Nitrate enters groundwater from fertilizer use and septic systems, while lead can come from pipes and plumbing in older wells.
Groundwater in this county is very hard, driven by elevated calcium and magnesium from the limestone and other rock layers below. As water flows through these mineral-rich layers, it dissolves these elements and carries them into wells. Very hard water is common across Bexar County wells.
Bexar County well water contains several contaminants that exceed EPA health standards. Arsenic can damage your kidneys and increase cancer risk over time. Lead harms children's brain development and learning. Nitrate is especially dangerous for infants and can interfere with how their blood carries oxygen. Radon is a radioactive gas that increases lung cancer risk when breathed in over years. Fluoride, chloride, and manganese at elevated levels also pose health concerns.
Bexar County has very hard water, which causes white crusty scale buildup on faucets and shower heads. You may notice rust-colored staining on laundry and fixtures from iron. This extreme hardness can shorten the lifespan of water heaters and dishwashers. Hard water also makes soap less effective and can leave your skin and hair feeling dry.
Since wells in this county show multiple contaminant concerns, we recommend a comprehensive water test that checks for metals, minerals, bacteria, and nitrate. A comprehensive panel typically costs $200 to $400. Your well is different from others in the county and may have higher or lower levels, so testing is the only way to know what is actually in your water and how to treat it. Water softeners, reverse osmosis systems, and radon removal are options depending on your results.
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 ⓘ |
|---|---|---|---|---|---|
| Sulfate | 3487 | 28% | High | High | |
| Chloride | 3582 | 27% | High | High | |
| Iron | 3269 | 6% | High | Moderate | |
| Radon | 39 | 5% | Moderate | Moderate ⓘ | |
| Manganese | 3090 | 3% | High | Low | |
| Fluoride | 5791 | 2% | High | Low | |
| Nitrate | 1575 | 1% | High | Low | |
| Lead | 2132 | 0% | High | Low | |
| Arsenic | 2601 | 0% | High | Low | |
| HFPO-DA (GenX) ⓘ municipal | 225 | 0% | High | Safe | |
| Nitrite | 1116 | 0% | High | Low | |
| PFHxS ⓘ municipal | 225 | 0% | High | Safe | |
| PFNA ⓘ municipal | 225 | 0% | High | Safe | |
| PFOA ⓘ municipal | 225 | 0% | High | Safe | |
| PFOS ⓘ municipal | 225 | 0% | High | Low | |
| Uranium | 685 | 0% | High | Low | |
| Hardness | 3428 | — | High | Low | |
| E. coli | 40* | 0% | Moderate | Low | |
| Total Coliform | 37* | 0% | Moderate | Low | |
| Sodium | 2462 | — | High | Low | |
| pH | 3587 | — | High | Low | |
| PFBS ⓘ municipal | 225 | — | High | 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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