Groundwater in Comal County contains arsenic, chloride, fluoride, iron, lead, manganese, nitrate, perfluorinated compounds, and sulfate. Several of these contaminants exceed EPA health standards, which means well owners should test their water and consider treatment options.
These contaminants come from a mix of natural and human sources in the rock and soil. Arsenic, iron, and manganese occur naturally in the underlying rock formations. Chloride and sulfate enter groundwater from natural mineral deposits and from road salt and agricultural activity on the land surface. Nitrate comes mainly from fertilizer and septic systems, while lead and fluoride can leach from pipes and industrial sources.
Groundwater in this county is very hard, driven by elevated calcium and magnesium from the limestone and carbonate rock beneath the surface. The acidic water moving through these rocks dissolves calcium and magnesium as it flows, concentrating them underground. Most wells in Comal County show this very hard water character.
Wells in Comal County have been found to contain arsenic, lead, nitrate, chloride, fluoride, sulfate, and PFOS and PFHXS at levels above EPA health standards. Arsenic and lead can damage your kidneys and nervous system over time. Nitrate is especially dangerous for babies and can affect how blood carries oxygen. PFOS and PFHXS are chemicals that build up in your body and may weaken your immune system. Fluoride at high levels can cause bone problems.
County wells are very hard, which means mineral buildup happens fast. You will probably see white crusty deposits on faucets and in pipes. Your water may taste chalky or have a slightly bitter flavor. Hard water also makes soap work poorly and can leave spots on dishes and shower doors. Very hard water like this shortens the life of water heaters, dishwashers, and washing machines.
We recommend testing your well with a comprehensive panel because multiple contaminants are common in this county. Every well is different--yours could have higher or lower levels than what we see across the county. 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 costs between $200 and $400. Treatment options include reverse osmosis systems for contaminants and water softeners 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 ⓘ |
|---|---|---|---|---|---|
| Sulfate | 671 | 15% | High | Moderate | |
| Chloride | 678 | 14% | High | Moderate | |
| Iron | 696 | 7% | High | Moderate | |
| Manganese | 687 | 3% | High | Low | |
| PFOS ⓘ municipal | 101 | 2% | High | Low | |
| PFHxS ⓘ municipal | 101 | 2% | High | Low | |
| Fluoride | 1480 | 1% | High | Low | |
| Nitrate | 341 | 1% | High | Low | |
| Lead | 515 | 1% | High | Low | |
| Arsenic | 586 | 0% | High | Low | |
| HFPO-DA (GenX) ⓘ municipal | 101 | 0% | High | Safe | |
| Nitrite | 198 | 0% | High | Low | |
| PFNA ⓘ municipal | 101 | 0% | High | Safe | |
| PFOA ⓘ municipal | 101 | 0% | High | Safe | |
| Radon | 17 | 0% | Moderate | Low ⓘ | |
| Uranium | 206 | 0% | High | Low | |
| Total Coliform | 5* | 0% | Low | Low ⓘ | |
| Sodium | 392 | — | High | Low | |
| pH | 583 | — | High | Low | |
| PFBS ⓘ municipal | 101 | — | High | Low | |
| Hardness | 635 | — | High | Low | |
| E. coli | 5* | 0% | 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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