Groundwater in Comal County contains arsenic, chloride, fluoride, iron, lead, manganese, nitrate, PFHXS, PFOS, and sulfate at levels that exceed EPA health standards. These contaminant levels are concerning and warrant attention from well owners in the area.
These contaminants come from a mix of natural and human sources. The rock beneath Comal County naturally releases some minerals like arsenic, iron, and manganese as water flows through it over time. Chloride, nitrate, and industrial chemicals like PFOS enter groundwater from human activities including agriculture, urban development, and past industrial use. The local geology combined with land use patterns creates conditions where these substances accumulate in the water.
Groundwater in Comal County is very hard, driven primarily by calcium and magnesium dissolved from the rock below. The underlying geology naturally concentrates these minerals as water passes through the ground layers over many years. This hard water character is widespread across wells throughout the county, making it a common feature of private water supplies here.
Wells in Comal County contain several contaminants that exceed EPA health standards. Arsenic can harm your kidneys and increase cancer risk. Lead damages children's developing brains and nervous systems. Nitrate is especially dangerous for babies under six months old. Fluoride at elevated levels can weaken bones and teeth. Manganese can affect the nervous system. PFOS and PFHXS are industrial chemicals linked to serious health problems. Chloride at high levels can be harmful to people with certain heart or kidney conditions.
The very hard water found in county wells can shorten the lifespan of water heaters, dishwashers, and other appliances. You may notice rust-colored staining on fixtures and laundry. Soap doesn't lather well and leaves a residue on skin and hair. The water may taste salty or have a mineral flavor. Scale buildup inside pipes and appliances is common.
Testing is the only way to know what is actually in your well, since every well is different and yours may have higher or lower levels than what is common here. We recommend a comprehensive metals and minerals panel, which typically costs two hundred to four hundred dollars. Treatment options like reverse osmosis systems or ion exchange water softeners can address multiple contaminants at once.
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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