Radon, PFOA, and PFOS are present in Harris County groundwater and well owners should be aware of all three. PFOA and PFOS exceed EPA health standards, and radon levels are high enough to warrant concern.
PFOA and PFOS are human-made chemicals that have entered groundwater through industrial use and disposal across the region. Radon seeps into groundwater naturally from cracks and decay in the crystalline bedrock that lies beneath Harris County.
Groundwater in this county is soft, with low levels of calcium, magnesium, sodium, and sulfate. The granite and metamorphic rocks beneath the surface do not dissolve easily into water, which keeps mineral content low. Most wells in Harris County show this soft-water character.
Wells in Harris County contain PFOA and PFOS at levels that exceed EPA health standards. These chemicals are linked to serious health concerns including liver damage, thyroid problems, and increased cholesterol levels. Radon is also found in county wells at levels above the EPA standard. Radon is a radioactive gas that increases the risk of lung cancer when breathed in over time.
The good news is that Harris County has soft water with very low sodium and sulfate levels. This means your water should not cause staining, scale buildup, or taste and odor problems that harder water brings. Your appliances should not experience premature wear from mineral buildup.
We recommend a comprehensive water test to find out what is actually in your well, since every well is different and yours could have higher or lower levels than what is common in the county. Testing is the only way to know what needs treatment. A comprehensive panel for these contaminants typically costs $200-400. Treatment options like activated carbon filters and radon ventilation systems can address these concerns.
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 ⓘ | |
| PFOS ⓘ municipal | 10 | 80% | Low | High | |
| PFOA ⓘ municipal | 10 | 70% | Low | High | |
| Chloride | 4 | 0% | Low | Low ⓘ | |
| Iron | 1 | 0% | Low | Safe ⓘ | |
| Arsenic | 1 | 0% | Low | Low ⓘ | |
| Fluoride | 4 | 0% | Low | Low ⓘ | |
| HFPO-DA (GenX) ⓘ municipal | 10 | 0% | Low | Safe | |
| Nitrite | 1 | 0% | Low | Safe ⓘ | |
| PFNA ⓘ municipal | 10 | 0% | Low | Safe | |
| Arsenic | 1 | 0% | Low | Low ⓘ | |
| Chloride | 4 | 0% | Low | Low ⓘ | |
| Fluoride | 4 | 0% | Low | Low ⓘ | |
| HFPO-DA (GenX) ⓘ municipal | 10 | 0% | Low | Safe | |
| Iron | 1 | 0% | Low | Safe ⓘ | |
| Manganese | 1 | 0% | Low | Safe ⓘ | |
| Nitrate | 4 | 0% | Low | Low ⓘ | |
| Nitrite | 1 | 0% | Low | Safe ⓘ | |
| PFHxS ⓘ municipal | 10 | 0% | Low | Safe | |
| PFNA ⓘ municipal | 10 | 0% | Low | Safe | |
| Sulfate | 4 | 0% | Low | Low ⓘ | |
| Uranium | 1 | 0% | Low | Low ⓘ | |
| Hardness | 4 | — | Low | Low ⓘ | |
| PFBS ⓘ municipal | 10 | — | Low | Low | |
| pH | 4 | — | Low | Low ⓘ | |
| Sodium | 4 | — | 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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