Groundwater in Jefferson County contains radon, chloride, and PFOA, all of which exceed EPA health standards in this area. These contaminants are present at levels serious enough that well owners should test their water.
Radon comes from natural radioactive breakdown in the sandstone bedrock beneath the county. Chloride and PFOA enter the groundwater from road salt and industrial chemicals that seep down through the soil and sand layers. The sandstone here is porous and allows contaminants to move through it more easily than denser rock would.
The water in Jefferson County is soft and low in iron and sulfate, which means it lacks the minerals that typically cause aesthetic problems. The sandstone aquifer does not contain much limestone or other mineral-rich rock, so fewer dissolved minerals accumulate in the water. Most wells in the county show this soft-water pattern.
Wells in Jefferson County commonly have four analytes that exceed EPA health standards: chloride, PFOA, radon, and sulfate. Radon is a radioactive gas that enters groundwater naturally and can increase the risk of lung cancer when inhaled over time. PFOA is a chemical linked to health problems including high cholesterol, liver damage, and immune system effects. Chloride and sulfate at elevated levels can affect people with certain health conditions, though they pose less concern for most households.
The good news is that Jefferson County wells are soft, meaning you likely won't see the staining, scale buildup, or appliance wear that comes with hard water. Iron levels in the county are low, so you should not notice orange or brown discoloration in sinks or laundry. Sodium levels are also low, which is helpful for people watching their salt intake. Water quality here should not create the typical mineral-related taste or odor problems found in other regions.
We recommend testing your well to find out what is actually in your water, since every well is different and yours could have higher or lower levels than what is common countywide. A comprehensive metals and minerals panel typically costs $200 to $400 and will check for all four concerning analytes. Testing is the only way to know if treatment is needed for your specific situation. Radon aeration systems and reverse osmosis filters can address these contaminants if your results show elevated levels.
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 | 23 | 43% | Moderate | High ⓘ | |
| Manganese | 83 | 18% | Moderate | High | |
| Iron | 121 | 12% | High | Moderate | |
| Chloride | 132 | 7% | High | Moderate | |
| PFOA ⓘ municipal | 22 | 5% | Moderate |
Moderate
Elevated concentration, not % above limit
|
|
| Lead | 47 | 2% | Moderate | Low | |
| Sulfate | 121 | 1% | High | Low | |
| Arsenic | 47 | 0% | Moderate | Low | |
| Fluoride | 121 | 0% | High | Low | |
| HFPO-DA (GenX) ⓘ municipal | 22 | 0% | Moderate | Safe | |
| Nitrate | 111 | 0% | High | Low | |
| Nitrite | 33 | 0% | Moderate | Low | |
| PFHxS ⓘ municipal | 22 | 0% | Moderate | Low | |
| PFNA ⓘ municipal | 22 | 0% | Moderate | Safe | |
| PFOS ⓘ municipal | 22 | 0% | Moderate | Safe | |
| Uranium | 32 | 0% | Moderate | Low | |
| Total Coliform | 5* | 0% | Low | Low ⓘ | |
| Sodium | 70 | — | Moderate | Low | |
| pH | 128 | — | High | Low | |
| PFBS ⓘ municipal | 22 | — | Moderate | Low | |
| Hardness | 130 | — | High | Low | |
| Fecal Coliform | 5* | 0% | Low | Low ⓘ | |
| E. coli | 2* | 0% | Low | Safe ⓘ |
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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