Groundwater in Johnson County contains radon, iron, and manganese at levels that exceed EPA health standards. These contaminants are present at concerning levels and warrant attention from well owners.
The rock beneath Johnson County naturally releases these elements into groundwater. Radon comes from radioactive decay in the bedrock, while iron and manganese leach from the minerals in the rock layers. This combination is common across this region and the surrounding counties with similar geology.
Groundwater in this county is notably high in sodium, which is the defining character of the water here. Sodium concentrations reach very high levels because it dissolves easily from the surrounding rock and soil as water moves through them. Many wells across Johnson County show this same sodium signature, making it a widespread feature of the groundwater.
Wells in Johnson County commonly have fluoride, iron, manganese, and radon at levels that exceed EPA health standards. Fluoride at high levels can affect bone health and cause dental problems, especially in children whose teeth are still developing. Iron and manganese in drinking water can cause nervous system effects with long-term exposure. Radon is a radioactive gas that increases the risk of lung cancer when inhaled over time.
County well water has very high sodium content, which can affect how water tastes and feels on your skin. While the water is relatively soft, the high sodium means you may notice a salty taste or that soap doesn't lather well. High sodium is a concern for people on restricted diets, and it can make water unsuitable for certain uses like watering plants or filling pools.
We recommend testing your well water with a comprehensive panel since multiple analytes exceed health standards in this county. Every well is different, and your water could have higher or lower levels than what is common here. Testing is the only way to know exactly what is in your water so you can treat it properly if needed. A comprehensive metals and minerals panel typically costs between two hundred and four hundred dollars, and treatment options like radon mitigation systems or ion exchange filters can address these specific 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 ⓘ | |
| Iron | 252 | 15% | High | High | |
| Manganese | 169 | 11% | High | Moderate | |
| Fluoride | 430 | 4% | High |
Moderate
Elevated concentration, not % above limit
|
|
| Arsenic | 88 | 0% | Moderate | Low | |
| Chloride | 1 | 0% | Low | Low ⓘ | |
| HFPO-DA (GenX) ⓘ municipal | 117 | 0% | High | Safe | |
| Lead | 86 | 0% | Moderate | Low | |
| Nitrate | 32 | 0% | Moderate | Low | |
| Nitrite | 1 | 0% | Low | Safe ⓘ | |
| PFHxS ⓘ municipal | 117 | 0% | High | Safe | |
| PFNA ⓘ municipal | 117 | 0% | High | Safe | |
| PFOA ⓘ municipal | 117 | 0% | High | Safe | |
| PFOS ⓘ municipal | 117 | 0% | High | Safe | |
| Sulfate | 1 | 0% | Low | Low ⓘ | |
| Uranium | 21 | 0% | Moderate | Low | |
| Total Coliform | 1* | 0% | Low | Safe ⓘ | |
| Sodium | 1 | — | Low | Low ⓘ | |
| pH | 1 | — | Low | Low ⓘ | |
| PFBS ⓘ municipal | 117 | — | High | Low | |
| Hardness | 1 | — | Low | Low ⓘ | |
| E. coli | 1* | 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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