Well owners in Johnson County should be aware of radon, iron, manganese, and fluoride in their groundwater. These contaminants exceed EPA health standards at concentrations that warrant attention.
These metals and radioactive radon enter groundwater from the local rocks beneath the county. As water moves slowly through the fractured rock layers, it dissolves radon released by natural radioactive decay and picks up iron and manganese from the rock matrix itself. Fluoride also occurs naturally in these rock formations.
Groundwater in this county is characterized by very high sodium and moderate sulfate levels alongside moderate iron. The rock layers here naturally release sodium into water that passes through them, while sulfate comes from minerals in the same formations. These mineral characteristics are common across wells throughout the county, though individual wells vary in their exact composition.
Wells in Johnson County commonly have fluoride, iron, manganese, and radon at levels that exceed EPA health standards. Fluoride at elevated levels can harm tooth and bone development, especially in children. Iron and manganese can damage the nervous system over time. Radon is a radioactive gas that increases the risk of lung cancer when breathed in over many years.
The high sodium content in county well water gives it a noticeably salty taste for some people. Although the water here is relatively soft, the elevated iron can cause rust-colored staining in sinks, bathtubs, and laundry. You might notice a metallic or slightly bitter taste in the water. These stains and taste issues affect your daily life and can be frustrating to manage.
Every well in Johnson County is different, and your water may have higher or lower levels than what is common in the county. Testing is the only way to know what is actually in your well so it can be properly treated. We recommend a comprehensive metals and minerals panel, which typically costs between $200 and $400. Iron removal systems and radon mitigation 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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