Johnson County's groundwater contains iron, arsenic, and chloride, with iron reaching levels high enough to exceed EPA health standards. The arsenic and chloride are present but at levels below EPA thresholds, so iron is the main health concern for well owners here.
Iron enters the groundwater naturally from the rocks and sediment of the Southeastern Coastal Plain aquifer system in this area. As water moves slowly through these rocks underground, it dissolves iron minerals, which is a common process in this type of geology. Arsenic and chloride also occur naturally in these aquifer rocks and are released into the water over time.
Groundwater in Johnson County is moderately hard and notably high in iron, with iron being the dominant mineral that gives the water its distinctive character. The Southeastern Coastal Plain rocks release iron into groundwater as water passes through them over many years. Most wells in this county show these same iron and hardness patterns.
Wells in Johnson County commonly have iron at levels that exceed EPA health standards. Elevated iron in drinking water can cause health concerns with long-term exposure, affecting the kidneys and other organs over time. Children and people with certain health conditions are at higher risk from drinking water with too much iron.
The high iron in county wells creates real problems around the house. It stains laundry, sinks, and bathtubs with red or brown marks that are hard to remove. You may notice a metallic taste in your water and rust-colored buildup on faucets and fixtures. The moderately hard water in this county can also form scale inside pipes and water heaters, shortening how long those appliances last.
We recommend testing your well as soon as possible, since every well is different and yours could have higher or lower levels than what is common here. A comprehensive metals and minerals panel costs between $200 and $400 and is the only way to know exactly what is in your water so you can treat it properly. Iron removal systems and water softeners can address these concerns in your home.
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 ⓘ |
|---|---|---|---|---|---|
| Iron | 2 | 100% | Low | High ⓘ | |
| PFOA ⓘ municipal | 6 | 0% | Low | Safe ⓘ | |
| PFNA ⓘ municipal | 6 | 0% | Low | Safe ⓘ | |
| Arsenic | 1 | 0% | Low | Low ⓘ | |
| Chloride | 7 | 0% | Low | Low ⓘ | |
| HFPO-DA (GenX) ⓘ municipal | 6 | 0% | Low | Safe ⓘ | |
| Fluoride | 6 | 0% | Low | Low ⓘ | |
| Nitrite | 1 | 0% | Low | Low ⓘ | |
| Arsenic | 1 | 0% | Low | Low ⓘ | |
| Chloride | 7 | 0% | Low | Low ⓘ | |
| PFNA ⓘ municipal | 6 | 0% | Low | Safe ⓘ | |
| PFOA ⓘ municipal | 6 | 0% | Low | Safe ⓘ | |
| Radon | 1 | 0% | Low | Low ⓘ | |
| Uranium | 1 | 0% | Low | Safe ⓘ | |
| HFPO-DA (GenX) ⓘ municipal | 6 | 0% | Low | Safe ⓘ | |
| Fluoride | 6 | 0% | Low | Low ⓘ | |
| Lead | 1 | 0% | Low | Low ⓘ | |
| Manganese | 2 | 0% | Low | Low ⓘ | |
| Nitrate | 6 | 0% | Low | Low ⓘ | |
| PFHxS ⓘ municipal | 6 | 0% | Low | Safe ⓘ | |
| PFOS ⓘ municipal | 6 | 0% | Low | Safe ⓘ | |
| Sulfate | 6 | 0% | Low | Low ⓘ | |
| PFBS ⓘ municipal | 6 | — | Low | Safe ⓘ | |
| Hardness | 6 | — | Low | Low ⓘ | |
| pH | 6 | — | Low | Low ⓘ | |
| Sodium | 6 | — | 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.
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