Groundwater in Johnston County contains iron, PFOA, and PFOS that exceed EPA health standards, along with elevated sulfate and lead. These contaminants are present at levels serious enough to warrant attention and testing of your well.
Iron comes from natural breakdown of rock minerals in the coastal plain aquifer beneath your county. PFOA and PFOS are industrial chemicals that have entered groundwater through contamination from manufacturing, military sites, or disposal areas and persist in the water over time. Sulfate and lead also accumulate from natural rock sources and human activities in the area.
Groundwater in Johnston County is notably high in iron, which comes from the sandy and clay layers of the coastal plain aquifer where iron-rich minerals naturally dissolve into water. This iron concentration is common across wells throughout the county due to the composition of the rock and soil that supply your water.
Wells in Johnston County have been found to contain PFOA, PFOS, PFHXS, sulfate, iron, and lead at levels above EPA health standards. PFOA and PFOS are industrial chemicals that can build up in your body over time and may affect your immune system, thyroid function, and liver health. Lead damages the brain and nervous system, especially in children, and can harm kidney function in adults. High sulfate levels can cause digestive problems.
Iron in county wells creates rust-colored staining on fixtures, laundry, and dishes. It can give water a metallic taste and create an unpleasant odor. These stains are hard to remove and can be frustrating to deal with over time.
We recommend getting your well tested with a comprehensive panel that checks for metals, PFOA, PFOS, and other contaminants. A comprehensive test typically costs between $200 and $400. Every well is different, and your water could have higher or lower levels than what is common in the county. Testing is the only way to know what is actually in your water so you can treat it properly. Filters and water treatment systems can remove iron and some PFOA and PFOS compounds from your water.
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 ⓘ |
|---|---|---|---|---|---|
| PFOS ⓘ municipal | 60 | 63% | Moderate | High | |
| PFOA ⓘ municipal | 60 | 55% | Moderate | High | |
| Iron | 137 | 43% | High | High | |
| Manganese | 137 | 34% | High | High | |
| Nitrate | 101 | 6% | High | Moderate | |
| PFHxS ⓘ municipal | 60 | 2% | Moderate | Low | |
| Fluoride | 99 | 1% | Moderate | Low | |
| Sulfate | 128 | 1% | High | Low | |
| Chloride | 169 | 0% | High | Low | |
| HFPO-DA (GenX) ⓘ municipal | 60 | 0% | Moderate | Safe | |
| Nitrite | 9 | 0% | Low | Safe ⓘ | |
| PFNA ⓘ municipal | 60 | 0% | Moderate | Safe | |
| Hardness | 131 | — | High | Low | |
| PFBS ⓘ municipal | 60 | — | Moderate | Low | |
| pH | 170 | — | High | Low | |
| Sodium | 111 | — | High | 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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