Groundwater in Darke County contains iron, manganese, arsenic, and PFOS at levels that exceed EPA health standards. The sulfate levels are moderate, but the combination of these contaminants is concerning enough that well owners should have their water tested.
These contaminants come from the rock layers beneath the county. Iron and manganese dissolve naturally as groundwater moves slowly through cracks in the bedrock. Arsenic sits trapped in the same rock formations. PFOS is an industrial chemical that can enter groundwater from certain land uses and spreads through the water underground.
Groundwater in this county is very hard, driven by elevated calcium and magnesium that dissolve from the limestone and shale below. Iron levels are notably elevated, adding to the mineral character of the water. These hard-water and high-iron characteristics are widespread across wells in Darke County.
Wells in Darke County commonly contain arsenic, iron, manganese, and PFOS at levels exceeding EPA health standards. Arsenic builds up in your body over time and can increase the risk of cancer and organ damage. Manganese can harm brain development and nervous system function, especially in children. PFOS is an industrial chemical linked to immune system problems and other serious health effects. Iron and sulfate at elevated levels also pose health concerns with long-term exposure.
Wells in this county are extremely hard, meaning white crusty scale builds up heavily on faucets, showerheads, and inside pipes and appliances. Iron causes orange and rust-colored stains on sinks, toilets, and laundry. Sulfate at high levels can give water a bitter or metallic taste. This extreme hardness can shorten the lifespan of water heaters, dishwashers, and other appliances.
We recommend testing your well with a comprehensive metals and minerals panel, since every well is different and yours 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 water so it can be properly treated. A comprehensive panel typically costs $200-$400. Treatment options include water softeners for hardness combined with iron and arsenic removal systems.
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 | 100 | 97% | High | High | |
| Manganese | 98 | 63% | Moderate | High | |
| Arsenic | 99 | 34% | Moderate | High | |
| PFOS ⓘ municipal | 5 | 20% | Low | High ⓘ | |
| Sulfate | 29 | 10% | Moderate | Moderate | |
| Chloride | 99 | 0% | Moderate | Low | |
| Fluoride | 74 | 0% | Moderate | Low | |
| HFPO-DA (GenX) ⓘ municipal | 5 | 0% | Low | Safe ⓘ | |
| Lead | 99 | 0% | Moderate | Low | |
| Nitrate | 12 | 0% | Low | Low | |
| Nitrite | 14 | 0% | Low | Low | |
| PFHxS ⓘ municipal | 5 | 0% | Low | Low ⓘ | |
| PFNA ⓘ municipal | 5 | 0% | Low | Safe ⓘ | |
| PFOA ⓘ municipal | 5 | 0% | Low | Safe ⓘ | |
| Radon | 2 | 0% | Low | Low ⓘ | |
| Uranium | 8 | 0% | Low | Low ⓘ | |
| Sodium | 100 | — | High | Low | |
| pH | 94 | — | Moderate | Low | |
| PFBS ⓘ municipal | 5 | — | Low | Safe ⓘ | |
| Hardness | 98 | — | Moderate | 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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