Iron, manganese, and sulfate are present in Marion County groundwater at levels that exceed EPA health standards. These are serious contaminants that well owners need to address.
The underlying rock in this area naturally contains these metals and sulfur compounds. As groundwater moves slowly through cracks and fractures in the limestone and shale, it dissolves iron and manganese from the rock itself. Sulfate accumulates the same way--it comes from minerals baked into the bedrock over time.
Groundwater in Marion County is very hard, driven by elevated calcium and magnesium from the limestone below, and is also high in iron and sulfur-bearing compounds from the same rock layers. The slow movement of water through these fractured rocks concentrates these minerals over time. These characteristics are widespread across most wells in the county.
Iron, manganese, and sulfate in wells across Marion County exceed EPA health standards. Iron and manganese can build up in your body over time and affect your organs. Manganese is particularly concerning for brain and nervous system development. Sulfate at elevated levels can cause digestive problems, especially in infants and people with certain conditions.
Wells in this county have extremely hard water, which leaves thick white scale buildup on faucets, showerheads, and inside pipes. The high iron content causes orange-brown staining on sinks, toilets, and laundry. You may also notice a rotten-egg smell from the sulfate. This extreme hardness can shorten the lifespan of water heaters and dishwashers, making them fail sooner than normal.
We recommend testing your well with a comprehensive minerals and metals panel, which typically costs $200-$400. Every well is different, and your water may have higher or lower levels than what is common in Marion County. Testing is the only way to know what is actually in your well so it can be treated properly. A water softener paired with an iron filter can address most of these mineral 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 ⓘ |
|---|---|---|---|---|---|
| Iron | 63 | 79% | Moderate | High | |
| Sulfate | 11 | 73% | Low | High | |
| Manganese | 57 | 4% | Moderate |
Moderate
Elevated concentration, not % above limit
|
|
| Arsenic | 52 | 0% | Moderate | Low | |
| Chloride | 63 | 0% | Moderate | Low | |
| Fluoride | 46 | 0% | Moderate | Low | |
| HFPO-DA (GenX) ⓘ municipal | 4 | 0% | Low | Safe ⓘ | |
| Lead | 49 | 0% | Moderate | Low | |
| Nitrate | 7 | 0% | Low | Low ⓘ | |
| Nitrite | 1 | 0% | Low | Low ⓘ | |
| PFHxS ⓘ municipal | 4 | 0% | Low | Safe ⓘ | |
| PFNA ⓘ municipal | 4 | 0% | Low | Safe ⓘ | |
| PFOA ⓘ municipal | 4 | 0% | Low | Safe ⓘ | |
| PFOS ⓘ municipal | 4 | 0% | Low | Safe ⓘ | |
| Hardness | 49 | — | Moderate | Low | |
| PFBS ⓘ municipal | 4 | — | Low | Safe ⓘ | |
| pH | 50 | — | Moderate | Low | |
| Sodium | 64 | — | 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.
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