Groundwater in Madison County contains arsenic, chloride, and bacteria that well owners should know about. The good news is that none of these contaminants exceed EPA health standards in this county, so levels here are low.
These contaminants come from both natural and human sources. Arsenic occurs naturally in the bedrock beneath the county. Chloride and bacteria can enter groundwater from road salt, septic systems, and animal waste. The geology here--early Mesozoic basin rocks with varied composition--does not concentrate these contaminants the way some other rock types do, which keeps levels down.
Groundwater in this county is moderately hard, driven mainly by calcium and magnesium dissolved from the local bedrock. As water moves through these basin rocks, it picks up these minerals naturally. Moderate hardness is a common characteristic across wells in Madison County.
Wells in Madison County contain some contaminants that warrant attention. Arsenic and E. coli bacteria are present in groundwater here. Arsenic exposure over time can damage your kidneys and increase cancer risk. E. coli causes serious stomach illness and diarrhea, especially in young children and people with weak immune systems. Chloride levels in county wells are also elevated enough to be a concern for people with heart disease or high blood pressure.
The water in Madison County is moderately hard, which means you may notice some buildup of scale inside pipes and appliances. Hard water can reduce how long water heaters and dishwashers last. You might see spots on dishes after they dry, or feel a slight film on your skin after showering. The sodium content is low, so that is not a problem here.
We recommend testing your well for bacteria, arsenic, and chloride, since multiple contaminants concern wells in this county. Every well is different, and yours could have higher or lower levels than what is common here. Testing is the only way to know exactly what is in your water so you can treat it properly. A comprehensive panel that checks for metals and bacteria typically costs two hundred to four hundred dollars. Water testing labs can guide you toward appropriate treatment if needed.
| Contaminant | Samples ⓘ | % Above MCL ⓘ | Distribution ⓘ | Confidence ⓘ | Risk ⓘ |
|---|---|---|---|---|---|
| Radon | 1 | 0% | Low | Low ⓘ | |
| Sulfate | 1 | 0% | Low | Low ⓘ | |
| PFOA ⓘ municipal | 1 | 0% | Low | Safe ⓘ | |
| PFNA ⓘ municipal | 1 | 0% | Low | Safe ⓘ | |
| PFOS ⓘ municipal | 1 | 0% | Low | Safe ⓘ | |
| Uranium | 1 | 0% | Low | Safe ⓘ | |
| Lead | 1 | 0% | Low | Safe ⓘ | |
| Manganese | 1 | 0% | Low | Safe ⓘ | |
| Iron | 1 | 0% | Low | Safe ⓘ | |
| PFHxS ⓘ municipal | 1 | 0% | Low | Safe ⓘ | |
| Arsenic | 1 | 0% | Low | Low ⓘ | |
| Chloride | 1 | 0% | Low | Low ⓘ | |
| Fluoride | 1 | 0% | Low | Low ⓘ | |
| HFPO-DA (GenX) ⓘ municipal | 1 | 0% | Low | Safe ⓘ | |
| Hardness | 1 | — | Low | Low ⓘ | |
| PFBS ⓘ municipal | 1 | — | Low | Safe ⓘ | |
| pH | 1 | — | Low | Low ⓘ | |
| Sodium | 1 | — | 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.
Order a Tap Score Test →Population-level CDC data. Not individual risk prediction.
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