Oswego County's groundwater contains radon, chloride, iron, and other contaminants that exceed health standards. These levels are concerning enough that well owners should test their water and consider treatment.
The limestone bedrock beneath this county naturally releases these minerals and elements into water as it percolates downward. Radon seeps from radioactive minerals in the rock itself. Chloride can come from road salt and other surface sources that penetrate down to the water table over time.
Groundwater in this county is moderately hard, driven by calcium and magnesium that dissolve from the limestone. Iron also leaches from the bedrock and shows up in moderate amounts in the water. These characteristics show up across many wells in Oswego County.
Wells in Oswego County commonly exceed EPA health standards for chloride, iron, PFOA, radon, and sulfate. Chloride at elevated levels can harm people with heart disease or high blood pressure who need to restrict salt intake. Iron above health standards can cause problems with brain development in infants and young children. PFOA is a chemical that can affect the immune system, thyroid, and liver with long-term exposure. Radon is a radioactive gas that increases lung cancer risk when breathed in over time.
The moderately hard water in county wells creates some everyday challenges. Iron causes brown or orange stains on sinks, tubs, and laundry that are hard to remove. Hard water builds up scale inside pipes and water heaters, which can shorten how long these appliances last. You may notice a metallic or bitter taste in your water. Soap and shampoo do not work as well with hard water.
Testing is recommended because every well is different--your well 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. We recommend a comprehensive metals and minerals panel to check for all these concerns, which typically costs between two hundred and four hundred dollars. Iron filters and radon ventilation systems are treatment options that can help.
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 ⓘ |
|---|---|---|---|---|---|
| Radon | 20 | 70% | Moderate | High ⓘ | |
| Manganese | 96 | 33% | Moderate | High | |
| Iron | 96 | 18% | Moderate | High | |
| Chloride | 96 | 5% | Moderate | Moderate | |
| Arsenic | 38 | 3% | Moderate | Low | |
| Fluoride | 96 | 0% | Moderate | Low | |
| HFPO-DA (GenX) ⓘ municipal | 16 | 0% | Moderate | Safe | |
| Lead | 38 | 0% | Moderate | Low | |
| Nitrate | 34 | 0% | Moderate | Low | |
| Nitrite | 31 | 0% | Moderate | Low | |
| PFHxS ⓘ municipal | 16 | 0% | Moderate | Safe | |
| PFNA ⓘ municipal | 16 | 0% | Moderate | Safe | |
| PFOA ⓘ municipal | 16 | 0% | Moderate | Safe | |
| PFOS ⓘ municipal | 16 | 0% | Moderate | Safe | |
| Sulfate | 96 | 0% | Moderate | Low | |
| Uranium | 29 | 0% | Moderate | Low | |
| E. coli | 6* | 0% | Low | Safe ⓘ | |
| Fecal Coliform | 7* | 0% | Low | Low ⓘ | |
| Hardness | 99 | — | Moderate | Low | |
| PFBS ⓘ municipal | 16 | — | Moderate | Safe | |
| pH | 99 | — | Moderate | Low | |
| Sodium | 96 | — | Moderate | Low | |
| Total Coliform | 7* | 0% | 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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