Well owners in Ontario County should be aware that radon, sulfate, iron, chloride, and lead are present in groundwater at levels exceeding EPA health standards. These contaminants are present at concerning levels and demand attention.
The carbonate limestone bedrock beneath Ontario County naturally releases radon from uranium decay and dissolves minerals like sulfate and chloride into water as it flows through cracks and pores. Road salt applied to winter roads also contributes chloride that seeps down into the aquifer. Lead enters through older pipes and plumbing fixtures in some homes.
Groundwater in this county is very hard, driven by elevated calcium and magnesium leached from the limestone below, and also contains moderate iron and moderate sulfate. As water sits in contact with limestone for years, these minerals dissolve slowly and accumulate. These hard-water characteristics with elevated iron and sulfate are common across wells throughout Ontario County.
Wells in Ontario County commonly exceed EPA health standards for chloride, iron, lead, radon, and sulfate. Lead damages developing brains and kidneys in children and harms adults' kidneys and blood pressure. Radon is a radioactive gas that increases lung cancer risk. Chloride and sulfate at elevated levels can damage organs over time. Iron itself is not toxic but indicates other minerals are in your water.
The very hard water in this county causes real problems around your home. You will see rust-colored staining on sinks, toilets, and laundry. White scale builds up inside pipes and on fixtures, clogging them over time. Hard water shortens the lifespan of water heaters, dishwashers, and washing machines. You may notice a metallic taste or sulfur odor in your water.
Every well is different, and yours could have higher or lower levels than what is common here. 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, which typically costs $200 to $400. Treatment options like radon aeration systems, whole-house filters, and water softeners can address multiple problems at once.
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 ⓘ |
|---|---|---|---|---|---|
| Manganese | 42 | 36% | Moderate | High | |
| Radon | 15 | 27% | Moderate | High ⓘ | |
| Sulfate | 65 | 26% | Moderate | High | |
| Iron | 45 | 20% | Moderate | High | |
| Chloride | 69 | 7% | Moderate | Moderate | |
| Nitrate | 46 | 2% | Moderate | Low | |
| Arsenic | 23 | 0% | Moderate | Low | |
| Fluoride | 44 | 0% | Moderate | Low | |
| HFPO-DA (GenX) ⓘ municipal | 42 | 0% | Moderate | Safe | |
| Lead | 22 | 0% | Moderate | Low | |
| Nitrite | 16 | 0% | Moderate | Low | |
| PFHxS ⓘ municipal | 42 | 0% | Moderate | Safe | |
| PFNA ⓘ municipal | 42 | 0% | Moderate | Safe | |
| PFOA ⓘ municipal | 42 | 0% | Moderate | Safe | |
| PFOS ⓘ municipal | 42 | 0% | Moderate | Safe | |
| Uranium | 15 | 0% | Moderate | Low | |
| E. coli | 8* | 0% | Low | Low ⓘ | |
| Fecal Coliform | 8* | 0% | Low | Low ⓘ | |
| Hardness | 69 | — | Moderate | Low | |
| PFBS ⓘ municipal | 42 | — | Moderate | Low | |
| pH | 69 | — | Moderate | Low | |
| Sodium | 45 | — | Moderate | Low | |
| Total Coliform | 8* | 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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