Well Water in Ontario County: What to Test and Why

High Risk
Testing Strongly Recommended 3476 samples analyzed
Top Concerns in This County
Radon Iron Lead

Why This Happens Here

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.

What This Means for You

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 Detection Data

Contaminant Samples % Above MCL Distribution Confidence Risk
Radon 15 33% 40% · 27% · 33% Moderate High
Sulfate 66 26% 61% · 14% · 26% Moderate High
Iron 8 14% 62% · 25% · 12% Low Moderate
Lead 26 12% 88% · 0% · 12% Moderate Moderate
Chloride 73 8% 78% · 14% · 8% Moderate Moderate
Manganese 2 0% 100% · 0% · 0% Low Low
Uranium 9 0% 100% · 0% · 0% Low Low
Fluoride 3 0% 100% · 0% · 0% Low Low
PFHxS ⓘ municipal 42 0% 100% · 0% · 0% Moderate Safe
HFPO-DA (GenX) ⓘ municipal 42 0% 100% · 0% · 0% Moderate Safe
PFOS ⓘ municipal 42 0% 100% · 0% · 0% Moderate Safe
PFOA ⓘ municipal 42 0% 100% · 0% · 0% Moderate Safe
PFNA ⓘ municipal 42 0% 100% · 0% · 0% Moderate Safe
Hardness 17 Moderate Low
Nitrate 1 0% 100% · 0% · 0% Low Safe
Arsenic 1 0% 100% · 0% · 0% Low Safe
Nitrite 1 0% 100% · 0% · 0% Low Safe
E. coli 1 0% 100% · 0% · 0% Low Safe
Total Coliform 1 0% 100% · 0% · 0% Low Safe
Fecal Coliform 1 0% 100% · 0% · 0% Low Safe
pH 9 Low Low
Sodium 35 Moderate Low
PFBS ⓘ municipal 42 100% · 0% · 0% 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.

Data shows potential risk — a certified test confirms whether your water is affected.

Order a Tap Score Test →

Population Health Context

Population-level CDC data. Not individual risk prediction.

6.9%
Heart Disease Rate
(state avg: 6.4%)
6.1%
Cancer Prevalence
(state avg: 6.7%)

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