Well Water in Jefferson County: What to Test and Why

High Risk
Testing Strongly Recommended 9351 samples analyzed
Top Concerns in This County
Manganese Iron Radon

Why This Happens Here

Groundwater in Jefferson County contains manganese, iron, radon, chloride, lead, and sulfate. Several of these contaminants exceed EPA health standards and warrant immediate attention.

The Mississippian rock beneath this county naturally contains iron and manganese that dissolve into groundwater as water moves slowly through cracks in the stone. Radon seeps from uranium traces scattered throughout the rock. Chloride enters from road salt and deep mineral sources, while sulfate forms when water contacts sulfur-bearing minerals in the bedrock.

Groundwater in this county is moderately hard, with elevated iron being the most noticeable characteristic. Iron dissolves naturally from the Mississippian rock, and moderate sulfate levels also accumulate as water sits in the rock for long periods. These mineral characteristics are widespread across wells in Jefferson County.

What This Means for You

Wells in Jefferson County commonly exceed EPA health standards for chloride, iron, lead, manganese, radon, and sulfate. Lead damages brain development and kidney function in children and adults. Radon is a radioactive gas that increases lung cancer risk with long-term exposure. Manganese can harm brain function and the nervous system. Chloride and sulfate at elevated levels can cause digestive problems over time.

The water in this county is moderately hard, which causes visible problems around the house. Iron stains sinks, toilets, and laundry orange-brown and leaves rust-colored buildup on fixtures. Sulfate gives the water a bitter or unpleasant taste. Scale builds up inside pipes, kettles, and on appliances. Over time, this hard water can shorten the lifespan of water heaters and dishwashers.

We recommend testing your well water right away with a comprehensive metals and radon panel, since multiple contaminants exceed health standards in this county. Every well is different--your well may have higher or lower levels than what is common here. Testing is the only way to know what is actually in your water so it can be properly treated. A comprehensive panel typically costs between $200 and $400. Treatment options like water softeners, aeration systems, and specialized filters can address these concerns.

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
Manganese 29 93% 3% · 7% · 90% Moderate High
Iron 77 71% 20% · 10% · 70% Moderate High
Radon 36 25% 53% · 22% · 25% Moderate High
Sulfate 73 24% 64% · 12% · 23% Moderate High
Chloride 60 5% 93% · 2% · 5% Moderate Moderate
Lead 28 4% 82% · 14% · 4% Moderate Moderate
Elevated concentration, not % above limit
Fluoride 5 0% 100% · 0% · 0% Low Low
PFOA ⓘ municipal 35 0% 97% · 3% · 0% Moderate Low
PFOS ⓘ municipal 35 0% 100% · 0% · 0% Moderate Safe
PFHxS ⓘ municipal 16 0% 100% · 0% · 0% Moderate Safe
PFNA ⓘ municipal 16 0% 100% · 0% · 0% Moderate Safe
HFPO-DA (GenX) ⓘ municipal 30 0% 100% · 0% · 0% Moderate Safe
Uranium 4 0% 100% · 0% · 0% Low Low
Nitrate 1 0% 100% · 0% · 0% Low Safe
Arsenic 1 0% 100% · 0% · 0% Low Safe
Hardness 42 Moderate Low
pH 17 Moderate Low
E. coli 1 0% 100% · 0% · 0% Low Safe
Sodium 60 Moderate Low
PFBS ⓘ municipal 30 100% · 0% · 0% Moderate Low
Nitrite 1 0% 100% · 0% · 0% Low Safe

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.

9.1%
Heart Disease Rate
(state avg: 7.2%)
8.2%
Cancer Prevalence
(state avg: 7.0%)

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