Well Water in Jefferson County: What to Test and Why

Moderate Risk
Testing Recommended 6383 samples analyzed
Top Concerns in This County
Iron Radon

Why This Happens Here

Groundwater in Jefferson County contains radon, iron, and PFOS that well owners should know about. Iron, PFOS, and radon all exceed EPA health standards in this county, making them genuine concerns that warrant testing.

These contaminants come from different sources. Iron and radon occur naturally as groundwater moves through the deep rock layers beneath the county. PFOS is a human-made chemical that enters groundwater from industrial sites, firefighting activities, or contaminated soil, and persists in the environment for a long time.

Groundwater in this county is very hard, driven by elevated calcium and magnesium from the limestone and rock below. As water sits in contact with these rock layers over time, it dissolves minerals and becomes harder. Very hard water is common across wells throughout Jefferson County.

What This Means for You

Wells in Jefferson County commonly contain iron, PFOS, radon, and sulfate at levels that exceed EPA health standards. Iron can cause problems with blood and organs over time. PFOS is a chemical that builds up in the body and can affect the immune system and liver. Radon is a radioactive gas that enters water from underground rocks, and breathing it from your tap water increases lung cancer risk.

The county's water is very hard, which means scale builds up on pipes, fixtures, and inside water heaters and dishwashers. This scale buildup shortens the lifespan of appliances. You may see rust-colored or orange staining on sinks, bathtubs, and clothes from the high iron levels. Hard water also makes soap less effective for cleaning and bathing.

We recommend testing your well with a comprehensive panel since multiple contaminants exceed health standards in county wells. Every well is different, and your water may have higher or lower levels than what is common here. Testing is the only way to know what is actually in your well so you can treat it properly. A comprehensive metals and minerals panel typically costs $200 to $400. Water softeners can reduce hardness, and radon or iron removal systems address those specific 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
Radon 2 100% 0% · 0% · 100% Low High
Iron 14 77% 21% · 7% · 71% Low High
PFOS ⓘ municipal 33 6% 94% · 0% · 6% Moderate Moderate
Sulfate 43 2% 88% · 9% · 2% Moderate Low
Lead 4 0% 100% · 0% · 0% Low Low
Arsenic 6 0% 100% · 0% · 0% Low Low
Chloride 57 0% 98% · 2% · 0% Moderate Low
PFOA ⓘ municipal 33 0% 100% · 0% · 0% Moderate Safe
HFPO-DA (GenX) ⓘ municipal 33 0% 100% · 0% · 0% Moderate Safe
PFHxS ⓘ municipal 33 0% 100% · 0% · 0% Moderate Low
PFNA ⓘ municipal 33 0% 100% · 0% · 0% Moderate Safe
Uranium 1 0% 100% · 0% · 0% Low Low
pH 17 Moderate Low
Sodium 36 Moderate Low
Manganese 1 0% 100% · 0% · 0% Low Safe
Nitrate 1 0% 100% · 0% · 0% Low Safe
Nitrite 1 0% 100% · 0% · 0% Low Safe
Total Coliform 1 0% 100% · 0% · 0% Low Safe
Hardness 9 Low Low
Fecal Coliform 1 Low Safe
E. coli 2 0% 100% · 0% · 0% Low Safe
Fluoride 1 0% 100% · 0% · 0% Low Safe
PFBS ⓘ municipal 33 100% · 0% · 0% Moderate 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.

6.1%
Cancer Prevalence
(state avg: 7.0%)

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