Hunterdon County, NJ: EPA's radon zone, explained

Hunterdon County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. Nationally that's the 95th percentile for radon potential — Hunterdon County outranks 95% of every county EPA has rated.

Where Hunterdon County sits nationally

Hunterdon County, New Jersey is home to about 131,708 people across 427.835 square miles. That works out to roughly 308 people per square mile. By population, Hunterdon County is the 152nd largest of every county sharing its EPA zone — the 86th percentile by population within that zone. Geologically, Hunterdon County is grouped into EPA Region 2 alongside 82 other counties that share its rock and soil setting.

What this actually means for a house in Hunterdon County

Fixing a home becomes an EPA recommendation past 4 pCi/L, and that is precisely the side of the line Hunterdon County's Zone 1 prediction lands on, well above the roughly 1.3 pCi/L most US homes average. Being in Zone 1 raises the odds Hunterdon County homes test above the action level, but it does not mean any specific house does — EPA recommends every home be tested, in every zone, because the only way to know is to test.

If Hunterdon County tests above the action level

For a Hunterdon County homeowner, the order is simple: test first, since a kit costs a small fraction of what mitigation would. Only if the result clears 4 pCi/L does a system — typically $800–$2,500, about $1,200 for a common install — become worth pricing out.

Find New Jersey's state radon program

For Hunterdon County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Hunterdon County's levels over time. RadonZoneCheck earns a commission there, at no extra cost to you. Code RADONZONE-10OFF takes 10% off at checkout.

Where Hunterdon County's figures come from

The methodology guide shows exactly which EPA and Census sources feed Hunterdon County's numbers. Whatever zone Hunterdon County carries, the zone explainer covers what it does and doesn't tell you about any one house.