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

EPA's own radon map rates Union County zone 2 - moderate potential, predicting a county-wide average indoor level between 2 and 4 pCi/L. Union County sits at the 65th percentile nationally for radon potential — above 65 of every 100 rated counties.

Where Union County sits nationally

Union County, New Jersey is home to about 594,160 people across 102.767 square miles. Population density there runs about 5,782 people per square mile. By population, Union County is the 40th largest of every county sharing its EPA zone — the 96th percentile by population within that zone. Geologically, Union County is grouped into EPA Region 2 alongside 82 other counties that share its rock and soil setting.

Zone vs. an actual test

Union County's predicted average falls between EPA's 4 pCi/L action level and the national indoor average of about 1.3 pCi/L (outdoor air runs roughly 0.4 pCi/L). A Zone 2 rating is a moderate county-wide average, not a guarantee about any one house in Union County — testing is the only way to know an individual home's actual level.

Next steps for a home in Union County

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

Where Union County's figures come from

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