Columbia County, NY: EPA's radon zone, explained

Columbia 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 91st percentile for radon potential — Columbia County outranks 91% of every county EPA has rated.

Columbia County by the numbers

Columbia County, New York is home to about 60,299 people across 634.663 square miles. That works out to roughly 95 people per square mile. By population, Columbia County is the 274th largest of every county sharing its EPA zone — the 74th percentile by population within that zone. EPA's geology-based Region 2 groups Columbia County with 82 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

Columbia County carries a Zone 1 label because its predicted average clears 4 pCi/L outright — three-plus times the 0.4 pCi/L typical outdoors and above the 1.3 pCi/L most homes see. EPA's guidance doesn't change because of a Zone 1 label: test the house. What changes is the reason to not put it off in Columbia County specifically.

If Columbia County tests above the action level

For a Columbia 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 York's state radon program

For Columbia County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Columbia 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 Columbia County's figures come from

The methodology guide shows exactly which EPA and Census sources feed Columbia County's numbers. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.