Transylvania County, NC: EPA's radon zone, explained

EPA places Transylvania County in Zone 1 - Highest Potential — a predicted county-wide average indoor radon level above 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Transylvania County sits at the 86th percentile nationally for radon potential — above 86 of every 100 rated counties.

Where Transylvania County sits nationally

Transylvania County, North Carolina is home to about 34,103 people across 378.365 square miles. Population density there runs about 90 people per square mile. By population, Transylvania County is the 431st largest of every county sharing its EPA zone — the 60th percentile by population within that zone. Transylvania County falls in EPA Radon Region 4, one of 736 counties nationally EPA assigns to that same geologic province.

Why the zone isn't the answer by itself

Where the national indoor average runs about 1.3 pCi/L, Transylvania County's Zone 1 rating puts its predicted county average above EPA's 4 pCi/L action level itself. A Zone 1 rating means testing is worth doing sooner rather than later, but it is still county-wide average, not a reading for any single house — some homes in Transylvania County will test well under the action level, and EPA's guidance is to test regardless of zone.

Next steps for a home in Transylvania County

For a Transylvania 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 North Carolina's state radon program

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

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.