What EPA's radon map says about Ulster County

Ulster County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. Nationally, Ulster County ranks higher in radon potential than 97% of rated counties (the 97th percentile).

Ulster County by the numbers

About 182,977 people live in Ulster County, New York, spread over 1,124.236 square miles. Population density there runs about 163 people per square mile. Among counties sharing Ulster County's EPA zone, it outranks 90% of them by population. EPA's geology-based Region 2 groups Ulster County with 82 other counties nationally sharing its underlying rock and soil profile.

What this actually means for a house in Ulster County

Ulster 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. 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 Ulster County will test well under the action level, and EPA's guidance is to test regardless of zone.

Next steps for a home in Ulster County

Mitigation cost doesn't depend on Ulster County's zone — it depends on the house's foundation. A typical system runs $800–$2,500 (about $1,200 typical), and testing first is what tells you whether that's needed at all.

Find New York's state radon program

Ulster County's test kit answers today; a Airthings radon monitor keeps answering for Ulster County over time. Affiliate link, RadonZoneCheck earns a commission there, at no extra cost to you. Code RADONZONE-10OFF takes 10% off at checkout.

More on how this number was built

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