Is Onondaga County, NY a radon risk area?

Onondaga County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. Rank it against the rest of the country and Onondaga County lands in the 99th percentile for radon potential.

Where Onondaga County sits nationally

About 469,812 people live in Onondaga County, New York, spread over 778.393 square miles. That works out to roughly 604 people per square mile. Rank 47 by population within its EPA zone puts Onondaga County at the 96th percentile among zone peers. Geologically, Onondaga County is grouped into EPA Region 2 alongside 82 other counties that share its rock and soil setting.

Why the zone isn't the answer by itself

Outdoor air nationally averages about 0.4 pCi/L, indoor air about 1.3 pCi/L — Onondaga County's Zone 1 prediction clears both of those and EPA's fix-it threshold besides. 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 Onondaga County will test well under the action level, and EPA's guidance is to test regardless of zone.

Testing and mitigation in Onondaga County

Nothing about Onondaga County's EPA zone changes the mitigation number: $800–$2,500 nationally (around $1,200 typical), set by the house's foundation rather than the county it sits in — and only relevant once a test actually clears 4 pCi/L.

Find New York's state radon program

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

More on how this number was built

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.