Is Hendricks County, IN a radon risk area?
EPA's own radon map rates Hendricks County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Rank it against the rest of the country and Hendricks County lands in the 97th percentile for radon potential.
Where Hendricks County sits nationally
About 190,629 people live in Hendricks County, Indiana, spread over 406.894 square miles. Averaged across its land area, Hendricks County runs about 468 people per square mile. Rank 102 by population within its EPA zone puts Hendricks County at the 91st percentile among zone peers. EPA's geology-based Region 5 groups Hendricks County with 523 other counties nationally sharing its underlying rock and soil profile.
Zone vs. an actual test
Where the national indoor average runs about 1.3 pCi/L, Hendricks 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 Hendricks County will test well under the action level, and EPA's guidance is to test regardless of zone.
Next steps for a home in Hendricks County
Nothing about Hendricks 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 Indiana's state radon program
Hendricks County's test kit answers today; a Airthings radon monitor keeps answering for Hendricks 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
Hendricks County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. Whatever zone Hendricks County carries, the zone explainer covers what it does and doesn't tell you about any one house.