Is Louisa County, VA a radon risk area?

EPA's own radon map rates Louisa County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Nationally that's the 88th percentile for radon potential — Louisa County outranks 88% of every county EPA has rated.

Where Louisa County sits nationally

About 42,109 people live in Louisa County, Virginia, spread over 495.064 square miles. Averaged across its land area, Louisa County runs about 85 people per square mile. Rank 365 by population within its EPA zone puts Louisa County at the 66th percentile among zone peers. Louisa County falls in EPA Radon Region 3, one of 245 counties nationally EPA assigns to that same geologic province.

Why the zone isn't the answer by itself

Louisa County's predicted average sits above EPA's own action level of 4 pCi/L — the concentration at which EPA recommends fixing a home — versus a national average around 1.3 pCi/L indoors and 0.4 pCi/L outdoors. Being in Zone 1 raises the odds Louisa County homes test above the action level, but it does not mean any specific house does — EPA recommends every home be tested, in every zone, because the only way to know is to test.

If Louisa County tests above the action level

Nothing about Louisa 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 Virginia's state radon program

Louisa County's test kit answers today; a Airthings radon monitor keeps answering for Louisa 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

Louisa County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.