What EPA's radon map says about Davidson County

Davidson County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. Nationally, Davidson County ranks higher in radon potential than 99% of rated counties (the 99th percentile).

Davidson County by the numbers

About 729,505 people live in Davidson County, Tennessee, spread over 503.521 square miles. Population density there runs about 1,449 people per square mile. Among counties sharing Davidson County's EPA zone, it outranks 98% of them by population. Davidson County falls in EPA Radon Region 4, one of 736 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

Fixing a home becomes an EPA recommendation past 4 pCi/L, and that is precisely the side of the line Davidson County's Zone 1 prediction lands on, well above the roughly 1.3 pCi/L most US homes average. Being in Zone 1 raises the odds Davidson 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 Davidson County tests above the action level

Mitigation cost doesn't depend on Davidson 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 Tennessee's state radon program

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