Doña Ana County, NM: EPA's radon zone, explained

EPA's own radon map rates Doña Ana County zone 2 - moderate potential, predicting a county-wide average indoor level between 2 and 4 pCi/L. Nationally, Doña Ana County ranks higher in radon potential than 63% of rated counties (the 63rd percentile).

Doña Ana County by the numbers

Doña Ana County, New Mexico is home to about 229,366 people across 3,808.179 square miles. That works out to roughly 60 people per square mile. By population, Doña Ana County is the 105th largest of every county sharing its EPA zone — the 90th percentile by population within that zone. Doña Ana County falls in EPA Radon Region 6, one of 503 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

Doña Ana County's predicted average falls between EPA's 4 pCi/L action level and the national indoor average of about 1.3 pCi/L (outdoor air runs roughly 0.4 pCi/L). A Zone 2 rating is a moderate county-wide average, not a guarantee about any one house in Doña Ana County — testing is the only way to know an individual home's actual level.

Next steps for a home in Doña Ana County

For a Doña Ana County homeowner, the order is simple: test first, since a kit costs a small fraction of what mitigation would. Only if the result clears 4 pCi/L does a system — typically $800–$2,500, about $1,200 for a common install — become worth pricing out.

Find New Mexico's state radon program

For Doña Ana County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Doña Ana County's levels over time. RadonZoneCheck earns a commission there, at no extra cost to you. Code RADONZONE-10OFF takes 10% off at checkout.

Where Doña Ana County's figures come from

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.