El Paso County, CO: EPA's radon zone, explained

EPA places El Paso County in Zone 1 - Highest Potential — a predicted county-wide average indoor radon level above 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Nationally, El Paso County ranks higher in radon potential than 99% of rated counties (the 99th percentile).

El Paso County by the numbers

El Paso County, Colorado is home to about 752,772 people across 2,126.424 square miles. That works out to roughly 354 people per square mile. By population, El Paso County is the 20th largest of every county sharing its EPA zone — the 98th percentile by population within that zone. El Paso County falls in EPA Radon Region 8, one of 291 counties nationally EPA assigns to that same geologic province.

What this actually means for a house in El Paso County

El Paso County carries a Zone 1 label because its predicted average clears 4 pCi/L outright — three-plus times the 0.4 pCi/L typical outdoors and above the 1.3 pCi/L most homes see. That doesn't mean every El Paso County house tests high — a zone is a county-wide prediction, never a single-home reading — but it's a reason to test sooner rather than let it wait.

Testing and mitigation in El Paso County

For a El Paso 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 Colorado's state radon program

For El Paso County, an ongoing number beats a one-time test - a Airthings radon monitor tracks El Paso 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 El Paso County's figures come from

El Paso County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.