What EPA's radon map says about Niobrara County

Niobrara County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. Niobrara County sits at the 67th percentile nationally for radon potential — above 67 of every 100 rated counties.

Niobrara County by the numbers

About 2,301 people live in Niobrara County, Wyoming, spread over 2,626.028 square miles. Population density there runs about 1 people per square mile. Among counties sharing Niobrara County's EPA zone, it outranks 4% of them by population. Geologically, Niobrara County is grouped into EPA Region 8 alongside 290 other counties that share its rock and soil setting.

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 Niobrara 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 Niobrara 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 Niobrara County tests above the action level

Mitigation cost doesn't depend on Niobrara 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 Wyoming's state radon program

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

Niobrara County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. Whatever zone Niobrara County carries, the zone explainer covers what it does and doesn't tell you about any one house.