What EPA's radon map says about Dillingham Census Area

EPA's own radon map rates Dillingham Census Area zone 3 - low potential, predicting a county-wide average indoor level below 2 pCi/L. Rank it against the rest of the country and Dillingham Census Area lands in the 3rd percentile for radon potential.

Where Dillingham Census Area sits nationally

About 4,642 people live in Dillingham Census Area, Alaska, spread over 18,353.188 square miles. Averaged across its land area, Dillingham Census Area runs about 0 people per square mile. Among counties sharing Dillingham Census Area's EPA zone, it outranks 8% of them by population. EPA's geology-based Region 10 groups Dillingham Census Area with 141 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

Dillingham Census Area's predicted average sits below the national indoor average of about 1.3 pCi/L, well under EPA's 4 pCi/L action level. A Zone 3 rating means Dillingham Census Area's county-wide average is predicted low, but EPA is explicit that a meaningful share of homes in low-potential zones still test above the action level — a low zone is not a reason to skip testing.

If Dillingham Census Area tests above the action level

Mitigation cost doesn't depend on Dillingham Census Area'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 Alaska's state radon program

Dillingham Census Area's test kit answers today; a Airthings radon monitor keeps answering for Dillingham Census Area over time. Affiliate link, RadonZoneCheck earns a commission there, at no extra cost to you. Use code RADONZONE-10OFF at checkout for 10% off.

More on how this number was built

The methodology guide shows exactly which EPA and Census sources feed Dillingham Census Area's numbers. Whatever zone Dillingham Census Area carries, the zone explainer covers what it does and doesn't tell you about any one house.