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Iowa Radon Data

Iowa Radon Levels by County

Every county in Iowa is an EPA Radon Zone 1 county. Use the table to find your county, see its zone, and get to a local radon resource. Radon varies home to home, so testing your own home is the only way to know your level.

All 99 Iowa counties are EPA Radon Zone 1, the highest-risk category. Iowa averages about 8.5 pCi/L of indoor radon versus a US average near 1.3 pCi/L, and roughly 71.6% of Iowa homes test at or above the 4 pCi/L action level, the highest share of any state.

99

Iowa counties, all EPA Radon Zone 1

Source: EPA

8.5

Iowa average indoor radon (pCi/L)

Source: Iowa HHS

71.6%

of Iowa homes at or above 4 pCi/L

Source: Iowa Radon Survey

Sources:

A note on county averages

We publish only figures we can attribute to a primary source. The EPA Radon Zone (1 for every Iowa county) is official. A single official average for each individual county is not published by the EPA or Iowa HHS, and the county or zip-code averages shown on many radon directory sites are user-submitted estimates rather than authoritative data. Where a county average is not backed by a primary Iowa HHS or Iowa Radon Survey figure, the table shows a [VERIFY] marker instead of a number we cannot stand behind. Because radon varies house to house, radon testing of your own home is the only accurate measure. If a test comes back at or above the EPA action level of 4.0 pCi/L, a radon mitigation system is what brings the level down, and what that costs in Iowa is set by the foundation type rather than by the county reading.

All 99 Iowa Counties

Sort by county or zone. Filter to find yours.

Avg indoor radon (pCi/L) Local resource
Adair County Zone 1 [VERIFY] Get a quote
Adams County Zone 1 [VERIFY] Get a quote
Allamakee County Zone 1 [VERIFY] Get a quote
Appanoose County Zone 1 [VERIFY] Get a quote
Audubon County Zone 1 [VERIFY] Get a quote
Benton County Zone 1 [VERIFY] Get a quote
Black Hawk County Zone 1 [VERIFY] Get a quote
Boone County Zone 1 [VERIFY] Get a quote
Bremer County Zone 1 [VERIFY] Get a quote
Buchanan County Zone 1 [VERIFY] Get a quote
Buena Vista County Zone 1 [VERIFY] Get a quote
Butler County Zone 1 [VERIFY] Get a quote
Calhoun County Zone 1 [VERIFY] Get a quote
Carroll County Zone 1 [VERIFY] Get a quote
Cass County Zone 1 [VERIFY] Get a quote
Cedar County Zone 1 [VERIFY] Get a quote
Cerro Gordo County Zone 1 [VERIFY] Get a quote
Cherokee County Zone 1 [VERIFY] Get a quote
Chickasaw County Zone 1 [VERIFY] Get a quote
Clarke County Zone 1 [VERIFY] Get a quote
Clay County Zone 1 [VERIFY] Get a quote
Clayton County Zone 1 [VERIFY] Get a quote
Clinton County Zone 1 [VERIFY] Get a quote
Crawford County Zone 1 [VERIFY] Get a quote
Dallas County Zone 1 [VERIFY] Get a quote
Davis County Zone 1 [VERIFY] Get a quote
Decatur County Zone 1 [VERIFY] Get a quote
Delaware County Zone 1 [VERIFY] Get a quote
Des Moines County Zone 1 [VERIFY] Get a quote
Dickinson County Zone 1 [VERIFY] Get a quote
Dubuque County Zone 1 [VERIFY] Dubuque
Emmet County Zone 1 [VERIFY] Get a quote
Fayette County Zone 1 [VERIFY] Get a quote
Floyd County Zone 1 [VERIFY] Get a quote
Franklin County Zone 1 [VERIFY] Get a quote
Fremont County Zone 1 [VERIFY] Get a quote
Greene County Zone 1 [VERIFY] Get a quote
Grundy County Zone 1 [VERIFY] Get a quote
Guthrie County Zone 1 [VERIFY] Get a quote
Hamilton County Zone 1 [VERIFY] Get a quote
Hancock County Zone 1 [VERIFY] Get a quote
Hardin County Zone 1 [VERIFY] Get a quote
Harrison County Zone 1 [VERIFY] Get a quote
Henry County Zone 1 [VERIFY] Get a quote
Howard County Zone 1 [VERIFY] Get a quote
Humboldt County Zone 1 [VERIFY] Get a quote
Ida County Zone 1 [VERIFY] Get a quote
Iowa County Zone 1 [VERIFY] Get a quote
Jackson County Zone 1 [VERIFY] Get a quote
Jasper County Zone 1 [VERIFY] Get a quote
Jefferson County Zone 1 [VERIFY] Get a quote
Johnson County Zone 1 [VERIFY] Get a quote
Jones County Zone 1 [VERIFY] Get a quote
Keokuk County Zone 1 [VERIFY] Get a quote
Kossuth County Zone 1 [VERIFY] Get a quote
Lee County Zone 1 [VERIFY] Get a quote
Linn County Zone 1 [VERIFY] Get a quote
Louisa County Zone 1 [VERIFY] Get a quote
Lucas County Zone 1 [VERIFY] Get a quote
Lyon County Zone 1 [VERIFY] Get a quote
Madison County Zone 1 [VERIFY] Get a quote
Mahaska County Zone 1 [VERIFY] Get a quote
Marion County Zone 1 [VERIFY] Get a quote
Marshall County Zone 1 [VERIFY] Get a quote
Mills County Zone 1 [VERIFY] Get a quote
Mitchell County Zone 1 [VERIFY] Get a quote
Monona County Zone 1 [VERIFY] Get a quote
Monroe County Zone 1 [VERIFY] Get a quote
Montgomery County Zone 1 [VERIFY] Get a quote
Muscatine County Zone 1 [VERIFY] Get a quote
O'Brien County Zone 1 [VERIFY] Get a quote
Osceola County Zone 1 [VERIFY] Get a quote
Page County Zone 1 [VERIFY] Get a quote
Palo Alto County Zone 1 [VERIFY] Get a quote
Plymouth County Zone 1 [VERIFY] Get a quote
Pocahontas County Zone 1 [VERIFY] Get a quote
Polk County Zone 1 [VERIFY] Get a quote
Pottawattamie County Zone 1 [VERIFY] Get a quote
Poweshiek County Zone 1 [VERIFY] Get a quote
Ringgold County Zone 1 [VERIFY] Get a quote
Sac County Zone 1 [VERIFY] Get a quote
Scott County Zone 1 [VERIFY] Get a quote
Shelby County Zone 1 [VERIFY] Get a quote
Sioux County Zone 1 [VERIFY] Get a quote
Story County Zone 1 [VERIFY] Get a quote
Tama County Zone 1 [VERIFY] Get a quote
Taylor County Zone 1 [VERIFY] Get a quote
Union County Zone 1 [VERIFY] Get a quote
Van Buren County Zone 1 [VERIFY] Get a quote
Wapello County Zone 1 [VERIFY] Get a quote
Warren County Zone 1 [VERIFY] Get a quote
Washington County Zone 1 [VERIFY] Get a quote
Wayne County Zone 1 [VERIFY] Get a quote
Webster County Zone 1 [VERIFY] Get a quote
Winnebago County Zone 1 [VERIFY] Get a quote
Winneshiek County Zone 1 [VERIFY] Get a quote
Woodbury County Zone 1 [VERIFY] Sioux City
Worth County Zone 1 [VERIFY] Get a quote
Wright County Zone 1 [VERIFY] Get a quote

EPA Radon Zone from the US EPA Map of Radon Zones. Statewide figures from Iowa HHS and the Iowa Radon Survey. County-specific averages marked [VERIFY] are not published from a primary source and should not be treated as official.

Frequently Asked Questions

What are radon levels by county in Iowa?

All 99 Iowa counties are classified by the EPA as Radon Zone 1, the highest-risk category, meaning the predicted average indoor level is above 4 pCi/L. Statewide, Iowa averages about 8.5 pCi/L per Iowa HHS. Iowa does not publish a single official average for every individual county, and county averages listed on third-party sites are usually user-submitted rather than official, so the only reliable way to know a specific home is to test it.

Which Iowa counties are in EPA Radon Zone 1?

Every one of Iowa’s 99 counties is in EPA Radon Zone 1. Iowa is the only state where all counties carry the highest-risk EPA zone designation, according to the EPA Map of Radon Zones.

How do I find radon levels by zip code in Iowa?

There is no official radon average by zip code, and online zip-code or county averages are typically user-submitted estimates, not authoritative figures. Because radon varies house to house even on the same street, a short-term or long-term test of your own home is the only accurate way to find your level. We can connect you with a credentialed specialist to test.

What is the average radon level in Iowa?

The Iowa Department of Health and Human Services reports a statewide average indoor radon level around 8.5 pCi/L, compared with a US average near 1.3 pCi/L. The Iowa Radon Survey found roughly 71.6% of Iowa homes test at or above the EPA action level of 4 pCi/L, the highest share of any state.

Know Your County. Now Test Your Home.

Zone and county data cannot tell you your home’s level. Connect with an NRPP-certified, Iowa HHS-credentialed specialist for a free, no-obligation quote.

Get My Free Radon Quote Call (712) 218-3501

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