Radon levels in Indiana: Moderate
The model predicts a population-weighted basement average of 2.3 pCi/L (model estimate) across Indiana's 92 counties - about 1.3× the US average of 1.8 pCi/L. Above-ground floors average 1.4 pCi/L.
Predicted (model estimate). The pCi/L figures on this page are long-term area averages from a peer-reviewed national model built on millions of real radon tests (2001-2021). They describe the typical home in this area - not your home, which can be several times higher or lower. The EPA radon zone is a separate, 1993 county-level classification. How the numbers work.
57 / 92
EPA Zone 1 counties (62%)
35 / 0
Zone 2 / Zone 3 counties
0
counties predicted ≥ 4 pCi/L
0.1%
of ZIP codes predicted ≥ 4 pCi/L
Test Indiana - the EPA says "consider fixing" in this range
The predicted basement average here is 2.3 pCi/L, in the 2-4 pCi/L band where the EPA recommends considering mitigation. Plenty of individual homes in a moderate area test above 4. Start with a short-term test; if it comes back at 2 or higher, follow up with a long-term test or a continuous monitor.
Monitor link goes to the Airthings store - use code RADONGRADE-10OFF at checkout for 10% off any Airthings monitor.
Already tested at 4 pCi/L or higher? Find a certified mitigation professional (EPA). A mitigation system typically runs $800-$2,500 installed.
Affiliate links: we may earn a commission from Airthings or Amazon at no extra cost to you.
What the data says about radon in Indiana
On the EPA's 1993 radon zone map, 57 of Indiana's 92 counties are EPA Zone 1 (62%), 35 are Zone 2 and 0 are Zone 3. Zone 1 - the highest-potential class, predicted screening average above 4 pCi/L - is the most common designation in Indiana. That classification has not been revised since 1993; it describes counties, not homes, and elevated readings turn up in Zone 3 counties every year.
Indiana models out at 2.3 pCi/L predicted basement average (moderate; 1.3× the US population-weighted average of 1.8). Of the 92 counties with predictions, 0 are predicted at or above 4 pCi/L, 79 in the 2-4 band and 13 below 2. The highest predicted county is Blackford County at 3.5 pCi/L; the lowest is Lake County at 1.3 - a 2.2 pCi/L spread that means a statewide average tells you little about any one county.
At ZIP-code resolution, 0.1% of Indiana ZIPs are predicted at 4 pCi/L or higher in the basement and 73.3% at 2 or higher - below the national 4.2% at the action level but above the national 48.7% at 2 pCi/L. With more than half of ZIPs above 2, a test is worth doing before any purchase or renovation here.
Indiana counties by predicted radon
Sorted highest to lowest predicted basement average (model estimate). 92 counties.
| County | Predicted basement | Upstairs | Grade | EPA zone | ZIPs |
|---|---|---|---|---|---|
| Blackford County | 3.5 pCi/L | 1.9 | Moderate | EPA Zone 1 | 2 |
| Jay County | 3.5 pCi/L | 1.9 | Moderate | EPA Zone 1 | 6 |
| Randolph County | 3.4 pCi/L | 1.9 | Moderate | EPA Zone 1 | 9 |
| Fayette County | 3.3 pCi/L | 1.9 | Moderate | EPA Zone 1 | 1 |
| Henry County | 3.3 pCi/L | 2.0 | Moderate | EPA Zone 1 | 9 |
| Rush County | 3.3 pCi/L | 1.9 | Moderate | EPA Zone 1 | 7 |
| Adams County | 3.3 pCi/L | 1.9 | Moderate | EPA Zone 1 | 4 |
| Huntington County | 3.2 pCi/L | 2.1 | Moderate | EPA Zone 1 | 4 |
| Wabash County | 3.2 pCi/L | 1.9 | Moderate | EPA Zone 1 | 7 |
| Clinton County | 3.2 pCi/L | 1.7 | Moderate | EPA Zone 1 | 7 |
| Tipton County | 3.2 pCi/L | 1.9 | Moderate | EPA Zone 1 | 4 |
| Whitley County | 3.2 pCi/L | 1.8 | Moderate | EPA Zone 1 | 4 |
| Union County | 3.2 pCi/L | 1.8 | Moderate | EPA Zone 1 | 3 |
| Carroll County | 3.1 pCi/L | 1.8 | Moderate | EPA Zone 1 | 5 |
| DeKalb County | 3.1 pCi/L | 1.8 | Moderate | EPA Zone 1 | 8 |
| Grant County | 3.1 pCi/L | 1.8 | Moderate | EPA Zone 1 | 9 |
| Warren County | 3.1 pCi/L | 1.9 | Moderate | EPA Zone 1 | 5 |
| Benton County | 3.1 pCi/L | 1.8 | Moderate | EPA Zone 1 | 4 |
| Wells County | 3.0 pCi/L | 1.9 | Moderate | EPA Zone 1 | 8 |
| Miami County | 3.0 pCi/L | 1.8 | Moderate | EPA Zone 1 | 5 |
| Noble County | 3.0 pCi/L | 1.8 | Moderate | EPA Zone 1 | 9 |
| Fountain County | 3.0 pCi/L | 1.7 | Moderate | EPA Zone 1 | 5 |
| Vermillion County | 2.9 pCi/L | 1.7 | Moderate | EPA Zone 1 | 5 |
| Cass County | 2.9 pCi/L | 1.9 | Moderate | EPA Zone 1 | 6 |
| Decatur County | 2.9 pCi/L | 1.8 | Moderate | EPA Zone 1 | 3 |
| Shelby County | 2.9 pCi/L | 1.6 | Moderate | EPA Zone 1 | 8 |
| Wayne County | 2.9 pCi/L | 1.8 | Moderate | EPA Zone 1 | 9 |
| Montgomery County | 2.8 pCi/L | 1.8 | Moderate | EPA Zone 1 | 9 |
| Fulton County | 2.8 pCi/L | 1.7 | Moderate | EPA Zone 1 | 3 |
| Putnam County | 2.8 pCi/L | 1.6 | Moderate | EPA Zone 1 | 7 |
| Steuben County | 2.8 pCi/L | 1.8 | Moderate | EPA Zone 1 | 6 |
| Franklin County | 2.8 pCi/L | 1.6 | Moderate | EPA Zone 2 | 7 |
| White County | 2.8 pCi/L | 1.6 | Moderate | EPA Zone 1 | 8 |
| Madison County | 2.7 pCi/L | 1.7 | Moderate | EPA Zone 1 | 13 |
| Delaware County | 2.7 pCi/L | 1.7 | Moderate | EPA Zone 1 | 10 |
| Jennings County | 2.7 pCi/L | 1.5 | Moderate | EPA Zone 1 | 6 |
| LaGrange County | 2.7 pCi/L | 1.9 | Moderate | EPA Zone 1 | 5 |
| Howard County | 2.7 pCi/L | 1.7 | Moderate | EPA Zone 1 | 4 |
| Kosciusko County | 2.7 pCi/L | 1.5 | Moderate | EPA Zone 1 | 12 |
| Marshall County | 2.7 pCi/L | 1.5 | Moderate | EPA Zone 1 | 6 |
| Harrison County | 2.6 pCi/L | 1.6 | Moderate | EPA Zone 1 | 12 |
| Clark County | 2.6 pCi/L | 1.5 | Moderate | EPA Zone 1 | 11 |
| LaPorte County | 2.6 pCi/L | 1.2 | Moderate | EPA Zone 2 | 10 |
| Allen County | 2.6 pCi/L | 1.5 | Moderate | EPA Zone 1 | 26 |
| Bartholomew County | 2.5 pCi/L | 1.5 | Moderate | EPA Zone 1 | 5 |
| Tippecanoe County | 2.5 pCi/L | 1.5 | Moderate | EPA Zone 1 | 9 |
| Boone County | 2.5 pCi/L | 1.6 | Moderate | EPA Zone 1 | 5 |
| Brown County | 2.5 pCi/L | 1.3 | Moderate | EPA Zone 2 | 3 |
| Jackson County | 2.4 pCi/L | 1.1 | Moderate | EPA Zone 2 | 7 |
| Scott County | 2.4 pCi/L | 1.4 | Moderate | EPA Zone 1 | 3 |
| Washington County | 2.4 pCi/L | 1.6 | Moderate | EPA Zone 1 | 5 |
| Hancock County | 2.4 pCi/L | 1.4 | Moderate | EPA Zone 1 | 6 |
| Jefferson County | 2.4 pCi/L | 1.4 | Moderate | EPA Zone 2 | 6 |
| Elkhart County | 2.4 pCi/L | 1.5 | Moderate | EPA Zone 1 | 11 |
| Morgan County | 2.3 pCi/L | 1.4 | Moderate | EPA Zone 2 | 7 |
| Hendricks County | 2.3 pCi/L | 1.5 | Moderate | EPA Zone 1 | 11 |
| Jasper County | 2.3 pCi/L | 1.3 | Moderate | EPA Zone 2 | 4 |
| Orange County | 2.3 pCi/L | 1.4 | Moderate | EPA Zone 1 | 4 |
| Pulaski County | 2.3 pCi/L | 1.3 | Moderate | EPA Zone 2 | 6 |
| Lawrence County | 2.2 pCi/L | 1.5 | Moderate | EPA Zone 1 | 6 |
| Marion County | 2.2 pCi/L | 1.3 | Moderate | EPA Zone 1 | 34 |
| Newton County | 2.2 pCi/L | 1.4 | Moderate | EPA Zone 2 | 6 |
| Johnson County | 2.2 pCi/L | 1.3 | Moderate | EPA Zone 1 | 7 |
| Dubois County | 2.2 pCi/L | 1.3 | Moderate | EPA Zone 2 | 9 |
| Daviess County | 2.2 pCi/L | 1.2 | Moderate | EPA Zone 2 | 6 |
| Owen County | 2.1 pCi/L | 1.3 | Moderate | EPA Zone 2 | 6 |
| Dearborn County | 2.1 pCi/L | 1.3 | Moderate | EPA Zone 2 | 7 |
| Ripley County | 2.1 pCi/L | 1.2 | Moderate | EPA Zone 2 | 6 |
| Clay County | 2.1 pCi/L | 1.2 | Moderate | EPA Zone 2 | 6 |
| Perry County | 2.1 pCi/L | 1.2 | Moderate | EPA Zone 2 | 8 |
| Ohio County | 2.1 pCi/L | 1.3 | Moderate | EPA Zone 2 | 1 |
| Porter County | 2.1 pCi/L | 1.2 | Moderate | EPA Zone 2 | 6 |
| Crawford County | 2.1 pCi/L | 1.2 | Moderate | EPA Zone 2 | 7 |
| Monroe County | 2.1 pCi/L | 1.6 | Moderate | EPA Zone 1 | 6 |
| Floyd County | 2.0 pCi/L | 1.3 | Moderate | EPA Zone 2 | 4 |
| Parke County | 2.0 pCi/L | 1.2 | Moderate | EPA Zone 2 | 6 |
| Switzerland County | 2.0 pCi/L | 1.2 | Moderate | EPA Zone 2 | 4 |
| Martin County | 2.0 pCi/L | 1.1 | Moderate | EPA Zone 2 | 3 |
| Gibson County | 2.0 pCi/L | 1.2 | Moderate | EPA Zone 2 | 10 |
| Greene County | 2.0 pCi/L | 1.2 | Low | EPA Zone 2 | 9 |
| Sullivan County | 2.0 pCi/L | 1.1 | Low | EPA Zone 2 | 7 |
| Pike County | 1.9 pCi/L | 1.2 | Low | EPA Zone 2 | 5 |
| Vigo County | 1.9 pCi/L | 1.2 | Low | EPA Zone 2 | 7 |
| Posey County | 1.9 pCi/L | 1.2 | Low | EPA Zone 2 | 4 |
| Spencer County | 1.9 pCi/L | 1.2 | Low | EPA Zone 2 | 11 |
| Hamilton County | 1.8 pCi/L | 1.4 | Low | EPA Zone 1 | 13 |
| St. Joseph County | 1.8 pCi/L | 1.2 | Low | EPA Zone 1 | 18 |
| Knox County | 1.8 pCi/L | 1.1 | Low | EPA Zone 2 | 9 |
| Starke County | 1.8 pCi/L | 1.0 | Low | EPA Zone 2 | 5 |
| Vanderburgh County | 1.8 pCi/L | 1.1 | Low | EPA Zone 2 | 9 |
| Warrick County | 1.7 pCi/L | 1.2 | Low | EPA Zone 2 | 7 |
| Lake County | 1.3 pCi/L | 0.9 | Low | EPA Zone 2 | 26 |
Radon levels in Indiana cities
The 23 most-populous Indiana places among the 1,000 largest US cities (Census incorporated places and CDPs), by population. City figures are ZIP-land-weighted means of the model's ZIP predictions (model estimate).
| City | Population | Predicted basement | Upstairs | Grade | ZIPs ≥ 4 |
|---|---|---|---|---|---|
| Indianapolis | 879,293 | 2.2 pCi/L | 1.3 | Moderate | 0% |
| Fort Wayne | 269,994 | 2.5 pCi/L | 1.5 | Moderate | 0% |
| Evansville | 115,332 | 1.7 pCi/L | 1.1 | Low | 0% |
| Fishers | 104,094 | 1.6 pCi/L | 1.3 | Low | 0% |
| South Bend | 103,395 | 1.8 pCi/L | 1.2 | Low | 0% |
| Carmel | 102,296 | 1.8 pCi/L | 1.4 | Low | 0% |
| Bloomington | 78,840 | 2.1 pCi/L | 1.6 | Moderate | 0% |
| Hammond | 76,193 | 0.9 pCi/L | 0.7 | Low | 0% |
| Noblesville | 73,916 | 2.0 pCi/L | 1.4 | Low | 0% |
| Lafayette | 71,216 | 2.5 pCi/L | 1.6 | Moderate | 0% |
| Gary | 67,652 | 0.9 pCi/L | 0.7 | Low | 0% |
| Greenwood | 66,296 | 1.9 pCi/L | 1.2 | Low | 0% |
| Muncie | 65,081 | 2.6 pCi/L | 1.6 | Moderate | 0% |
| Kokomo | 59,890 | 2.6 pCi/L | 1.7 | Moderate | 0% |
| Terre Haute | 58,502 | 1.9 pCi/L | 1.1 | Low | 0% |
| Westfield | 57,746 | 1.6 pCi/L | 1.3 | Low | 0% |
| Anderson | 55,199 | 2.6 pCi/L | 1.6 | Moderate | 0% |
| Elkhart | 53,484 | 2.1 pCi/L | 1.4 | Moderate | 0% |
| Columbus | 51,522 | 2.5 pCi/L | 1.5 | Moderate | 0% |
| Jeffersonville | 51,235 | 2.6 pCi/L | 1.6 | Moderate | 0% |
| Mishawaka | 50,842 | 1.9 pCi/L | 1.2 | Low | 0% |
| Lawrence | 49,235 | 2.0 pCi/L | 1.2 | Low | 0% |
| West Lafayette | 44,829 | 2.5 pCi/L | 1.5 | Moderate | 0% |
Highest-radon ZIP codes in Indiana
The 10 Indiana ZIP codes with the highest predicted basement average (model estimate), out of 681 modeled. A ZIP average is still an area figure - neighboring homes routinely test several pCi/L apart.
| ZIP | County | Predicted basement | Upstairs | Grade |
|---|---|---|---|---|
| 46350 | LaPorte County | 4.0 pCi/L | 1.4 | High |
| 47356 | Henry County | 3.7 pCi/L | 2.2 | Moderate |
| 47346 | Wayne County | 3.7 pCi/L | 2.2 | Moderate |
| 47341 | Wayne County | 3.6 pCi/L | 2.1 | Moderate |
| 46740 | Adams County | 3.6 pCi/L | 2.0 | Moderate |
| 47393 | Wayne County | 3.6 pCi/L | 2.2 | Moderate |
| 47371 | Jay County | 3.6 pCi/L | 2.0 | Moderate |
| 47330 | Wayne County | 3.6 pCi/L | 2.2 | Moderate |
| 46788 | DeKalb County | 3.5 pCi/L | 2.0 | Moderate |
| 47348 | Blackford County | 3.5 pCi/L | 1.9 | Moderate |
Indiana radon questions
- Is radon high in Indiana?
- Indiana's population-weighted predicted basement average is 2.3 pCi/L, about 1.3× the US average of 1.8. 0 of its 92 modeled counties are predicted at or above the EPA action level of 4 pCi/L, 79 are in the 2-4 "consider fixing" range and 13 are below 2. 0.1% of Indiana ZIP codes are predicted at 4 or higher.
- Which Indiana county has the highest radon?
- Blackford County has the highest predicted basement average in Indiana at 3.5 pCi/L (EPA Zone 1). The lowest is Lake County at 1.3 pCi/L. These are area figures; individual homes in any county can test far higher.
- How many EPA Zone 1 counties are in Indiana?
- 57 of Indiana's 92 counties (62%) are EPA Zone 1 (highest potential), 35 are Zone 2 and 0 are Zone 3. The EPA zone map dates from 1993; the predicted values on this page come from a 2001-2021 model built on millions of actual tests, so the two can disagree for a given county.
- Should I test for radon in Indiana?
- Yes - with some urgency. Indiana's predicted average is in the moderate range, and 73.3% of its ZIP codes are predicted at 2 pCi/L or higher. A short-term charcoal kit or a continuous digital monitor will tell you your actual level within days.
Indiana radon program
State programs keep lists of certified testers and mitigators and sometimes run kit programs. We link only pages we could verify, and Indiana's program page did not respond when we checked, so start from the EPA state radon contacts page. Then read how to test and what mitigation costs.