Radon levels in South Dakota: Moderate
The model predicts a population-weighted basement average of 3.9 pCi/L (model estimate) across South Dakota's 66 counties - about 2.1× the US average of 1.8 pCi/L. Above-ground floors average 2.2 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.
48 / 66
EPA Zone 1 counties (73%)
18 / 0
Zone 2 / Zone 3 counties
34
counties predicted ≥ 4 pCi/L
42.1%
of ZIP codes predicted ≥ 4 pCi/L
Test South Dakota - the EPA says "consider fixing" in this range
The predicted basement average here is 3.9 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.
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What the data says about radon in South Dakota
According to the EPA zone map, 48 of South Dakota's 66 counties are EPA Zone 1 (73%), 18 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 South Dakota. Treat the map as a coarse prior: it predates two decades of test data and never replaces a test in your own home.
The 2001-2021 national model predicts a population-weighted basement average of 3.9 pCi/L for South Dakota (moderate range, 2.1× the US population-weighted average of 1.8). Of the 66 counties with predictions, 34 are predicted at or above 4 pCi/L, 32 in the 2-4 band and 0 below 2. The highest predicted county is Jerauld County at 5.2 pCi/L; the lowest is Todd County at 2.6 - a 2.5 pCi/L spread that means a statewide average tells you little about any one county.
100% of the state's modeled ZIP codes are predicted at or above 2 pCi/L, and 42.1% at or above the 4 pCi/L action level - above the national shares of 4.2% and 48.7%. With more than half of ZIPs above 2, a test is worth doing before any purchase or renovation here.
South Dakota counties by predicted radon
Sorted highest to lowest predicted basement average (model estimate). 66 counties.
| County | Predicted basement | Upstairs | Grade | EPA zone | ZIPs |
|---|---|---|---|---|---|
| Jerauld County | 5.2 pCi/L | 2.5 | High | EPA Zone 1 | 1 |
| Yankton County | 4.9 pCi/L | 2.5 | High | EPA Zone 1 | 7 |
| Hughes County | 4.8 pCi/L | 2.3 | High | EPA Zone 1 | 3 |
| Bon Homme County | 4.8 pCi/L | 2.5 | High | EPA Zone 1 | 5 |
| Hutchinson County | 4.7 pCi/L | 2.4 | High | EPA Zone 1 | 6 |
| Codington County | 4.6 pCi/L | 2.6 | High | EPA Zone 1 | 6 |
| Pennington County | 4.6 pCi/L | 2.6 | High | EPA Zone 2 | 9 |
| Hyde County | 4.5 pCi/L | 2.5 | High | EPA Zone 1 | 2 |
| Aurora County | 4.5 pCi/L | 2.4 | High | EPA Zone 1 | 3 |
| Douglas County | 4.5 pCi/L | 2.4 | High | EPA Zone 1 | 5 |
| Turner County | 4.5 pCi/L | 2.4 | High | EPA Zone 1 | 7 |
| Kingsbury County | 4.5 pCi/L | 2.5 | High | EPA Zone 1 | 6 |
| Hanson County | 4.4 pCi/L | 2.4 | High | EPA Zone 1 | 3 |
| Miner County | 4.4 pCi/L | 2.5 | High | EPA Zone 1 | 4 |
| Charles Mix County | 4.4 pCi/L | 2.3 | High | EPA Zone 1 | 5 |
| Brule County | 4.4 pCi/L | 2.3 | High | EPA Zone 1 | 3 |
| Lawrence County | 4.4 pCi/L | 2.2 | High | EPA Zone 2 | 6 |
| Sanborn County | 4.4 pCi/L | 2.5 | High | EPA Zone 1 | 3 |
| Hand County | 4.3 pCi/L | 2.5 | High | EPA Zone 1 | 6 |
| Deuel County | 4.3 pCi/L | 2.5 | High | EPA Zone 1 | 7 |
| Moody County | 4.3 pCi/L | 2.4 | High | EPA Zone 1 | 4 |
| Sully County | 4.3 pCi/L | 2.4 | High | EPA Zone 1 | 2 |
| Hamlin County | 4.3 pCi/L | 2.5 | High | EPA Zone 1 | 5 |
| Lake County | 4.3 pCi/L | 2.4 | High | EPA Zone 1 | 7 |
| Potter County | 4.3 pCi/L | 2.4 | High | EPA Zone 1 | 4 |
| McCook County | 4.2 pCi/L | 2.4 | High | EPA Zone 1 | 6 |
| Faulk County | 4.2 pCi/L | 2.3 | High | EPA Zone 1 | 4 |
| Custer County | 4.2 pCi/L | 2.1 | High | EPA Zone 2 | 3 |
| Spink County | 4.2 pCi/L | 2.4 | High | EPA Zone 1 | 10 |
| Brown County | 4.2 pCi/L | 2.4 | High | EPA Zone 1 | 12 |
| Clark County | 4.1 pCi/L | 2.4 | High | EPA Zone 1 | 6 |
| Grant County | 4.1 pCi/L | 2.4 | High | EPA Zone 1 | 10 |
| Beadle County | 4.1 pCi/L | 2.3 | High | EPA Zone 1 | 8 |
| Brookings County | 4.0 pCi/L | 2.3 | High | EPA Zone 1 | 6 |
| Walworth County | 4.0 pCi/L | 2.4 | Moderate | EPA Zone 1 | 3 |
| Marshall County | 4.0 pCi/L | 2.3 | Moderate | EPA Zone 1 | 6 |
| McPherson County | 3.9 pCi/L | 2.3 | Moderate | EPA Zone 1 | 4 |
| Day County | 3.9 pCi/L | 2.3 | Moderate | EPA Zone 1 | 7 |
| Roberts County | 3.9 pCi/L | 2.2 | Moderate | EPA Zone 1 | 8 |
| Union County | 3.9 pCi/L | 2.3 | Moderate | EPA Zone 1 | 4 |
| Davison County | 3.8 pCi/L | 2.4 | Moderate | EPA Zone 1 | 3 |
| Buffalo County | 3.8 pCi/L | 2.1 | Moderate | EPA Zone 1 | 2 |
| Stanley County | 3.7 pCi/L | 2.2 | Moderate | EPA Zone 1 | 2 |
| Butte County | 3.7 pCi/L | 2.2 | Moderate | EPA Zone 2 | 4 |
| Clay County | 3.7 pCi/L | 2.0 | Moderate | EPA Zone 1 | 3 |
| Meade County | 3.7 pCi/L | 1.9 | Moderate | EPA Zone 2 | 12 |
| Campbell County | 3.6 pCi/L | 2.2 | Moderate | EPA Zone 1 | 2 |
| Lincoln County | 3.5 pCi/L | 2.1 | Moderate | EPA Zone 1 | 9 |
| Lyman County | 3.4 pCi/L | 1.9 | Moderate | EPA Zone 1 | 6 |
| Fall River County | 3.3 pCi/L | 1.8 | Moderate | EPA Zone 2 | 5 |
| Perkins County | 3.3 pCi/L | 2.0 | Moderate | EPA Zone 1 | 6 |
| Minnehaha County | 3.2 pCi/L | 2.0 | Moderate | EPA Zone 1 | 16 |
| Dewey County | 3.2 pCi/L | 2.0 | Moderate | EPA Zone 2 | 4 |
| Corson County | 3.1 pCi/L | 2.0 | Moderate | EPA Zone 1 | 8 |
| Harding County | 3.1 pCi/L | 1.8 | Moderate | EPA Zone 2 | 5 |
| Tripp County | 3.1 pCi/L | 1.8 | Moderate | EPA Zone 2 | 6 |
| Edmunds County | 3.1 pCi/L | 2.2 | Moderate | EPA Zone 1 | 3 |
| Jones County | 3.1 pCi/L | 1.6 | Moderate | EPA Zone 2 | 3 |
| Gregory County | 3.0 pCi/L | 1.6 | Moderate | EPA Zone 2 | 6 |
| Haakon County | 3.0 pCi/L | 1.7 | Moderate | EPA Zone 2 | 3 |
| Mellette County | 2.9 pCi/L | 1.6 | Moderate | EPA Zone 2 | 4 |
| Ziebach County | 2.8 pCi/L | 1.7 | Moderate | EPA Zone 2 | 2 |
| Jackson County | 2.8 pCi/L | 1.6 | Moderate | EPA Zone 2 | 4 |
| Bennett County | 2.7 pCi/L | 1.7 | Moderate | EPA Zone 2 | 3 |
| Oglala Lakota County | 2.6 pCi/L | 1.5 | Moderate | EPA Zone 2 | 7 |
| Todd County | 2.6 pCi/L | 1.4 | Moderate | EPA Zone 2 | 3 |
Radon levels in South Dakota cities
The 2 most-populous South Dakota 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 |
|---|---|---|---|---|---|
| Sioux Falls | 206,410 | 3.0 pCi/L | 1.9 | Moderate | 0% |
| Rapid City | 79,404 | 4.8 pCi/L | 2.6 | High | 67% |
Highest-radon ZIP codes in South Dakota
The 10 South Dakota ZIP codes with the highest predicted basement average (model estimate), out of 347 modeled. A ZIP average is still an area figure - neighboring homes routinely test several pCi/L apart.
| ZIP | County | Predicted basement | Upstairs | Grade |
|---|---|---|---|---|
| 57703 | Pennington County | 7.1 pCi/L | 3.1 | High |
| 57001 | Union County | 5.5 pCi/L | 2.9 | High |
| 57025 | Union County | 5.3 pCi/L | 2.9 | High |
| 57034 | Lincoln County | 5.3 pCi/L | 2.7 | High |
| 57382 | Jerauld County | 5.2 pCi/L | 2.4 | High |
| 57004 | Lincoln County | 5.1 pCi/L | 2.9 | High |
| 57783 | Lawrence County | 5.1 pCi/L | 2.3 | High |
| 57330 | Douglas County | 5.1 pCi/L | 2.6 | High |
| 57013 | Lincoln County | 5.0 pCi/L | 2.7 | High |
| 57062 | Bon Homme County | 5.0 pCi/L | 2.6 | High |
South Dakota radon questions
- Is radon high in South Dakota?
- South Dakota's population-weighted predicted basement average is 3.9 pCi/L, about 2.1× the US average of 1.8. 34 of its 66 modeled counties are predicted at or above the EPA action level of 4 pCi/L, 32 are in the 2-4 "consider fixing" range and 0 are below 2. 42.1% of South Dakota ZIP codes are predicted at 4 or higher.
- Which South Dakota county has the highest radon?
- Jerauld County has the highest predicted basement average in South Dakota at 5.2 pCi/L (EPA Zone 1). The lowest is Todd County at 2.6 pCi/L. These are area figures; individual homes in any county can test far higher.
- How many EPA Zone 1 counties are in South Dakota?
- 48 of South Dakota's 66 counties (73%) are EPA Zone 1 (highest potential), 18 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 South Dakota?
- Yes - with some urgency. South Dakota's predicted average is in the moderate range, and 100% 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.
South Dakota radon program
South Dakota's radon program page is at danr.sd.gov and, when we checked it, offered a limited number of free radon test kits (500 announced). The EPA also keeps a directory of every state radon contact: EPA state radon contacts page. Then read how to test and what mitigation costs.