Short-term kit
Air Chek Short-Term radon test kit you hang, lab fee included
- Lab fee included
In home: 72 to 168 hours
Locations and reports
Radon Levels in Harding County, South Dakota
EPA puts Harding County in Zone 2, its middle radon zone, and only 1 radon test from it is on file with CDC (2008 to 2017, laboratory totals). Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Highest bordering
69.6%
Bowman County
- Bowman
- 69.6%
1 of 6 neighbours have 30+ tests, 2006 to 2015
Nearest county
54.5%
Meade County, 80 miles
- Meade
- 54.5%
- SD
- 58.8%
Share at 4+ pCi/L, 112 tests, 2006 to 2015
Ground above low
100.0%
1.0 pts above SD
- Harding
- 100.0%
- SD
- 99.0%
Share of land USGS rates moderate or high potential
Tests reported
2
Too few for a share
- Harding
- 2
- Needed
- 30
2006 to 2015, laboratory
EPA radon zone
Zone 2
Moderate potential
- 1
- Zone 2
- 3
1 highest, 3 lowest
EPA predicts 2 to 4 pCi/L indoors
Read a result for Harding County
Starts at EPA's action level
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 4.0 pCi/L
At or above 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is at or above 4 pCi/L. EPA recommends fixing a home when the radon level is 4 pCi/L or higher.
The data
Harding County, At a glance
Harding County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Harding County is a
USGS geologic potential: Moderate across 70% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Harding County, 2008 to 2017, laboratory
CDC holds 1 reported test for Harding County over the 2008 to 2017 laboratory totals, a result of 5.1 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Harding County beside the counties around it is how this page reads it.
What these figures count
Only 1 test was reported to CDC for Harding County over 2008 to 2017 (laboratory totals), and tests are often run on homes being sold or already suspected of a problem: so few describe neither the county nor this house.
Measured: CDC tracking data. Figure above: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).
Harding County, Compared
Harding County radon figures, compared
Calculated by Radon411CDC's largest figure for Harding County rests on 2 tests over the 2006 to 2015 laboratory totals, 2 of them at or above 4 pCi/L, so each test moves its share by 50.0 points and no rank or comparison is drawn from it. Results reached as high as 8.7 pCi/L, with a middle value of 7.9 pCi/L.
Bowman County, ND, the one bordering county with a figure over the 2006 to 2015 laboratory totals, reported 69.6% of its tests at or above 4 pCi/L. Farther out, Meade County (80 miles away) at 54.5%, Lawrence County (86 miles away) at 60.5% and Pennington County (114 miles away) at 51.8% have figures too. Pooled across 63 South Dakota counties, 58.8% of reported tests reached that level; across every county in the country with a figure, 36.3%.
Statewide for the same period, Bon Homme County reported the highest share (79.5%) and Davison County the lowest (47.9%). EPA's 1993 map puts Harding County in Zone 2, its middle label: a predicted county average between 2 and 4 pCi/L. USGS geology rates 70% of the county's land moderate radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Harding County, Geology
The ground under Harding County
PredictedUSGS's geologic map splits Harding County: 69.9% of its land is moderate radon potential and 30.1% high. The map puts 68.5% of Harding County in the area it calls Pierre Hills and 30.0% in Great Plains (Unglaciated), with one smaller area beside them. USGS gives the first a radon index of 10, in the moderate band (9 to 11), and the second 14, in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Pierre Hills | Pierre Shale and Fox Hills sandstone. | Moderate | 10 | 68.5% |
| Great Plains (Unglaciated) | Early Tertiary sandstones. Some units host uranium deposits. | High | 14 | 30.0% |
| Eastern Great Plains | Cretaceous marine shale and marine and nearshore sandstone, siltstone. | Moderate | 11 | 1.5% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Harding County beside the ground around it
South Dakota as a whole has more high-potential ground than Harding County: 56.7% of its land, against 30.1% here. Of the 6 counties that border it, 4 have more high-potential ground, Adams County, ND the most at 100%.
The map rates the ground, not the air in any home.
Local help
Harding County, Local resources
Radon testing and mitigation in Harding County
- South Dakota's radon programDepartment of Agriculture and Natural ResourcesSouth Dakota's radon program offers free or discounted test kits, and answers questions about testing and mitigation in South Dakota.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
The Department of Agriculture and Natural Resources (DANR) will provide 500 free Radon test kits to South Dakota Residents.
- Compare kits
- Professionals in South Dakota5 professionals are listed in South Dakota.
What South Dakota's program says
- Phone
- 1-800-438-3367
What it means
Harding County, Questions
Questions about radon in Harding County
Are radon levels high in Harding County?
Over the 2008 to 2017 laboratory totals, 100.0% of the radon tests reported to CDC for Harding County, South Dakota were at or above 4 pCi/L, and the median reported pre-mitigation result was 5.1 pCi/L. Bowman County, ND, the one bordering county with a figure over the 2006 to 2015 laboratory totals, reported 69.6% of its tests at or above 4 pCi/L.
Which counties border Harding County?
Harding County borders 6 counties: Bowman County, ND, Butte County, SD, Carter County, MT, Perkins County, SD, Adams County, ND and Fallon County, MT.
Products
Harding County, Products
Testing a home in Harding County
No CDC figure names Harding County; the nearest county with one, Meade County (80 miles away), reported 54.5% of its tests at or above 4 pCi/L over the 2006 to 2015 laboratory totals, the only reading nearby until a test of this home. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Harding County; a long-term test tells the year-round average.
Test kits and monitors3
See every kit and monitor
Long-term kit
RL116 long-term radon test kit
- Lab fee extra
Method: Alpha track
In home: 90 days to 12 months
Monitor
RadonScan USB-powered radon monitor with a color screen
- C-NRPP 2024/25: Not included
- Plug-in
- Alarm
- Screen
First reading: Within 5 minutes
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Harding County, Bordering counties
Counties bordering Harding County
Calculated by Radon411- Radon levels in Adams County, NDEPA zone 1
77.8%at or above 4 pCi/L
Median 8.0 pCi/L · 27 tests
- Radon levels in Fallon County, MTEPA zone 1
71.4%at or above 4 pCi/L
Median 5.2 pCi/L · 7 tests
- Radon levels in Bowman County, NDEPA zone 1
69.6%at or above 4 pCi/L
Median 5.8 pCi/L · 46 tests
- Radon levels in Perkins County, SDEPA zone 1
62.5%at or above 4 pCi/L
Median 7.9 pCi/L · 16 tests
- Radon levels in Butte County, SDEPA zone 2
45.8%at or above 4 pCi/L
Median 3.3 pCi/L · 24 tests
- Radon levels in Carter County, MTEPA zone 1
No CDC figure for 2006 to 2015; its page reads it against its own neighbours.
Harding County, Cities and towns
Cities and towns in Harding County
The Census Bureau estimates 1,331 residents in Harding County for July 1, 2025, 28 more than in 2020 (+2.1%). Spread over its land, that is 0.5 people to the square mile. Its largest town, Buffalo, has 358 residents, 26.9% of the total. Together its 2 incorporated places hold 32.1% of those residents; the other 67.9% live outside any of them. Reported testing is thin here: 2 tests over 2006 to 2015, or 1.5 for every 1,000 residents (2025 estimate), where South Dakota as a whole comes to 5.2.
From Buffalo to Camp Crook, CDC publishes no figure by town: each reads Harding County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Buffalo | 358 | +2.3% | 26.9% |
| Camp Crook | 69 | +16.9% | 5.2% |
2 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025).
Harding County, Homes
Homes in Harding County
Of Harding County's 702 homes, 73% are detached houses, against 67% across South Dakota; 21% are mobile homes. The homes are older than South Dakota's as a whole: half were built before 1970 (1979 for South Dakota), and 46% date from before 1960. Owners live in 77% of the occupied homes (South Dakota: 69%), so for most households a test and a fix are their own to order.
| Homes | Harding County | South Dakota |
|---|---|---|
| Housing units | 702 | 402,364 |
| Detached houses | 73% | 67% |
| In buildings of 5 or more | 1% | 16% |
| Mobile homes | 21% | 8% |
| Built before 1960 | 46% | 29% |
| Built since 2000 | 16% | 28% |
| Middle year built | 1970 | 1979 |
| Owner-occupied | 77% | 69% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.