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 Todd County, South Dakota
EPA puts Todd 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
Nearest county
62.5%
Brule County, 90 miles
- Brule
- 62.5%
- SD
- 58.8%
Share at 4+ pCi/L, 32 tests, 2006 to 2015
Ground above low
67.2%
31.8 pts below SD
- Todd
- 67.2%
- SD
- 99.0%
Share of land USGS rates moderate or high potential
Tests reported
1
Too few for a share
- Todd
- 1
- Needed
- 30
2008 to 2017, 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 Todd 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
Todd County, At a glance
Todd County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Todd County is a
USGS geologic potential: Moderate across 67% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Todd County, 2008 to 2017, laboratory
CDC holds 1 reported test for Todd County over the 2008 to 2017 laboratory totals, a result of 4.7 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Todd County beside the counties around it is how this page reads it.
What these figures count
Only 1 test was reported to CDC for Todd 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. Measured data period: 2008 to 2017.
Todd County, Compared
Todd County radon figures, compared
Calculated by Radon411CDC's largest figure for Todd County rests on 1 test over the 2008 to 2017 laboratory totals, 1 of them at or above 4 pCi/L, so each test moves its share by 100.0 points and no rank or comparison is drawn from it. Results reached as high as 4.7 pCi/L, with a middle value of 4.7 pCi/L.
The nearest counties with a figure are Brule County (90 miles away) at 62.5%, Hughes County (90 miles away) at 66.7% and Pennington County (120 miles away) at 51.8%. 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 Todd County in Zone 2, its middle label: a predicted county average between 2 and 4 pCi/L. USGS geology rates 67% of the county's land moderate radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Todd County, Geology
The ground under Todd County
PredictedUSGS's geologic map splits Todd County: 67.2% of its land is moderate radon potential and 32.8% low. The map puts 64.8% of Todd County in the area it calls Southern Plateaus and 32.8% in Sand Hills, with one smaller area beside them. USGS gives the first a radon index of 11, in the moderate band (9 to 11), and the second 8, in the low band (5 to 8).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Southern Plateaus | Late Tertiary continental sandstone. | Moderate | 11 | 64.8% |
| Sand Hills | Tertiary sandstone, siltstone, shale. | Low | 8 | 32.8% |
| Pierre Hills | Pierre Shale and Fox Hills sandstone. | Moderate | 10 | 2.4% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Todd County beside the ground around it
Across South Dakota 56.7% of the land is rated high; none of Todd County's is. Of the 6 counties that border it, 2 have more high-potential ground, Keya Paha County, NE the most at 7.8%.
The map rates the ground, not the air in any home.
Local help
Todd County, Local resources
Radon testing and mitigation in Todd 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
Todd County, Questions
Questions about radon in Todd County
Are radon levels high in Todd County?
Over the 2008 to 2017 laboratory totals, 100.0% of the radon tests reported to CDC for Todd County, South Dakota were at or above 4 pCi/L, and the median reported pre-mitigation result was 4.7 pCi/L. Of the 8 nearest counties with a figure, within 148 miles, the share of tests at or above 4 pCi/L runs from 47.9% to 79.5%.
Which counties border Todd County?
Todd County borders 6 counties: Mellette County, SD, Tripp County, SD, Bennett County, SD, Cherry County, NE, Jackson County, SD and Keya Paha County, NE.
Products
Todd County, Products
Testing a home in Todd County
No CDC figure names Todd County; the nearest county with one, Brule County (90 miles away), reported 62.5% 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 Todd 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
RM-63Pro rechargeable radon monitor with a touchscreen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Todd County, Bordering counties
Counties bordering Todd County
Calculated by Radon411- Radon levels in Tripp County, SDEPA zone 2
57.1%at or above 4 pCi/L
Median 4.2 pCi/L · 7 tests
- Radon levels in Bennett County, SDEPA zone 2
33.3%at or above 4 pCi/L
Median 3.0 pCi/L · 3 tests
- Radon levels in Keya Paha County, NEEPA zone 2
23.1%at or above 4 pCi/L
Median 2.7 pCi/L · 13 tests
- Radon levels in Cherry County, NEEPA zone 3
4.5%at or above 4 pCi/L
Median 1.9 pCi/L · 22 tests
- Radon levels in Jackson County, SDEPA zone 2
0.0%at or above 4 pCi/L
Median 1.1 pCi/L · 1 test
- Radon levels in Mellette County, SDEPA zone 2
No CDC figure for 2006 to 2015; its page reads it against its own neighbours.
Todd County, Cities and towns
Cities and towns in Todd County
About 8,863 people live in Todd County by the Census Bureau's estimate for July 1, 2025, 453 fewer than in 2020 (−4.9%). Spread over its land, that is 6.4 people to the square mile. No town dominates: Mission, the largest, has 1,101 residents, 12.4% of the total. Together its 2 incorporated places hold 17.5% of those residents; the other 82.5% live outside any of them. Reported testing is thin here: 1 test over 2008 to 2017, or 0.1 for every 1,000 residents (2025 estimate), where South Dakota as a whole comes to 6.7.
From Mission to St. Francis, CDC publishes no figure by town: each reads Todd County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Mission | 1,101 | −4.5% | 12.4% |
| St. Francis | 449 | −4.7% | 5.1% |
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).
Todd County, Homes
Homes in Todd County
Of Todd County's 2,885 homes, 66% are detached houses, against 67% across South Dakota; 15% are mobile homes. Half of its homes were built before 1979, close to South Dakota's 1979: 15% date from before 1960 and 17% from 2000 or later. Most occupied homes here are rented: owners live in 45% (South Dakota: 69%). A tenant can run a test; a fix is the landlord's to make.
| Homes | Todd County | South Dakota |
|---|---|---|
| Housing units | 2,885 | 402,364 |
| Detached houses | 66% | 67% |
| In buildings of 5 or more | 11% | 16% |
| Mobile homes | 15% | 8% |
| Built before 1960 | 15% | 29% |
| Built since 2000 | 17% | 28% |
| Middle year built | 1979 | 1979 |
| Owner-occupied | 45% | 69% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.