
Long-term kit![]()
RL416 long-term radon test kit, lab fee included
- Lab fee included
Method: Alpha track
In home: 90 days to 12 months
Locations and reports
EPA puts Hanson County in Zone 1, its highest radon zone, and only 8 radon tests from it are 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
47.9%
Davison County
1 of 5 neighbours have 30+ tests, 2006 to 2015
Nearest county
47.9%
Davison County, 18 miles
Share at 4+ pCi/L, 71 tests, 2006 to 2015
Ground above low
100.0%
1.0 pts above SD
Share of land USGS rates moderate or high potential
Tests reported
8
Too few for a share
2008 to 2017, laboratory
EPA radon zone
Zone 1
Highest potential
1 highest, 3 lowest
EPA predicts over 4 pCi/L indoors
Read a result for Hanson County
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
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
Hanson County, At a glance
Predicted: EPA radon zone
EPA puts all of Hanson County in
USGS geologic potential: High across 100% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
CDC holds 8 reported tests for Hanson County over the 2008 to 2017 laboratory totals, with a median of 2.8 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Hanson County beside the counties around it is how this page reads it.
Only 8 tests were reported to CDC for Hanson 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).
Hanson County, Compared
CDC's largest figure for Hanson County rests on 8 tests over the 2008 to 2017 laboratory totals, 2 of them at or above 4 pCi/L, so each test moves its share by 12.5 points and no rank or comparison is drawn from it. Results reached as high as 8.0 pCi/L, with a middle value of 2.8 pCi/L.
Davison County, the one bordering county with a figure over the 2006 to 2015 laboratory totals, reported 47.9% of its tests at or above 4 pCi/L. Farther out, Lake County (41 miles away) at 73.7%, Turner County (41 miles away) at 53.3% and Bon Homme County (48 miles away) at 79.5% 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 Hanson County in Zone 1, the map's highest label: a predicted county average above 4 pCi/L. USGS geology rates 100% of the county's land high radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Hanson County, Geology
USGS's geologic map puts all of Hanson County's mapped land in one class: high radon potential. All of it lies in the area the map calls Missouri Coteau/James River Lowland/Coteau des Prairies, to which USGS gives a radon index of 14, in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Missouri Coteau/James River Lowland/Coteau des Prairies | Glacial drift derived largely from Cretaceous marine shale. | High | 14 | 100% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Hanson County has more high-potential ground than South Dakota as a whole: 100% of its land against 56.7%. Of the 5 counties that border it, none has as large a share of high-potential ground; Davison County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Hanson County, Local resources
The Department of Agriculture and Natural Resources (DANR) will provide 500 free Radon test kits to South Dakota Residents.
What it means
Hanson County, Questions
Over the 2008 to 2017 laboratory totals, 25.0% of the radon tests reported to CDC for Hanson County, South Dakota were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.8 pCi/L. Davison County, the one bordering county with a figure over the 2006 to 2015 laboratory totals, reported 47.9% of its tests at or above 4 pCi/L.
Hanson County borders 5 counties: Davison County, McCook County, Hutchinson County, Miner County and Sanborn County.
Products
Hanson County, Products
No CDC figure names Hanson County; the nearest county with one, Davison County (18 miles away), reported 47.9% 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 1 the year-round level in Hanson County is the one to know: a long-term test (more than 90 days) or a monitor, with a short-term kit for a first answer.
Test kits and monitors: 1 of 3
Hanson County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Hanson County
Explore
Hanson County, Bordering counties
80.0%at or above 4 pCi/L
Median 10.0 pCi/L · 10 tests
76.0%at or above 4 pCi/L
Median 8.2 pCi/L · 25 tests
66.7%at or above 4 pCi/L
Median 5.8 pCi/L · 3 tests
50.0%at or above 4 pCi/L
Median 4.3 pCi/L · 18 tests
47.9%at or above 4 pCi/L
Median 3.7 pCi/L · 71 tests
Hanson County, Cities and towns
Hanson County's population has barely moved since 2020: 3,456 residents on July 1, 2025 against 3,466 then, by the Census Bureau's estimates. Spread over its land, that is 8.0 people to the square mile. No town dominates: Alexandria, the largest, has 655 residents, 19.0% of the total. Together its 4 incorporated places hold 35.3% of those residents; the other 64.7% live outside any of them. Reported testing is thin here: 8 tests over 2008 to 2017, or 2.3 for every 1,000 residents (2025 estimate), where South Dakota as a whole comes to 6.7.
From Alexandria to Farmer, CDC publishes no figure by town: each reads Hanson County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Alexandria | 655 | +0.3% | 19.0% |
| Emery | 465 | −3.9% | 13.5% |
| Fulton | 85 | +1.2% | 2.5% |
| Farmer | 16 | Level | 0.5% |
4 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).
Hanson County, Homes
Hanson County is a place of houses on their own lots: 92% of its 1,289 homes are detached single-family houses, against 67% across South Dakota. The homes are older than South Dakota's as a whole: half were built before 1958 (1979 for South Dakota), and 52% date from before 1960. Owners live in 89% of the occupied homes (South Dakota: 69%), so for most households a test and a fix are their own to order.
| Homes | Hanson County | South Dakota |
|---|---|---|
| Housing units | 1,289 | 402,364 |
| Detached houses | 92% | 67% |
| In buildings of 5 or more | 1% | 16% |
| Mobile homes | 4% | 8% |
| Built before 1960 | 52% | 29% |
| Built since 2000 | 20% | 28% |
| Middle year built | 1958 | 1979 |
| Owner-occupied | 89% | 69% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.