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
Radon Levels in Hamlin County, South Dakota
EPA puts Hamlin County in Zone 1, its highest radon zone, and only 13 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
68.8%
Kingsbury County
- Kingsbury
- 68.8%
- Codington
- 65.3%
3 of 5 neighbours have 30+ tests, 2006 to 2015
Nearest county
65.3%
Codington County, 21 miles
- Codington
- 65.3%
- SD
- 58.8%
Share at 4+ pCi/L, 72 tests, 2006 to 2015
Ground above low
100.0%
1.0 pts above SD
- Hamlin
- 100.0%
- SD
- 99.0%
Share of land USGS rates moderate or high potential
Tests reported
17
Too few for a share
- Hamlin
- 17
- Needed
- 30
2006 to 2015, laboratory
EPA radon zone
Zone 1
Highest potential
- Zone 1
- 2
- 3
1 highest, 3 lowest
EPA predicts over 4 pCi/L indoors
Read a result for Hamlin 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
Hamlin County, At a glance
Hamlin County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Hamlin County in
USGS geologic potential: High across 100% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Hamlin County, 2008 to 2017, laboratory
CDC holds 13 reported tests for Hamlin County over the 2008 to 2017 laboratory totals, with a median of 6.3 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Hamlin County beside the counties around it is how this page reads it.
What these figures count
Only 13 tests were reported to CDC for Hamlin 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).
Hamlin County, Compared
Hamlin County radon figures, compared
Calculated by Radon411CDC's largest figure for Hamlin County rests on 17 tests over the 2006 to 2015 laboratory totals, 12 of them at or above 4 pCi/L, so each test moves its share by 5.9 points and no rank or comparison is drawn from it. Results reached as high as 14.6 pCi/L, with a middle value of 4.8 pCi/L.
Of the counties bordering it, 3 have a figure over the 2006 to 2015 laboratory totals: Kingsbury County reported the largest share at or above 4 pCi/L, 68.8%, and Codington County the smallest, 65.3%, with Brookings County at 67.4% between. Farther out, Grant County (40 miles away) at 64.6%, Lake County (45 miles away) at 73.7% and Beadle County (57 miles away) at 63.0% 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 Hamlin 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.
Hamlin County, Geology
The ground under Hamlin County
PredictedUSGS's geologic map puts all of Hamlin County's mapped land in one class: high radon potential. The map puts 54.6% of Hamlin County in the area it calls Missouri Coteau/James River Lowland/Coteau des Prairies and 45.4% in Loess-Covered Drift Plains. USGS gives the first a radon index of 14 and the second 13, both 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 | 54.6% |
| Loess-Covered Drift Plains | Pre-Illinoian and Illinoian glacial deposits, and loess. | High | 13 | 45.4% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Hamlin County beside the ground around it
Hamlin 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; Brookings County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Hamlin County, Local resources
Radon testing and mitigation in Hamlin 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
Hamlin County, Questions
Questions about radon in Hamlin County
Are radon levels high in Hamlin County?
Over the 2008 to 2017 laboratory totals, 76.9% of the radon tests reported to CDC for Hamlin County, South Dakota were at or above 4 pCi/L, and the median reported pre-mitigation result was 6.3 pCi/L. Of the counties bordering it, 3 have a figure over the 2006 to 2015 laboratory totals: Kingsbury County reported the largest share at or above 4 pCi/L, 68.8%, and Codington County the smallest, 65.3%, with Brookings County at 67.4% between.
Which counties border Hamlin County?
Hamlin County borders 5 counties: Deuel County, Kingsbury County, Codington County, Brookings County and Clark County.
Products
Hamlin County, Products
Testing a home in Hamlin County
No CDC figure names Hamlin County; the nearest county with one, Codington County (21 miles away), reported 65.3% 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 Hamlin 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 monitors3
See every kit and monitor
MonitorAEGTEST
HOUND-1085 palm-sized rechargeable radon detector
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
First reading: Within 6 hours
Short-term kit
Radon Short Term Test Kit short-term charcoal radon test kit, lab fee included
- Lab fee included
Method: Charcoal
In home: 2 to 7 days
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Hamlin County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Hamlin County
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Hamlin County, Bordering counties
Counties bordering Hamlin County
Calculated by Radon411- Radon levels in Deuel CountyEPA zone 1
70.4%at or above 4 pCi/L
Median 5.9 pCi/L · 27 tests
- Radon levels in Kingsbury CountyEPA zone 1
68.8%at or above 4 pCi/L
Median 8.4 pCi/L · 32 tests
- Radon levels in Brookings CountyEPA zone 1
67.4%at or above 4 pCi/L
Median 6.4 pCi/L · 328 tests
- Radon levels in Clark CountyEPA zone 1
66.7%at or above 4 pCi/L
Median 6.2 pCi/L · 3 tests
- Radon levels in Codington CountyEPA zone 1
65.3%at or above 4 pCi/L
Median 6.0 pCi/L · 72 tests
Hamlin County, Cities and towns
Cities and towns in Hamlin County
Hamlin County is growing: the Census Bureau puts it at 6,900 residents on July 1, 2025, up 11.8% from 6,169 in 2020. That works out to 14 people per square mile of land. No town dominates: Estelline, the largest, has 792 residents, 11.5% of the total. Together its 6 incorporated places hold 47.2% of those residents; the other 52.8% live outside any of them. Reported testing is thin here: 17 tests over 2006 to 2015, or 2.5 for every 1,000 residents (2025 estimate), where South Dakota as a whole comes to 5.2.
From Estelline to Hazel, CDC publishes no figure by town: each reads Hamlin County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Estelline | 792 | +6.3% | 11.5% |
| Castlewood | 739 | +5.6% | 10.7% |
| Lake Norden | 651 | +16.3% | 9.4% |
| Bryant | 488 | +4.3% | 7.1% |
| Hayti | 482 | +25.8% | 7.0% |
| Hazel | 105 | +1.9% | 1.5% |
6 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).
Hamlin County, Homes
Homes in Hamlin County
Hamlin County is a place of houses on their own lots: 89% of its 2,831 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 1970 (1979 for South Dakota), and 43% date from before 1960. Owners live in 82% of the occupied homes (South Dakota: 69%), so for most households a test and a fix are their own to order.
| Homes | Hamlin County | South Dakota |
|---|---|---|
| Housing units | 2,831 | 402,364 |
| Detached houses | 89% | 67% |
| In buildings of 5 or more | 3% | 16% |
| Mobile homes | 4% | 8% |
| Built before 1960 | 43% | 29% |
| Built since 2000 | 25% | 28% |
| Middle year built | 1970 | 1979 |
| Owner-occupied | 82% | 69% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.