Long-term kit
RL116 long-term radon test kit
- Lab fee extra
Method: Alpha track
In home: 90 days to 12 months
Locations and reports
Radon Levels in Brown County, Kansas
EPA puts Brown County in Zone 1, its highest radon zone, and only 5 radon tests from it are on file with CDC (2022). Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Share at 4+ pCi/L
28.6%
3.2 pts below KS
- Brown
- 28.6%
- Kansas
- 31.8%
42 tests, 2021
Median result
2.0pCi/L
Below action level
- Brown
- 2.0 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2021
Tests reported
42
56th of 62 by tests
- Brown
- 42
- Johnson
- 25,860
Reported to CDC before any fix, 2021
EPA radon zone
Zone 1
Highest potential
- Zone 1
- 2
- 3
1 highest, 3 lowest
EPA predicts over 4 pCi/L indoors
Rank in Kansas
48 of 62
Lowest quarter
- Brown
- 28.6%
- Norton
- 93.8%
By share, of 62 with 30+ tests
Read a result for Brown County
Starts at Brown County's median, 2.0 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.0 pCi/L
Between 2 and 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is between 2 and 4 pCi/L. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. Brown County's median reported result, 2021.
The data
Brown County, At a glance
Brown County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Brown County in
USGS geologic potential: High across 92% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Brown County, 2022
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2016 | 68.0% |
| 2017 | 63.6% |
| 2018 | 53.6% |
| 2019 | 32.0% |
| 2020 | 23.7% |
| 2021 | 28.6% |
| 2022 | 60.0% |
2022: 60.0%. Across these years the share ran from 23.7% to 68.0%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
Only 5 tests were reported to CDC for Brown County over 2022, 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: 2022. Measured data period: 2016 to 2022 (every CDC figure on file).
Brown County, Compared
Brown County radon figures, compared
Calculated by Radon411Brown County's 42 reported tests in 2021 had a middle value of 2.0 pCi/L and a maximum of 11.6 pCi/L, and 28.6% reached 4 pCi/L. Kansas as a whole (96 Kansas counties, pooled) comes to 31.8%: 3.2 points higher than here.
The newest figure, in 2022, counts only 5 tests (60.0% at or above 4 pCi/L), too few to compare, so this reading uses the 42-test figure.
Among its state's counties it ranks 48th of 62 Kansas counties with 30 or more tests for the same period. Statewide for the same period, Norton County reported the highest share (93.8%) and Doniphan County the lowest (0.0%).
Below the action level, 18 tests (42.9%) came in under 2 pCi/L, against 45.3% statewide, and 12 tests (28.6%) fell between 2 and 4, against 22.9% statewide. The busiest year on file was 2021, with 42 tests reported; the quietest, 2022, had 5.
EPA's 1993 zone map puts Brown County in Zone 1, a predicted county average above 4 pCi/L. USGS geology rates 92% of the county's land high radon potential.
Next door, the shares run from 0.0% in Doniphan County to 53.8% in Nemaha County, with Jackson County and Doniphan County below Brown County.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Brown County, Geology
The ground under Brown County
PredictedMost of the ground under Brown County is one class on USGS's geologic map: 92.5% of its land is high radon potential, with 7.5% moderate. The map puts 92.5% of Brown County in the area it calls Glacial Drift and 7.5% in Glaciated Area. USGS gives the first a radon index of 12, in the high band (12 to 17), and the second 9, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Glacial Drift | Glacial drift and loess of varying thickness, largely locally derived from underlying and nearby Paleozoic sedimentary rocks. | High | 12 | 92.5% |
| Glaciated Area | Glacial till underlain by Pennsylvanian and Permian marine and nonmarine sedimentary shale, sandstone, limestone, coal. | Moderate | 9 | 7.5% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Brown County beside the ground around it
Brown County has more high-potential ground than Kansas as a whole: 92.5% of its land against 59.9%. Of the 5 counties that border it, 3 have more high-potential ground, Doniphan County the most at 100%.
The map rates the ground, not the air in any home.
Local help
Brown County, Local resources
Radon testing and mitigation in Brown County
- Kansas Radon ProgramKansas Radon Program answers questions about testing, mitigation and the rules in Kansas.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsAsk the program whether it has free or discounted kits, or compare kits you can buy.
- Compare kits
- Professionals in Kansas178 professionals are listed in Kansas.
What Kansas's program says
- Phone
- (800) 693-5343
What it means
Brown County, Questions
Questions about radon in Brown County
Are radon levels high in Brown County?
In 2022, 60.0% of the radon tests reported to CDC for Brown County, Kansas were at or above 4 pCi/L, and the median reported pre-mitigation result was 5.0 pCi/L. Of 62 Kansas counties with 30 or more tests for the same period, 47 reported a higher share; pooled, the state comes to 31.8%.
Which counties border Brown County?
Brown County borders 5 counties: Atchison County, KS, Richardson County, NE, Nemaha County, KS, Doniphan County, KS and Jackson County, KS.
Products
Brown County, Products
Testing a home in Brown County
In Brown County, 28.6% of 42 tests reported to CDC in 2021 reached 4 pCi/L, against 31.8% pooled across Kansas. In Zone 1 the year-round level in Brown 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-3699 radon monitor with a 2.1-inch touchscreen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
First reading: Within 1 hour
Short-term kitempowerDX
Standard Radon Test short-term mail-in radon test kit
- Lab fee included
Method: Passive sampler
In home: 48 to 96 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Brown County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Brown County
Explore
Brown County, Bordering counties
Counties bordering Brown County
Calculated by Radon411- Radon levels in Nemaha County, KSEPA zone 1
53.8%at or above 4 pCi/L
Median 4.8 pCi/L · 39 tests · 25.2 points above Brown County
- Radon levels in Atchison County, KSEPA zone 1
44.4%at or above 4 pCi/L
Median 3.5 pCi/L · 162 tests · 15.8 points above Brown County
- Radon levels in Richardson County, NEEPA zone 1
36.6%at or above 4 pCi/L
Median 2.9 pCi/L · 402 tests · 8.0 points above Brown County
- Radon levels in Jackson County, KSEPA zone 1
15.8%at or above 4 pCi/L
Median 1.6 pCi/L · 57 tests · 12.8 points below Brown County
- Radon levels in Doniphan County, KSEPA zone 2
0.0%at or above 4 pCi/L
Median 1.7 pCi/L · 33 tests · 28.6 points below Brown County
Brown County, Cities and towns
Cities and towns in Brown County
About 9,104 people live in Brown County by the Census Bureau's estimate for July 1, 2025, 376 fewer than in 2020 (−4.0%). That works out to 16 people per square mile of land. Its largest town, Hiawatha, has 3,124 residents, 34.3% of the total. Reported testing is thin here: 42 tests over 2021, or 4.6 for every 1,000 residents (2025 estimate), where Kansas as a whole comes to 23.5.
From Hiawatha to Willis, CDC publishes no figure by town: each reads Brown County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Hiawatha | 3,124 | −3.9% | 34.3% |
| Sabethaextends beyond Brown County | 2,474 | −2.6% | Counted whole |
| Horton | 1,460 | −4.2% | 16.0% |
| Everest | 248 | −4.2% | 2.7% |
| Fairview | 233 | −2.5% | 2.6% |
| Morrill | 209 | −4.6% | 2.3% |
| Robinson | 173 | −4.9% | 1.9% |
| Reserve | 68 | −4.2% | 0.7% |
| Powhattan | 64 | −4.5% | 0.7% |
| Hamlin | 36 | −2.7% | 0.4% |
| Willis | 28 | −3.4% | 0.3% |
11 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). A place that extends beyond Brown County is counted whole, so it has no share.
Brown County, Homes
Homes in Brown County
Brown County is a place of houses on their own lots: 85% of its 4,489 homes are detached single-family houses, against 72% across Kansas. The homes are older than Kansas' as a whole: half were built before 1962 (1975 for Kansas), and 48% date from before 1960. Owners live in 75% of the occupied homes (Kansas: 67%), so for most households a test and a fix are their own to order.
| Homes | Brown County | Kansas |
|---|---|---|
| Housing units | 4,489 | 1,285,221 |
| Detached houses | 85% | 72% |
| In buildings of 5 or more | 4% | 13% |
| Mobile homes | 2% | 4% |
| Built before 1960 | 48% | 33% |
| Built since 2000 | 12% | 20% |
| Middle year built | 1962 | 1975 |
| Owner-occupied | 75% | 67% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.