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 Greene County, Iowa
EPA puts Greene County in Zone 1, its highest radon zone, and high results are common there: 71.3% of the 143 radon tests reported to CDC (2008 to 2017, laboratory totals) came back at or above 4 pCi/L. Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Share at 4+ pCi/L
71.3%
12.8 pts above IA
- Greene
- 71.3%
- Iowa
- 58.5%
143 tests, 2008 to 2017
Median result
6.2pCi/L
Action level reached
- Greene
- 6.2 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
143
85th of 99 by tests
- Greene
- 143
- Polk
- 10,945
Reported to CDC before any fix, 2008 to 2017
EPA radon zone
Zone 1
Highest potential
- Zone 1
- 2
- 3
1 highest, 3 lowest
EPA predicts over 4 pCi/L indoors
Rank in Iowa
22 of 99
Top quarter
- Greene
- 71.3%
- Sioux
- 84.2%
By share, of 99 with 30+ tests
Read a result for Greene County
Starts at Greene County's median, 6.2 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 6.2 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. Greene County's median reported result, 2008 to 2017.
The data
Greene County, At a glance
Greene County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Greene 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 Greene County, 2008 to 2017, laboratory
Under 2 pCi/L: 15%2 to 4 pCi/L: 14%4 pCi/L and above: 71%
Of 143 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 21 | 14.7% |
| 2 to 4 pCi/L | 20 | 14.0% |
| 4 pCi/L and above | 102 | 71.3% |
What these figures count
These are the 143 tests reported to CDC for Greene County over 2008 to 2017 (laboratory totals), many from homes being sold or already suspected of a problem: they describe the county's reported tests, not this house.
Measured: CDC tracking data. Figure above: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).
Greene County, Compared
Greene County radon figures, compared
Calculated by Radon411More than half: 71.3% of the 143 radon tests reported to CDC for Greene County over the 2008 to 2017 laboratory totals read at least 4 pCi/L. That places it 22nd of 99 Iowa counties with 30 or more tests for the same period. That is 12.8 points above the 58.5% pooled from 99 Iowa counties.
The median result, 6.2 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 79.5 pCi/L. The rest split 14.7% under 2 pCi/L and 14.0% from 2 to 4 (Iowa: 21.8% and 19.7%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 71.3% share point the same way here.
1 of its 6 bordering counties with figures ran higher, led by Carroll County at 77.6%; Dallas County reported 58.5%. Statewide for the same period, Sioux County reported the highest share (84.2%) and Decatur County the lowest (25.9%).
CDC's ten-year totals for Greene County went from 219 tests (2005 to 2014) to 143 (2008 to 2017), the share going from 68.5% to 71.3%.
Nationally, every county with a figure for the same period pools to 35.7%; Greene County sits 35.6 points above it.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Greene County, Geology
The ground under Greene County
PredictedUSGS's geologic map puts all of Greene County's mapped land in one class: high radon potential. All of it lies in the area the map calls Des Moines Lobe, to which USGS gives a radon index of 12, in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Des Moines Lobe | Calcareous loamy till derived from shale, limestone, dolomite, sandstone. | High | 12 | 100% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Greene County beside the ground around it
On high-potential ground Greene County is close to Iowa as a whole: 100% of its land against 98.8%. Of the 6 counties that border it, none has as large a share of high-potential ground; Boone County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Greene County, Local resources
Radon testing and mitigation in Greene County
- Iowa HHS Radon ProgramIowa HHS Radon Program, run by Iowa Department of Health and Human Services, licenses or certifies radon professionals, offers free or discounted test kits and states the rule for disclosing radon when a home is sold, and answers questions about testing and mitigation in Iowa.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
You can reach the Hotline by calling 1-800-383-5992 to order low-cost radon test kits and find answers to your radon questions.
- Compare kits
- Professionals in Iowa185 professionals are listed in Iowa.
What Iowa's program says
- Phone
- (515) 281-4928
- Licensing of radon professionals
Iowa’s radon program approves applications for persons who wish to become certified to perform radon testing or credentialed to perform mitigation and laboratories that provide radon testing devices and analytical services.
- Disclosure when a home is sold or rented
However, per Iowa Code chapters 543B.9 and 543B.18 and Iowa Administrative Code 193E Chapter 14 administered by the Iowa Real Estate Commission, a seller must disclose any known tests for the presence of radon and if yes, provide the date of last report and the result(s).
What it means
Greene County, Questions
Questions about radon in Greene County
Are radon levels high in Greene County?
Over the 2008 to 2017 laboratory totals, 71.3% of the radon tests reported to CDC for Greene County, Iowa were at or above 4 pCi/L, and the median reported pre-mitigation result was 6.2 pCi/L. Of 99 Iowa counties with 30 or more tests for the same period, 21 reported a higher share; pooled, the state comes to 58.5%.
Which counties border Greene County?
Greene County borders 6 counties: Guthrie County, Carroll County, Boone County, Calhoun County, Webster County and Dallas County.
Products
Greene County, Products
Testing a home in Greene County
In Greene County, 71.3% of 143 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 58.5% pooled across Iowa. In Zone 1 the year-round level in Greene 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
Monitor
RadonEye RD200 plug-in continuous radon monitor
- C-NRPP 2024/25: Approved
- Plug-in
- Bluetooth
- Alarm
- Screen, app
Method: Ion chamber
First reading: Within 10 minutes
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
Greene County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Greene County
Explore
Greene County, Bordering counties
Counties bordering Greene County
Calculated by Radon411- Radon levels in Carroll CountyEPA zone 1
77.6%at or above 4 pCi/L
Median 7.8 pCi/L · 594 tests · 6.3 points above Greene County
- Radon levels in Guthrie CountyEPA zone 1
70.8%at or above 4 pCi/L
Median 6.9 pCi/L · 257 tests · 0.5 points below Greene County
- Radon levels in Calhoun CountyEPA zone 1
69.8%at or above 4 pCi/L
Median 6.1 pCi/L · 507 tests · 1.5 points below Greene County
- Radon levels in Webster CountyEPA zone 1
69.4%at or above 4 pCi/L
Median 6.5 pCi/L · 1,189 tests · 1.9 points below Greene County
- Radon levels in Boone CountyEPA zone 1
68.7%at or above 4 pCi/L
Median 6.0 pCi/L · 1,134 tests · 2.6 points below Greene County
- Radon levels in Dallas CountyEPA zone 1
58.5%at or above 4 pCi/L
Median 4.9 pCi/L · 2,352 tests · 12.8 points below Greene County
Greene County, Cities and towns
Cities and towns in Greene County
About 8,658 people live in Greene County by the Census Bureau's estimate for July 1, 2025, 91 fewer than in 2020 (−1.0%). That works out to 15 people per square mile of land. Its largest town, Jefferson, has 4,150 residents, 47.9% of the total. Reported testing is thin here: 143 tests over 2008 to 2017, or 16.5 for every 1,000 residents (2025 estimate), where Iowa as a whole comes to 29.4.
From Jefferson to Dana, CDC publishes no figure by town: each reads Greene County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Jefferson | 4,150 | −0.7% | 47.9% |
| Grand Junction | 715 | −0.8% | 8.3% |
| Scranton | 493 | −2.6% | 5.7% |
| Churdan | 359 | −1.4% | 4.1% |
| Paton | 217 | −1.4% | 2.5% |
| Rippey | 216 | −1.8% | 2.5% |
| Ralstonextends beyond Greene County | 75 | −3.8% | Counted whole |
| Dana | 34 | Level | 0.4% |
8 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 Greene County is counted whole, so it has no share.
Greene County, Homes
Homes in Greene County
Greene County is a place of houses on their own lots: 83% of its 4,316 homes are detached single-family houses, against 72% across Iowa. The homes are older than Iowa's as a whole: half were built before 1954 (1971 for Iowa), and 58% date from before 1960. 74% of occupied homes are lived in by their owner (Iowa: 72%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Greene County | Iowa |
|---|---|---|
| Housing units | 4,316 | 1,427,175 |
| Detached houses | 83% | 72% |
| In buildings of 5 or more | 6% | 14% |
| Mobile homes | 3% | 3% |
| Built before 1960 | 58% | 39% |
| Built since 2000 | 10% | 21% |
| Middle year built | 1954 | 1971 |
| Owner-occupied | 74% | 72% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.