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 Hendricks County, Indiana
EPA puts Hendricks County in Zone 1, its highest radon zone, and high results are common there: 41.5% of the 1,170 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
41.5%
2.6 pts above IN
- Hendricks
- 41.5%
- Indiana
- 38.9%
1,170 tests, 2008 to 2017
Median result
3.2pCi/L
Below action level
- Hendricks
- 3.2 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
1,170
12th of 69 by tests
- Hendricks
- 1,170
- St. Joseph
- 7,346
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 Indiana
40 of 69
Middle half
- Hendricks
- 41.5%
- Miami
- 63.3%
By share, of 69 with 30+ tests
Read a result for Hendricks County
Starts at Hendricks County's median, 3.2 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 3.2 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. Hendricks County's median reported result, 2008 to 2017.
The data
Hendricks County, At a glance
Hendricks County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Hendricks 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 Hendricks County, 2008 to 2017, laboratory
Under 2 pCi/L: 34%2 to 4 pCi/L: 24%4 pCi/L and above: 42%
Of 1,170 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 400 | 34.2% |
| 2 to 4 pCi/L | 284 | 24.3% |
| 4 pCi/L and above | 486 | 41.5% |
What these figures count
These are the 1,170 tests reported to CDC for Hendricks 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).
Hendricks County, Compared
Hendricks County radon figures, compared
Calculated by Radon411In Hendricks County, about 4 in 10 reported tests over the 2008 to 2017 laboratory totals (486 of 1,170) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 5.8 points higher. Across 92 Indiana counties pooled together, 38.9% of tests reached that level, so Hendricks County runs 2.6 points above its state.
Of 5 neighbours with a figure, 1 reported a larger share at or above 4 pCi/L and 4 a smaller one; the spread is 34.5% (Putnam County) to 44.2% (Morgan County). By share, Hendricks County is 40th of 69 Indiana counties with 30 or more tests for the same period.
Half the tests came in under 3.2 pCi/L and half over it; the single highest reached 78.9 pCi/L. Below the action level, 400 tests (34.2%) came in under 2 pCi/L, against 32.8% statewide, and 284 tests (24.3%) fell between 2 and 4, against 28.3% statewide.
Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 41.5% share point the same way here. USGS geology rates 100% of the county's land high radon potential. CDC also counts 146 tests taken after mitigation in Hendricks County for the same period: tests in homes where a fix was already in.
CDC's ten-year totals for Hendricks County went from 948 tests (2005 to 2014) to 1,170 (2008 to 2017), the share going from 39.6% to 41.5%.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Hendricks County, Geology
The ground under Hendricks County
PredictedUSGS's geologic map puts all of Hendricks County's mapped land in one class: high radon potential. All of it lies in the area the map calls Huron-Erie Lobe, to which USGS gives a radon index of 13, in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Huron-Erie Lobe | Calcareous clayey and loamy glacial deposits derived from marine carbonate and clastic sedimentary rocks. | High | 13 | 100% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Hendricks County beside the ground around it
Hendricks County has more high-potential ground than Indiana as a whole: 100% of its land against 56.6%. Of the 5 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
Hendricks County, Local resources
Radon testing and mitigation in Hendricks County
- Indiana's radon programIndiana Department of HealthIndiana's radon program licenses or certifies radon professionals and offers free or discounted test kits, and answers questions about testing and mitigation in Indiana.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
To purchase a low-cost radon short term or long term test kit, please visit the American Lung Association
- Compare kits
- Professionals in Indiana17 professionals are listed in Indiana.
What Indiana's program says
- Phone
- 1-800-272-9723
- Licensing of radon professionals
According to the Indiana Radon Rule, 410 IAC 5.1, everyone who is serving Indiana by doing radon testing, analysis and mitigation (radon reduction) in residential structures must be certified by the Indiana State Department of Health.
What it means
Hendricks County, Questions
Questions about radon in Hendricks County
Are radon levels high in Hendricks County?
Over the 2008 to 2017 laboratory totals, 41.5% of the radon tests reported to CDC for Hendricks County, Indiana were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.2 pCi/L. Of 69 Indiana counties with 30 or more tests for the same period, 39 reported a higher share; pooled, the state comes to 38.9%.
Which counties border Hendricks County?
Hendricks County borders 5 counties: Boone County, Putnam County, Marion County, Morgan County and Montgomery County.
Products
Hendricks County, Products
Testing a home in Hendricks County
In Hendricks County, 41.5% of 1,170 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 38.9% pooled across Indiana. In Zone 1 the year-round level in Hendricks 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
EcoBlu plug-in digital radon monitor with a display
- C-NRPP 2024/25: Not included
- Plug-in
- Alarm
- Screen
Method: Ion chamber
First reading: Within 10 minutes
Short-term kit
RA400 short-term liquid scintillation radon test kit, lab fee included
- Lab fee included
Method: Liquid scintillation
In home: 48 to 96 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Hendricks County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Hendricks County
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Hendricks County, Bordering counties
Counties bordering Hendricks County
Calculated by Radon411- Radon levels in Morgan CountyEPA zone 2
44.2%at or above 4 pCi/L
Median 3.5 pCi/L · 226 tests · 2.7 points above Hendricks County
- Radon levels in Montgomery CountyEPA zone 1
41.4%at or above 4 pCi/L
Median 2.9 pCi/L · 152 tests · 0.1 points below Hendricks County
- Radon levels in Marion CountyEPA zone 1
40.1%at or above 4 pCi/L
Median 3.1 pCi/L · 3,668 tests · 1.4 points below Hendricks County
- Radon levels in Boone CountyEPA zone 1
39.7%at or above 4 pCi/L
Median 3.0 pCi/L · 614 tests · 1.8 points below Hendricks County
- Radon levels in Putnam CountyEPA zone 1
34.5%at or above 4 pCi/L
Median 2.7 pCi/L · 119 tests · 7.0 points below Hendricks County
Hendricks County, Cities and towns
Cities and towns in Hendricks County
Hendricks County is growing: the Census Bureau puts it at 193,510 residents on July 1, 2025, up 10.2% from 175,607 in 2020. That works out to 476 people per square mile of land. No town dominates: Plainfield, the largest, has 38,574 residents, 19.9% of the total. CDC's 1,170 reported tests for 2008 to 2017 work out to 6.0 per 1,000 residents (2025 estimate), close to Indiana's 6.2.
From Plainfield to Stilesville, CDC publishes no figure by town: each reads Hendricks County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Plainfield | 38,574 | +10.5% | 19.9% |
| Brownsburg | 34,089 | +16.8% | 17.6% |
| Avon | 25,350 | +16.0% | 13.1% |
| Danville | 13,415 | +25.5% | 6.9% |
| Pittsboro | 4,443 | +18.0% | 2.3% |
| Jamestownextends beyond Hendricks County | 960 | +2.0% | Counted whole |
| Clayton | 948 | +3.5% | 0.5% |
| Coatesville | 573 | +3.1% | 0.3% |
| Lizton | 505 | −0.2% | 0.3% |
| North Salem | 473 | +2.8% | 0.2% |
| Amo | 428 | +2.9% | 0.2% |
| Stilesville | 276 | +3.4% | 0.1% |
12 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 Hendricks County is counted whole, so it has no share.
Hendricks County, Homes
Homes in Hendricks County
Hendricks County is a place of houses on their own lots: 80% of its 68,433 homes are detached single-family houses, against 73% across Indiana. Much of Hendricks County is recent building: 44% of its homes have gone up since 2000 and the middle year built is 1997, against 1976 for Indiana. Owners live in 78% of the occupied homes (Indiana: 70%), so for most households a test and a fix are their own to order.
| Homes | Hendricks County | Indiana |
|---|---|---|
| Housing units | 68,433 | 2,953,344 |
| Detached houses | 80% | 73% |
| In buildings of 5 or more | 11% | 13% |
| Mobile homes | 2% | 4% |
| Built before 1960 | 12% | 32% |
| Built since 2000 | 44% | 21% |
| Middle year built | 1997 | 1976 |
| Owner-occupied | 78% | 70% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.