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 Randolph County, Indiana
EPA puts Randolph County in Zone 1, its highest radon zone, and only 28 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
63.7%
Darke County
- Darke
- 63.7%
- Henry
- 50.5%
4 of 5 neighbours have 30+ tests, 2008 to 2017
Nearest county
56.4%
Wayne County, 20 miles
- Wayne
- 56.4%
- Indiana
- 38.9%
Share at 4+ pCi/L, 140 tests, 2008 to 2017
Ground above low
100.0%
Level with Indiana
- Randolph
- 100.0%
- Indiana
- 100.0%
Share of land USGS rates moderate or high potential
Tests reported
28
Too few for a share
- Randolph
- 28
- Needed
- 30
2008 to 2017, 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 Randolph 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
Randolph County, At a glance
Randolph County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Randolph 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 Randolph County, 2008 to 2017, laboratory
CDC holds 28 reported tests for Randolph County over the 2008 to 2017 laboratory totals, with a median of 4.5 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Randolph County beside the counties around it is how this page reads it.
What these figures count
Only 28 tests were reported to CDC for Randolph 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).
Randolph County, Compared
Randolph County radon figures, compared
Calculated by Radon411CDC's largest figure for Randolph County rests on 28 tests over the 2008 to 2017 laboratory totals, 17 of them at or above 4 pCi/L, so each test moves its share by 3.6 points and no rank or comparison is drawn from it. Results reached as high as 24.2 pCi/L, with a middle value of 4.5 pCi/L.
Of the counties bordering it, 4 have a figure over the 2008 to 2017 laboratory totals: Darke County, OH reported the largest share at or above 4 pCi/L, 63.7%, and Henry County the smallest, 50.5%, with Wayne County at 56.4% and Delaware County at 55.1% between. Farther out, Madison County (37 miles away) at 49.0%, Adams County (41 miles away) at 48.5% and Wells County (41 miles away) at 47.8% have figures too. Pooled across 92 Indiana counties, 38.9% of reported tests reached that level; across every county in the country with a figure, 35.7%.
Statewide for the same period, Miami County reported the highest share (63.3%) and Jasper County the lowest (14.1%). EPA's 1993 map puts Randolph 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.
Randolph County, Geology
The ground under Randolph County
PredictedUSGS's geologic map puts all of Randolph County's mapped land in one class: high radon potential. 99.5% 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 | 99.5% |
| Till Plains | Glacial deposits underlain by Ordovician through Devonian limestone and shale. | High | 14 | 0.5% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Randolph County beside the ground around it
Randolph 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; Darke County, OH comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Randolph County, Local resources
Radon testing and mitigation in Randolph 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
Randolph County, Questions
Questions about radon in Randolph County
Are radon levels high in Randolph County?
Over the 2008 to 2017 laboratory totals, 60.7% of the radon tests reported to CDC for Randolph County, Indiana were at or above 4 pCi/L, and the median reported pre-mitigation result was 4.5 pCi/L. Of the counties bordering it, 4 have a figure over the 2008 to 2017 laboratory totals: Darke County, OH reported the largest share at or above 4 pCi/L, 63.7%, and Henry County the smallest, 50.5%, with Wayne County at 56.4% and Delaware County at 55.1% between.
Which counties border Randolph County?
Randolph County borders 5 counties: Jay County, IN, Delaware County, IN, Darke County, OH, Wayne County, IN and Henry County, IN.
Products
Randolph County, Products
Testing a home in Randolph County
No CDC figure names Randolph County; the nearest county with one, Wayne County (20 miles away), reported 56.4% of its tests at or above 4 pCi/L over the 2008 to 2017 laboratory totals, the only reading nearby until a test of this home. In Zone 1 the year-round level in Randolph 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-1011 rechargeable radon detector with a screen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
First reading: Within 6 hours
Short-term kit
Air Chek Short-Term radon test kit you hang, lab fee included
- Lab fee included
In home: 72 to 168 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Randolph County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Randolph County
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Randolph County, Bordering counties
Counties bordering Randolph County
Calculated by Radon411- Radon levels in Darke County, OHEPA zone 1
63.7%at or above 4 pCi/L
Median 5.6 pCi/L · 270 tests
- Radon levels in Wayne County, INEPA zone 1
56.4%at or above 4 pCi/L
Median 4.5 pCi/L · 140 tests
- Radon levels in Delaware County, INEPA zone 1
55.1%at or above 4 pCi/L
Median 4.2 pCi/L · 187 tests
- Radon levels in Henry County, INEPA zone 1
50.5%at or above 4 pCi/L
Median 4.0 pCi/L · 95 tests
- Radon levels in Jay County, INEPA zone 1
44.4%at or above 4 pCi/L
Median 2.7 pCi/L · 9 tests
Randolph County, Cities and towns
Cities and towns in Randolph County
Randolph County's population has barely moved since 2020: 24,438 residents on July 1, 2025 against 24,414 then, by the Census Bureau's estimates. That works out to 54 people per square mile of land. No town dominates: Winchester, the largest, has 4,817 residents, 19.7% of the total. Reported testing is thin here: 28 tests over 2008 to 2017, or 1.1 for every 1,000 residents (2025 estimate), where Indiana as a whole comes to 6.2.
From Winchester to Modoc, CDC publishes no figure by town: each reads Randolph County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Winchester | 4,817 | −0.1% | 19.7% |
| Union City | 3,450 | +0.2% | 14.1% |
| Albanyextends beyond Randolph County | 2,269 | −0.4% | Counted whole |
| Parker City | 1,279 | −0.5% | 5.2% |
| Farmland | 1,265 | +0.2% | 5.2% |
| Lynn | 950 | Level | 3.9% |
| Ridgeville | 694 | +1.0% | 2.8% |
| Saratoga | 229 | −0.4% | 0.9% |
| Losantville | 220 | Level | 0.9% |
| Modoc | 159 | Level | 0.7% |
10 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 Randolph County is counted whole, so it has no share.
Randolph County, Homes
Homes in Randolph County
Randolph County is a place of houses on their own lots: 80% of its 11,407 homes are detached single-family houses, against 73% across Indiana. The homes are older than Indiana's as a whole: half were built before 1957 (1976 for Indiana), and 52% date from before 1960. Owners live in 77% of the occupied homes (Indiana: 70%), so for most households a test and a fix are their own to order.
| Homes | Randolph County | Indiana |
|---|---|---|
| Housing units | 11,407 | 2,953,344 |
| Detached houses | 80% | 73% |
| In buildings of 5 or more | 4% | 13% |
| Mobile homes | 8% | 4% |
| Built before 1960 | 52% | 32% |
| Built since 2000 | 10% | 21% |
| Middle year built | 1957 | 1976 |
| Owner-occupied | 77% | 70% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.