Short-term kit
RA100 short-term liquid scintillation radon test kit
- Lab fee extra
Method: Liquid scintillation
In home: 48 to 96 hours
Locations and reports
Radon Levels in Sullivan County, Indiana
EPA puts Sullivan County in Zone 2, its middle 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
44.0%
Vigo County
- Vigo
- 44.0%
- Crawford
- 19.3%
5 of 6 neighbours have 30+ tests, 2008 to 2017
Nearest county
44.0%
Vigo County, 24 miles
- Vigo
- 44.0%
- Indiana
- 38.9%
Share at 4+ pCi/L, 455 tests, 2008 to 2017
Ground above low
100.0%
Level with Indiana
- Sullivan
- 100.0%
- Indiana
- 100.0%
Share of land USGS rates moderate or high potential
Tests reported
14
Too few for a share
- Sullivan
- 14
- Needed
- 30
2007 to 2016, laboratory
EPA radon zone
Zone 2
Moderate potential
- 1
- Zone 2
- 3
1 highest, 3 lowest
EPA predicts 2 to 4 pCi/L indoors
Read a result for Sullivan 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
Sullivan County, At a glance
Sullivan County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Sullivan County is a
USGS geologic potential: Moderate across 100% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Sullivan County, 2008 to 2017, laboratory
CDC holds 13 reported tests for Sullivan County over the 2008 to 2017 laboratory totals, with a median of 3.1 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Sullivan County beside the counties around it is how this page reads it.
What these figures count
Only 13 tests were reported to CDC for Sullivan 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).
Sullivan County, Compared
Sullivan County radon figures, compared
Calculated by Radon411CDC's largest figure for Sullivan County rests on 14 tests over the 2007 to 2016 laboratory totals, 6 of them at or above 4 pCi/L, so each test moves its share by 7.1 points and no rank or comparison is drawn from it. Results reached as high as 8.2 pCi/L, with a middle value of 3.0 pCi/L.
Of the counties bordering it, 5 have a figure over the 2008 to 2017 laboratory totals: Vigo County reported the largest share at or above 4 pCi/L, 44.0%, and Crawford County, IL the smallest, 19.3%, with Knox County at 43.1%, Greene County at 32.7% and Clark County, IL at 22.1% between. Farther out, Daviess County (32 miles away) at 34.5%, Owen County (35 miles away) at 39.1% and Monroe County (48 miles away) at 34.2% 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 Sullivan County in Zone 2, its middle label: a predicted county average between 2 and 4 pCi/L. USGS geology rates 100% of the county's land moderate radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Sullivan County, Geology
The ground under Sullivan County
PredictedUSGS's geologic map puts all of Sullivan County's mapped land in one class: moderate radon potential. 99.3% of it lies in the area the map calls Wabash Lowland, to which USGS gives a radon index of 10, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Wabash Lowland | Loess, pre-Wisconsinan glacial deposits, Pennsylvanian shale, sandstone, and carbonate bedrock. | Moderate | 10 | 99.3% |
| Southern Central Lowland Province | Illinoian glacial deposits, sandstone, and gray shale. | Moderate | 9 | 0.7% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Sullivan County beside the ground around it
Across Indiana 56.6% of the land is rated high; none of Sullivan County's is. Of the 6 counties that border it, 2 have more high-potential ground, Vigo County the most at 13.8%.
The map rates the ground, not the air in any home.
Local help
Sullivan County, Local resources
Radon testing and mitigation in Sullivan 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
Sullivan County, Questions
Questions about radon in Sullivan County
Are radon levels high in Sullivan County?
Over the 2008 to 2017 laboratory totals, 46.2% of the radon tests reported to CDC for Sullivan County, Indiana were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.1 pCi/L. Of the counties bordering it, 5 have a figure over the 2008 to 2017 laboratory totals: Vigo County reported the largest share at or above 4 pCi/L, 44.0%, and Crawford County, IL the smallest, 19.3%, with Knox County at 43.1%, Greene County at 32.7% and Clark County, IL at 22.1% between.
Which counties border Sullivan County?
Sullivan County borders 6 counties: Crawford County, IL, Vigo County, IN, Greene County, IN, Clark County, IL, Clay County, IN and Knox County, IN.
Products
Sullivan County, Products
Testing a home in Sullivan County
No CDC figure names Sullivan County; the nearest county with one, Vigo County (24 miles away), reported 44.0% 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 2 a short-term kit (2 to 90 days) is the quick first check in Sullivan County; a long-term test tells the year-round average.
Test kits and monitors3
See every kit and monitor
Long-term kit
RL116 long-term radon test kit
- Lab fee extra
Method: Alpha track
In home: 90 days to 12 months
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
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Sullivan County, Bordering counties
Counties bordering Sullivan County
Calculated by Radon411- Radon levels in Vigo County, INEPA zone 2
44.0%at or above 4 pCi/L
Median 3.6 pCi/L · 455 tests
- Radon levels in Knox County, INEPA zone 2
43.1%at or above 4 pCi/L
Median 3.4 pCi/L · 58 tests
- Radon levels in Greene County, INEPA zone 2
32.7%at or above 4 pCi/L
Median 3.0 pCi/L · 49 tests
- Radon levels in Clay County, INEPA zone 2
26.1%at or above 4 pCi/L
Median 2.9 pCi/L · 23 tests
- Radon levels in Clark County, ILEPA zone 2
22.1%at or above 4 pCi/L
Median 2.0 pCi/L · 77 tests
- Radon levels in Crawford County, ILEPA zone 2
19.3%at or above 4 pCi/L
Median 1.8 pCi/L · 181 tests
Sullivan County, Cities and towns
Cities and towns in Sullivan County
Sullivan County's population has barely moved since 2020: 20,831 residents on July 1, 2025 against 20,820 then, by the Census Bureau's estimates. That works out to 47 people per square mile of land. Its largest town, Sullivan, has 4,229 residents, 20.3% of the total. Together its 7 incorporated places hold 41.7% of those residents; the other 58.3% live outside any of them. Reported testing is thin here: 14 tests over 2007 to 2016, or 0.7 for every 1,000 residents (2025 estimate), where Indiana as a whole comes to 5.7.
From Sullivan to Merom, CDC publishes no figure by town: each reads Sullivan County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Sullivan | 4,229 | −0.6% | 20.3% |
| Shelburn | 1,103 | +0.6% | 5.3% |
| Farmersburg | 1,067 | +0.3% | 5.1% |
| Dugger | 797 | +0.1% | 3.8% |
| Hymera | 665 | +1.4% | 3.2% |
| Carlisle | 621 | −0.2% | 3.0% |
| Merom | 210 | +1.0% | 1.0% |
7 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).
Sullivan County, Homes
Homes in Sullivan County
Sullivan County is a place of houses on their own lots: 77% of its 8,798 homes are detached single-family houses, against 73% across Indiana. Half of its homes were built before 1972, close to Indiana's 1976: 38% date from before 1960 and 18% from 2000 or later. Owners live in 76% of the occupied homes (Indiana: 70%), so for most households a test and a fix are their own to order.
| Homes | Sullivan County | Indiana |
|---|---|---|
| Housing units | 8,798 | 2,953,344 |
| Detached houses | 77% | 73% |
| In buildings of 5 or more | 5% | 13% |
| Mobile homes | 12% | 4% |
| Built before 1960 | 38% | 32% |
| Built since 2000 | 18% | 21% |
| Middle year built | 1972 | 1976 |
| Owner-occupied | 76% | 70% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.