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 Warren County, Indiana
EPA puts Warren County in Zone 1, its highest radon zone, and only 27 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
Share at 4+ pCi/L
35.3%
4.3 pts below IN
- Warren
- 35.3%
- Indiana
- 39.6%
34 tests, 2006 to 2015
Median result
3.5pCi/L
Below action level
- Warren
- 3.5 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2006 to 2015
Tests reported
34
68th of 69 by tests
- Warren
- 34
- St. Joseph
- 5,182
Reported to CDC before any fix, 2006 to 2015
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
57 of 69
Lowest quarter
- Warren
- 35.3%
- Harrison
- 67.2%
By share, of 69 with 30+ tests
Read a result for Warren County
Starts at Warren County's median, 3.5 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 3.5 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. Warren County's median reported result, 2006 to 2015.
The data
Warren County, At a glance
Warren County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Warren 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 Warren County, 2008 to 2017, laboratory
CDC holds 27 reported tests for Warren County over the 2008 to 2017 laboratory totals, with a median of 3.5 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Warren County beside the counties around it is how this page reads it.
What these figures count
Only 27 tests were reported to CDC for Warren 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).
Warren County, Compared
Warren County radon figures, compared
Calculated by Radon411In Warren County, about 4 in 10 reported tests over the 2006 to 2015 laboratory totals (12 of 34) were at or above EPA's action level. Against the national pool of 36.3%, the gap is 1.0 points lower. Across 92 Indiana counties pooled together, 39.6% of tests reached that level, so Warren County runs 4.3 points below its state.
The newest figure, over the 2008 to 2017 laboratory totals, counts only 27 tests (33.3% at or above 4 pCi/L), too few to compare, so this reading uses the 34-test figure.
Of 4 neighbours with a figure, all 4 reported a larger share at or above 4 pCi/L; the spread is 36.6% (Tippecanoe County) to 57.1% (Benton County). By share, Warren County is 57th of 69 Indiana counties with 30 or more tests for the same period.
Half the tests came in under 3.5 pCi/L and half over it; the single highest reached 12.0 pCi/L. Below the action level, 9 tests (26.5%) came in under 2 pCi/L, against 32.6% statewide, and 13 tests (38.2%) fell between 2 and 4, against 27.9% statewide.
Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 35.3% share point the same way here. USGS geology rates 100% of the county's land high radon potential.
CDC's ten-year totals for Warren County went from 28 tests (2005 to 2014) to 27 (2008 to 2017), the share going from 39.3% to 33.3%.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Warren County, Geology
The ground under Warren County
PredictedUSGS's geologic map puts all of Warren 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 | 99.9% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Warren County beside the ground around it
Warren 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; Benton County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Warren County, Local resources
Radon testing and mitigation in Warren 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
Warren County, Questions
Questions about radon in Warren County
Are radon levels high in Warren County?
Over the 2008 to 2017 laboratory totals, 33.3% of the radon tests reported to CDC for Warren County, Indiana were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.5 pCi/L. Of 69 Indiana counties with 30 or more tests for the same period, 56 reported a higher share; pooled, the state comes to 39.6%.
Which counties border Warren County?
Warren County borders 5 counties: Fountain County, IN, Vermilion County, IL, Vermillion County, IN, Benton County, IN and Tippecanoe County, IN.
Products
Warren County, Products
Testing a home in Warren County
In Warren County, 35.3% of 34 tests reported to CDC over the 2006 to 2015 laboratory totals reached 4 pCi/L, against 39.6% pooled across Indiana. In Zone 1 the year-round level in Warren 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-1011S rechargeable radon detector with a screen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
First reading: Within 12 hours
Short-term kit
PicoCan short-term charcoal canister radon test
- Lab fee included
Method: Charcoal
In home: 48 to 96 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Warren County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Warren County
Explore
Warren County, Bordering counties
Counties bordering Warren County
Calculated by Radon411- Radon levels in Benton County, INEPA zone 1
57.1%at or above 4 pCi/L
Median 6.1 pCi/L · 35 tests · 21.8 points above Warren County
- Radon levels in Fountain County, INEPA zone 1
50.9%at or above 4 pCi/L
Median 4.1 pCi/L · 55 tests · 15.6 points above Warren County
- Radon levels in Vermilion County, ILEPA zone 1
50.3%at or above 4 pCi/L
Median 4.0 pCi/L · 346 tests · 15.0 points above Warren County
- Radon levels in Tippecanoe County, INEPA zone 1
36.6%at or above 4 pCi/L
Median 2.7 pCi/L · 1,348 tests · 1.3 points above Warren County
- Radon levels in Vermillion County, INEPA zone 1
31.3%at or above 4 pCi/L
Median 2.2 pCi/L · 16 tests · 4.0 points below Warren County
Warren County, Cities and towns
Cities and towns in Warren County
The Census Bureau estimates 8,474 residents in Warren County for July 1, 2025, 49 more than in 2020 (+0.6%). That works out to 23 people per square mile of land. Its largest town, Williamsport, has 1,954 residents, 23.1% of the total. Together its 4 incorporated places hold 35.1% of those residents; the other 64.9% live outside any of them. CDC's 34 reported tests for 2006 to 2015 work out to 4.0 per 1,000 residents (2025 estimate), close to Indiana's 5.2.
From Williamsport to State Line City, CDC publishes no figure by town: each reads Warren County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Williamsport | 1,954 | +0.6% | 23.1% |
| West Lebanon | 685 | +0.1% | 8.1% |
| Pine Village | 214 | +1.4% | 2.5% |
| State Line City | 122 | Level | 1.4% |
4 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).
Warren County, Homes
Homes in Warren County
Warren County is a place of houses on their own lots: 90% of its 3,687 homes are detached single-family houses, against 73% across Indiana. Half of its homes were built before 1971, close to Indiana's 1976: 37% date from before 1960 and 16% from 2000 or later. Owners live in 81% of the occupied homes (Indiana: 70%), so for most households a test and a fix are their own to order.
| Homes | Warren County | Indiana |
|---|---|---|
| Housing units | 3,687 | 2,953,344 |
| Detached houses | 90% | 73% |
| In buildings of 5 or more | 2% | 13% |
| Mobile homes | 4% | 4% |
| Built before 1960 | 37% | 32% |
| Built since 2000 | 16% | 21% |
| Middle year built | 1971 | 1976 |
| Owner-occupied | 81% | 70% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.