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 St. Joseph County, Indiana
EPA puts St. Joseph County in Zone 1, its highest radon zone, and 29.3% of its 7,346 reported radon tests (2008 to 2017, laboratory totals) were 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
29.3%
9.6 pts below IN
- St. Joseph
- 29.3%
- Indiana
- 38.9%
7,346 tests, 2008 to 2017
Median result
2.7pCi/L
Below action level
- St. Joseph
- 2.7 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
7,346
Most tested in Indiana
- 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
62 of 69
Lowest quarter
- St. Joseph
- 29.3%
- Miami
- 63.3%
By share, of 69 with 30+ tests
Read a result for St. Joseph County
Starts at St. Joseph County's median, 2.7 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.7 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. St. Joseph County's median reported result, 2008 to 2017.
The data
St. Joseph County, At a glance
St. Joseph County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of St. Joseph County in
USGS geologic potential: High across 57% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for St. Joseph County, 2008 to 2017, laboratory
Under 2 pCi/L: 32%2 to 4 pCi/L: 39%4 pCi/L and above: 29%
Of 7,346 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 2,363 | 32.2% |
| 2 to 4 pCi/L | 2,833 | 38.6% |
| 4 pCi/L and above | 2,150 | 29.3% |
What these figures count
These are the 7,346 tests reported to CDC for St. Joseph 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).
St. Joseph County, Compared
St. Joseph County radon figures, compared
Calculated by Radon411St. Joseph County's 7,346 reported tests over the 2008 to 2017 laboratory totals had a middle value of 2.7 pCi/L and a maximum of 621.3 pCi/L, and 29.3% reached 4 pCi/L. Indiana as a whole (92 Indiana counties, pooled) comes to 38.9%: 9.6 points higher than here.
Among its state's counties it ranks 62nd of 69 Indiana counties with 30 or more tests for the same period. Statewide for the same period, Miami County reported the highest share (63.3%) and Jasper County the lowest (14.1%).
Below the action level, 2,363 tests (32.2%) came in under 2 pCi/L, against 32.8% statewide, and 2,833 tests (38.6%) fell between 2 and 4, against 28.3% statewide. CDC's ten-year totals for St. Joseph County went from 4,353 tests (2005 to 2014) to 7,346 (2008 to 2017), the share going from 30.1% to 29.3%.
EPA's 1993 zone map puts St. Joseph County in Zone 1, a predicted county average above 4 pCi/L. USGS geology rates 57% of the county's land high radon potential.
Next door, the shares run from 24.2% in Berrien County, MI to 58.2% in LaPorte County, with Berrien County, MI below St. Joseph County.
CDC also counts 184 tests taken after mitigation in St. Joseph County for the same period: tests in homes where a fix was already in.
Pooled shares: Radon411's sum of CDC's county counts for one period.
St. Joseph County, Geology
The ground under St. Joseph County
PredictedUSGS's geologic map splits St. Joseph County: 56.7% of its land is high radon potential and 43.3% moderate. The map puts 56.7% of St. Joseph County in the area it calls Saginaw Lobe and 42.5% in Kankakee Outwash and Lacustrine Plain, with one smaller area beside them. USGS gives the first a radon index of 12, in the high band (12 to 17), and the second 10, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Saginaw Lobe | Clayey and loamy glacial deposits. | High | 12 | 56.7% |
| Kankakee Outwash and Lacustrine Plain | Moraine deposits, outwash and dune sands. | Moderate | 10 | 42.5% |
| Calumet Lacustrine Plain/Valparaiso Morainal Area | Silty to clayey glacial lake deposits and sand dunes. | Moderate | 11 | 0.7% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
St. Joseph County beside the ground around it
On high-potential ground St. Joseph County is close to Indiana as a whole: 56.7% of its land against 56.6%. Of the 6 counties that border it, 3 have more high-potential ground, Elkhart County the most at 100%.
The map rates the ground, not the air in any home.
Local help
St. Joseph County, Local resources
Radon testing and mitigation in St. Joseph 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
St. Joseph County, Questions
Questions about radon in St. Joseph County
Are radon levels high in St. Joseph County?
Over the 2008 to 2017 laboratory totals, 29.3% of the radon tests reported to CDC for St. Joseph County, Indiana were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.7 pCi/L. Of 69 Indiana counties with 30 or more tests for the same period, 61 reported a higher share; pooled, the state comes to 38.9%.
Which counties border St. Joseph County?
St. Joseph County borders 6 counties: Marshall County, IN, Elkhart County, IN, LaPorte County, IN, Berrien County, MI, Cass County, MI and Starke County, IN.
Products
St. Joseph County, Products
Testing a home in St. Joseph County
In St. Joseph County, 29.3% of 7,346 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 St. Joseph 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
St. Joseph County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like St. Joseph County
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St. Joseph County, Bordering counties
Counties bordering St. Joseph County
Calculated by Radon411- Radon levels in LaPorte County, INEPA zone 2
58.2%at or above 4 pCi/L
Median 5.0 pCi/L · 792 tests · 28.9 points above St. Joseph County
- Radon levels in Elkhart County, INEPA zone 1
46.4%at or above 4 pCi/L
Median 3.7 pCi/L · 2,856 tests · 17.1 points above St. Joseph County
- Radon levels in Marshall County, INEPA zone 1
39.7%at or above 4 pCi/L
Median 3.2 pCi/L · 383 tests · 10.4 points above St. Joseph County
- Radon levels in Cass County, MIEPA zone 1
30.4%at or above 4 pCi/L
Median 2.6 pCi/L · 572 tests · 1.1 points above St. Joseph County
- Radon levels in Berrien County, MIEPA zone 3
24.2%at or above 4 pCi/L
Median 2.0 pCi/L · 1,192 tests · 5.1 points below St. Joseph County
- Radon levels in Starke County, INEPA zone 2
4.2%at or above 4 pCi/L
Median 1.6 pCi/L · 24 tests · 25.1 points below St. Joseph County
St. Joseph County, Cities and towns
Cities and towns in St. Joseph County
St. Joseph County's population has barely moved since 2020: 272,861 residents on July 1, 2025 against 272,686 then, by the Census Bureau's estimates. That works out to 596 people per square mile of land. Its largest town, South Bend, has 103,201 residents, 37.8% of the total. Together its 9 incorporated places hold 60.3% of those residents; the other 39.7% live outside any of them. Testing is reported here more often than across the state: CDC's 7,346 reported tests for 2008 to 2017 come to 26.9 for every 1,000 residents (2025 estimate), against 6.2 for Indiana.
From South Bend to Indian Village, CDC publishes no figure by town: each reads St. Joseph County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| South Bend | 103,201 | −0.1% | 37.8% |
| Mishawaka | 51,226 | +0.3% | 18.8% |
| Osceola | 2,586 | Level | 0.9% |
| Walkerton | 2,074 | −1.0% | 0.8% |
| New Carlisle | 1,884 | −0.7% | 0.7% |
| North Liberty | 1,624 | −0.1% | 0.6% |
| Lakeville | 873 | Level | 0.3% |
| Roseland | 850 | Level | 0.3% |
| Indian Village | 117 | Level | Under 0.1% |
9 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).
St. Joseph County, Homes
Homes in St. Joseph County
Of St. Joseph County's 118,329 homes, 74% are detached houses, against 73% across Indiana; 16% are in buildings of five or more homes. The homes are older than Indiana's as a whole: half were built before 1968 (1976 for Indiana), and 42% date from before 1960. 69% of occupied homes are lived in by their owner (Indiana: 70%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | St. Joseph County | Indiana |
|---|---|---|
| Housing units | 118,329 | 2,953,344 |
| Detached houses | 74% | 73% |
| In buildings of 5 or more | 16% | 13% |
| Mobile homes | 2% | 4% |
| Built before 1960 | 42% | 32% |
| Built since 2000 | 14% | 21% |
| Middle year built | 1968 | 1976 |
| Owner-occupied | 69% | 70% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.