Short-term kitKidde
442020 short-term charcoal radon test kit
- Lab fee included
Method: Charcoal
In home: 3 days
Locations and reports
Radon Levels in Shiawassee County, Michigan
EPA puts Shiawassee County in Zone 2, its middle radon zone, and 31.6% of its 1,515 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
31.6%
4.7 pts above MI
- Shiawassee
- 31.6%
- Michigan
- 26.9%
1,515 tests, 2008 to 2017
Median result
2.5pCi/L
Below action level
- Shiawassee
- 2.5 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
1,515
21st of 82 by tests
- Shiawassee
- 1,515
- Oakland
- 16,224
Reported to CDC before any fix, 2008 to 2017
EPA radon zone
Zone 2
Moderate potential
- 1
- Zone 2
- 3
1 highest, 3 lowest
EPA predicts 2 to 4 pCi/L indoors
Rank in Michigan
18 of 82
Top quarter
- Shiawassee
- 31.6%
- Lenawee
- 56.7%
By share, of 82 with 30+ tests
Read a result for Shiawassee County
Starts at Shiawassee County's median, 2.5 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.5 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. Shiawassee County's median reported result, 2008 to 2017.
The data
Shiawassee County, At a glance
Shiawassee County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Shiawassee County is a
USGS geologic potential: Moderate across 76% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Shiawassee County, 2008 to 2017, laboratory
Under 2 pCi/L: 41%2 to 4 pCi/L: 28%4 pCi/L and above: 31%
Of 1,515 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 617 | 40.7% |
| 2 to 4 pCi/L | 420 | 27.7% |
| 4 pCi/L and above | 478 | 31.6% |
What these figures count
These are the 1,515 tests reported to CDC for Shiawassee 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).
Shiawassee County, Compared
Shiawassee County radon figures, compared
Calculated by Radon411In Shiawassee County, about 3 in 10 reported tests over the 2008 to 2017 laboratory totals (478 of 1,515) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 4.1 points lower. Across 83 Michigan counties pooled together, 26.9% of tests reached that level, so Shiawassee County runs 4.7 points above its state.
Of 6 neighbours with a figure, 2 reported a larger share at or above 4 pCi/L and 4 a smaller one; the spread is 16.8% (Gratiot County) to 43.1% (Livingston County). By share, Shiawassee County is 18th of 82 Michigan counties with 30 or more tests for the same period.
Half the tests came in under 2.5 pCi/L and half over it; the single highest reached 87.9 pCi/L. Below the action level, 617 tests (40.7%) came in under 2 pCi/L, against 46.4% statewide, and 420 tests (27.7%) fell between 2 and 4, against 26.7% statewide.
Zone 2 on EPA's map (predicted average between 2 and 4 pCi/L) and a 31.6% share point the same way here. USGS geology rates 76% of the county's land moderate radon potential. CDC also counts 86 tests taken after mitigation in Shiawassee County for the same period: tests in homes where a fix was already in.
CDC's ten-year totals for Shiawassee County went from 1,420 tests (2005 to 2014) to 1,515 (2008 to 2017), the share going from 31.3% to 31.6%.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Shiawassee County, State data
Michigan's own radon test data
MeasuredWhat Michigan's own agencies publish about radon tests in Shiawassee County, with their period. These are not CDC's figures and are never added to them.
MeasuredState figures, not CDC's
What Michigan EGLE reports for the ZIP codes in Shiawassee County
Michigan EGLE publishes its figures by ZIP code, not by county. These are the 19 ZIP codes that lie wholly or partly in Shiawassee County, each with the state's own figures for it. Period: About 10 years to 2026-05-15.
| ZIP code | What the state reports |
|---|---|
| 48414 | 41% greater than 4 pCi/L, median 3.9 pCi/L, 17 tests |
| 48418 | 44% greater than 4 pCi/L, median 3.0 pCi/L, 18 tests |
| 48429 | 33% greater than 4 pCi/L, median 2.4 pCi/L, 55 tests |
| 48433 | 13% greater than 4 pCi/L, median 1.8 pCi/L, 48 tests |
| 48436 | 33% greater than 4 pCi/L, median 3.0 pCi/L, 9 tests |
| 48449 | 33% greater than 4 pCi/L, median 2.8 pCi/L, 18 tests |
| 48460 | 6% greater than 4 pCi/L, median 2.2 pCi/L, 17 tests |
| 48476 | 0% greater than 4 pCi/L, median 0.0 pCi/L, 5 tests |
| 48616 | 16% greater than 4 pCi/L, median 1.8 pCi/L, 49 tests |
| 48649 | 27% greater than 4 pCi/L, median 3.1 pCi/L, 11 tests |
| 48817 | 22% greater than 4 pCi/L, median 1.5 pCi/L, 82 tests |
| 48831 | 49% greater than 4 pCi/L, median 3.6 pCi/L, 35 tests |
| 48840 | 22% greater than 4 pCi/L, median 2.1 pCi/L, 91 tests |
| 48841 | 30% greater than 4 pCi/L, median 2.0 pCi/L, 10 tests |
| 48848 | 37% greater than 4 pCi/L, median 2.7 pCi/L, 81 tests |
| 48857 | 19% greater than 4 pCi/L, median 2.8 pCi/L, 27 tests |
| 48866 | 47% greater than 4 pCi/L, median 3.9 pCi/L, 36 tests |
| 48867 | 25% greater than 4 pCi/L, median 2.1 pCi/L, 254 tests |
| 48872 | 33% greater than 4 pCi/L, median 2.9 pCi/L, 66 tests |
- EGLE's figures cover first-time tests only, from organizations willing to provide data.
- EGLE does not publish figures for a ZIP code with fewer than 5 test results.
- EGLE says the map is not intended to decide whether a home should be tested: all homes should be tested.
- ZIP code boundaries are postal delivery areas, not legal or administrative boundaries.
- A ZIP code that crosses the county line is listed whole; its figures cover all of it.
Measured: Michigan EGLE data, About 10 years to 2026-05-15.
Shiawassee County, Geology
The ground under Shiawassee County
PredictedMost of the ground under Shiawassee County is one class on USGS's geologic map: 75.9% of its land is moderate radon potential, with 24.1% low. The map puts 75.9% of Shiawassee County in the area it calls South-Central Michigan Basin and 24.1% in Glacial Lakes. USGS gives the first a radon index of 10, in the moderate band (9 to 11), and the second 7, in the low band (5 to 8).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| South-Central Michigan Basin | Sandy and silty glacial deposits derived from sandstones, gray shales, limestones, and dolomites. | Moderate | 10 | 75.9% |
| Glacial Lakes | Silt and clay glacial lake deposits. | Low | 7 | 24.1% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Shiawassee County beside the ground around it
Across Michigan 9.6% of the land is rated high; none of Shiawassee County's is. Of the 6 counties that border it, 1 has more high-potential ground, Livingston County the most at 46.4%.
The map rates the ground, not the air in any home.
Local help
Shiawassee County, Local resources
Radon testing and mitigation in Shiawassee County
- Michigan Indoor Radon ProgramMichigan Indoor Radon Program, run by Michigan Department of Environment, Great Lakes, and Energy, does not license radon professionals, and answers questions about testing and mitigation in Michigan.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsAsk the program whether it has free or discounted kits, or compare kits you can buy.
- Compare kits
- Professionals in Michigan69 professionals are listed in Michigan.
What Michigan's program says
- Phone
- 800-723-6642
- Radon@Michigan.gov
- Licensing of radon professionals
Michigan does not license or regulate radon testing and mitigation contractors.
What it means
Shiawassee County, Questions
Questions about radon in Shiawassee County
Are radon levels high in Shiawassee County?
Over the 2008 to 2017 laboratory totals, 31.6% of the radon tests reported to CDC for Shiawassee County, Michigan were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.5 pCi/L. Of 82 Michigan counties with 30 or more tests for the same period, 17 reported a higher share; pooled, the state comes to 26.9%.
Which counties border Shiawassee County?
Shiawassee County borders 6 counties: Genesee County, Clinton County, Livingston County, Ingham County, Gratiot County and Saginaw County.
Products
Shiawassee County, Products
Testing a home in Shiawassee County
In Shiawassee County, 31.6% of 1,515 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 26.9% pooled across Michigan. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Shiawassee County; a long-term test tells the year-round average.
Test kits and monitors3
See every kit and monitor
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
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
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Shiawassee County, Bordering counties
Counties bordering Shiawassee County
Calculated by Radon411- Radon levels in Livingston CountyEPA zone 2
43.1%at or above 4 pCi/L
Median 3.4 pCi/L · 4,885 tests · 11.5 points above Shiawassee County
- Radon levels in Clinton CountyEPA zone 2
38.5%at or above 4 pCi/L
Median 3.1 pCi/L · 2,313 tests · 6.9 points above Shiawassee County
- Radon levels in Ingham CountyEPA zone 2
24.9%at or above 4 pCi/L
Median 2.2 pCi/L · 2,932 tests · 6.7 points below Shiawassee County
- Radon levels in Genesee CountyEPA zone 2
21.9%at or above 4 pCi/L
Median 2.0 pCi/L · 1,699 tests · 9.7 points below Shiawassee County
- Radon levels in Saginaw CountyEPA zone 3
17.0%at or above 4 pCi/L
Median 1.7 pCi/L · 3,037 tests · 14.6 points below Shiawassee County
- Radon levels in Gratiot CountyEPA zone 3
16.8%at or above 4 pCi/L
Median 1.7 pCi/L · 457 tests · 14.8 points below Shiawassee County
Shiawassee County, Cities and towns
Cities and towns in Shiawassee County
Shiawassee County's population has barely moved since 2020: 67,681 residents on July 1, 2025 against 67,990 then, by the Census Bureau's estimates. That works out to 127 people per square mile of land. Its largest town, Owosso, has 14,437 residents, 21.3% of the total. Testing is reported here more often than across the state: CDC's 1,515 reported tests for 2008 to 2017 come to 22.4 for every 1,000 residents (2025 estimate), against 11.3 for Michigan.
From Owosso to Lennon, CDC publishes no figure by town: each reads Shiawassee County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Owosso | 14,437 | −1.7% | 21.3% |
| Durand | 3,457 | −1.1% | 5.1% |
| Corunna | 3,000 | −1.5% | 4.4% |
| Perry | 2,134 | +2.9% | 3.2% |
| Laingsburg | 1,402 | −1.8% | 2.1% |
| Morrice | 975 | +1.6% | 1.4% |
| Vernon | 715 | −2.2% | 1.1% |
| New Lothrop | 582 | −1.7% | 0.9% |
| Byron | 525 | −1.3% | 0.8% |
| Bancroft | 473 | −0.6% | 0.7% |
| Lennonextends beyond Shiawassee County | 466 | −1.9% | Counted whole |
11 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 Shiawassee County is counted whole, so it has no share.
Shiawassee County, Homes
Homes in Shiawassee County
Shiawassee County is a place of houses on their own lots: 80% of its 30,272 homes are detached single-family houses, against 72% across Michigan. Half of its homes were built before 1969, close to Michigan's 1972: 40% date from before 1960 and 12% from 2000 or later. Owners live in 79% of the occupied homes (Michigan: 73%), so for most households a test and a fix are their own to order.
| Homes | Shiawassee County | Michigan |
|---|---|---|
| Housing units | 30,272 | 4,599,683 |
| Detached houses | 80% | 72% |
| In buildings of 5 or more | 6% | 13% |
| Mobile homes | 7% | 5% |
| Built before 1960 | 40% | 36% |
| Built since 2000 | 12% | 15% |
| Middle year built | 1969 | 1972 |
| Owner-occupied | 79% | 73% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.