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
Locations and reports
Radon Levels in Gratiot County, Michigan
EPA puts Gratiot County in Zone 3, its lowest radon zone, and 16.8% of its 457 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
16.8%
10.1 pts below MI
- Gratiot
- 16.8%
- Michigan
- 26.9%
457 tests, 2008 to 2017
Median result
1.7pCi/L
Below action level
- Gratiot
- 1.7 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
457
50th of 82 by tests
- Gratiot
- 457
- Oakland
- 16,224
Reported to CDC before any fix, 2008 to 2017
EPA radon zone
Zone 3
Lower potential
- 1
- 2
- Zone 3
1 highest, 3 lowest
EPA predicts under 2 pCi/L indoors
Rank in Michigan
41 of 82
Middle half
- Gratiot
- 16.8%
- Lenawee
- 56.7%
By share, of 82 with 30+ tests
Read a result for Gratiot County
Starts at Gratiot County's median, 1.7 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 1.7 pCi/L
Below 2 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is below 2 pCi/L, the level at which EPA says a fix should be considered. Gratiot County's median reported result, 2008 to 2017.
The data
Gratiot County, At a glance
Gratiot County at a glance
Predicted: EPA radon zone
EPA Zone 3: lower predicted potential
USGS geologic potential: Low across 58% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Gratiot County, 2008 to 2017, laboratory
Under 2 pCi/L: 57%2 to 4 pCi/L: 26%4 pCi/L and above: 17%
Of 457 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 262 | 57.3% |
| 2 to 4 pCi/L | 118 | 25.8% |
| 4 pCi/L and above | 77 | 16.8% |
What these figures count
These are the 457 tests reported to CDC for Gratiot 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).
Gratiot County, Compared
Gratiot County radon figures, compared
Calculated by Radon411Gratiot County's 457 reported tests over the 2008 to 2017 laboratory totals had a middle value of 1.7 pCi/L and a maximum of 31.7 pCi/L, and 16.8% reached 4 pCi/L. Michigan as a whole (83 Michigan counties, pooled) comes to 26.9%: 10.1 points higher than here.
Among its state's counties it ranks 41st of 82 Michigan counties with 30 or more tests for the same period. Statewide for the same period, Lenawee County reported the highest share (56.7%) and Muskegon County the lowest (3.2%).
Below the action level, 262 tests (57.3%) came in under 2 pCi/L, against 46.4% statewide, and 118 tests (25.8%) fell between 2 and 4, against 26.7% statewide. CDC's ten-year totals for Gratiot County went from 489 tests (2005 to 2014) to 457 (2008 to 2017), the share going from 16.4% to 16.8%.
EPA's 1993 zone map puts Gratiot County in Zone 3, a predicted county average under 2 pCi/L. USGS geology rates 58% of the county's land low radon potential.
Next door, the shares run from 5.3% in Midland County to 38.5% in Clinton County, with Isabella County and Midland County below Gratiot County.
CDC also counts 18 tests taken after mitigation in Gratiot 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.
Gratiot County, State data
Michigan's own radon test data
MeasuredWhat Michigan's own agencies publish about radon tests in Gratiot 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 Gratiot County
Michigan EGLE publishes its figures by ZIP code, not by county. These are the 18 ZIP codes that lie wholly or partly in Gratiot County, each with the state's own figures for it. Period: About 10 years to 2026-05-15.
| ZIP code | What the state reports |
|---|---|
| 48614 | 3 tests, figures not shown |
| 48615 | 14% greater than 4 pCi/L, median 0.8 pCi/L, 7 tests |
| 48637 | 0% greater than 4 pCi/L, median 0.7 pCi/L, 15 tests |
| 48662 | 3 tests, figures not shown |
| 48801 | 7% greater than 4 pCi/L, median 1.3 pCi/L, 42 tests |
| 48806 | 0% greater than 4 pCi/L, median 1.0 pCi/L, 12 tests |
| 48811 | 3 tests, figures not shown |
| 48831 | 49% greater than 4 pCi/L, median 3.6 pCi/L, 35 tests |
| 48832 | 42% greater than 4 pCi/L, median 3.5 pCi/L, 12 tests |
| 48845 | 0% greater than 4 pCi/L, median 0.0 pCi/L, 5 tests |
| 48847 | 13% greater than 4 pCi/L, median 1.6 pCi/L, 32 tests |
| 48862 | 1 tests, figures not shown |
| 48871 | 23% greater than 4 pCi/L, median 3.0 pCi/L, 13 tests |
| 48877 | 0% greater than 4 pCi/L, median 0.0 pCi/L, 5 tests |
| 48879 | 35% greater than 4 pCi/L, median 3.0 pCi/L, 241 tests |
| 48880 | 10% greater than 4 pCi/L, median 1.6 pCi/L, 42 tests |
| 48883 | 31% greater than 4 pCi/L, median 3.1 pCi/L, 32 tests |
| 48889 | 1 tests, figures not shown |
- 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.
Gratiot County, Geology
The ground under Gratiot County
PredictedUSGS's geologic map splits Gratiot County: 57.9% of its land is low radon potential and 42.1% moderate. The map puts 57.9% of Gratiot County in the area it calls Glacial Lakes and 42.1% in South-Central Michigan Basin. USGS gives the first a radon index of 7, in the low band (5 to 8), and the second 10, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Glacial Lakes | Silt and clay glacial lake deposits. | Low | 7 | 57.9% |
| South-Central Michigan Basin | Sandy and silty glacial deposits derived from sandstones, gray shales, limestones, and dolomites. | Moderate | 10 | 42.1% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Gratiot County beside the ground around it
Across Michigan 9.6% of the land is rated high; none of Gratiot County's is. Of the 7 counties that border it, 4 have more moderate-potential ground, Ionia County the most at 100%.
The map rates the ground, not the air in any home.
Local help
Gratiot County, Local resources
Radon testing and mitigation in Gratiot County
Listed radon businesses with an address in Gratiot 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.
Listed radon professionals by town: Alma, Ithaca
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
Gratiot County, Questions
Questions about radon in Gratiot County
Are radon levels high in Gratiot County?
Over the 2008 to 2017 laboratory totals, 16.8% of the radon tests reported to CDC for Gratiot County, Michigan were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.7 pCi/L. Of 82 Michigan counties with 30 or more tests for the same period, 40 reported a higher share; pooled, the state comes to 26.9%.
Which counties border Gratiot County?
Gratiot County borders 7 counties: Clinton County, Montcalm County, Shiawassee County, Ionia County, Saginaw County, Isabella County and Midland County.
Products
Gratiot County, Products
Testing a home in Gratiot County
In Gratiot County, 16.8% of 457 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 26.9% pooled across Michigan. Zone 3 is the lowest label, yet homes at or above 4 pCi/L occur in every zone: a short-term kit (2 to 90 days) is the quick first check in Gratiot County.
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
Monitor
EcoBlu plug-in digital radon monitor with a display
- C-NRPP 2024/25: Not included
- Plug-in
- Alarm
- Screen
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
Gratiot County, Bordering counties
Counties bordering Gratiot County
Calculated by Radon411- Radon levels in Clinton CountyEPA zone 2
38.5%at or above 4 pCi/L
Median 3.1 pCi/L · 2,313 tests · 21.7 points above Gratiot County
- Radon levels in Ionia CountyEPA zone 2
36.8%at or above 4 pCi/L
Median 2.9 pCi/L · 1,391 tests · 20.0 points above Gratiot County
- Radon levels in Shiawassee CountyEPA zone 2
31.6%at or above 4 pCi/L
Median 2.5 pCi/L · 1,515 tests · 14.8 points above Gratiot County
- Radon levels in Montcalm CountyEPA zone 2
23.6%at or above 4 pCi/L
Median 2.1 pCi/L · 550 tests · 6.8 points above Gratiot County
- Radon levels in Saginaw CountyEPA zone 3
17.0%at or above 4 pCi/L
Median 1.7 pCi/L · 3,037 tests · 0.2 points above Gratiot County
- Radon levels in Isabella CountyEPA zone 3
16.4%at or above 4 pCi/L
Median 1.6 pCi/L · 870 tests · 0.4 points below Gratiot County
- Radon levels in Midland CountyEPA zone 3
5.3%at or above 4 pCi/L
Median 1.0 pCi/L · 2,006 tests · 11.5 points below Gratiot County
Gratiot County, Cities and towns
Cities and towns in Gratiot County
About 41,190 people live in Gratiot County by the Census Bureau's estimate for July 1, 2025, 467 fewer than in 2020 (−1.1%). That works out to 72 people per square mile of land. Its largest town, Alma, has 9,304 residents, 22.6% of the total. Together its 6 incorporated places hold 52.6% of those residents; the other 47.4% live outside any of them. CDC's 457 reported tests for 2008 to 2017 work out to 11.1 per 1,000 residents (2025 estimate), close to Michigan's 11.3.
From Alma to Perrinton, CDC publishes no figure by town: each reads Gratiot County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Alma | 9,304 | −1.4% | 22.6% |
| St. Louis | 7,406 | −0.6% | 18.0% |
| Ithaca | 2,807 | −1.5% | 6.8% |
| Breckenridge | 1,265 | −1.6% | 3.1% |
| Ashley | 513 | −0.4% | 1.2% |
| Perrinton | 388 | −0.8% | 0.9% |
6 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).
Gratiot County, Homes
Homes in Gratiot County
Gratiot County is a place of houses on their own lots: 78% of its 16,051 homes are detached single-family houses, against 72% across Michigan. Half of its homes were built before 1966, close to Michigan's 1972: 43% date from before 1960 and 10% 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 | Gratiot County | Michigan |
|---|---|---|
| Housing units | 16,051 | 4,599,683 |
| Detached houses | 78% | 72% |
| In buildings of 5 or more | 6% | 13% |
| Mobile homes | 9% | 5% |
| Built before 1960 | 43% | 36% |
| Built since 2000 | 10% | 15% |
| Middle year built | 1966 | 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.