Short-term kitFirst Alert
RD1 short-term charcoal radon test kit
- Lab fee included
Method: Charcoal
In home: 2 to 4 days
Locations and reports
Radon Levels in Mason County, Michigan
EPA puts Mason County in Zone 3, its lowest radon zone, and most reported tests there come back low, though 6.3% of 462 (2008 to 2017, laboratory totals) reached 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
6.3%
20.6 pts below MI
- Mason
- 6.3%
- Michigan
- 26.9%
462 tests, 2008 to 2017
Median result
1.1pCi/L
Below action level
- Mason
- 1.1 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
462
49th of 82 by tests
- Mason
- 462
- 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
78 of 82
Lowest quarter
- Mason
- 6.3%
- Lenawee
- 56.7%
By share, of 82 with 30+ tests
Read a result for Mason County
Starts at Mason County's median, 1.1 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 1.1 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. Mason County's median reported result, 2008 to 2017.
The data
Mason County, At a glance
Mason County at a glance
Predicted: EPA radon zone
EPA Zone 3: lower predicted potential
USGS geologic potential: Low across 100% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Mason County, 2008 to 2017, laboratory
Under 2 pCi/L: 72%2 to 4 pCi/L: 22%4 pCi/L and above: 6%
Of 462 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 333 | 72.1% |
| 2 to 4 pCi/L | 100 | 21.6% |
| 4 pCi/L and above | 29 | 6.3% |
What these figures count
These are the 462 tests reported to CDC for Mason 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).
Mason County, Compared
Mason County radon figures, compared
Calculated by Radon411Mason County reports fewer high tests than Michigan overall. 6.3% of its 462 tests over the 2008 to 2017 laboratory totals were at or above 4 pCi/L. That is 20.6 points below the 26.9% pooled from 83 Michigan counties.
Ordered from highest share down, it comes 78th of 82 Michigan counties with 30 or more tests for the same period. Nationally, every county with a figure for the same period pools to 35.7%; Mason County sits 29.4 points below it.
Next door, the shares run from 5.9% in Oceana County to 16.5% in Manistee County, with Oceana County below Mason County. Zone 3 on EPA's map (predicted average under 2 pCi/L) and a 6.3% share point the same way here.
Half the tests came in under 1.1 pCi/L and half over it; the single highest reached 13.5 pCi/L. The rest split 72.1% under 2 pCi/L and 21.6% from 2 to 4 (Michigan: 46.4% and 26.7%).
CDC's ten-year totals for Mason County went from 527 tests (2005 to 2014) to 462 (2008 to 2017), the share going from 5.9% to 6.3%.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Mason County, State data
Michigan's own radon test data
MeasuredWhat Michigan's own agencies publish about radon tests in Mason 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 Mason County
Michigan EGLE publishes its figures by ZIP code, not by county. These are the 9 ZIP codes that lie wholly or partly in Mason County, each with the state's own figures for it. Period: About 10 years to 2026-05-15.
| ZIP code | What the state reports |
|---|---|
| 49402 | 0% greater than 4 pCi/L, median 1.9 pCi/L, 12 tests |
| 49405 | 7% greater than 4 pCi/L, median 1.3 pCi/L, 14 tests |
| 49410 | 0% greater than 4 pCi/L, median 1.6 pCi/L, 11 tests |
| 49411 | 11% greater than 4 pCi/L, median 1.0 pCi/L, 18 tests |
| 49431 | 4% greater than 4 pCi/L, median 0.9 pCi/L, 195 tests |
| 49449 | 4% greater than 4 pCi/L, median 1.1 pCi/L, 27 tests |
| 49454 | 4% greater than 4 pCi/L, median 1.1 pCi/L, 23 tests |
| 49644 | 35% greater than 4 pCi/L, median 3.0 pCi/L, 17 tests |
| 49660 | 15% greater than 4 pCi/L, median 1.8 pCi/L, 181 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.
Mason County, Geology
The ground under Mason County
PredictedUSGS's geologic map puts all of Mason County's mapped land in one class: low radon potential. All of it lies in the area the map calls Lake Michigan Lobe Deposits, to which USGS gives a radon index of 8, in the low band (5 to 8).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Lake Michigan Lobe Deposits | Sandy to clayey glacial deposits and some glacial lake deposits. | Low | 8 | 99.7% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Mason County beside the ground around it
Across Michigan 9.6% of the land is rated high; none of Mason County's is. Of the 4 counties that border it, 1 has more moderate-potential ground, Newaygo County the most at 9.8%.
The map rates the ground, not the air in any home.
Local help
Mason County, Local resources
Radon testing and mitigation in Mason 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
Mason County, Questions
Questions about radon in Mason County
Are radon levels high in Mason County?
Over the 2008 to 2017 laboratory totals, 6.3% of the radon tests reported to CDC for Mason County, Michigan were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.1 pCi/L. Of 82 Michigan counties with 30 or more tests for the same period, 77 reported a higher share; pooled, the state comes to 26.9%.
Which counties border Mason County?
Mason County borders 4 counties: Manistee County, Lake County, Oceana County and Newaygo County.
Products
Mason County, Products
Testing a home in Mason County
In Mason County, 6.3% of 462 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 Mason 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
View Plus radon and air quality monitor
- C-NRPP 2024/25: Approved
- Battery
- Wi-Fi, Bluetooth
- Screen, app
Method: Alpha spectrometry
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Mason County, Bordering counties
Counties bordering Mason County
Calculated by Radon411- Radon levels in Manistee CountyEPA zone 3
16.5%at or above 4 pCi/L
Median 1.6 pCi/L · 388 tests · 10.2 points above Mason County
- Radon levels in Lake CountyEPA zone 3
14.9%at or above 4 pCi/L
Median 1.4 pCi/L · 94 tests · 8.6 points above Mason County
- Radon levels in Newaygo CountyEPA zone 3
7.9%at or above 4 pCi/L
Median 1.3 pCi/L · 467 tests · 1.6 points above Mason County
- Radon levels in Oceana CountyEPA zone 3
5.9%at or above 4 pCi/L
Median 1.2 pCi/L · 338 tests · 0.4 points below Mason County
Mason County, Cities and towns
Cities and towns in Mason County
Mason County's population has barely moved since 2020: 29,040 residents on July 1, 2025 against 29,033 then, by the Census Bureau's estimates. That works out to 59 people per square mile of land. Its largest town, Ludington, has 7,634 residents, 26.3% of the total. Together its 5 incorporated places hold 33.1% of those residents; the other 66.9% live outside any of them. CDC's 462 reported tests for 2008 to 2017 work out to 15.9 per 1,000 residents (2025 estimate), close to Michigan's 11.3.
From Ludington to Free Soil, CDC publishes no figure by town: each reads Mason County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Ludington | 7,634 | −0.6% | 26.3% |
| Scottville | 1,348 | −0.7% | 4.6% |
| Custer | 300 | −0.7% | 1.0% |
| Fountain | 185 | +0.5% | 0.6% |
| Free Soil | 148 | −0.7% | 0.5% |
5 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).
Mason County, Homes
Homes in Mason County
Of Mason County's 17,499 homes, 75% are detached houses, against 72% across Michigan; 11% are mobile homes. Half of its homes were built before 1976, close to Michigan's 1972: 33% date from before 1960 and 20% from 2000 or later. Owners live in 78% of the occupied homes (Michigan: 73%), so for most households a test and a fix are their own to order.
| Homes | Mason County | Michigan |
|---|---|---|
| Housing units | 17,499 | 4,599,683 |
| Detached houses | 75% | 72% |
| In buildings of 5 or more | 8% | 13% |
| Mobile homes | 11% | 5% |
| Built before 1960 | 33% | 36% |
| Built since 2000 | 20% | 15% |
| Middle year built | 1976 | 1972 |
| Owner-occupied | 78% | 73% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.