Short-term kit
RA100 short-term liquid scintillation radon test kit
- Lab fee extra
Method: Liquid scintillation
In home: 48 to 96 hours
Locations and reports
Radon Levels in Bay County, Michigan
EPA puts Bay County in Zone 3, its lowest radon zone, and most reported tests there come back low, though 8.5% of 624 (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
8.5%
18.4 pts below MI
- Bay
- 8.5%
- Michigan
- 26.9%
624 tests, 2008 to 2017
Median result
1.4pCi/L
Below action level
- Bay
- 1.4 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
624
40th of 82 by tests
- Bay
- 624
- 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
73 of 82
Lowest quarter
- Bay
- 8.5%
- Lenawee
- 56.7%
By share, of 82 with 30+ tests
Read a result for Bay County
Starts at Bay County's median, 1.4 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 1.4 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. Bay County's median reported result, 2008 to 2017.
The data
Bay County, At a glance
Bay County at a glance
Predicted: EPA radon zone
EPA Zone 3: lower predicted potential
USGS geologic potential: Low across 99% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Bay County, 2008 to 2017, laboratory
Under 2 pCi/L: 65%2 to 4 pCi/L: 26%4 pCi/L and above: 9%
Of 624 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 407 | 65.2% |
| 2 to 4 pCi/L | 164 | 26.3% |
| 4 pCi/L and above | 53 | 8.5% |
What these figures count
These are the 624 tests reported to CDC for Bay 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).
Bay County, Compared
Bay County radon figures, compared
Calculated by Radon411Bay County reports fewer high tests than Michigan overall. 8.5% of its 624 tests over the 2008 to 2017 laboratory totals were at or above 4 pCi/L. That is 18.4 points below the 26.9% pooled from 83 Michigan counties.
Ordered from highest share down, it comes 73rd 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%; Bay County sits 27.2 points below it.
Next door, the shares run from 5.3% in Midland County to 35.5% in Tuscola County, with Midland County below Bay County. Zone 3 on EPA's map (predicted average under 2 pCi/L) and a 8.5% share point the same way here.
Half the tests came in under 1.4 pCi/L and half over it; the single highest reached 17.5 pCi/L. The rest split 65.2% under 2 pCi/L and 26.3% from 2 to 4 (Michigan: 46.4% and 26.7%).
CDC's ten-year totals for Bay County went from 650 tests (2005 to 2014) to 624 (2008 to 2017), the share going from 9.8% to 8.5%.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Bay County, State data
Michigan's own radon test data
MeasuredWhat Michigan's own agencies publish about radon tests in Bay 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 Bay County
Michigan EGLE publishes its figures by ZIP code, not by county. These are the 16 ZIP codes that lie wholly or partly in Bay County, each with the state's own figures for it. Period: About 10 years to 2026-05-15.
| ZIP code | What the state reports |
|---|---|
| 48604 | 14% greater than 4 pCi/L, median 1.9 pCi/L, 59 tests |
| 48611 | 13% greater than 4 pCi/L, median 0.9 pCi/L, 23 tests |
| 48613 | 1 tests, figures not shown |
| 48623 | 22% greater than 4 pCi/L, median 1.7 pCi/L, 103 tests |
| 48631 | 0% greater than 4 pCi/L, median 1.3 pCi/L, 9 tests |
| 48634 | 3 tests, figures not shown |
| 48642 | 2% greater than 4 pCi/L, median 1.0 pCi/L, 315 tests |
| 48650 | 20% greater than 4 pCi/L, median 0.8 pCi/L, 10 tests |
| 48652 | 2 tests, figures not shown |
| 48658 | 0% greater than 4 pCi/L, median 0.6 pCi/L, 15 tests |
| 48659 | 25% greater than 4 pCi/L, median 2.8 pCi/L, 8 tests |
| 48706 | 5% greater than 4 pCi/L, median 1.4 pCi/L, 74 tests |
| 48708 | 13% greater than 4 pCi/L, median 1.9 pCi/L, 47 tests |
| 48732 | 8% greater than 4 pCi/L, median 1.8 pCi/L, 25 tests |
| 48747 | 4 tests, figures not shown |
| 48757 | 36% greater than 4 pCi/L, median 2.8 pCi/L, 25 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.
Bay County, Geology
The ground under Bay County
PredictedUSGS's geologic map puts all of Bay County's mapped land in one class: low radon potential. 99.1% of it lies in the area the map calls Glacial Lakes, to which USGS gives a radon index of 7, in the low band (5 to 8).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Glacial Lakes | Silt and clay glacial lake deposits. | Low | 7 | 99.1% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Bay County beside the ground around it
Across Michigan 9.6% of the land is rated high; none of Bay County's is. Of the 5 counties that border it, 1 has more moderate-potential ground, Tuscola County the most at 32.9%.
The map rates the ground, not the air in any home.
Local help
Bay County, Local resources
Radon testing and mitigation in Bay 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
Bay County, Questions
Questions about radon in Bay County
Are radon levels high in Bay County?
Over the 2008 to 2017 laboratory totals, 8.5% of the radon tests reported to CDC for Bay County, Michigan were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.4 pCi/L. Of 82 Michigan counties with 30 or more tests for the same period, 72 reported a higher share; pooled, the state comes to 26.9%.
Which counties border Bay County?
Bay County borders 5 counties: Midland County, Gladwin County, Saginaw County, Arenac County and Tuscola County.
Products
Bay County, Products
Testing a home in Bay County
In Bay County, 8.5% of 624 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 Bay 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
Wave Plus battery radon and air quality monitor
- C-NRPP 2024/25: Not included
- Battery
- Bluetooth
- App only
Method: Alpha spectrometry
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Bay County, Bordering counties
Counties bordering Bay County
Calculated by Radon411- Radon levels in Tuscola CountyEPA zone 3
35.5%at or above 4 pCi/L
Median 2.6 pCi/L · 369 tests · 27.0 points above Bay County
- Radon levels in Saginaw CountyEPA zone 3
17.0%at or above 4 pCi/L
Median 1.7 pCi/L · 3,037 tests · 8.5 points above Bay County
- Radon levels in Gladwin CountyEPA zone 3
15.4%at or above 4 pCi/L
Median 1.3 pCi/L · 247 tests · 6.9 points above Bay County
- Radon levels in Arenac CountyEPA zone 3
8.9%at or above 4 pCi/L
Median 0.7 pCi/L · 79 tests · 0.4 points above Bay County
- Radon levels in Midland CountyEPA zone 3
5.3%at or above 4 pCi/L
Median 1.0 pCi/L · 2,006 tests · 3.2 points below Bay County
Bay County, Cities and towns
Cities and towns in Bay County
About 102,123 people live in Bay County by the Census Bureau's estimate for July 1, 2025, 1,616 fewer than in 2020 (−1.6%). That works out to 231 people per square mile of land. Midland, the largest place on its list (42,806 residents in all), extends beyond Bay County, so no share of the total is worked out for it. Reported testing is thin here: 624 tests over 2008 to 2017, or 6.1 for every 1,000 residents (2025 estimate), where Michigan as a whole comes to 11.3.
From Midland to Pinconning, CDC publishes no figure by town: each reads Bay County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Midlandextends beyond Bay County | 42,806 | +0.4% | Counted whole |
| Bay City | 31,868 | −2.3% | 31.2% |
| Essexville | 3,284 | −2.6% | 3.2% |
| Auburn | 2,039 | −1.4% | 2.0% |
| Pinconning | 1,176 | −1.8% | 1.2% |
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). A place that extends beyond Bay County is counted whole, so it has no share.
Bay County, Homes
Homes in Bay County
Bay County is a place of houses on their own lots: 76% of its 48,620 homes are detached single-family houses, against 72% across Michigan. The homes are older than Michigan's as a whole: half were built before 1962 (1972 for Michigan), and 47% date from before 1960. Owners live in 76% of the occupied homes (Michigan: 73%), so for most households a test and a fix are their own to order.
| Homes | Bay County | Michigan |
|---|---|---|
| Housing units | 48,620 | 4,599,683 |
| Detached houses | 76% | 72% |
| In buildings of 5 or more | 10% | 13% |
| Mobile homes | 5% | 5% |
| Built before 1960 | 47% | 36% |
| Built since 2000 | 10% | 15% |
| Middle year built | 1962 | 1972 |
| Owner-occupied | 76% | 73% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.