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Radon Levels in Hillsdale County, Michigan

EPA puts Hillsdale County in Zone 1, its highest radon zone, and high results are common there: 54.8% of the 2,086 radon tests reported to CDC (2008 to 2017, laboratory totals) came back 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

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  • Share at 4+ pCi/L

    54.8%

    27.9 pts above MI

    Hillsdale
    54.8%
    Michigan
    26.9%

    2,086 tests, 2008 to 2017

  • Median result

    4.4pCi/L

    Action level reached

    Hillsdale
    4.4 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    2,086

    14th of 82 by tests

    Hillsdale
    2,086
    Oakland
    16,224

    Reported to CDC before any fix, 2008 to 2017

  • EPA radon zone

    Zone 1

    Highest potential

    1. Zone 1
    2. 2
    3. 3

    1 highest, 3 lowest

    EPA predicts over 4 pCi/L indoors

  • Rank in Michigan

    3 of 82

    Top quarter

    Hillsdale
    54.8%
    Lenawee
    56.7%

    By share, of 82 with 30+ tests

Read a result for Hillsdale County

Starts at Hillsdale County's median, 4.4 pCi/L

4.4pCi/L

EPA’s own thresholds; the figures are the area’s, never this home’s.

EPA’s reading of 4.4 pCi/L

At or above 4 pCi/L

  1. Under 20 to 1.9 pCi/L
  2. 2 to 4consider a fix
  3. 4 and aboveEPA says fix it

This result is at or above 4 pCi/L. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. Hillsdale County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Hillsdale County, At a glance

Hillsdale County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Hillsdale County in and predicts an average indoor of greater than 4 pCi/L (greater than 150 Bq/m³) across the county. That is one forecast for the whole county, not a reading of any address in it; homes above EPA's turn up in all three zones.

USGS geologic potential: High across 100% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Hillsdale County, 2008 to 2017, laboratory

Reported results by concentration band, Hillsdale County, 2008 to 2017, laboratory
Under 2 pCi/L: 23%2 to 4 pCi/L: 22%4 pCi/L and above: 55%

Of 2,086 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Hillsdale County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L47923.0%
2 to 4 pCi/L46322.2%
4 pCi/L and above1,14454.8%
What these figures count

These are the 2,086 tests reported to CDC for Hillsdale 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).

How to read these figures

Hillsdale County, Compared

Hillsdale County radon figures, compared

Calculated by Radon411

More than half: 54.8% of the 2,086 radon tests reported to CDC for Hillsdale County over the 2008 to 2017 laboratory totals read at least 4 pCi/L. That places it 3rd of 82 Michigan counties with 30 or more tests for the same period. That is 27.9 points above the 26.9% pooled from 83 Michigan counties.

The median result, 4.4 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 275.6 pCi/L. The rest split 23.0% under 2 pCi/L and 22.2% from 2 to 4 (Michigan: 46.4% and 26.7%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 54.8% share point the same way here.

3 of its 6 bordering counties with figures ran higher, led by Lenawee County at 56.7%; Calhoun County reported 36.4%. Statewide for the same period, Lenawee County reported the highest share (56.7%) and Muskegon County the lowest (3.2%).

CDC's ten-year totals for Hillsdale County went from 2,479 tests (2005 to 2014) to 2,086 (2008 to 2017), the share going from 54.1% to 54.8%.

Nationally, every county with a figure for the same period pools to 35.7%; Hillsdale County sits 19.1 points above it. CDC also counts 161 tests taken after mitigation in Hillsdale County for the same period: tests in homes where a fix was already in.

Hillsdale County against Michigan, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Hillsdale County
Hillsdale County2,08654.8%4.4 pCi/LThis county
Michigan, pooled83 counties, pooled114,40726.9%Not pooled−27.9 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−19.1 points
Livingston Countyhighest in the state4,88543.1%3.4 pCi/L−11.7 points
Muskegon Countylowest in the state6293.2%1.2 pCi/L−51.6 points
Lenawee County, MIborders it1,90756.7%4.6 pCi/L+1.9 points
Steuben County, INborders it14055.7%4.5 pCi/L+0.9 points
Branch County, MIborders it1,04855.4%4.4 pCi/L+0.6 points
Jackson County, MIborders it2,96449.7%3.9 pCi/L−5.1 points
Fulton County, OHborders it6245.2%3.1 pCi/L−9.6 points
Williams County, OHborders it2842.9%3.3 pCi/L−11.9 points
Calhoun County, MIborders it1,64936.4%3.0 pCi/L−18.4 points
Where Hillsdale County's reported results fell, 2008 to 2017, laboratory, beside Michigan and the United States
ResultHillsdale County testsHillsdale County shareMichigan shareU.S. shareAgainst Michigan
Under 2 pCi/L47923.0%46.4%39.6%−23.4 points
2 to 4 pCi/L46322.2%26.7%24.7%−4.5 points
4 pCi/L and above1,14454.8%26.9%35.7%+27.9 points
Hillsdale County ranked among the 82 Michigan counties with 30 or more tests, by share at or above 4 pCi/L, 2008 to 2017, laboratory
CountyRankTestsAt or above 4 pCi/LMedian
Lenawee County1 of 821,90756.7%4.6 pCi/L
Branch County2 of 821,04855.4%4.4 pCi/L
Hillsdale County3 of 822,08654.8%4.4 pCi/L
Jackson County4 of 822,96449.7%3.9 pCi/L
Livingston County5 of 824,88543.1%3.4 pCi/L
Washtenaw County6 of 828,50041.3%3.2 pCi/L
Dickinson County7 of 8284339.3%3.1 pCi/L
Clinton County8 of 822,31338.5%3.1 pCi/L
Otsego County9 of 821,08038.2%3.2 pCi/L
Ionia County10 of 821,39136.8%2.9 pCi/L
Calhoun County11 of 821,64936.4%3.0 pCi/L
Hillsdale County ten-year laboratory totals, against Michigan's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestMichigan, pooledChange from the row before
2008 to 20172,08654.8%4.4 pCi/L275.6 pCi/L26.9%−0.9 points
2007 to 20162,17555.7%4.4 pCi/L275.6 pCi/L26.8%+0.1 points
2006 to 20152,37955.6%4.4 pCi/L275.6 pCi/L26.8%+1.5 points
2005 to 20142,47954.1%4.3 pCi/L275.6 pCi/L26.2%First on file

Pooled shares: Radon411's sum of CDC's county counts for one period.

Hillsdale County, State data

Michigan's own radon test data

Measured

What Michigan's own agencies publish about radon tests in Hillsdale 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 Hillsdale County

Michigan EGLE publishes its figures by ZIP code, not by county. These are the 17 ZIP codes that lie wholly or partly in Hillsdale County, each with the state's own figures for it. Period: About 10 years to 2026-05-15.

ZIP codes in Hillsdale County
ZIP codeWhat the state reports
4908236% greater than 4 pCi/L, median 3.3 pCi/L, 45 tests
4922059% greater than 4 pCi/L, median 4.3 pCi/L, 22 tests
4922747% greater than 4 pCi/L, median 3.6 pCi/L, 15 tests
4923219% greater than 4 pCi/L, median 2.7 pCi/L, 16 tests
4923362% greater than 4 pCi/L, median 5.2 pCi/L, 29 tests
4924243% greater than 4 pCi/L, median 3.0 pCi/L, 248 tests
4924662% greater than 4 pCi/L, median 6.6 pCi/L, 29 tests
4924755% greater than 4 pCi/L, median 4.5 pCi/L, 31 tests
4924962% greater than 4 pCi/L, median 5.5 pCi/L, 34 tests
4925052% greater than 4 pCi/L, median 4.6 pCi/L, 88 tests
4925254% greater than 4 pCi/L, median 4.6 pCi/L, 26 tests
4925564% greater than 4 pCi/L, median 4.3 pCi/L, 11 tests
4926214% greater than 4 pCi/L, median 2.9 pCi/L, 7 tests
4926656% greater than 4 pCi/L, median 4.5 pCi/L, 34 tests
4927136% greater than 4 pCi/L, median 2.6 pCi/L, 22 tests
4927421% greater than 4 pCi/L, median 2.2 pCi/L, 29 tests
4928871% greater than 4 pCi/L, median 7.1 pCi/L, 7 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.

Hillsdale County, Geology

The ground under Hillsdale County

Predicted

USGS's geologic map puts all of Hillsdale County's mapped land in one class: high radon potential. All of it lies in the area the map calls Saginaw Lobe Moraine Area, to which USGS gives a radon index of 12, in the high band (12 to 17).

USGS's geologic areas under Hillsdale County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Saginaw Lobe Moraine AreaGlacial deposits derived from Sandstone and shale.High1299.7%

Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.

Hillsdale County beside the ground around it

Hillsdale County has more high-potential ground than Michigan as a whole: 100% of its land against 9.6%. Of the 7 counties that border it, none has as large a share of high-potential ground; Branch County comes nearest at 100%.

Share of land by USGS radon potential: Hillsdale County, the 7 counties bordering it and Michigan
AreaEPA zoneLow potentialModerate potentialHigh potential
Hillsdale CountyZone 1NoneNone100%
Jackson CountyZone 1None9.4%90.6%
Williams County, OHZone 2None9.7%90.3%
Branch CountyZone 1NoneNone100%
Lenawee CountyZone 1None31.4%68.6%
Calhoun CountyZone 1None25.0%75.0%
Steuben County, INZone 1NoneNone100%
Fulton County, OHZone 2None64.9%35.1%
Michigan83 counties, pooled by land areaVaries45.0%44.3%9.6%

The map rates the ground, not the air in any home.

Local help

Hillsdale County, Local resources

Radon testing and mitigation in Hillsdale County

Listed radon businesses with an address in Hillsdale County:

Listed radon professionals by town: Jonesville

What Michigan's program says
Phone
800-723-6642
Email
Radon@Michigan.gov
Licensing of radon professionals
Michigan does not license or regulate radon testing and mitigation contractors.

What it means

Hillsdale County, Questions

Questions about radon in Hillsdale County

Are radon levels high in Hillsdale County?

Over the 2008 to 2017 laboratory totals, 54.8% of the radon tests reported to CDC for Hillsdale County, Michigan were at or above 4 pCi/L, and the median reported pre-mitigation result was 4.4 pCi/L. Of 82 Michigan counties with 30 or more tests for the same period, 2 reported a higher share; pooled, the state comes to 26.9%.

Which counties border Hillsdale County?

Hillsdale County borders 7 counties: Jackson County, MI, Williams County, OH, Branch County, MI, Lenawee County, MI, Calhoun County, MI, Steuben County, IN and Fulton County, OH.

Products

Hillsdale County, Products

Testing a home in Hillsdale County

In Hillsdale County, 54.8% of 2,086 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 26.9% pooled across Michigan. In Zone 1 the year-round level in Hillsdale 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

Hillsdale County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Hillsdale County

Explore

Hillsdale County, Bordering counties

Counties bordering Hillsdale County

Calculated by Radon411

Hillsdale County, Cities and towns

Cities and towns in Hillsdale County

Hillsdale County's population has barely moved since 2020: 45,738 residents on July 1, 2025 against 45,740 then, by the Census Bureau's estimates. That works out to 76 people per square mile of land. No town dominates: Hillsdale, the largest, has 8,002 residents, 17.5% of the total. Together its 9 incorporated places hold 32.2% of those residents; the other 67.8% live outside any of them. Testing is reported here more often than across the state: CDC's 2,086 reported tests for 2008 to 2017 come to 45.6 for every 1,000 residents (2025 estimate), against 11.3 for Michigan.

From Hillsdale to Allen, CDC publishes no figure by town: each reads Hillsdale County's.

The cities and towns in Hillsdale County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Hillsdale8,002−0.3%17.5%
Jonesville2,175−0.3%4.8%
Litchfield1,394−0.1%3.0%
Reading1,084−0.9%2.4%
Waldron550−0.7%1.2%
Camden514−0.4%1.1%
North Adams465−1.1%1.0%
Montgomery318−0.3%0.7%
Allen213−0.5%0.5%

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).

Hillsdale County, Homes

Homes in Hillsdale County

Hillsdale County is a place of houses on their own lots: 82% of its 21,490 homes are detached single-family houses, against 72% across Michigan. Half of its homes were built before 1970, close to Michigan's 1972: 41% date from before 1960 and 13% from 2000 or later. Owners live in 81% of the occupied homes (Michigan: 73%), so for most households a test and a fix are their own to order.

Homes in Hillsdale County, Michigan, 2019 to 2023
HomesHillsdale CountyMichigan
Housing units21,4904,599,683
Detached houses82%72%
In buildings of 5 or more5%13%
Mobile homes9%5%
Built before 196041%36%
Built since 200013%15%
Middle year built19701972
Owner-occupied81%73%

Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.