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Radon Levels in Kent County, Michigan

EPA puts Kent County in Zone 2, its middle radon zone, and 16.5% of its 8,449 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

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  • Share at 4+ pCi/L

    16.5%

    10.4 pts below MI

    Kent
    16.5%
    Michigan
    26.9%

    8,449 tests, 2008 to 2017

  • Median result

    1.8pCi/L

    Below action level

    Kent
    1.8 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    8,449

    3rd of 82 by tests

    Kent
    8,449
    Oakland
    16,224

    Reported to CDC before any fix, 2008 to 2017

  • EPA radon zone

    Zone 2

    Moderate potential

    1. 1
    2. Zone 2
    3. 3

    1 highest, 3 lowest

    EPA predicts 2 to 4 pCi/L indoors

  • Rank in Michigan

    43 of 82

    Middle half

    Kent
    16.5%
    Lenawee
    56.7%

    By share, of 82 with 30+ tests

Read a result for Kent County

Starts at Kent County's median, 1.8 pCi/L

1.8pCi/L

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

EPA’s reading of 1.8 pCi/L

Below 2 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 below 2 pCi/L, the level at which EPA says a fix should be considered. Kent County's median reported result, 2008 to 2017.

Interpret this reading

The data

Kent County, At a glance

Kent County at a glance

Predicted: EPA radon zone

EPA Zone 2: moderate predicted potential

Kent County is a county: EPA's forecast for it as a whole is an average indoor of 2 to 4 pCi/L (75 to 150 Bq/m³). It describes no single address, and homes above EPA's are found in every zone, this one included.

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 Kent County, 2008 to 2017, laboratory

Reported results by concentration band, Kent County, 2008 to 2017, laboratory
Under 2 pCi/L: 55%2 to 4 pCi/L: 29%4 pCi/L and above: 16%

Of 8,449 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Kent County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L4,63054.8%
2 to 4 pCi/L2,42528.7%
4 pCi/L and above1,39416.5%
What these figures count

These are the 8,449 tests reported to CDC for Kent 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

Kent County, Compared

Kent County radon figures, compared

Calculated by Radon411

Kent County's 8,449 reported tests over the 2008 to 2017 laboratory totals had a middle value of 1.8 pCi/L and a maximum of 76.5 pCi/L, and 16.5% reached 4 pCi/L. Michigan as a whole (83 Michigan counties, pooled) comes to 26.9%: 10.4 points higher than here.

Among its state's counties it ranks 43rd 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, 4,630 tests (54.8%) came in under 2 pCi/L, against 46.4% statewide, and 2,425 tests (28.7%) fell between 2 and 4, against 26.7% statewide. CDC's ten-year totals for Kent County went from 7,759 tests (2005 to 2014) to 8,449 (2008 to 2017), the share going from 16.2% to 16.5%.

EPA's 1993 zone map puts Kent County in Zone 2, a predicted county average between 2 and 4 pCi/L. USGS geology rates 76% of the county's land moderate radon potential.

Next door, the shares run from 3.2% in Muskegon County to 36.8% in Ionia County, with Newaygo County and Muskegon County below Kent County.

CDC also counts 445 tests taken after mitigation in Kent County for the same period: tests in homes where a fix was already in.

Kent County against Michigan, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Kent County
Kent County8,44916.5%1.8 pCi/LThis county
Michigan, pooled83 counties, pooled114,40726.9%Not pooled+10.4 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled+19.2 points
Lenawee Countyhighest in the state1,90756.7%4.6 pCi/L+40.2 points
Midland Countylowest in the state2,0065.3%1.0 pCi/L−11.2 points
Ionia County, MIborders it1,39136.8%2.9 pCi/L+20.3 points
Barry County, MIborders it1,61530.7%2.6 pCi/L+14.2 points
Montcalm County, MIborders it55023.6%2.1 pCi/L+7.1 points
Allegan County, MIborders it76618.4%1.7 pCi/L+1.9 points
Ottawa County, MIborders it2,54616.8%1.6 pCi/L+0.3 points
Newaygo County, MIborders it4677.9%1.3 pCi/L−8.6 points
Muskegon County, MIborders it6293.2%1.2 pCi/L−13.3 points
Where Kent County's reported results fell, 2008 to 2017, laboratory, beside Michigan and the United States
ResultKent County testsKent County shareMichigan shareU.S. shareAgainst Michigan
Under 2 pCi/L4,63054.8%46.4%39.6%+8.4 points
2 to 4 pCi/L2,42528.7%26.7%24.7%+2.0 points
4 pCi/L and above1,39416.5%26.9%35.7%−10.4 points
Kent 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
Wayne County38 of 825,59417.5%1.8 pCi/L
Saginaw County39 of 823,03717.0%1.7 pCi/L
Ottawa County40 of 822,54616.8%1.6 pCi/L
Gratiot County41 of 8245716.8%1.7 pCi/L
Sanilac County42 of 8232516.6%1.6 pCi/L
Kent County43 of 828,44916.5%1.8 pCi/L
Manistee County44 of 8238816.5%1.6 pCi/L
Isabella County45 of 8287016.4%1.6 pCi/L
Alger County46 of 8218916.4%1.2 pCi/L
Gladwin County47 of 8224715.4%1.3 pCi/L
Emmet County48 of 8281515.2%1.6 pCi/L
Kent County ten-year laboratory totals, against Michigan's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestMichigan, pooledChange from the row before
2008 to 20178,44916.5%1.8 pCi/L76.5 pCi/L26.9%Level
2007 to 20168,46816.5%1.7 pCi/L65.3 pCi/L26.8%+0.5 points
2006 to 20158,01016.0%1.7 pCi/L48.8 pCi/L26.8%−0.2 points
2005 to 20147,75916.2%1.7 pCi/L43.9 pCi/L26.2%First on file

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

Kent County, State data

Michigan's own radon test data

Measured

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

Michigan EGLE publishes its figures by ZIP code, not by county. These are the 38 ZIP codes that lie wholly or partly in Kent County, each with the state's own figures for it. Period: About 10 years to 2026-05-15.

ZIP codes in Kent County
ZIP codeWhat the state reports
4880927% greater than 4 pCi/L, median 2.6 pCi/L, 62 tests
4881522% greater than 4 pCi/L, median 1.7 pCi/L, 27 tests
4883833% greater than 4 pCi/L, median 2.4 pCi/L, 92 tests
4930117% greater than 4 pCi/L, median 1.8 pCi/L, 226 tests
4930216% greater than 4 pCi/L, median 1.9 pCi/L, 79 tests
4930624% greater than 4 pCi/L, median 2.2 pCi/L, 165 tests
4931511% greater than 4 pCi/L, median 1.5 pCi/L, 132 tests
4931615% greater than 4 pCi/L, median 1.9 pCi/L, 155 tests
493184 tests, figures not shown
4931915% greater than 4 pCi/L, median 2.2 pCi/L, 123 tests
493219% greater than 4 pCi/L, median 1.6 pCi/L, 96 tests
4932531% greater than 4 pCi/L, median 3.0 pCi/L, 13 tests
493268% greater than 4 pCi/L, median 1.3 pCi/L, 13 tests
4932713% greater than 4 pCi/L, median 1.7 pCi/L, 15 tests
493306% greater than 4 pCi/L, median 2.0 pCi/L, 16 tests
4933121% greater than 4 pCi/L, median 2.0 pCi/L, 146 tests
4933331% greater than 4 pCi/L, median 2.4 pCi/L, 189 tests
4934123% greater than 4 pCi/L, median 2.3 pCi/L, 451 tests
493438% greater than 4 pCi/L, median 1.6 pCi/L, 26 tests
493458% greater than 4 pCi/L, median 1.6 pCi/L, 77 tests
493474 tests, figures not shown
4934815% greater than 4 pCi/L, median 1.6 pCi/L, 52 tests
4941820% greater than 4 pCi/L, median 1.9 pCi/L, 207 tests
494356% greater than 4 pCi/L, median 1.6 pCi/L, 17 tests
4950311% greater than 4 pCi/L, median 1.2 pCi/L, 247 tests
4950410% greater than 4 pCi/L, median 1.3 pCi/L, 252 tests
4950516% greater than 4 pCi/L, median 1.7 pCi/L, 348 tests
495066% greater than 4 pCi/L, median 1.3 pCi/L, 349 tests
495074% greater than 4 pCi/L, median 1.2 pCi/L, 277 tests
495083% greater than 4 pCi/L, median 1.1 pCi/L, 233 tests
4950917% greater than 4 pCi/L, median 1.9 pCi/L, 94 tests
495128% greater than 4 pCi/L, median 1.0 pCi/L, 79 tests
4951923% greater than 4 pCi/L, median 2.1 pCi/L, 97 tests
4952521% greater than 4 pCi/L, median 1.8 pCi/L, 346 tests
4953414% greater than 4 pCi/L, median 1.6 pCi/L, 148 tests
4954416% greater than 4 pCi/L, median 1.6 pCi/L, 45 tests
4954610% greater than 4 pCi/L, median 1.8 pCi/L, 349 tests
4954818% greater than 4 pCi/L, median 1.8 pCi/L, 92 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.

Kent County, Geology

The ground under Kent County

Predicted

Most of the ground under Kent County is one class on USGS's geologic map: 76.4% of its land is moderate radon potential, with 23.6% low. The map puts 76.4% of Kent County in the area it calls South-Central Michigan Basin and 23.6% in Lake Michigan Lobe Deposits. USGS gives the first a radon index of 10, in the moderate band (9 to 11), and the second 8, in the low band (5 to 8).

USGS's geologic areas under Kent County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
South-Central Michigan BasinSandy and silty glacial deposits derived from sandstones, gray shales, limestones, and dolomites.Moderate1076.4%
Lake Michigan Lobe DepositsSandy to clayey glacial deposits and some glacial lake deposits.Low823.6%

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

Kent County beside the ground around it

Across Michigan 9.6% of the land is rated high; none of Kent County's is. Of the 7 counties that border it, 1 has more high-potential ground, Barry County the most at 7.1%.

Share of land by USGS radon potential: Kent County, the 7 counties bordering it and Michigan
AreaEPA zoneLow potentialModerate potentialHigh potential
Kent CountyZone 223.6%76.4%None
Ottawa CountyZone 399.9%NoneNone
Ionia CountyZone 2None100%None
Montcalm CountyZone 22.6%97.4%None
Barry CountyZone 2None92.9%7.1%
Muskegon CountyZone 398.4%NoneNone
Allegan CountyZone 391.3%8.7%None
Newaygo CountyZone 390.2%9.8%None
Michigan83 counties, pooled by land areaVaries45.0%44.3%9.6%

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

Local help

Kent County, Local resources

Radon testing and mitigation in Kent County

Listed radon businesses with an address in Kent County:

Listed radon professionals by town: Grand Rapids, Grandville, Cedar Springs

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

Kent County, Questions

Questions about radon in Kent County

Are radon levels high in Kent County?

Over the 2008 to 2017 laboratory totals, 16.5% of the radon tests reported to CDC for Kent County, Michigan were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.8 pCi/L. Of 82 Michigan counties with 30 or more tests for the same period, 42 reported a higher share; pooled, the state comes to 26.9%.

Which counties border Kent County?

Kent County borders 7 counties: Ottawa County, Ionia County, Montcalm County, Barry County, Muskegon County, Allegan County and Newaygo County.

Products

Kent County, Products

Testing a home in Kent County

In Kent County, 16.5% of 8,449 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 Kent County; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Kent County homes, compared

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Kent County, Bordering counties

Counties bordering Kent County

Calculated by Radon411

Kent County, Cities and towns

Cities and towns in Kent County

The Census Bureau estimates 675,232 residents in Kent County for July 1, 2025, 16,724 more than in 2020 (+2.5%). That works out to 795 people per square mile of land. Its largest town, Grand Rapids, has 201,183 residents, 29.8% of the total. CDC's 8,449 reported tests for 2008 to 2017 work out to 12.5 per 1,000 residents (2025 estimate), close to Michigan's 11.3.

From Grand Rapids to Casnovia, CDC publishes no figure by town: each reads Kent County's.

The 12 largest cities and towns in Kent County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Grand Rapids201,183+1.3%29.8%
Wyoming78,588+2.4%11.6%
Kentwood54,776+0.9%8.1%
Walker25,881+2.5%3.8%
Grandville17,018+6.0%2.5%
East Grand Rapids11,663+2.1%1.7%
Rockford6,313+2.2%0.9%
Sparta4,255+1.7%0.6%
Lowell4,134−0.3%0.6%
Cedar Springs3,789+4.4%0.6%
Caledonia1,778+6.7%0.3%
Kent City1,395+7.6%0.2%
  • Sand Lake
  • Casnovia (part)

14 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. “(part)” marks a place that extends into another county. Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025).

Kent County, Homes

Homes in Kent County

Of Kent County's 267,071 homes, 65% are detached houses, against 72% across Michigan; 17% are in buildings of five or more homes. Half of its homes were built before 1976, close to Michigan's 1972: 33% date from before 1960 and 21% from 2000 or later. 70% of occupied homes are lived in by their owner (Michigan: 73%); in the rest a tenant can run a test, but a fix is the landlord's to make.

Homes in Kent County, Michigan, 2019 to 2023
HomesKent CountyMichigan
Housing units267,0714,599,683
Detached houses65%72%
In buildings of 5 or more17%13%
Mobile homes4%5%
Built before 196033%36%
Built since 200021%15%
Middle year built19761972
Owner-occupied70%73%

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