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Radon Levels in Whiteside County, Illinois

EPA puts Whiteside County in Zone 1, its highest radon zone, and high results are common there: 43.1% of the 696 radon tests reported to CDC (2017) 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

How to test this homeFind a certified tester

  • Share at 4+ pCi/L

    43.1%

    9.4 pts above IL

    Whiteside
    43.1%
    Illinois
    33.7%

    696 tests, 2017

  • Median result

    3.3pCi/L

    Below action level

    Whiteside
    3.3 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2017

  • Tests reported

    696

    23rd of 70 by tests

    Whiteside
    696
    Cook
    26,937

    Reported to CDC before any fix, 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 Illinois

    37 of 70

    Middle half

    Whiteside
    43.1%
    Stark
    69.2%

    By share, of 70 with 30+ tests

Read a result for Whiteside County

Starts at Whiteside County's median, 3.3 pCi/L

3.3pCi/L

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

EPA’s reading of 3.3 pCi/L

Between 2 and 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 between 2 and 4 pCi/L. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. Whiteside County's median reported result, 2017.

Interpret this readingWhat a fix costs

The data

Whiteside County, At a glance

Whiteside County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Whiteside 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 Whiteside County, 2017

Share of reported tests at or above 4 pCi/L, by year, Whiteside County
Share of reported tests at or above 4 pCi/L, by year, Whiteside County
YearShare of reported tests at or above 4 pCi/L
201456.2%
201539.1%
201650.0%
201743.1%

2017: 43.1%. Across these years the share ran from 39.1% to 56.2%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

These are the 696 tests reported to CDC for Whiteside County over 2017, 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: 2017. Measured data period: 2005 to 2017 (every CDC figure on file).

How to read these figures

Whiteside County, Compared

Whiteside County radon figures, compared

Calculated by Radon411

In Whiteside County, about 4 in 10 reported tests in 2017 (300 of 696) were at or above EPA's action level. Against the national pool of 31.7%, the gap is 11.4 points higher. Across 93 Illinois counties pooled together, 33.7% of tests reached that level, so Whiteside County runs 9.4 points above its state.

Of 6 neighbours with a figure, all 6 reported a larger share at or above 4 pCi/L; the spread is 43.8% (Lee County) to 62.9% (Carroll County). By share, Whiteside County is 37th of 70 Illinois counties with 30 or more tests for the same period.

Year by year, 2014 opened at 56.2% and 2017 closed at 43.1% (down 13.1 points), with 2014 the high at 56.2%. Half the tests came in under 3.3 pCi/L and half over it; the single highest reached 37.4 pCi/L. Below the action level, 192 tests (27.6%) came in under 2 pCi/L, against 37.7% statewide, and 204 tests (29.3%) fell between 2 and 4, against 28.6% statewide.

Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 43.1% share point the same way here. USGS geology rates 100% of the county's land high radon potential.

The busiest year on file was 2014, with 897 tests reported; the quietest, 2016, had 6.

Share of reported tests at or above 4 pCi/L by year, Whiteside County against Illinois2014 to 2017, years with 30 or more tests: Whiteside County 56.2% to 43.1%, the state's pooled share 33.7% in 2017.
Whiteside CountyIllinois, pooled
Share of reported tests at or above 4 pCi/L by year, Whiteside County against Illinois: data table
YearTestsWhiteside County, at or above 4 pCi/LIllinois, pooled
201489756.2%37.8%
201545339.1%36.6%
201769643.1%33.7%
Whiteside County against Illinois, the United States and nearby counties, 2017
AreaTestsAt or above 4 pCi/LMedianDifference from Whiteside County
Whiteside County69643.1%3.3 pCi/LThis county
Illinois, pooled93 counties, pooled138,00633.7%Not pooled−9.4 points
United States, pooled937 counties, pooled528,06231.7%Not pooled−11.4 points
Stark Countyhighest in the state3969.2%5.8 pCi/L+26.1 points
Williamson Countylowest in the state2498.4%0.9 pCi/L−34.7 points
Carroll County, ILborders it21062.9%5.5 pCi/L+19.8 points
Bureau County, ILborders it33358.6%5.1 pCi/L+15.5 points
Henry County, ILborders it42055.7%4.6 pCi/L+12.6 points
Ogle County, ILborders it63652.4%4.1 pCi/L+9.3 points
Rock Island County, ILborders it2,28346.5%3.7 pCi/L+3.4 points
Lee County, ILborders it21943.8%3.3 pCi/L+0.7 points
Where Whiteside County's reported results fell, 2017, beside Illinois and the United States
ResultWhiteside County testsWhiteside County shareIllinois shareU.S. shareAgainst Illinois
Under 2 pCi/L19227.6%37.7%43.5%−10.1 points
2 to 4 pCi/L20429.3%28.6%24.8%+0.7 points
4 pCi/L and above30043.1%33.7%31.7%+9.4 points
Whiteside County ranked among the 70 Illinois counties with 30 or more tests, by share at or above 4 pCi/L, 2017
CountyRankTestsAt or above 4 pCi/LMedian
Jo Daviess County32 of 7051345.0%3.5 pCi/L
Champaign County33 of 703,15944.7%3.4 pCi/L
Montgomery County34 of 7012343.9%3.3 pCi/L
Lee County35 of 7021943.8%3.3 pCi/L
Sangamon County36 of 703,37843.7%3.7 pCi/L
Whiteside County37 of 7069643.1%3.3 pCi/L
McLean County38 of 704,54842.5%3.3 pCi/L
Christian County39 of 7021342.3%3.5 pCi/L
DeKalb County40 of 701,70741.1%3.3 pCi/L
Peoria County41 of 703,81640.2%3.1 pCi/L
Will County42 of 7010,77640.0%3.1 pCi/L
Whiteside County radon tests by year, against Illinois' pooled share
YearTestsAt or above 4 pCi/LMedianHighestIllinois, pooledChange from the row before
201769643.1%3.3 pCi/L37.4 pCi/L33.7%−6.9 points
2016650.0%4.5 pCi/L6.6 pCi/L17.4%+10.9 points
201545339.1%3.5 pCi/L28.6 pCi/L36.6%−17.1 points
201489756.2%4.5 pCi/L184.0 pCi/L37.8%First on file

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

Whiteside County, Geology

The ground under Whiteside County

Predicted

USGS's geologic map puts all of Whiteside County's mapped land in one class: high radon potential. All of it lies in the area the map calls Galesburg Plain, to which USGS gives a radon index of 13, in the high band (12 to 17).

USGS's geologic areas under Whiteside County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Galesburg PlainIllinoian glacial deposits and loess over Paleozoic sedimentary rocks.High13100%

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

Whiteside County beside the ground around it

Whiteside County has more high-potential ground than Illinois as a whole: 100% of its land against 64.5%. Of the 7 counties that border it, none has as large a share of high-potential ground; Henry County comes nearest at 100%.

Share of land by USGS radon potential: Whiteside County, the 7 counties bordering it and Illinois
AreaEPA zoneLow potentialModerate potentialHigh potential
Whiteside CountyZone 1NoneNone100%
Carroll CountyZone 1NoneNone100%
Rock Island CountyZone 1NoneNone100%
Henry CountyZone 1NoneNone100%
Bureau CountyZone 1NoneNone100%
Clinton County, IAZone 1NoneNone100%
Lee CountyZone 1NoneNone100%
Ogle CountyZone 1NoneNone100%
Illinois102 counties, pooled by land areaVaries0.9%34.5%64.5%

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

Local help

Whiteside County, Local resources

Radon testing and mitigation in Whiteside County

Listed radon businesses with an address in Whiteside County:

Listed radon professionals by town: Rock Falls

What Illinois's program says
Phone
(800) 325-1245
Licensing of radon professionals
The Agency also licenses and regulates the individuals who provide radon measurement and mitigation to the public.
Disclosure when a home is sold or rented
Illinois Radon Awareness Act - This is the legislation that requires the seller to provide to the buyer of any interest in residential real property the IEMA-OHS pamphlet entitled "Radon Testing Guidelines for Real Estate Transactions" and the Illinois Disclosure of Information on Radon Hazards.

What it means

Whiteside County, Questions

Questions about radon in Whiteside County

Are radon levels high in Whiteside County?

In 2017, 43.1% of the radon tests reported to CDC for Whiteside County, Illinois were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.3 pCi/L. Of 70 Illinois counties with 30 or more tests for the same period, 36 reported a higher share; pooled, the state comes to 33.7%.

Which counties border Whiteside County?

Whiteside County borders 7 counties: Carroll County, IL, Rock Island County, IL, Henry County, IL, Bureau County, IL, Clinton County, IA, Lee County, IL and Ogle County, IL.

Products

Whiteside County, Products

Testing a home in Whiteside County

In Whiteside County, 43.1% of 696 tests reported to CDC in 2017 reached 4 pCi/L, against 33.7% pooled across Illinois. In Zone 1 the year-round level in Whiteside 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

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

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Whiteside County, Bordering counties

Counties bordering Whiteside County

Calculated by Radon411

Whiteside County, Cities and towns

Cities and towns in Whiteside County

About 54,121 people live in Whiteside County by the Census Bureau's estimate for July 1, 2025, 1,434 fewer than in 2020 (−2.6%). That works out to 79 people per square mile of land. Its largest town, Sterling, has 14,394 residents, 26.6% of the total. Together its 11 incorporated places hold 66.5% of those residents; the other 33.5% live outside any of them. CDC's 696 reported tests for 2017 work out to 12.9 per 1,000 residents (2025 estimate), close to Illinois' 10.9.

From Sterling to Deer Grove, CDC publishes no figure by town: each reads Whiteside County's.

The cities and towns in Whiteside County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Sterling14,394−3.0%26.6%
Rock Falls8,521−2.8%15.7%
Morrison3,945−3.0%7.3%
Fulton3,540−2.8%6.5%
Prophetstown1,887−2.8%3.5%
Erie1,484−2.2%2.7%
Albany838−2.1%1.5%
Tampico668−3.3%1.2%
Lyndon526−1.7%1.0%
Coleta159−2.5%0.3%
Deer Grove39+8.3%Under 0.1%

11 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).

Whiteside County, Homes

Homes in Whiteside County

Whiteside County is a place of houses on their own lots: 81% of its 25,850 homes are detached single-family houses, against 58% across Illinois. The homes are older than Illinois' as a whole: half were built before 1960 (1970 for Illinois), and 50% date from before 1960. Owners live in 75% of the occupied homes (Illinois: 67%), so for most households a test and a fix are their own to order.

Homes in Whiteside County, Illinois, 2019 to 2023
HomesWhiteside CountyIllinois
Housing units25,8505,443,501
Detached houses81%58%
In buildings of 5 or more7%22%
Mobile homes2%2%
Built before 196050%38%
Built since 200010%16%
Middle year built19601970
Owner-occupied75%67%

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