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Radon in Sycamore, Illinois

EPA puts DeKalb County, where Sycamore is, in Zone 1, its highest radon zone, and high results are common there: 41.1% of the 1,707 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

    41.1%

    7.4 pts above IL

    DeKalb
    41.1%
    Illinois
    33.7%

    DeKalb, 40th of 70 in IL, 2017

  • Median result

    3.3pCi/L

    Below action level

    DeKalb
    3.3 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of DeKalb's tests, 2017

  • Nearest county

    36.6%

    Kane, 14 miles

    Kane
    36.6%
    DeKalb
    41.1%

    8,682 tests, 2017

  • EPA radon zone

    Zone 1

    Highest potential

    1. Zone 1
    2. 2
    3. 3

    1 highest, 3 lowest

    DeKalb, where Sycamore is

  • Tests reported

    1,707

    In DeKalb

    DeKalb
    1,707
    Kane
    8,682

    Reported to CDC before any fix, 2017

Read a result for Sycamore

Starts at DeKalb 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. DeKalb County's median reported result, 2017.

Interpret this readingWhat a fix costs

The data

Sycamore, What is published

What is published for Sycamore

Information:

Every figure for Sycamore is a county's

Radon data is published by county, not by city, so for Sycamore it is DeKalb County's: its EPA zone (Zone 1) and the 1,707 tests reported to CDC for 2017. Only a test tells you about one home.

Sycamore covers 10.1 square miles of land, all of it in DeKalb County. About 19,083 people live there, 1,886 to the square mile.

Sycamore, Counties

The county Sycamore lies in

Measured

DeKalb County's EPA zone and the figures CDC publishes for it, 2017.

DeKalb CountyZone 1Highest predicted potential

41.1%
Reported tests at or above 4 pCi/L
3.3 pCi/L
Median reported result
1,707 tests
Tests reported to CDC
4
Annual years on file

DeKalb County ranks 40th of 70 Illinois counties with 30 or more tests for that period, 7.4 points above the 33.7% pooled across Illinois's counties, 9.4 points above the national pool of 31.7%.

The counties nearest Sycamore with a CDC figure for 2017, measured from the middle of the city: Kane County (14 miles, 36.6% of 8,682 tests), Boone County (24 miles, 46.9% of 525 tests) and McHenry County (26 miles, 35.1% of 6,474 tests). Across the 8 nearest, the share at or above 4 pCi/L runs from 33.7% to 52.4%; the farthest of them, Lee County, is 36 miles away at 43.8%.

The directory lists 2 businesses with an address in Sycamore, 2 for testing. Illinois's other cities with a page of their own: Chicago, Rockford, Naperville and Springfield.

The counties around Sycamore

By distance from the middle of Sycamore; counties with 30 or more tests.

Nearest counties to Sycamore with 30 or more tests
CountyDistanceTestsAt or above 4 pCi/LMedian
Kane County14 mi8,68236.6%2.8 pCi/L
Boone County24 mi52546.9%3.4 pCi/L
McHenry County26 mi6,47435.1%2.9 pCi/L
Kendall County31 mi3,04535.0%2.8 pCi/L
DuPage County32 mi19,40133.7%2.7 pCi/L
Ogle County33 mi63652.4%4.1 pCi/L
Winnebago County34 mi2,70334.9%2.9 pCi/L
Lee County36 mi21943.8%3.3 pCi/L

Predicted: EPA Map of Radon Zones, by county. Measured: CDC tracking data, by county, 2017.

Sycamore, Geology

The ground under Sycamore

Predicted

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

USGS's geologic areas under Sycamore
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Bloomington Ridged PlainWisconsinan 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.

Sycamore beside its county and Illinois

All of Sycamore, like all of DeKalb County, is rated high. Sycamore has more high-potential ground than Illinois as a whole: 100% of its land against 64.5%.

Share of land by USGS radon potential: Sycamore, the county it lies in and Illinois
AreaEPA zoneLow potentialModerate potentialHigh potential
SycamoreBy countyNoneNone100%
DeKalb CountyZone 1NoneNone100%
Illinois102 counties, pooled by land areaVaries0.9%34.5%64.5%

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

Sycamore, Homes

Homes in Sycamore

Fewer than six in ten of Sycamore's 7,868 homes are detached houses (54%, against 57% across DeKalb County); the rest are attached, in shared buildings or mobile. Much of Sycamore is recent building: 40% of its homes have gone up since 2000 and the middle year built is 1992, against 1978 for DeKalb County. 71% of occupied homes are lived in by their owner (DeKalb County: 61%); in the rest a tenant can run a test, but a fix is the landlord's to make.

Homes in Sycamore, DeKalb County, Illinois, 2019 to 2023
HomesSycamoreDeKalb CountyIllinois
Housing units7,86841,4995,443,501
Detached houses54%57%58%
In buildings of 5 or more12%22%22%
Mobile homes2%2%2%
Built before 196023%26%38%
Built since 200040%26%16%
Middle year built199219781970
Owner-occupied71%61%67%

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

Local help

Sycamore, Professionals

Radon professionals listed in Sycamore

Businesses whose listed city is Sycamore, from the state registries and listings in the Radon411 directory, with the same business and certification status the directory shows.

2 listings with Sycamore as the city. See radon testing in Sycamore, or all radon professionals in Illinois.

Sycamore, Local resources

Local resources for Sycamore

Who to ask in Illinois: its radon program, test kits and professionals.

The program's own words on licensing and disclosure are on the Illinois page.

What it means

Sycamore, Questions

Questions about radon in Sycamore

What radon zone is Sycamore in?

Sycamore has no zone of its own: it shares DeKalb County's, Zone 1, the map's highest class: a predicted county average above 4 pCi/L.

What are radon levels in Sycamore?

41.1% of the 1,707 tests reported from DeKalb County for 2017 were at or above 4 pCi/L, the level at which EPA says to fix a home: high results are ordinary around Sycamore. The median reported result was 3.3 pCi/L.

Should I test my home in Sycamore?

Yes. About 702 of the 1,707 tests reported from DeKalb County were at or above 4 pCi/L. That is above Illinois' pooled 33.7%, and ranks DeKalb County 40th of the 70 Illinois counties with 30 or more tests. No map says which homes those are. How to test a home.

What ground is Sycamore built on, as far as radon goes?

USGS's geologic map puts all of Sycamore on one named area, "Bloomington Ridged Plain", rated high for radon potential, radon index 13.

Is radon higher in the counties around Sycamore?

Some are and some are not. Against DeKalb County's 41.1%, 3 of the 8 nearest counties with a figure report more and 5 less, from DuPage County (33.7%, 32 miles off) to Ogle County (52.4%, 33 miles off).

Who tests for or fixes radon in Sycamore?

Radon411's directory has 2 businesses with an address in Sycamore, all listed for testing, none for mitigation. Every entry names the public list it was taken from. Radon professionals in Sycamore.

The answers use the published figures of DeKalb County, the county Sycamore lies in.

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