Listed for: Testing
Verified:Illinois state license
Call Amerispec Home Inspection at (630) 554-5900No website listed
Locations and reports
Radon in Naperville, Illinois
Naperville lies in 2 counties, in EPA Zone 2; 65.6% of it is in DuPage County, where 33.7% of 19,401 reported tests (2017) were at or above 4 pCi/L. Homes with elevated levels occur in all three zones, so the only way to know your home's level is to test it.
Data checked By Radon411Methodology
Share at 4+ pCi/L
33.7%
0.0 pts below IL
- DuPage
- 33.7%
- Illinois
- 33.7%
DuPage, 53rd of 70 in IL, 2017
Median result
2.7pCi/L
Below action level
- DuPage
- 2.7 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of DuPage's tests, 2017
Highest county
40.0%
Will
- Will
- 40.0%
- DuPage
- 33.7%
2 counties, 2 with 30+ tests, 2017
EPA radon zone
Zone 2
Moderate potential
- 1
- Zone 2
- 3
1 highest, 3 lowest
DuPage; Will Zone 2
Tests reported
19,401
In DuPage
- DuPage
- 19,401
- Will
- 10,776
Reported to CDC before any fix, 2017
Read a result for Naperville
Starts at DuPage County's median, 2.7 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.7 pCi/L
Between 2 and 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 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. DuPage County's median reported result, 2017.
The data
Naperville, What is published
What is published for Naperville
Information:
Every figure for Naperville is a county's
Radon data is published by county, not by city, and Naperville reaches into 2 counties: DuPage County and Will County. Each has its own EPA zone and its own CDC test figures, set side by side below and each labelled with its county. Only a test tells you about one home.
Naperville covers 39.1 square miles of land: 65.6% of it lies in DuPage County and 34.4% in Will County. About 153,114 people live there, 3,918 to the square mile.
Naperville, Counties
Naperville's counties, side by side
MeasuredEach county's own EPA zone and its own published CDC figures for 2017, the newest period any of them has. A county without a figure for that period is shown without one, never with a figure from another year.
- DuPage County
- EPA zone
- Zone 2: Moderate predicted potential
- At or above 4 pCi/L
- 33.7%
- Median result
- 2.7 pCi/L
- Tests reported
- 19,401 tests
- Annual years on file
- 4
- Will County
- EPA zone
- Zone 2: Moderate predicted potential
- At or above 4 pCi/L
- 40.0%
- Median result
- 3.1 pCi/L
- Tests reported
- 10,776 tests
- Annual years on file
- 4
| County | EPA zone | Reported tests at or above 4 pCi/L | Median reported result | Tests reported | Annual years on file |
|---|---|---|---|---|---|
| DuPage County | Zone 2: Moderate predicted potential | 33.7% | 2.7 pCi/L | 19,401 tests | 4 |
| Will County | Zone 2: Moderate predicted potential | 40.0% | 3.1 pCi/L | 10,776 tests | 4 |
Naperville spans 2 counties, each with its own EPA zone and its own CDC figure: DuPage County (Zone 2, 33.7% of 19,401 tests) and Will County (Zone 2, 40.0% of 10,776 tests).
DuPage County ranks 53rd of 70 Illinois counties with 30 or more tests for that period, 0.0 points below the 33.7% pooled across Illinois's counties, 2.0 points above the national pool of 31.7%. Of the city's other county, Will County reported 40.0%.
The counties nearest Naperville with a CDC figure for 2017, measured from the middle of the city: Kendall County (17 miles, 35.0% of 3,045 tests), Kane County (19 miles, 36.6% of 8,682 tests) and Cook County (19 miles, 19.4% of 26,937 tests). Across the 8 nearest, the share at or above 4 pCi/L runs from 19.4% to 41.1%; the farthest of them, Kankakee County, is 45 miles away at 31.6%.
The directory lists 12 businesses with an address in Naperville, 9 for testing and 3 for mitigation. Illinois's other cities with a page of their own: Chicago, Rockford, Springfield and Glenview.
Against Illinois and its other counties
Shares of tests people chose to run and report, by county (2017); the state's is its counties' counts added up, calculated by Radon411. Only a test measures a home.
The counties around Naperville
By distance from the middle of Naperville; counties with 30 or more tests.
The median reported pre-mitigation result for 2017 was 2.7 pCi/L in DuPage County and 3.1 pCi/L in Will County.
Predicted: EPA Map of Radon Zones, by county. Measured: CDC tracking data, by county, 2017.
Naperville, Geology
The ground under Naperville
PredictedUSGS's geologic map splits Naperville: 64.3% of its land is high radon potential and 35.7% moderate. The map puts 64.3% of Naperville in the area it calls Bloomington Ridged Plain and 35.7% in Wheaton Morainal Country. USGS gives the first a radon index of 13, in the high band (12 to 17), and the second 11, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Bloomington Ridged Plain | Wisconsinan glacial deposits and loess over Paleozoic sedimentary rocks. | High | 13 | 64.3% |
| Wheaton Morainal Country | Glacial lake deposits and clay-rich glacial till. | Moderate | 11 | 35.7% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Naperville beside its counties and Illinois
Naperville sits on more high-potential ground than DuPage County as a whole: 64.3% of the city against 19.9% of the county. On high-potential ground Naperville is close to Illinois as a whole: 64.3% of its land against 64.5%.
The map rates the ground, not the air in any home.
Naperville, Homes
Homes in Naperville
Of Naperville's 56,575 homes, 62% are detached houses, against 58% across DuPage County; 21% are in buildings of five or more homes. Much of Naperville is recent building: 21% of its homes have gone up since 2000 and the middle year built is 1989, against 1978 for DuPage County. 74% of occupied homes are lived in by their owner (DuPage County: 73%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Naperville | DuPage County | Illinois |
|---|---|---|---|
| Housing units | 56,575 | 366,099 | 5,443,501 |
| Detached houses | 62% | 58% | 58% |
| In buildings of 5 or more | 21% | 25% | 22% |
| Mobile homes | under 1% | under 1% | 2% |
| Built before 1960 | 6% | 18% | 38% |
| Built since 2000 | 21% | 14% | 16% |
| Middle year built | 1989 | 1978 | 1970 |
| Owner-occupied | 74% | 73% | 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
Naperville, Professionals
Radon professionals listed in Naperville
Businesses whose listed city is Naperville, from the state registries and listings in the Radon411 directory, with the same business and certification status the directory shows.
Radon professionals listed in Naperville: 1 of 6
12 listings with Naperville as the city. See radon mitigation and testing in Naperville, or all radon professionals in Illinois.
Naperville, Local resources
Local resources for Naperville
Who to ask in Illinois: its radon program, test kits and professionals.
- IEMA-OHS Radon ProgramRun by Illinois Emergency Management Agency and Office of Homeland Security, phone (800) 325-1245.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 Illinois12 listings cover Naperville.
The program's own words on licensing and disclosure are on the Illinois page.
What it means
Naperville, Questions
Questions about radon in Naperville
What radon zone is Naperville in?
Both counties Naperville reaches into (DuPage County and Will County) are in Zone 2, the map's middle class: a predicted county average of 2 to 4 pCi/L. EPA zones counties, not cities, so that is the zone for every part of Naperville.
What are radon levels in Naperville?
A high result is no surprise around Naperville: 33.7% of 19,401 tests reported from DuPage County for 2017 reached 4 pCi/L or more. The median reported result was 2.7 pCi/L. Will County reported 40.0% of 10,776 tests; the counties are kept apart.
Should I test my home in Naperville?
Yes. About 6,538 of the 19,401 tests reported from DuPage County were at or above 4 pCi/L. That is about what Illinois as a whole reports (33.7%), and ranks DuPage County 53rd 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 Naperville built on, as far as radon goes?
64.3% of Naperville sits on what USGS's map calls "Bloomington Ridged Plain", rated high for radon potential, radon index 13; another 35.7% is "Wheaton Morainal Country", rated moderate for radon potential, radon index 11. So the ground changes within Naperville itself.
Is radon higher in the counties around Naperville?
Some are and some are not. Against DuPage County's 33.7%, 4 of the 8 nearest counties with a figure report more and 4 less, from Cook County (19.4%, 19 miles off) to DeKalb County (41.1%, 33 miles off).
Who tests for or fixes radon in Naperville?
Radon411's directory has 12 businesses with an address in Naperville, 9 listed for testing and 3 for mitigation. Every entry names the public list it was taken from. Radon professionals in Naperville.
The answers use the published figures of DuPage County and Will County, the counties Naperville lies in.
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