Short-term kit
Radon Short Term Test Kit short-term charcoal radon test kit, lab fee included
- Lab fee included
Method: Charcoal
In home: 2 to 7 days
Locations and reports
Radon Levels in Lake County, Illinois
EPA puts Lake County in Zone 2, its middle radon zone, and 27.4% of its 13,050 reported radon tests (2017) 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
Share at 4+ pCi/L
27.4%
6.3 pts below IL
- Lake
- 27.4%
- Illinois
- 33.7%
13,050 tests, 2017
Median result
2.4pCi/L
Below action level
- Lake
- 2.4 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2017
Tests reported
13,050
3rd of 70 by tests
- Lake
- 13,050
- Cook
- 26,937
Reported to CDC before any fix, 2017
EPA radon zone
Zone 2
Moderate potential
- 1
- Zone 2
- 3
1 highest, 3 lowest
EPA predicts 2 to 4 pCi/L indoors
Rank in Illinois
59 of 70
Lowest quarter
- Lake
- 27.4%
- Stark
- 69.2%
By share, of 70 with 30+ tests
Read a result for Lake County
Starts at Lake County's median, 2.4 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.4 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. Lake County's median reported result, 2017.
The data
Lake County, At a glance
Lake County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Lake County is a
USGS geologic potential: Moderate across 86% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Lake County, 2017
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 32.6% |
| 2015 | 32.7% |
| 2016 | 14.0% |
| 2017 | 27.4% |
2017: 27.4%. Across these years the share ran from 14.0% to 32.7%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 13,050 tests reported to CDC for Lake 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).
Lake County, Compared
Lake County radon figures, compared
Calculated by Radon411Lake County's 13,050 reported tests in 2017 had a middle value of 2.4 pCi/L and a maximum of 76.0 pCi/L, and 27.4% reached 4 pCi/L. Illinois as a whole (93 Illinois counties, pooled) comes to 33.7%: 6.3 points higher than here.
Among its state's counties it ranks 59th of 70 Illinois counties with 30 or more tests for the same period. Statewide for the same period, Stark County reported the highest share (69.2%) and Williamson County the lowest (8.4%).
Below the action level, 5,223 tests (40.0%) came in under 2 pCi/L, against 37.7% statewide, and 4,257 tests (32.6%) fell between 2 and 4, against 28.6% statewide. The busiest year on file was 2014, with 19,008 tests reported; the quietest, 2016, had 1,071.
EPA's 1993 zone map puts Lake County in Zone 2, a predicted county average between 2 and 4 pCi/L. USGS geology rates 86% of the county's land moderate radon potential.
Next door, the shares run from 19.4% in Cook County to 41.9% in Kenosha County, WI, with Cook County below Lake County. Over 4 years of annual figures the share fell 5.2 points, from 32.6% in 2014 to 27.4% in 2017; its peak was 32.7% in 2015.
Lake CountyIllinois, pooled
| Year | Tests | Lake County, at or above 4 pCi/L | Illinois, pooled |
|---|---|---|---|
| 2014 | 19,008 | 32.6% | 37.8% |
| 2015 | 10,512 | 32.7% | 36.6% |
| 2016 | 1,071 | 14.0% | 17.4% |
| 2017 | 13,050 | 27.4% | 33.7% |
Pooled shares: Radon411's sum of CDC's county counts for one period.
Lake County, Geology
The ground under Lake County
PredictedMost of the ground under Lake County is one class on USGS's geologic map: 85.8% of its land is moderate radon potential, with 14.1% high. The map puts 85.8% of Lake County in the area it calls Wheaton Morainal Country and 14.1% in Bloomington Ridged Plain. USGS gives the first a radon index of 11, in the moderate band (9 to 11), and the second 13, in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Wheaton Morainal Country | Glacial lake deposits and clay-rich glacial till. | Moderate | 11 | 85.8% |
| Bloomington Ridged Plain | Wisconsinan glacial deposits and loess over Paleozoic sedimentary rocks. | High | 13 | 14.1% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Lake County beside the ground around it
Illinois as a whole has more high-potential ground than Lake County: 64.5% of its land, against 14.1% here. Of the 3 counties that border it, 2 have more high-potential ground, McHenry County the most at 100%.
The map rates the ground, not the air in any home.
Local help
Lake County, Local resources
Radon testing and mitigation in Lake County
Listed radon businesses with an address in Lake County:
- IEMA-OHS Radon ProgramIEMA-OHS Radon Program, run by Illinois Emergency Management Agency and Office of Homeland Security, licenses or certifies radon professionals and states the rule for disclosing radon when a home is sold, and answers questions about testing and mitigation in Illinois.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 Illinois339 professionals are listed in Illinois.
Listed radon professionals by town: Buffalo Grove, Mundelein, Highland Park, Gurnee, Grayslake, Libertyville, Lake Zurich, Lake Forest, Deerfield, Wauconda, Fox Lake, Barrington, Lake Villa, Lincolnshire, Volo, Lake Bluff
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
Lake County, Questions
Questions about radon in Lake County
Are radon levels high in Lake County?
In 2017, 27.4% of the radon tests reported to CDC for Lake County, Illinois were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.4 pCi/L. Of 70 Illinois counties with 30 or more tests for the same period, 58 reported a higher share; pooled, the state comes to 33.7%.
Which counties border Lake County?
Lake County borders 3 counties: Kenosha County, WI, McHenry County, IL and Cook County, IL.
Products
Lake County, Products
Testing a home in Lake County
In Lake County, 27.4% of 13,050 tests reported to CDC in 2017 reached 4 pCi/L, against 33.7% pooled across Illinois. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Lake County; a long-term test tells the year-round average.
Test kits and monitors3
See every kit and monitor
Long-term kit
RL116 long-term radon test kit
- Lab fee extra
Method: Alpha track
In home: 90 days to 12 months
Monitor
Corentium Home battery digital radon detector
- C-NRPP 2024/25: Approved
- Battery
- Screen
Method: Alpha spectrometry
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Lake County, Bordering counties
Counties bordering Lake County
Calculated by Radon411- Radon levels in Kenosha County, WIEPA zone 2
41.9%at or above 4 pCi/L
Median 3.4 pCi/L · 210 tests · 14.5 points above Lake County
- Radon levels in McHenry County, ILEPA zone 2
35.1%at or above 4 pCi/L
Median 2.9 pCi/L · 6,474 tests · 7.7 points above Lake County
- Radon levels in Cook County, ILEPA zone 2
19.4%at or above 4 pCi/L
Median 1.9 pCi/L · 26,937 tests · 8.0 points below Lake County
Lake County, Cities and towns
Cities and towns in Lake County
The Census Bureau estimates 719,339 residents in Lake County for July 1, 2025, 5,962 more than in 2020 (+0.8%). Packed into its land, that is 1,622 people per square mile. No town dominates: Waukegan, the largest, has 87,940 residents, 12.2% of the total. Testing is reported here more often than across the state: CDC's 13,050 reported tests for 2017 come to 18.1 for every 1,000 residents (2025 estimate), against 10.9 for Illinois.
From Waukegan to Old Mill Creek, CDC publishes no figure by town: each reads Lake County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Waukegan | 87,940 | −1.3% | 12.2% |
| Buffalo Groveextends beyond Lake County | 42,812 | −0.6% | Counted whole |
| Wheelingextends beyond Lake County | 38,391 | −2.1% | Counted whole |
| North Chicago | 34,050 | +10.8% | 4.7% |
| Mundelein | 32,680 | +3.6% | 4.5% |
| Highland Park | 30,767 | +2.0% | 4.3% |
| Gurnee | 30,458 | −0.6% | 4.2% |
| Round Lake Beach | 26,902 | −1.1% | 3.7% |
| Vernon Hills | 26,825 | Level | 3.7% |
| Zion | 24,447 | −1.1% | 3.4% |
| Grayslake | 21,140 | −0.4% | 2.9% |
| Libertyville | 20,701 | +0.7% | 2.9% |
- Lake Zurich
- Lake Forest
- Deerfield (part)
- Round Lake
- Antioch
- Lindenhurst
- Beach Park
- Wauconda
- Fox Lake (part)
- Barrington (part)
- Hawthorn Woods
- Lake Villa
- Long Grove
- Island Lake (part)
- Lincolnshire
- Park City
- Round Lake Park
- Volo
- Winthrop Harbor
- Lakemoor (part)
- Lake Bluff
- Highwood
- Lake Barrington
- Fox River Grove (part)
The other 16 places in Lake County
- Kildeer
- Barrington Hills (part)
- Green Oaks
- Riverwoods
- Deer Park (part)
- Hainesville
- Wadsworth
- North Barrington
- Round Lake Heights
- Port Barrington (part)
- Bannockburn
- Tower Lakes
- Third Lake
- Mettawa
- Indian Creek
- Old Mill Creek
52 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). A place that extends beyond Lake County is counted whole, so it has no share.
Lake County, Homes
Homes in Lake County
Of Lake County's 270,083 homes, 66% are detached houses, against 58% across Illinois; 16% are in buildings of five or more homes. Much of Lake County is recent building: 20% of its homes have gone up since 2000 and the middle year built is 1982, against 1970 for Illinois. 74% of occupied homes are lived in by their owner (Illinois: 67%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Lake County | Illinois |
|---|---|---|
| Housing units | 270,083 | 5,443,501 |
| Detached houses | 66% | 58% |
| In buildings of 5 or more | 16% | 22% |
| Mobile homes | 2% | 2% |
| Built before 1960 | 22% | 38% |
| Built since 2000 | 20% | 16% |
| Middle year built | 1982 | 1970 |
| Owner-occupied | 74% | 67% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.