Long-term kit
RL416 long-term radon test kit, lab fee included
- Lab fee included
Method: Alpha track
In home: 90 days to 12 months
Locations and reports
Radon Levels in Lake County, Colorado
EPA puts Lake County in Zone 1, its highest radon zone, and high results are common there: 54.3% of the 35 radon tests reported to CDC (2023) 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
Share at 4+ pCi/L
54.3%
15.4 pts above CO
- Lake
- 54.3%
- Colorado
- 38.9%
35 tests, 2023
Median result
4.7pCi/L
Action level reached
- Lake
- 4.7 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2023
Tests reported
35
37th of 38 by tests
- Lake
- 35
- Jefferson
- 3,068
Reported to CDC before any fix, 2023
EPA radon zone
Zone 1
Highest potential
- Zone 1
- 2
- 3
1 highest, 3 lowest
EPA predicts over 4 pCi/L indoors
Rank in Colorado
6 of 38
Top quarter
- Lake
- 54.3%
- Park
- 57.5%
By share, of 38 with 30+ tests
Read a result for Lake County
Starts at Lake County's median, 4.7 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 4.7 pCi/L
At or above 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is at or above 4 pCi/L. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. Lake County's median reported result, 2023.
The data
Lake County, At a glance
Lake County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Lake County in
USGS geologic potential: High across 71% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Lake County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 55.6% |
| 2015 | 48.3% |
| 2016 | 31.6% |
| 2017 | 42.7% |
| 2018 | 57.8% |
| 2019 | 52.7% |
| 2020 | 50.0% |
| 2021 | 54.4% |
| 2022 | 56.3% |
| 2023 | 54.3% |
2023: 54.3%. Across these years the share ran from 31.6% to 57.8%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 35 tests reported to CDC for Lake County over 2023, 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: 2023. Measured data period: 2005 to 2023 (every CDC figure on file).
Lake County, Compared
Lake County radon figures, compared
Calculated by Radon411More than half: 54.3% of the 35 radon tests reported to CDC for Lake County in 2023 read at least 4 pCi/L. That places it 6th of 38 Colorado counties with 30 or more tests for the same period. That is 15.4 points above the 38.9% pooled from 61 Colorado counties.
The median result, 4.7 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 59.9 pCi/L. The rest split 28.6% under 2 pCi/L and 17.1% from 2 to 4 (Colorado: 39.2% and 22.0%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 54.3% share point the same way here.
2 of its 5 bordering counties with figures ran higher, led by Park County at 57.5%; Pitkin County reported 36.6%. Statewide for the same period, Park County reported the highest share (57.5%) and Bent County the lowest (3.7%).
The busiest year on file was 2018, with 102 tests reported; the quietest, 2014, had 9.
Over 7 years of annual figures the share rose 6.0 points, from 48.3% in 2015 to 54.3% in 2023; its peak was 57.8% in 2018. Nationally, every county with a figure for the same period pools to 33.4%; Lake County sits 20.9 points above it. CDC also counts 5 tests taken after mitigation in Lake County for the same period: tests in homes where a fix was already in.
Lake CountyColorado, pooled
54.3% % of tests38.9% % of tests
| Year | Tests | Lake County, at or above 4 pCi/L | Colorado, pooled |
|---|---|---|---|
| 2015 | 60 | 48.3% | 47.2% |
| 2017 | 82 | 42.7% | 41.0% |
| 2018 | 102 | 57.8% | 44.2% |
| 2019 | 55 | 52.7% | 44.1% |
| 2021 | 57 | 54.4% | 47.3% |
| 2022 | 48 | 56.3% | 38.6% |
| 2023 | 35 | 54.3% | 38.9% |
Pooled shares: Radon411's sum of CDC's county counts for one period.
Lake County, State data
Colorado's own radon test data
MeasuredWhat Colorado's own agencies publish about radon tests in Lake County, with their period. These are not CDC's figures and are never added to them.
MeasuredState figures, not CDC's
What Colorado CDPHE reports for Lake County
Radon data (county results): radon test results received from radon testing labs, primarily short-term household tests taken by the homeowner. Period: 2005-2025.
Share over 4 pCi/L
54.7%
231 of 422 tests
Median result
4.4 pCi/L
Highest result
214.0 pCi/L
Tests behind these figures
422 tests
- CDPHE says these data do not give actual radon levels in homes that have not been tested.
- When possible, only tests conducted before a mitigation system was installed are used.
- Some counties have very small numbers of test results, and their summaries may be less representative.
- These figures describe tests reported to Colorado CDPHE in this area. They count a different set of tests than CDC's figures and are not a reading of any one home.
Measured: Colorado CDPHE data, 2005-2025.
Lake County, Geology
The ground under Lake County
PredictedUSGS's geologic map splits Lake County: 70.9% of its land is high radon potential and 29.1% moderate. The map puts 70.9% of Lake County in the area it calls Rocky Mountains and 29.1% in Western Slope. USGS gives the first a radon index of 15, 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 |
|---|---|---|---|---|
| Rocky Mountains | Precambrian granites, gneiss, amphibolite, variable uranium content, abundant shear zones.Sedimentary rocks shed from the granitic highlands. | High | 15 | 70.9% |
| Western Slope | Paleozoic and Mesozoic sandstone, siltstone, shale, basalt. | Moderate | 11 | 29.1% |
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
On high-potential ground Lake County is close to Colorado as a whole: 70.9% of its land against 74.8%. Of the 5 counties that border it, 3 have more high-potential ground, Chaffee 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
- Colorado's radon programColorado Department of Public Health and EnvironmentColorado's radon program licenses or certifies radon professionals, offers free or discounted test kits and states the rule for disclosing radon when a home is sold, and answers questions about testing and mitigation in Colorado.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
Order a discounted radon test kit
- Compare kits
- Professionals in Colorado25 professionals are listed in Colorado.
What Colorado's program says
- Licensing of radon professionals
Listed contractors are certified by the National Radon Proficiency Program or the National Radon Safety Board, and must be licensed by the Colorado Department of Regulatory Agencies.
- Disclosure when a home is sold or rented
As of August 7, 2023, landlords in Colorado are required to disclose radon information when a tenant signs a lease agreement.
What it means
Lake County, Questions
Questions about radon in Lake County
Are radon levels high in Lake County?
In 2023, 54.3% of the radon tests reported to CDC for Lake County, Colorado were at or above 4 pCi/L, and the median reported pre-mitigation result was 4.7 pCi/L. Of 38 Colorado counties with 30 or more tests for the same period, 5 reported a higher share; pooled, the state comes to 38.9%.
Which counties border Lake County?
Lake County borders 5 counties: Park County, Eagle County, Pitkin County, Summit County and Chaffee County.
Products
Lake County, Products
Testing a home in Lake County
In Lake County, 54.3% of 35 tests reported to CDC in 2023 reached 4 pCi/L, against 38.9% pooled across Colorado. In Zone 1 the year-round level in Lake 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
Monitor
View Radon Wi-Fi radon monitor with an e-paper display
- C-NRPP 2024/25: Approved
- Battery
- Wi-Fi, Bluetooth
- Screen, app
Method: Alpha spectrometry
Readings: Every 60 minutes
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
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Lake County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Lake County
Explore
Lake County, Bordering counties
Counties bordering Lake County
Calculated by Radon411- Radon levels in Park CountyEPA zone 1
57.5%at or above 4 pCi/L
Median 4.6 pCi/L · 106 tests · 3.2 points above Lake County
- Radon levels in Chaffee CountyEPA zone 1
55.2%at or above 4 pCi/L
Median 4.5 pCi/L · 165 tests · 0.9 points above Lake County
- Radon levels in Eagle CountyEPA zone 2
45.8%at or above 4 pCi/L
Median 3.5 pCi/L · 312 tests · 8.5 points below Lake County
- Radon levels in Summit CountyEPA zone 1
38.3%at or above 4 pCi/L
Median 2.0 pCi/L · 295 tests · 16.0 points below Lake County
- Radon levels in Pitkin CountyEPA zone 1
36.6%at or above 4 pCi/L
Median 2.5 pCi/L · 164 tests · 17.7 points below Lake County
Lake County, Cities and towns
Cities and towns in Lake County
The Census Bureau estimates 7,552 residents in Lake County for July 1, 2025, 143 more than in 2020 (+1.9%). That works out to 20 people per square mile of land. Leadville, its one incorporated place, has 2,668 residents, 35.3% of the total. CDC's 35 reported tests for 2023 work out to 4.6 per 1,000 residents (2025 estimate), close to Colorado's 3.6.
Leadville is the one incorporated place here; CDC publishes no figure by town, so it reads Lake County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Leadville | 2,668 | +1.9% | 35.3% |
One incorporated place, 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).
Lake County, Homes
Homes in Lake County
Lake County is a place of houses on their own lots: 77% of its 4,033 homes are detached single-family houses, against 62% across Colorado. The homes are older than Colorado's as a whole: half were built before 1971 (1987 for Colorado), and 39% date from before 1960. Owners live in 76% of the occupied homes (Colorado: 66%), so for most households a test and a fix are their own to order.
| Homes | Lake County | Colorado |
|---|---|---|
| Housing units | 4,033 | 2,545,124 |
| Detached houses | 77% | 62% |
| In buildings of 5 or more | 5% | 22% |
| Mobile homes | 10% | 4% |
| Built before 1960 | 39% | 16% |
| Built since 2000 | 17% | 31% |
| Middle year built | 1971 | 1987 |
| Owner-occupied | 76% | 66% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.