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 Pitkin County, Colorado
EPA puts Pitkin County in Zone 1, its highest radon zone, and 36.6% of its 164 reported radon tests (2023) 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
36.6%
2.3 pts below CO
- Pitkin
- 36.6%
- Colorado
- 38.9%
164 tests, 2023
Median result
2.5pCi/L
Below action level
- Pitkin
- 2.5 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2023
Tests reported
164
20th of 38 by tests
- Pitkin
- 164
- 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
27 of 38
Middle half
- Pitkin
- 36.6%
- Park
- 57.5%
By share, of 38 with 30+ tests
Read a result for Pitkin County
Starts at Pitkin County's median, 2.5 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.5 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. Pitkin County's median reported result, 2023.
The data
Pitkin County, At a glance
Pitkin County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Pitkin County in
USGS geologic potential: Moderate across 67% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Pitkin County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 47.6% |
| 2015 | 45.9% |
| 2016 | 34.2% |
| 2017 | 41.5% |
| 2018 | 48.6% |
| 2019 | 40.6% |
| 2020 | 46.6% |
| 2021 | 60.7% |
| 2022 | 34.4% |
| 2023 | 36.6% |
2023: 36.6%. Across these years the share ran from 34.2% to 60.7%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 164 tests reported to CDC for Pitkin 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).
Pitkin County, Compared
Pitkin County radon figures, compared
Calculated by Radon411In Pitkin County, about 4 in 10 reported tests in 2023 (60 of 164) were at or above EPA's action level. Against the national pool of 33.4%, the gap is 3.2 points higher. Across 61 Colorado counties pooled together, 38.9% of tests reached that level, so Pitkin County runs 2.3 points below its state.
Of 6 neighbours with a figure, 4 reported a larger share at or above 4 pCi/L and 2 a smaller one; the spread is 18.9% (Mesa County) to 55.2% (Chaffee County). By share, Pitkin County is 27th of 38 Colorado counties with 30 or more tests for the same period.
Year by year, 2014 opened at 47.6% and 2023 closed at 36.6% (down 11.0 points), with 2021 the high at 60.7%. Half the tests came in under 2.5 pCi/L and half over it; the single highest reached 36.8 pCi/L. Below the action level, 65 tests (39.6%) came in under 2 pCi/L, against 39.2% statewide, and 39 tests (23.8%) fell between 2 and 4, against 22.0% statewide.
Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 36.6% share point the same way here. USGS geology rates 67% of the county's land moderate radon potential. CDC also counts 22 tests taken after mitigation in Pitkin County for the same period: tests in homes where a fix was already in.
The busiest year on file was 2018, with 249 tests reported; the quietest, 2014, had 63.
Pitkin CountyColorado, pooled
| Year | Tests | Pitkin County, at or above 4 pCi/L | Colorado, pooled |
|---|---|---|---|
| 2014 | 63 | 47.6% | 46.5% |
| 2015 | 170 | 45.9% | 47.2% |
| 2016 | 155 | 34.2% | 38.5% |
| 2017 | 142 | 41.5% | 41.0% |
| 2018 | 249 | 48.6% | 44.2% |
| 2019 | 219 | 40.6% | 44.1% |
| 2020 | 249 | 46.6% | 41.9% |
| 2021 | 163 | 60.7% | 47.3% |
| 2022 | 154 | 34.4% | 38.6% |
| 2023 | 164 | 36.6% | 38.9% |
Pooled shares: Radon411's sum of CDC's county counts for one period.
Pitkin County, State data
Colorado's own radon test data
MeasuredWhat Colorado's own agencies publish about radon tests in Pitkin 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 Pitkin 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
45.8%
1,268 of 2,767 tests
Median result
3.5 pCi/L
Highest result
307.6 pCi/L
Tests behind these figures
2,767 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.
Pitkin County, Geology
The ground under Pitkin County
PredictedUSGS's geologic map splits Pitkin County: 67.2% of its land is moderate radon potential and 32.8% high. The map puts 67.2% of Pitkin County in the area it calls Western Slope and 31.2% in Rocky Mountains, with one smaller area beside them. USGS gives the first a radon index of 11, in the moderate band (9 to 11), and the second 15, in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Western Slope | Paleozoic and Mesozoic sandstone, siltstone, shale, basalt. | Moderate | 11 | 67.2% |
| Rocky Mountains | Precambrian granites, gneiss, amphibolite, variable uranium content, abundant shear zones.Sedimentary rocks shed from the granitic highlands. | High | 15 | 31.2% |
| Paradox Basin | Tertiary sandstone, siltstone and shale. | High | 13 | 1.6% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Pitkin County beside the ground around it
Colorado as a whole has more high-potential ground than Pitkin County: 74.8% of its land, against 32.8% here. Of the 6 counties that border it, 5 have more high-potential ground, Chaffee County the most at 100%.
The map rates the ground, not the air in any home.
Local help
Pitkin County, Local resources
Radon testing and mitigation in Pitkin 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
Pitkin County, Questions
Questions about radon in Pitkin County
Are radon levels high in Pitkin County?
In 2023, 36.6% of the radon tests reported to CDC for Pitkin County, Colorado were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.5 pCi/L. Of 38 Colorado counties with 30 or more tests for the same period, 26 reported a higher share; pooled, the state comes to 38.9%.
Which counties border Pitkin County?
Pitkin County borders 6 counties: Gunnison County, Lake County, Eagle County, Chaffee County, Garfield County and Mesa County.
Products
Pitkin County, Products
Testing a home in Pitkin County
In Pitkin County, 36.6% of 164 tests reported to CDC in 2023 reached 4 pCi/L, against 38.9% pooled across Colorado. In Zone 1 the year-round level in Pitkin 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
MonitorKidde
Radon Detector (RAB) battery digital radon detector with an alarm
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
First reading: Within 12 hours
Short-term kit
Air Chek Short-Term radon test kit you hang, lab fee included
- Lab fee included
In home: 72 to 168 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Pitkin County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Pitkin County
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Pitkin County, Bordering counties
Counties bordering Pitkin County
Calculated by Radon411- Radon levels in Chaffee CountyEPA zone 1
55.2%at or above 4 pCi/L
Median 4.5 pCi/L · 165 tests · 18.6 points above Pitkin County
- Radon levels in Lake CountyEPA zone 1
54.3%at or above 4 pCi/L
Median 4.7 pCi/L · 35 tests · 17.7 points above Pitkin County
- Radon levels in Eagle CountyEPA zone 2
45.8%at or above 4 pCi/L
Median 3.5 pCi/L · 312 tests · 9.2 points above Pitkin County
- Radon levels in Garfield CountyEPA zone 1
39.3%at or above 4 pCi/L
Median 2.9 pCi/L · 224 tests · 2.7 points above Pitkin County
- Radon levels in Gunnison CountyEPA zone 1
34.7%at or above 4 pCi/L
Median 2.5 pCi/L · 147 tests · 1.9 points below Pitkin County
- Radon levels in Mesa CountyEPA zone 1
18.9%at or above 4 pCi/L
Median 2.2 pCi/L · 567 tests · 17.7 points below Pitkin County
Pitkin County, Cities and towns
Cities and towns in Pitkin County
About 16,625 people live in Pitkin County by the Census Bureau's estimate for July 1, 2025, 738 fewer than in 2020 (−4.3%). That works out to 17 people per square mile of land. Its largest town, Aspen, has 6,489 residents, 39.0% of the total. Testing is reported here more often than across the state: CDC's 164 reported tests for 2023 come to 9.9 for every 1,000 residents (2025 estimate), against 3.6 for Colorado.
From Aspen to Snowmass Village, CDC publishes no figure by town: each reads Pitkin County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Aspen | 6,489 | −7.0% | 39.0% |
| Basaltextends beyond Pitkin County | 4,009 | +1.1% | Counted whole |
| Snowmass Village | 2,965 | −1.2% | 17.8% |
3 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). A place that extends beyond Pitkin County is counted whole, so it has no share.
Pitkin County, Homes
Homes in Pitkin County
Pitkin County has 13,350 homes, and many share a building: 35% are in buildings of five or more, 38% are detached houses, against 62% across Colorado. Half of its homes were built before 1985, close to Colorado's 1987: 5% date from before 1960 and 23% from 2000 or later. 68% of occupied homes are lived in by their owner (Colorado: 66%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Pitkin County | Colorado |
|---|---|---|
| Housing units | 13,350 | 2,545,124 |
| Detached houses | 38% | 62% |
| In buildings of 5 or more | 35% | 22% |
| Mobile homes | 5% | 4% |
| Built before 1960 | 5% | 16% |
| Built since 2000 | 23% | 31% |
| Middle year built | 1985 | 1987 |
| Owner-occupied | 68% | 66% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.