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 San Miguel County, Colorado
EPA puts San Miguel County in Zone 1, its highest radon zone, and only 16 radon tests from it are on file with CDC (2023). Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Share at 4+ pCi/L
37.7%
6.4 pts below CO
- San Miguel
- 37.7%
- Colorado
- 44.1%
61 tests, 2019
Median result
2.5pCi/L
Below action level
- San Miguel
- 2.5 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2019
Tests reported
61
32nd of 40 by tests
- San Miguel
- 61
- Jefferson
- 4,717
Reported to CDC before any fix, 2019
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
30 of 40
Middle half
- San Miguel
- 37.7%
- Hinsdale
- 80.6%
By share, of 40 with 30+ tests
Read a result for San Miguel County
Starts at San Miguel 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. San Miguel County's median reported result, 2019.
The data
San Miguel County, At a glance
San Miguel County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of San Miguel County in
USGS geologic potential: High across 96% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for San Miguel County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 37.5% |
| 2015 | 72.7% |
| 2016 | 40.0% |
| 2017 | 20.0% |
| 2018 | 37.7% |
| 2019 | 37.7% |
| 2020 | 41.7% |
| 2021 | 76.2% |
| 2022 | 36.8% |
| 2023 | 37.5% |
2023: 37.5%. Across these years the share ran from 20.0% to 76.2%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
Only 16 tests were reported to CDC for San Miguel County over 2023, and tests are often run on homes being sold or already suspected of a problem: so few describe neither the county nor this house.
Measured: CDC tracking data. Figure above: 2023. Measured data period: 2005 to 2023 (every CDC figure on file).
San Miguel County, Compared
San Miguel County radon figures, compared
Calculated by Radon411In San Miguel County, about 4 in 10 reported tests in 2019 (23 of 61) were at or above EPA's action level. Against the national pool of 29.0%, the gap is 8.7 points higher. Across 62 Colorado counties pooled together, 44.1% of tests reached that level, so San Miguel County runs 6.4 points below its state.
The newest figure, in 2023, counts only 16 tests (37.5% at or above 4 pCi/L), too few to compare, so this reading uses the 61-test figure.
Of 2 neighbours with a figure, all 2 reported a larger share at or above 4 pCi/L; the spread is 52.4% (Ouray County) to 66.6% (Montrose County). By share, San Miguel County is 30th of 40 Colorado counties with 30 or more tests for the same period.
Year by year, 2018 opened at 37.7% and 2020 closed at 41.7% (up 4.0 points), with 2020 the high at 41.7%. Half the tests came in under 2.5 pCi/L and half over it; the single highest reached 74.5 pCi/L. Below the action level, 24 tests (39.3%) came in under 2 pCi/L, against 33.7% statewide, and 14 tests (23.0%) fell between 2 and 4, against 22.3% statewide.
Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 37.7% share point the same way here. USGS geology rates 96% of the county's land high radon potential. CDC also counts 5 tests taken after mitigation in San Miguel County for the same period: tests in homes where a fix was already in.
The busiest year on file was 2018, with 61 tests reported; the quietest, 2016, had 5.
San Miguel CountyColorado, pooled
| Year | Tests | San Miguel County, at or above 4 pCi/L | Colorado, pooled |
|---|---|---|---|
| 2018 | 61 | 37.7% | 44.2% |
| 2019 | 61 | 37.7% | 44.1% |
| 2020 | 36 | 41.7% | 41.9% |
Pooled shares: Radon411's sum of CDC's county counts for one period.
San Miguel County, State data
Colorado's own radon test data
MeasuredWhat Colorado's own agencies publish about radon tests in San Miguel 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 San Miguel 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
42.3%
102 of 241 tests
Median result
3.1 pCi/L
Highest result
98.2 pCi/L
Tests behind these figures
241 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.
San Miguel County, Geology
The ground under San Miguel County
PredictedMost of the ground under San Miguel County is one class on USGS's geologic map: 96.5% of its land is high radon potential, with 3.5% moderate. 96.5% of it lies in the area the map calls Uravan Belt, to which USGS gives a radon index of 13, in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Uravan Belt | Uranium-bearing Cretaceous and Jurassic sedimentary rocks of the Uravan mineral belt. | High | 13 | 96.5% |
| San Juan Volcanic field | Volcanic rocks, rhyolite, tuff, basalt | Moderate | 11 | 3.5% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
San Miguel County beside the ground around it
San Miguel County has more high-potential ground than Colorado as a whole: 96.5% of its land against 74.8%. Of the 5 counties that border it, 1 has more high-potential ground, Montrose County the most at 100%.
The map rates the ground, not the air in any home.
Local help
San Miguel County, Local resources
Radon testing and mitigation in San Miguel 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
San Miguel County, Questions
Questions about radon in San Miguel County
Are radon levels high in San Miguel County?
In 2023, 37.5% of the radon tests reported to CDC for San Miguel County, Colorado were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.4 pCi/L. Of 40 Colorado counties with 30 or more tests for the same period, 29 reported a higher share; pooled, the state comes to 44.1%.
Which counties border San Miguel County?
San Miguel County borders 5 counties: Dolores County, CO, Montrose County, CO, Ouray County, CO, San Juan County, CO and San Juan County, UT.
Products
San Miguel County, Products
Testing a home in San Miguel County
In San Miguel County, 37.7% of 61 tests reported to CDC in 2019 reached 4 pCi/L, against 44.1% pooled across Colorado. In Zone 1 the year-round level in San Miguel 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
MonitorAEGTEST
HOUND-1011 rechargeable radon detector with a screen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
First reading: Within 6 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
San Miguel County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like San Miguel County
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San Miguel County, Bordering counties
Counties bordering San Miguel County
Calculated by Radon411- Radon levels in Montrose County, COEPA zone 1
66.6%at or above 4 pCi/L
Median 5.7 pCi/L · 479 tests · 28.9 points above San Miguel County
- Radon levels in Ouray County, COEPA zone 1
52.4%at or above 4 pCi/L
Median 4.0 pCi/L · 63 tests · 14.7 points above San Miguel County
- Radon levels in San Juan County, COEPA zone 2
25.0%at or above 4 pCi/L
Median 2.1 pCi/L · 4 tests · 12.7 points below San Miguel County
- Radon levels in Dolores County, COEPA zone 1
0.0%at or above 4 pCi/L
Median 2.4 pCi/L · 3 tests · 37.7 points below San Miguel County
- Radon levels in San Juan County, UTEPA zone 2
0.0%at or above 4 pCi/L
Median 1.1 pCi/L · 2 tests · 37.7 points below San Miguel County
San Miguel County, Cities and towns
Cities and towns in San Miguel County
About 7,753 people live in San Miguel County by the Census Bureau's estimate for July 1, 2025, 300 fewer than in 2020 (−3.7%). Spread over its land, that is 6.0 people to the square mile. Its largest town, Telluride, has 2,454 residents, 31.7% of the total. Together its 5 incorporated places hold 57.0% of those residents; the other 43.0% live outside any of them. CDC's 61 reported tests for 2019 work out to 7.9 per 1,000 residents (2025 estimate), close to Colorado's 5.6.
From Telluride to Sawpit, CDC publishes no figure by town: each reads San Miguel County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Telluride | 2,454 | −6.2% | 31.7% |
| Mountain Village | 1,234 | −2.1% | 15.9% |
| Norwood | 516 | −3.0% | 6.7% |
| Ophir | 185 | −5.1% | 2.4% |
| Sawpit | 34 | +3.0% | 0.4% |
5 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).
San Miguel County, Homes
Homes in San Miguel County
San Miguel County has 6,606 homes, and many share a building: 31% are in buildings of five or more, 52% are detached houses, against 62% across Colorado. Half of its homes were built before 1993, close to Colorado's 1987: 7% date from before 1960 and 31% from 2000 or later. 65% 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 | San Miguel County | Colorado |
|---|---|---|
| Housing units | 6,606 | 2,545,124 |
| Detached houses | 52% | 62% |
| In buildings of 5 or more | 31% | 22% |
| Mobile homes | 3% | 4% |
| Built before 1960 | 7% | 16% |
| Built since 2000 | 31% | 31% |
| Middle year built | 1993 | 1987 |
| Owner-occupied | 65% | 66% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.