Short-term kit
PicoCan short-term charcoal canister radon test
- Lab fee included
Method: Charcoal
In home: 48 to 96 hours
Locations and reports
Radon Levels in Alamosa County, Colorado
EPA puts Alamosa County in Zone 2, its middle radon zone, and only 12 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
26.6%
20.4 pts below CO
- Alamosa
- 26.6%
- Colorado
- 47.0%
79 tests, 2008 to 2017
Median result
2.1pCi/L
Below action level
- Alamosa
- 2.1 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
79
41st of 50 by tests
- Alamosa
- 79
- Jefferson
- 11,723
Reported to CDC before any fix, 2008 to 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 Colorado
50 of 50
Lowest quarter
- Alamosa
- 26.6%
- Kit Carson
- 71.4%
By share, of 50 with 30+ tests
Read a result for Alamosa County
Starts at Alamosa County's median, 2.1 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.1 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. Alamosa County's median reported result, 2008 to 2017.
The data
Alamosa County, At a glance
Alamosa County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Alamosa County is a
USGS geologic potential: Moderate across 92% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Alamosa County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 0.0% |
| 2015 | 33.3% |
| 2016 | 0.0% |
| 2017 | 0.0% |
| 2018 | 25.0% |
| 2019 | 33.3% |
| 2020 | 0.0% |
| 2021 | 70.0% |
| 2022 | 0.0% |
| 2023 | 25.0% |
2023: 25.0%. Across these years the share ran from 0.0% to 70.0%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
Only 12 tests were reported to CDC for Alamosa 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).
Alamosa County, Compared
Alamosa County radon figures, compared
Calculated by Radon411Alamosa County's 79 reported tests over the 2008 to 2017 laboratory totals had a middle value of 2.1 pCi/L and a maximum of 13.2 pCi/L, and 26.6% reached 4 pCi/L. Colorado as a whole (63 Colorado counties, pooled) comes to 47.0%: 20.4 points higher than here.
The newest figure, in 2023, counts only 12 tests (25.0% at or above 4 pCi/L), too few to compare, so this reading uses the 79-test figure.
Among its state's counties it ranks 50th of 50 Colorado counties with 30 or more tests for the same period. Statewide for the same period, Kit Carson County reported the highest share (71.4%) and Archuleta County the lowest (31.2%).
Below the action level, 30 tests (38.0%) came in under 2 pCi/L, against 31.4% statewide, and 28 tests (35.4%) fell between 2 and 4, against 21.5% statewide. The busiest year on file was 2022, with 22 tests reported; the quietest, 2014, had 4.
EPA's 1993 zone map puts Alamosa County in Zone 2, a predicted county average between 2 and 4 pCi/L. USGS geology rates 92% of the county's land moderate radon potential.
Next door, the shares run from 37.5% in Rio Grande County to 53.7% in Huerfano County.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Alamosa County, State data
Colorado's own radon test data
MeasuredWhat Colorado's own agencies publish about radon tests in Alamosa 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 Alamosa 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
27.4%
46 of 168 tests
Median result
2.0 pCi/L
Highest result
116.0 pCi/L
Tests behind these figures
168 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.
Alamosa County, Geology
The ground under Alamosa County
PredictedMost of the ground under Alamosa County is one class on USGS's geologic map: 91.9% of its land is moderate radon potential, with 8.1% high. The map puts 91.9% of Alamosa County in the area it calls San Juan Volcanic field and 8.1% in Rocky Mountains. 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 |
|---|---|---|---|---|
| San Juan Volcanic field | Volcanic rocks, rhyolite, tuff, basalt | Moderate | 11 | 91.9% |
| Rocky Mountains | Precambrian granites, gneiss, amphibolite, variable uranium content, abundant shear zones.Sedimentary rocks shed from the granitic highlands. | High | 15 | 8.1% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Alamosa County beside the ground around it
Colorado as a whole has more high-potential ground than Alamosa County: 74.8% of its land, against 8.1% here. Of the 5 counties that border it, 3 have more high-potential ground, Huerfano County the most at 87.7%.
The map rates the ground, not the air in any home.
Local help
Alamosa County, Local resources
Radon testing and mitigation in Alamosa 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
Alamosa County, Questions
Questions about radon in Alamosa County
Are radon levels high in Alamosa County?
In 2023, 25.0% of the radon tests reported to CDC for Alamosa County, Colorado were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.6 pCi/L. Of 50 Colorado counties with 30 or more tests for the same period, 49 reported a higher share; pooled, the state comes to 47.0%.
Which counties border Alamosa County?
Alamosa County borders 5 counties: Costilla County, Conejos County, Rio Grande County, Huerfano County and Saguache County.
Products
Alamosa County, Products
Testing a home in Alamosa County
In Alamosa County, 26.6% of 79 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 47.0% pooled across Colorado. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Alamosa County; a long-term test tells the year-round average.
Test kits and monitors3
See every kit and monitor
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
MonitorAranet
Radon Plus battery digital radon monitor with an e-ink screen
- C-NRPP 2024/25: Approved
- Battery
- Bluetooth
- Alarm
- Screen, app
Method: Ion chamber
First reading: Within 10 minutes
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Alamosa County, Bordering counties
Counties bordering Alamosa County
Calculated by Radon411- Radon levels in Saguache CountyEPA zone 2
53.8%at or above 4 pCi/L
Median 4.2 pCi/L · 26 tests · 27.2 points above Alamosa County
- Radon levels in Huerfano CountyEPA zone 1
53.7%at or above 4 pCi/L
Median 4.2 pCi/L · 67 tests · 27.1 points above Alamosa County
- Radon levels in Rio Grande CountyEPA zone 2
37.5%at or above 4 pCi/L
Median 3.0 pCi/L · 216 tests · 10.9 points above Alamosa County
- Radon levels in Costilla CountyEPA zone 2
36.4%at or above 4 pCi/L
Median 3.0 pCi/L · 11 tests · 9.8 points above Alamosa County
- Radon levels in Conejos CountyEPA zone 2
15.4%at or above 4 pCi/L
Median 2.4 pCi/L · 13 tests · 11.2 points below Alamosa County
Alamosa County, Cities and towns
Cities and towns in Alamosa County
The Census Bureau estimates 16,688 residents in Alamosa County for July 1, 2025, 311 more than in 2020 (+1.9%). That works out to 23 people per square mile of land. Alamosa alone is home to 9,849 of them, 59.0% of the total. Together its 2 incorporated places hold 59.5% of those residents; the other 40.5% live outside any of them. Reported testing is thin here: 79 tests over 2008 to 2017, or 4.7 for every 1,000 residents (2025 estimate), where Colorado as a whole comes to 16.0.
From Alamosa to Hooper, CDC publishes no figure by town: each reads Alamosa County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Alamosa | 9,849 | +0.4% | 59.0% |
| Hooper | 77 | −1.3% | 0.5% |
2 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).
Alamosa County, Homes
Homes in Alamosa County
Of Alamosa County's 7,148 homes, 64% are detached houses, against 62% across Colorado; 14% are in buildings of five or more homes. Half of its homes were built before 1984, close to Colorado's 1987: 20% date from before 1960 and 27% from 2000 or later. 56% 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 | Alamosa County | Colorado |
|---|---|---|
| Housing units | 7,148 | 2,545,124 |
| Detached houses | 64% | 62% |
| In buildings of 5 or more | 14% | 22% |
| Mobile homes | 11% | 4% |
| Built before 1960 | 20% | 16% |
| Built since 2000 | 27% | 31% |
| Middle year built | 1984 | 1987 |
| Owner-occupied | 56% | 66% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.