Short-term kit
RA400 short-term liquid scintillation radon test kit, lab fee included
- Lab fee included
Method: Liquid scintillation
In home: 48 to 96 hours
Locations and reports
Radon Levels in Sierra County, New Mexico
EPA puts Sierra County in Zone 2, its middle radon zone, and only 2 radon tests from it are on file with CDC (2008 to 2017, laboratory totals). Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Highest bordering
20.6%
Lincoln County
- Lincoln
- 20.6%
- Otero
- 10.7%
3 of 7 neighbours have 30+ tests, 2006 to 2015
Nearest county
16.3%
Doña Ana County, 58 miles
- Doña Ana
- 16.3%
- New Mexico
- 30.3%
Share at 4+ pCi/L, 104 tests, 2006 to 2015
Ground above low
98.9%
6.3 pts above New Mexico
- Sierra
- 98.9%
- New Mexico
- 92.6%
Share of land USGS rates moderate or high potential
Tests reported
7
Too few for a share
- Sierra
- 7
- Needed
- 30
2006 to 2015, laboratory
EPA radon zone
Zone 2
Moderate potential
- 1
- Zone 2
- 3
1 highest, 3 lowest
EPA predicts 2 to 4 pCi/L indoors
Read a result for Sierra County
Starts at EPA's action level
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 4.0 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.
The data
Sierra County, At a glance
Sierra County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Sierra County is a
USGS geologic potential: High across 50% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Sierra County, 2008 to 2017, laboratory
CDC holds 2 reported tests for Sierra County over the 2008 to 2017 laboratory totals, with a median of 2.2 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Sierra County beside the counties around it is how this page reads it.
What these figures count
Only 2 tests were reported to CDC for Sierra County over 2008 to 2017 (laboratory totals), 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: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).
Sierra County, Compared
Sierra County radon figures, compared
Calculated by Radon411CDC's largest figure for Sierra County rests on 7 tests over the 2006 to 2015 laboratory totals, 0 of them at or above 4 pCi/L, so each test moves its share by 14.3 points and no rank or comparison is drawn from it. Results reached as high as 3.5 pCi/L, with a middle value of 1.4 pCi/L.
Of the counties bordering it, 3 have a figure over the 2006 to 2015 laboratory totals: Lincoln County reported the largest share at or above 4 pCi/L, 20.6%, and Otero County the smallest, 10.7%, with Doña Ana County at 16.3% between. Farther out, Bernalillo County (136 miles away) at 25.2%, Sandoval County (177 miles away) at 24.7% and Santa Fe County (178 miles away) at 32.5% have figures too. Pooled across 30 New Mexico counties, 30.3% of reported tests reached that level; across every county in the country with a figure, 36.3%.
Statewide for the same period, Taos County reported the highest share (71.9%) and Otero County the lowest (10.7%). EPA's 1993 map puts Sierra County in Zone 2, its middle label: a predicted county average between 2 and 4 pCi/L. USGS geology rates 50% of the county's land high radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Sierra County, Geology
The ground under Sierra County
PredictedUSGS's geologic map splits Sierra County: 50.4% of its land is high radon potential and 48.6% moderate and 1.1% low. The map puts 50.4% of Sierra County in the area it calls Rocky Mountains (southern extension) and 48.6% in Datil-Mogollon Volcanic Field, with one smaller area beside them. USGS gives the first a radon index of 12, 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 (southern extension) | Sandstone, siltstone, shale, volcanic sediments, and valley-fill alluvium. | High | 12 | 50.4% |
| Datil-Mogollon Volcanic Field | Silicic to intermediate volcanic and volcaniclastic rocks, basin-fill gravel, sand, silt. | Moderate | 11 | 48.6% |
| Basin and Range Southern Mexican Highland | Volcanic, plutonic, and lesser sandstone, shale, limestone; Quaternary velley-fill alluvium. | Low | 8 | 1.1% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Sierra County beside the ground around it
Sierra County has more high-potential ground than New Mexico as a whole: 50.4% of its land against 19.2%. Of the 7 counties that border it, none has as large a share of high-potential ground; Doña Ana County comes nearest at 43.2%.
The map rates the ground, not the air in any home.
Local help
Sierra County, Local resources
Radon testing and mitigation in Sierra County
- New Mexico Indoor Radon Outreach ProgramNew Mexico Indoor Radon Outreach Program, run by New Mexico Environment Department, does not license radon professionals and offers free or discounted test kits, and answers questions about testing and mitigation in New Mexico.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
The New Mexico Environment Department seasonally distributes free radon testing kits to the public on a first-come, first-served basis.
- Compare kits
- See the New Mexico directoryNo professionals are listed in New Mexico yet. The state program can point you to registered testers and mitigators.
What New Mexico's program says
- Phone
- (505) 476-8600
- radon.questions@env.nm.gov
- Licensing of radon professionals
There is not currently a certification program within the state.
What it means
Sierra County, Questions
Questions about radon in Sierra County
Are radon levels high in Sierra County?
Over the 2008 to 2017 laboratory totals, 0.0% of the radon tests reported to CDC for Sierra County, New Mexico were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.2 pCi/L. Of the counties bordering it, 3 have a figure over the 2006 to 2015 laboratory totals: Lincoln County reported the largest share at or above 4 pCi/L, 20.6%, and Otero County the smallest, 10.7%, with Doña Ana County at 16.3% between.
Which counties border Sierra County?
Sierra County borders 7 counties: Doña Ana County, Luna County, Socorro County, Grant County, Otero County, Catron County and Lincoln County.
Products
Sierra County, Products
Testing a home in Sierra County
No CDC figure names Sierra County; the nearest county with one, Doña Ana County (58 miles away), reported 16.3% of its tests at or above 4 pCi/L over the 2006 to 2015 laboratory totals, the only reading nearby until a test of this home. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Sierra 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
MonitorAEGTEST
HOUND-3786 rechargeable radon monitor with a 3.5-inch color screen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
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
Sierra County, Bordering counties
Counties bordering Sierra County
Calculated by Radon411- Radon levels in Grant CountyEPA zone 2
40.0%at or above 4 pCi/L
Median 2.2 pCi/L · 20 tests
- Radon levels in Luna CountyEPA zone 2
30.0%at or above 4 pCi/L
Median 2.8 pCi/L · 10 tests
- Radon levels in Lincoln CountyEPA zone 2
20.6%at or above 4 pCi/L
Median 1.9 pCi/L · 34 tests
- Radon levels in Doña Ana CountyEPA zone 2
16.3%at or above 4 pCi/L
Median 1.4 pCi/L · 104 tests
- Radon levels in Otero CountyEPA zone 2
10.7%at or above 4 pCi/L
Median 1.1 pCi/L · 56 tests
- Radon levels in Socorro CountyEPA zone 2
0.0%at or above 4 pCi/L
Median 0.9 pCi/L · 8 tests
- Radon levels in Catron CountyEPA zone 2
0.0%at or above 4 pCi/L
Median 3.9 pCi/L · 1 test
Sierra County, Cities and towns
Cities and towns in Sierra County
About 11,395 people live in Sierra County by the Census Bureau's estimate for July 1, 2025, 167 fewer than in 2020 (−1.4%). Spread over its land, that is 2.7 people to the square mile. Truth or Consequences alone is home to 5,949 of them, 52.2% of the total. Together its 3 incorporated places hold 69.0% of those residents; the other 31.0% live outside any of them. Reported testing is thin here: 7 tests over 2006 to 2015, or 0.6 for every 1,000 residents (2025 estimate), where New Mexico as a whole comes to 2.0.
From Truth or Consequences to Williamsburg, CDC publishes no figure by town: each reads Sierra County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Truth or Consequences | 5,949 | −1.6% | 52.2% |
| Elephant Butte | 1,456 | +0.1% | 12.8% |
| Williamsburg | 458 | −1.3% | 4.0% |
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).
Sierra County, Homes
Homes in Sierra County
Mobile homes are 43% of Sierra County's 8,139 homes and detached houses 46%, against 65% across New Mexico. Half of its homes were built before 1983, close to New Mexico's 1984: 19% date from before 1960 and 18% from 2000 or later. 70% of occupied homes are lived in by their owner (New Mexico: 69%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Sierra County | New Mexico |
|---|---|---|
| Housing units | 8,139 | 949,524 |
| Detached houses | 46% | 65% |
| In buildings of 5 or more | 4% | 10% |
| Mobile homes | 43% | 16% |
| Built before 1960 | 19% | 17% |
| Built since 2000 | 18% | 24% |
| Middle year built | 1983 | 1984 |
| Owner-occupied | 70% | 69% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.