Short-term kitFirst Alert
RD1 short-term charcoal radon test kit
- Lab fee included
Method: Charcoal
In home: 2 to 4 days
Locations and reports
Radon Levels in McMullen County, Texas
EPA puts McMullen County in Zone 3, its lowest radon zone. Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Nearest county
0.0%
Nueces County, 73 miles
- Nueces
- 0.0%
- Texas
- 10.4%
Share at 4+ pCi/L, 45 tests, 2007 to 2016
Ground above low
None
27.3 pts below Texas
- McMullen
- 0.0%
- Texas
- 27.3%
Share of land USGS rates moderate or high potential
Tests reported
0
None published
A home here needs its own test
EPA radon zone
Zone 3
Lower potential
- 1
- 2
- Zone 3
1 highest, 3 lowest
EPA predicts under 2 pCi/L indoors
Read a result for McMullen 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
McMullen County, At a glance
McMullen County at a glance
Predicted: EPA radon zone
EPA Zone 3: lower predicted potential
USGS geologic potential: Low across 100% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
No CDC test figures here
CDC has published no radon test figures for McMullen County. Nueces County, 73 miles away, is the nearest county with a figure over the 2007 to 2016 laboratory totals.
McMullen County, Compared
McMullen County radon figures, compared
Calculated by Radon411CDC's county radon counts over the 2007 to 2016 laboratory totals cover 140 Texas counties, and McMullen County is not among them: no year's figure and no ten-year laboratory total names it. Pooled across 140 Texas counties, 10.4% of reported tests reached that level; across every county in the country with a figure, 35.8%.
The nearest counties with a figure are Nueces County (73 miles away) at 0.0%, Bexar County (76 miles away) at 6.6% and Travis County (145 miles away) at 9.3%. Statewide for the same period, Randall County reported the highest share (71.4%) and Nueces County the lowest (0.0%).
EPA's 1993 map puts McMullen County in Zone 3, its lowest label: a predicted county average under 2 pCi/L. USGS geology rates 100% of the county's land low radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
McMullen County, Geology
The ground under McMullen County
PredictedUSGS's geologic map puts all of McMullen County's mapped land in one class: low radon potential. 96.8% of it lies in the area the map calls South Texas Plain, to which USGS gives a radon index of 7, in the low band (5 to 8).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| South Texas Plain | Cretaceous through Quaternary marine sandstone, shale, chalk, limestone, siltstone, clay, and lignite. | Low | 7 | 96.8% |
| East Texas Province | Cretaceous through Quaternary marine sandstone, shale, chalk, limestone, siltstone, clay, and lignite. | Low | 6 | 3.2% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
McMullen County beside the ground around it
Across Texas 0.5% of the land is rated high; none of McMullen County's is. None of the 5 counties that border it has any moderate-potential ground either.
The map rates the ground, not the air in any home.
Local help
McMullen County, Local resources
Radon testing and mitigation in McMullen County
- Texas Radon GroupTexas Radon Group, run by Texas Tech University, does not license radon professionals and offers free or discounted test kits, and answers questions about testing and mitigation in Texas.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
The Texas Radon Group offers free radon test kits for Texas individuals who qualify.
- Compare kits
- Professionals in Texas7 professionals are listed in Texas.
What Texas's program says
- Licensing of radon professionals
There are no radon certification requirements for the State of Texas at this time, but the National Radon Proficiency Program lists radon testers and mitigators within Texas that have passed a rigorous national certification program.
What it means
McMullen County, Questions
Questions about radon in McMullen County
Are radon levels high in McMullen County?
No CDC testing statistics are published here for McMullen County, Texas yet. Of the 8 nearest counties with a figure, within 210 miles, the share of tests at or above 4 pCi/L runs from 0.0% to 14.3%.
Which counties border McMullen County?
McMullen County borders 5 counties: Live Oak County, La Salle County, Atascosa County, Duval County and Webb County.
Products
McMullen County, Products
Testing a home in McMullen County
No CDC figure names McMullen County; the nearest county with one, Nueces County (73 miles away), reported 0.0% of its tests at or above 4 pCi/L over the 2007 to 2016 laboratory totals, the only reading nearby until a test of this home. Zone 3 is the lowest label, yet homes at or above 4 pCi/L occur in every zone: a short-term kit (2 to 90 days) is the quick first check in McMullen County.
Test kits and monitors3
See every kit and monitor
Long-term kit
RL116 long-term radon test kit
- Lab fee extra
Method: Alpha track
In home: 90 days to 12 months
Monitor
EcoQube Flex battery digital radon monitor with an e-ink screen
- C-NRPP 2024/25: Not included
- Battery
- Bluetooth
- Alarm
- Screen, app
Method: Ion chamber
First reading: Within 15 minutes
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
McMullen County, Bordering counties
Counties bordering McMullen County
Calculated by Radon411- Radon levels in Atascosa CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 1.1 pCi/L · 1 test
- Radon levels in Webb CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 0.6 pCi/L · 6 tests
- Radon levels in Live Oak CountyEPA zone 3
No CDC figure for 2007 to 2016; its page reads it against its own neighbours.
- Radon levels in La Salle CountyEPA zone 3
No CDC figure for 2007 to 2016; its page reads it against its own neighbours.
- Radon levels in Duval CountyEPA zone 3
No CDC figure for 2007 to 2016; its page reads it against its own neighbours.
McMullen County, Residents
Who lives in McMullen County
McMullen County has been losing residents: from 598 in 2020 to 544 on July 1, 2025, a fall of 9.0% by the Census Bureau's estimates. Spread over its land, that is 0.5 people to the square mile. CDC publishes no radon test count for McMullen County; across Texas its counts for 2007 to 2016 come to 0.1 tests for every 1,000 residents (2025 estimate).
Census lists no incorporated place in McMullen County: every home in it reads the county's figures.
Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025).
McMullen County, Homes
Homes in McMullen County
Of McMullen County's 326 homes, 70% are detached houses, against 65% across Texas; 25% are mobile homes. Half of its homes were built before 1989, close to Texas' 1990: 21% date from before 1960 and 41% from 2000 or later. Owners live in 77% of the occupied homes (Texas: 63%), so for most households a test and a fix are their own to order.
| Homes | McMullen County | Texas |
|---|---|---|
| Housing units | 326 | 11,890,808 |
| Detached houses | 70% | 65% |
| In buildings of 5 or more | 0% | 21% |
| Mobile homes | 25% | 7% |
| Built before 1960 | 21% | 13% |
| Built since 2000 | 41% | 37% |
| Middle year built | 1989 | 1990 |
| Owner-occupied | 77% | 63% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.