Short-term kitempowerDX
Standard Radon Test short-term mail-in radon test kit
- Lab fee included
Method: Passive sampler
In home: 48 to 96 hours
Locations and reports
Radon Levels in McCulloch County, Texas
EPA puts McCulloch 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
2.0%
Williamson County, 110 miles
- Williamson
- 2.0%
- Texas
- 10.4%
Share at 4+ pCi/L, 98 tests, 2007 to 2016
Ground above low
21.5%
5.8 pts below Texas
- McCulloch
- 21.5%
- 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 McCulloch 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
McCulloch County, At a glance
McCulloch County at a glance
Predicted: EPA radon zone
EPA Zone 3: lower predicted potential
USGS geologic potential: Low across 79% 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 McCulloch County. Williamson County, 110 miles away, is the nearest county with a figure over the 2007 to 2016 laboratory totals.
McCulloch County, Compared
McCulloch County radon figures, compared
Calculated by Radon411McCulloch County has no radon test figure of its own from CDC, whose counts over the 2007 to 2016 laboratory totals name 140 other Texas counties and leave it out. 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 Williamson County (110 miles away) at 2.0%, Travis County (111 miles away) at 9.3% and Bell County (111 miles away) at 14.3%. 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 McCulloch County in Zone 3, its lowest label: a predicted county average under 2 pCi/L. USGS geology rates 79% of the county's land low radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
McCulloch County, Geology
The ground under McCulloch County
PredictedMost of the ground under McCulloch County is one class on USGS's geologic map: 78.5% of its land is low radon potential, with 21.5% moderate. The map puts 61.5% of McCulloch County in the area it calls Central Texas and 21.5% in Llano Uplift, with one smaller area beside them. USGS gives the first a radon index of 7, in the low band (5 to 8), and the second 10, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Central Texas | Cretaceous through Quaternary marine sandstone, shale, chalk, limestone, siltstone, clay, and lignite. | Low | 7 | 61.5% |
| Llano Uplift | Precambrian metamorphic and undifferentiated igneous rocks. | Moderate | 10 | 21.5% |
| Southern High Plains and Plateaus | Paleozoic and Mesozoic sandstone, limestone, shale. | Low | 7 | 17.0% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
McCulloch County beside the ground around it
Across Texas 0.5% of the land is rated high; none of McCulloch County's is. Of the 6 counties that border it, 2 have more moderate-potential ground, Mason County the most at 85.7%.
The map rates the ground, not the air in any home.
Local help
McCulloch County, Local resources
Radon testing and mitigation in McCulloch 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
McCulloch County, Questions
Questions about radon in McCulloch County
Are radon levels high in McCulloch County?
No CDC testing statistics are published here for McCulloch County, Texas yet. Of the 8 nearest counties with a figure, within 185 miles, the share of tests at or above 4 pCi/L runs from 0.0% to 17.1%.
Which counties border McCulloch County?
McCulloch County borders 6 counties: Concho County, Mason County, San Saba County, Menard County, Coleman County and Brown County.
Products
McCulloch County, Products
Testing a home in McCulloch County
No CDC figure names McCulloch County; the nearest county with one, Williamson County (110 miles away), reported 2.0% 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 McCulloch County.
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
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
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
McCulloch County, Bordering counties
Counties bordering McCulloch County
Calculated by Radon411- Radon levels in Brown CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 1.8 pCi/L · 1 test
- Radon levels in Concho CountyEPA zone 3
No CDC figure for 2007 to 2016; its page reads it against its own neighbours.
- Radon levels in Mason CountyEPA zone 2
No CDC figure for 2007 to 2016; its page reads it against its own neighbours.
- Radon levels in San Saba CountyEPA zone 3
No CDC figure for 2007 to 2016; its page reads it against its own neighbours.
- Radon levels in Menard CountyEPA zone 3
No CDC figure for 2007 to 2016; its page reads it against its own neighbours.
- Radon levels in Coleman CountyEPA zone 3
No CDC figure for 2007 to 2016; its page reads it against its own neighbours.
McCulloch County, Cities and towns
Cities and towns in McCulloch County
About 7,472 people live in McCulloch County by the Census Bureau's estimate for July 1, 2025, 120 fewer than in 2020 (−1.6%). Spread over its land, that is 7.0 people to the square mile. Brady alone is home to 4,980 of them, 66.6% of the total. Together its 2 incorporated places hold 68.3% of those residents; the other 31.7% live outside any of them. CDC publishes no radon test count for McCulloch County; across Texas its counts for 2007 to 2016 come to 0.1 tests for every 1,000 residents (2025 estimate).
From Brady to Melvin, CDC publishes no figure by town: each reads McCulloch County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Brady | 4,980 | −2.4% | 66.6% |
| Melvin | 122 | −1.6% | 1.6% |
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).
McCulloch County, Homes
Homes in McCulloch County
McCulloch County is a place of houses on their own lots: 79% of its 4,216 homes are detached single-family houses, against 65% across Texas. The homes are older than Texas' as a whole: half were built before 1967 (1990 for Texas), and 39% date from before 1960. 70% of occupied homes are lived in by their owner (Texas: 63%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | McCulloch County | Texas |
|---|---|---|
| Housing units | 4,216 | 11,890,808 |
| Detached houses | 79% | 65% |
| In buildings of 5 or more | 5% | 21% |
| Mobile homes | 7% | 7% |
| Built before 1960 | 39% | 13% |
| Built since 2000 | 12% | 37% |
| Middle year built | 1967 | 1990 |
| Owner-occupied | 70% | 63% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.