Short-term kitKidde
442020 short-term charcoal radon test kit
- Lab fee included
Method: Charcoal
In home: 3 days
Locations and reports
Radon Levels in Llano County, Texas
EPA puts Llano County in Zone 2, its middle radon zone, and only 6 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
Nearest county
9.3%
Travis County, 60 miles
- Travis
- 9.3%
- Texas
- 10.4%
Share at 4+ pCi/L, 408 tests, 2007 to 2016
Ground above low
100.0%
72.7 pts above Texas
- Llano
- 100.0%
- Texas
- 27.3%
Share of land USGS rates moderate or high potential
Tests reported
6
Too few for a share
- Llano
- 6
- Needed
- 30
2008 to 2017, 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 Llano 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
Llano County, At a glance
Llano County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Llano County is a
USGS geologic potential: Moderate across 100% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Llano County, 2008 to 2017, laboratory
CDC holds 6 reported tests for Llano County over the 2008 to 2017 laboratory totals, with a median of 1.5 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Llano County beside the counties around it is how this page reads it.
What these figures count
Only 6 tests were reported to CDC for Llano 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).
Llano County, Compared
Llano County radon figures, compared
Calculated by Radon411CDC's largest figure for Llano County rests on 6 tests over the 2008 to 2017 laboratory totals, 0 of them at or above 4 pCi/L, so each test moves its share by 16.7 points and no rank or comparison is drawn from it. Results reached as high as 3.6 pCi/L, with a middle value of 1.5 pCi/L.
The nearest counties with a figure are Travis County (60 miles away) at 9.3%, Williamson County (65 miles away) at 2.0% and Bell County (75 miles away) at 14.3%. Pooled across 140 Texas counties, 10.4% of reported tests reached that level; across every county in the country with a figure, 35.8%.
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 Llano County in Zone 2, its middle label: a predicted county average between 2 and 4 pCi/L. USGS geology rates 100% of the county's land moderate radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Llano County, Geology
The ground under Llano County
PredictedUSGS's geologic map puts all of Llano County's mapped land in one class: moderate radon potential. All of it lies in the area the map calls Llano Uplift, to which USGS gives a radon index of 10, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Llano Uplift | Precambrian metamorphic and undifferentiated igneous rocks. | Moderate | 10 | 100% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Llano County beside the ground around it
Across Texas 0.5% of the land is rated high; none of Llano County's is. Of the 5 counties that border it, none has as large a share of moderate-potential ground; Mason County comes nearest at 85.7%.
The map rates the ground, not the air in any home.
Local help
Llano County, Local resources
Radon testing and mitigation in Llano 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
Llano County, Questions
Questions about radon in Llano County
Are radon levels high in Llano County?
Over the 2008 to 2017 laboratory totals, 0.0% of the radon tests reported to CDC for Llano County, Texas were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.5 pCi/L. Of the 8 nearest counties with a figure, within 181 miles, the share of tests at or above 4 pCi/L runs from 0.0% to 17.1%.
Which counties border Llano County?
Llano County borders 5 counties: Gillespie County, Burnet County, Mason County, Blanco County and San Saba County.
Products
Llano County, Products
Testing a home in Llano County
No CDC figure names Llano County; the nearest county with one, Travis County (60 miles away), reported 9.3% 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. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Llano 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-1085 palm-sized rechargeable radon detector
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
First reading: Within 6 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Llano County, Bordering counties
Counties bordering Llano County
Calculated by Radon411- Radon levels in Burnet CountyEPA zone 3
71.4%at or above 4 pCi/L
Median 27.4 pCi/L · 7 tests
- Radon levels in Gillespie CountyEPA zone 3
20.0%at or above 4 pCi/L
Median 0.8 pCi/L · 10 tests
- Radon levels in Blanco CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 0.2 pCi/L · 2 tests
- 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.
Llano County, Cities and towns
Cities and towns in Llano County
Llano County is growing: the Census Bureau puts it at 23,353 residents on July 1, 2025, up 9.5% from 21,331 in 2020. That works out to 25 people per square mile of land. Horseshoe Bay, the largest place on its list (5,339 residents in all), extends beyond Llano County, so no share of the total is worked out for it. Testing is reported here more often than across the state: CDC's 6 reported tests for 2008 to 2017 come to 0.3 for every 1,000 residents (2025 estimate), against 0.1 for Texas.
From Horseshoe Bay to Sunrise Beach Village, CDC publishes no figure by town: each reads Llano County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Horseshoe Bayextends beyond Llano County | 5,339 | +24.6% | Counted whole |
| Llano | 3,587 | +6.7% | 15.4% |
| Sunrise Beach Village | 820 | +9.3% | 3.5% |
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). A place that extends beyond Llano County is counted whole, so it has no share.
Llano County, Homes
Homes in Llano County
Of Llano County's 15,583 homes, 73% are detached houses, against 65% across Texas; 12% are mobile homes. Half of its homes were built before 1990, close to Texas' 1990: 7% date from before 1960 and 34% 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 | Llano County | Texas |
|---|---|---|
| Housing units | 15,583 | 11,890,808 |
| Detached houses | 73% | 65% |
| In buildings of 5 or more | 5% | 21% |
| Mobile homes | 12% | 7% |
| Built before 1960 | 7% | 13% |
| Built since 2000 | 34% | 37% |
| Middle year built | 1990 | 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.