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 Medina County, Texas
EPA puts Medina County in Zone 3, its lowest 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
6.6%
Bexar County
- Bexar
- 6.6%
1 of 6 neighbours have 30+ tests, 2007 to 2016
Nearest county
6.6%
Bexar County, 36 miles
- Bexar
- 6.6%
- Texas
- 10.4%
Share at 4+ pCi/L, 197 tests, 2007 to 2016
Ground above low
None
27.3 pts below Texas
- Medina
- 0.0%
- Texas
- 27.3%
Share of land USGS rates moderate or high potential
Tests reported
2
Too few for a share
- Medina
- 2
- Needed
- 30
2008 to 2017, laboratory
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 Medina 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
Medina County, At a glance
Medina 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
Radon tests reported for Medina County, 2008 to 2017, laboratory
CDC holds 2 reported tests for Medina County over the 2008 to 2017 laboratory totals, with a median of 0.5 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Medina County beside the counties around it is how this page reads it.
What these figures count
Only 2 tests were reported to CDC for Medina 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).
Medina County, Compared
Medina County radon figures, compared
Calculated by Radon411CDC's largest figure for Medina County rests on 2 tests over the 2008 to 2017 laboratory totals, 0 of them at or above 4 pCi/L, so each test moves its share by 50.0 points and no rank or comparison is drawn from it. Results reached as high as 0.9 pCi/L, with a middle value of 0.5 pCi/L.
Bexar County, the one bordering county with a figure over the 2007 to 2016 laboratory totals, reported 6.6% of its tests at or above 4 pCi/L. Farther out, Travis County (104 miles away) at 9.3%, Williamson County (127 miles away) at 2.0% and Nueces County (145 miles away) at 0.0% have figures too. 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 Medina 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.
Medina County, Geology
The ground under Medina County
PredictedUSGS's geologic map puts all of Medina County's mapped land in one class: low radon potential. The map puts 60.0% of Medina County in the area it calls South Texas Plain and 24.6% in Southern High Plains and Plateaus, with one smaller area beside them. USGS gives both 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 | 60.0% |
| Southern High Plains and Plateaus | Paleozoic and Mesozoic sandstone, limestone, shale. | Low | 7 | 24.6% |
| East Texas Province | Cretaceous through Quaternary marine sandstone, shale, chalk, limestone, siltstone, clay, and lignite. | Low | 6 | 15.3% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Medina County beside the ground around it
Across Texas 0.5% of the land is rated high; none of Medina County's is. None of the 6 counties that border it has any moderate-potential ground either.
The map rates the ground, not the air in any home.
Local help
Medina County, Local resources
Radon testing and mitigation in Medina 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
Medina County, Questions
Questions about radon in Medina County
Are radon levels high in Medina County?
Over the 2008 to 2017 laboratory totals, 0.0% of the radon tests reported to CDC for Medina County, Texas were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.5 pCi/L. Bexar County, the one bordering county with a figure over the 2007 to 2016 laboratory totals, reported 6.6% of its tests at or above 4 pCi/L.
Which counties border Medina County?
Medina County borders 6 counties: Bandera County, Frio County, Bexar County, Uvalde County, Atascosa County and Zavala County.
Products
Medina County, Products
Testing a home in Medina County
No CDC figure names Medina County; the nearest county with one, Bexar County (36 miles away), reported 6.6% 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 Medina 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
Monitor
Corentium Home 2 battery digital radon monitor
- C-NRPP 2024/25: Not included
- Battery
- Bluetooth
- Screen, app
Method: Alpha spectrometry
Readings: Every 60 minutes
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Medina County, Bordering counties
Counties bordering Medina County
Calculated by Radon411- Radon levels in Bexar CountyEPA zone 3
6.6%at or above 4 pCi/L
Median 0.6 pCi/L · 197 tests
- 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 Bandera CountyEPA zone 3
No CDC figure for 2007 to 2016; its page reads it against its own neighbours.
- Radon levels in Frio CountyEPA zone 3
No CDC figure for 2007 to 2016; its page reads it against its own neighbours.
- Radon levels in Uvalde CountyEPA zone 3
No CDC figure for 2007 to 2016; its page reads it against its own neighbours.
- Radon levels in Zavala CountyEPA zone 3
No CDC figure for 2007 to 2016; its page reads it against its own neighbours.
Medina County, Cities and towns
Cities and towns in Medina County
Medina County is growing: the Census Bureau puts it at 56,881 residents on July 1, 2025, up 11.4% from 51,058 in 2020. That works out to 43 people per square mile of land. San Antonio, the largest place on its list (1,548,422 residents in all), extends beyond Medina County, so no share of the total is worked out for it. Reported testing is thin here: 2 tests over 2008 to 2017, or under 0.1 for every 1,000 residents (2025 estimate), where Texas as a whole comes to 0.1.
From San Antonio to LaCoste, CDC publishes no figure by town: each reads Medina County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| San Antonioextends beyond Medina County | 1,548,422 | +7.7% | Counted whole |
| Hondo | 9,130 | +8.6% | 16.1% |
| Devine | 4,652 | +8.0% | 8.2% |
| Lytleextends beyond Medina County | 3,626 | +23.8% | Counted whole |
| Castroville | 3,444 | +15.9% | 6.1% |
| Natalia | 1,373 | +14.3% | 2.4% |
| LaCoste | 1,255 | +15.7% | 2.2% |
Places in Medina County with a city page: 1 of 1
7 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 Medina County is counted whole, so it has no share.
Medina County, Homes
Homes in Medina County
Of Medina County's 19,758 homes, 67% are detached houses, against 65% across Texas; 27% are mobile homes. Half of its homes were built before 1994, close to Texas' 1990: 15% date from before 1960 and 38% from 2000 or later. Owners live in 83% of the occupied homes (Texas: 63%), so for most households a test and a fix are their own to order.
| Homes | Medina County | Texas |
|---|---|---|
| Housing units | 19,758 | 11,890,808 |
| Detached houses | 67% | 65% |
| In buildings of 5 or more | 3% | 21% |
| Mobile homes | 27% | 7% |
| Built before 1960 | 15% | 13% |
| Built since 2000 | 38% | 37% |
| Middle year built | 1994 | 1990 |
| Owner-occupied | 83% | 63% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.