Short-term kit
RA100 short-term liquid scintillation radon test kit
- Lab fee extra
Method: Liquid scintillation
In home: 48 to 96 hours
Locations and reports
Radon Levels in Zavala County, Texas
EPA puts Zavala 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
6.6%
Bexar County, 85 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
- Zavala
- 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 Zavala 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
Zavala County, At a glance
Zavala 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 Zavala County. Bexar County, 85 miles away, is the nearest county with a figure over the 2007 to 2016 laboratory totals.
Zavala County, Compared
Zavala County radon figures, compared
Calculated by Radon411Zavala 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 Bexar County (85 miles away) at 6.6%, Nueces County (153 miles away) at 0.0% and Travis County (156 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 Zavala 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.
Zavala County, Geology
The ground under Zavala County
PredictedUSGS's geologic map puts all of Zavala County's mapped land in one class: low radon potential. All 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 | 100% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Zavala County beside the ground around it
Across Texas 0.5% of the land is rated high; none of Zavala 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
Zavala County, Local resources
Radon testing and mitigation in Zavala 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
Zavala County, Questions
Questions about radon in Zavala County
Are radon levels high in Zavala County?
No CDC testing statistics are published here for Zavala County, Texas yet. Of the 8 nearest counties with a figure, within 245 miles, the share of tests at or above 4 pCi/L runs from 0.0% to 17.1%.
Which counties border Zavala County?
Zavala County borders 6 counties: Dimmit County, Uvalde County, Maverick County, Frio County, Kinney County and Medina County.
Products
Zavala County, Products
Testing a home in Zavala County
No CDC figure names Zavala County; the nearest county with one, Bexar County (85 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 Zavala 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
Wave Plus battery radon and air quality monitor
- C-NRPP 2024/25: Not included
- Battery
- Bluetooth
- App only
Method: Alpha spectrometry
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Zavala County, Bordering counties
Counties bordering Zavala County
Calculated by Radon411- Radon levels in Maverick CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 0.1 pCi/L · 2 tests
- Radon levels in Medina CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 0.5 pCi/L · 2 tests
- Radon levels in Dimmit 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 Frio CountyEPA zone 3
No CDC figure for 2007 to 2016; its page reads it against its own neighbours.
- Radon levels in Kinney CountyEPA zone 3
No CDC figure for 2007 to 2016; its page reads it against its own neighbours.
Zavala County, Cities and towns
Cities and towns in Zavala County
Zavala County has been losing residents: from 9,668 in 2020 to 9,037 on July 1, 2025, a fall of 6.5% by the Census Bureau's estimates. Spread over its land, that is 7.0 people to the square mile. Crystal City, its one incorporated place, has 5,871 residents, 65.0% of the total. CDC publishes no radon test count for Zavala County; across Texas its counts for 2007 to 2016 come to 0.1 tests for every 1,000 residents (2025 estimate).
Crystal City is the one incorporated place here; CDC publishes no figure by town, so it reads Zavala County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Crystal City | 5,871 | −7.6% | 65.0% |
One incorporated place, 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).
Zavala County, Homes
Homes in Zavala County
Of Zavala County's 3,951 homes, 66% are detached houses, against 65% across Texas; 19% are mobile homes. The homes are older than Texas' as a whole: half were built before 1977 (1990 for Texas), and 26% date from before 1960. 71% 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 | Zavala County | Texas |
|---|---|---|
| Housing units | 3,951 | 11,890,808 |
| Detached houses | 66% | 65% |
| In buildings of 5 or more | 3% | 21% |
| Mobile homes | 19% | 7% |
| Built before 1960 | 26% | 13% |
| Built since 2000 | 15% | 37% |
| Middle year built | 1977 | 1990 |
| Owner-occupied | 71% | 63% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.