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 Starr County, Texas
EPA puts Starr County in Zone 3, its lowest radon zone, and only 1 radon test from it is 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
0.0%
Nueces County, 106 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
- Starr
- 0.0%
- Texas
- 27.3%
Share of land USGS rates moderate or high potential
Tests reported
1
Too few for a share
- Starr
- 1
- 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 Starr 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
Starr County, At a glance
Starr 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 Starr County, 2008 to 2017, laboratory
CDC holds 1 reported test for Starr County over the 2008 to 2017 laboratory totals, a result of 1.2 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Starr County beside the counties around it is how this page reads it.
What these figures count
Only 1 test was reported to CDC for Starr 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).
Starr County, Compared
Starr County radon figures, compared
Calculated by Radon411CDC's largest figure for Starr County rests on 1 test over the 2008 to 2017 laboratory totals, 0 of them at or above 4 pCi/L, so each test moves its share by 100.0 points and no rank or comparison is drawn from it. Results reached as high as 1.2 pCi/L, with a middle value of 1.2 pCi/L.
The nearest counties with a figure are Nueces County (106 miles away) at 0.0%, Bexar County (199 miles away) at 6.6% and Travis County (266 miles away) at 9.3%. 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 Starr 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.
Starr County, Geology
The ground under Starr County
PredictedUSGS's geologic map puts all of Starr 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 | 99.6% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Starr County beside the ground around it
Across Texas 0.5% of the land is rated high; none of Starr County's is. None of the 4 counties that border it has any moderate-potential ground either.
The map rates the ground, not the air in any home.
Local help
Starr County, Local resources
Radon testing and mitigation in Starr 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
Starr County, Questions
Questions about radon in Starr County
Are radon levels high in Starr County?
Over the 2008 to 2017 laboratory totals, 0.0% of the radon tests reported to CDC for Starr County, Texas were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.2 pCi/L. Of the 8 nearest counties with a figure, within 305 miles, the share of tests at or above 4 pCi/L runs from 0.0% to 9.3%.
Which counties border Starr County?
Starr County borders 4 counties: Hidalgo County, Zapata County, Jim Hogg County and Brooks County.
Products
Starr County, Products
Testing a home in Starr County
No CDC figure names Starr County; the nearest county with one, Nueces County (106 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 Starr 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
EcoQube Wi-Fi continuous radon monitor
- C-NRPP 2024/25: Approved
- Plug-in
- Wi-Fi
- App only
Method: Ion chamber
First reading: Within 10 minutes
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Starr County, Bordering counties
Counties bordering Starr County
Calculated by Radon411- Radon levels in Hidalgo CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 0.8 pCi/L · 15 tests
- Radon levels in Zapata CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 0.1 pCi/L · 2 tests
- Radon levels in Jim Hogg CountyEPA zone 3
No CDC figure for 2007 to 2016; its page reads it against its own neighbours.
- Radon levels in Brooks CountyEPA zone 3
No CDC figure for 2007 to 2016; its page reads it against its own neighbours.
Starr County, Cities and towns
Cities and towns in Starr County
The Census Bureau estimates 66,319 residents in Starr County for July 1, 2025, 466 more than in 2020 (+0.7%). That works out to 54 people per square mile of land. Its largest town, Rio Grande City, has 15,451 residents, 23.3% of the total. Together its 4 incorporated places hold 46.5% of those residents; the other 53.5% live outside any of them. Reported testing is thin here: 1 test 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 Rio Grande City to La Grulla, CDC publishes no figure by town: each reads Starr County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Rio Grande City | 15,451 | +1.1% | 23.3% |
| Roma | 11,543 | +0.3% | 17.4% |
| Escobares | 2,585 | Level | 3.9% |
| La Grulla | 1,234 | −0.2% | 1.9% |
4 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).
Starr County, Homes
Homes in Starr County
Starr County is a place of houses on their own lots: 80% of its 23,008 homes are detached single-family houses, against 65% across Texas. Half of its homes were built before 1993, close to Texas' 1990: 5% date from before 1960 and 36% from 2000 or later. 72% 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 | Starr County | Texas |
|---|---|---|
| Housing units | 23,008 | 11,890,808 |
| Detached houses | 80% | 65% |
| In buildings of 5 or more | 4% | 21% |
| Mobile homes | 11% | 7% |
| Built before 1960 | 5% | 13% |
| Built since 2000 | 36% | 37% |
| Middle year built | 1993 | 1990 |
| Owner-occupied | 72% | 63% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.