Short-term kit
RA400 short-term liquid scintillation radon test kit, lab fee included
- Lab fee included
Method: Liquid scintillation
In home: 48 to 96 hours
Locations and reports
Radon Levels in Calhoun County, Texas
EPA puts Calhoun 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
0.0%
Nueces County, 82 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
- Calhoun
- 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 Calhoun 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
Calhoun County, At a glance
Calhoun County at a glance
Predicted: EPA radon zone
EPA Zone 3: lower predicted potential
USGS geologic potential: Low across 75% 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 Calhoun County. Nueces County, 82 miles away, is the nearest county with a figure over the 2007 to 2016 laboratory totals.
Calhoun County, Compared
Calhoun County radon figures, compared
Calculated by Radon411No CDC figure names Calhoun County, in any year or ten-year total; over the 2007 to 2016 laboratory totals, the agency's counts reach 140 Texas counties without it. 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 Nueces County (82 miles away) at 0.0%, Brazoria County (84 miles away) at 6.3% and Fort Bend County (86 miles away) at 3.4%. 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 Calhoun County in Zone 3, its lowest label: a predicted county average under 2 pCi/L. USGS geology rates 75% of the county's land low radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Calhoun County, Geology
The ground under Calhoun County
PredictedUSGS's geologic map puts all of Calhoun County's mapped land in one class: low radon potential. 75.2% of it lies in the area the map calls Coastal 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 |
|---|---|---|---|---|
| Coastal Plain | Cretaceous through Quaternary marine sandstone, shale, chalk, limestone, siltstone, clay, and lignite. | Low | 7 | 75.2% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Calhoun County beside the ground around it
Across Texas 0.5% of the land is rated high; none of Calhoun County's is. None of the 5 counties that border it has any moderate-potential ground either.
The map rates the ground, not the air in any home.
Local help
Calhoun County, Local resources
Radon testing and mitigation in Calhoun 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
Calhoun County, Questions
Questions about radon in Calhoun County
Are radon levels high in Calhoun County?
No CDC testing statistics are published here for Calhoun County, Texas yet. Of the 8 nearest counties with a figure, within 145 miles, the share of tests at or above 4 pCi/L runs from 0.0% to 9.3%.
Which counties border Calhoun County?
Calhoun County borders 5 counties: Aransas County, Victoria County, Refugio County, Jackson County and Matagorda County.
Products
Calhoun County, Products
Testing a home in Calhoun County
No CDC figure names Calhoun County; the nearest county with one, Nueces County (82 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 Calhoun 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
Wave Radon battery smart radon 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
Calhoun County, Bordering counties
Counties bordering Calhoun County
Calculated by Radon411- Radon levels in Matagorda CountyEPA zone 3
33.3%at or above 4 pCi/L
Median 0.1 pCi/L · 6 tests
- Radon levels in Aransas CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 0.1 pCi/L · 2 tests
- Radon levels in Victoria CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 0.6 pCi/L · 5 tests
- Radon levels in Refugio CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 1.2 pCi/L · 1 test
- Radon levels in Jackson CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 0.1 pCi/L · 1 test
Calhoun County, Cities and towns
Cities and towns in Calhoun County
About 19,599 people live in Calhoun County by the Census Bureau's estimate for July 1, 2025, 465 fewer than in 2020 (−2.3%). That works out to 39 people per square mile of land. Port Lavaca alone is home to 11,060 of them, 56.4% of the total. Together its 3 incorporated places hold 64.5% of those residents; the other 35.5% live outside any of them. CDC publishes no radon test count for Calhoun County; across Texas its counts for 2007 to 2016 come to 0.1 tests for every 1,000 residents (2025 estimate).
From Port Lavaca to Point Comfort, CDC publishes no figure by town: each reads Calhoun County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Port Lavaca | 11,060 | −4.0% | 56.4% |
| Seadrift | 1,031 | +3.1% | 5.3% |
| Point Comfort | 548 | −9.0% | 2.8% |
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).
Calhoun County, Homes
Homes in Calhoun County
Of Calhoun County's 10,743 homes, 74% are detached houses, against 65% across Texas; 14% are mobile homes. The homes are older than Texas' as a whole: half were built before 1977 (1990 for Texas), and 24% date from before 1960. Owners live in 76% of the occupied homes (Texas: 63%), so for most households a test and a fix are their own to order.
| Homes | Calhoun County | Texas |
|---|---|---|
| Housing units | 10,743 | 11,890,808 |
| Detached houses | 74% | 65% |
| In buildings of 5 or more | 5% | 21% |
| Mobile homes | 14% | 7% |
| Built before 1960 | 24% | 13% |
| Built since 2000 | 24% | 37% |
| Middle year built | 1977 | 1990 |
| Owner-occupied | 76% | 63% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.