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 Coryell County, Texas
EPA puts Coryell County in Zone 3, its lowest radon zone, and only 4 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
17.1%
McLennan County
- McLennan
- 17.1%
- Bell
- 14.3%
2 of 5 neighbours have 30+ tests, 2007 to 2016
Nearest county
14.3%
Bell County, 31 miles
- Bell
- 14.3%
- Texas
- 10.4%
Share at 4+ pCi/L, 35 tests, 2007 to 2016
Ground above low
None
27.3 pts below Texas
- Coryell
- 0.0%
- Texas
- 27.3%
Share of land USGS rates moderate or high potential
Tests reported
5
Too few for a share
- Coryell
- 5
- Needed
- 30
2007 to 2016, 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 Coryell 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
Coryell County, At a glance
Coryell 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 Coryell County, 2008 to 2017, laboratory
CDC holds 4 reported tests for Coryell County over the 2008 to 2017 laboratory totals, with a median of 0.8 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Coryell County beside the counties around it is how this page reads it.
What these figures count
Only 4 tests were reported to CDC for Coryell 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).
Coryell County, Compared
Coryell County radon figures, compared
Calculated by Radon411CDC's largest figure for Coryell County rests on 5 tests over the 2007 to 2016 laboratory totals, 1 of them at or above 4 pCi/L, so each test moves its share by 20.0 points and no rank or comparison is drawn from it. Results reached as high as 13.9 pCi/L, with a middle value of 0.8 pCi/L.
Of the counties bordering it, 2 have a figure over the 2007 to 2016 laboratory totals: McLennan County reported the largest share at or above 4 pCi/L, 17.1%, and Bell County the smallest, 14.3%. Farther out, Williamson County (53 miles away) at 2.0%, Travis County (73 miles away) at 9.3% and Tarrant County (100 miles away) at 10.6% 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 Coryell 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.
Coryell County, Geology
The ground under Coryell County
PredictedUSGS's geologic map puts all of Coryell County's mapped land in one class: low radon potential. All of it lies in the area the map calls Central Texas/Gulf Coast 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 |
|---|---|---|---|---|
| Central Texas/Gulf Coast 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.
Coryell County beside the ground around it
Across Texas 0.5% of the land is rated high; none of Coryell County's is. Of the 5 counties that border it, 3 have more moderate-potential ground, McLennan County the most at 28.0%.
The map rates the ground, not the air in any home.
Local help
Coryell County, Local resources
Radon testing and mitigation in Coryell 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
Coryell County, Questions
Questions about radon in Coryell County
Are radon levels high in Coryell County?
Over the 2008 to 2017 laboratory totals, 0.0% of the radon tests reported to CDC for Coryell County, Texas were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.8 pCi/L. Of the counties bordering it, 2 have a figure over the 2007 to 2016 laboratory totals: McLennan County reported the largest share at or above 4 pCi/L, 17.1%, and Bell County the smallest, 14.3%.
Which counties border Coryell County?
Coryell County borders 5 counties: Lampasas County, Bell County, Hamilton County, Bosque County and McLennan County.
Products
Coryell County, Products
Testing a home in Coryell County
No CDC figure names Coryell County; the nearest county with one, Bell County (31 miles away), reported 14.3% 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. 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 Coryell 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
MonitorAEGTEST
HOUND-3786 rechargeable radon monitor with a 3.5-inch color screen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
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
Coryell County, Bordering counties
Counties bordering Coryell County
Calculated by Radon411- Radon levels in McLennan CountyEPA zone 3
17.1%at or above 4 pCi/L
Median 1.0 pCi/L · 41 tests
- Radon levels in Bell CountyEPA zone 3
14.3%at or above 4 pCi/L
Median 1.1 pCi/L · 35 tests
- Radon levels in Hamilton CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 0.1 pCi/L · 1 test
- Radon levels in Lampasas CountyEPA zone 3
No CDC figure for 2007 to 2016; its page reads it against its own neighbours.
- Radon levels in Bosque CountyEPA zone 3
No CDC figure for 2007 to 2016; its page reads it against its own neighbours.
Coryell County, Cities and towns
Cities and towns in Coryell County
The Census Bureau estimates 85,592 residents in Coryell County for July 1, 2025, 2,490 more than in 2020 (+3.0%). That works out to 81 people per square mile of land. Copperas Cove, the largest place on its list (40,118 residents in all), extends beyond Coryell County, so no share of the total is worked out for it. Reported testing is thin here: 5 tests over 2007 to 2016, or 0.1 for every 1,000 residents (2025 estimate), where Texas as a whole comes to 0.1.
From Copperas Cove to South Mountain, CDC publishes no figure by town: each reads Coryell County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Copperas Coveextends beyond Coryell County | 40,118 | +9.2% | Counted whole |
| Gatesville | 16,422 | +2.0% | 19.2% |
| McGregorextends beyond Coryell County | 6,405 | +18.1% | Counted whole |
| Evantextends beyond Coryell County | 467 | +1.7% | Counted whole |
| Oglesby | 445 | +0.2% | 0.5% |
| South Mountain | 409 | +0.5% | 0.5% |
6 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 Coryell County is counted whole, so it has no share.
Coryell County, Homes
Homes in Coryell County
Of Coryell County's 29,180 homes, 67% are detached houses, against 65% across Texas; 7% are in buildings of five or more homes. Half of its homes were built before 1987, close to Texas' 1990: 12% date from before 1960 and 32% from 2000 or later. 59% 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 | Coryell County | Texas |
|---|---|---|
| Housing units | 29,180 | 11,890,808 |
| Detached houses | 67% | 65% |
| In buildings of 5 or more | 7% | 21% |
| Mobile homes | 5% | 7% |
| Built before 1960 | 12% | 13% |
| Built since 2000 | 32% | 37% |
| Middle year built | 1987 | 1990 |
| Owner-occupied | 59% | 63% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.