Short-term kit
Radon Short Term Test Kit short-term charcoal radon test kit, lab fee included
- Lab fee included
Method: Charcoal
In home: 2 to 7 days
Locations and reports
Radon Levels in Hill County, Texas
EPA puts Hill County in Zone 3, its lowest radon zone, and only 5 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%
1 of 6 neighbours have 30+ tests, 2007 to 2016
Nearest county
17.1%
McLennan County, 30 miles
- McLennan
- 17.1%
- Texas
- 10.4%
Share at 4+ pCi/L, 41 tests, 2007 to 2016
Ground above low
54.9%
27.6 pts above Texas
- Hill
- 54.9%
- Texas
- 27.3%
Share of land USGS rates moderate or high potential
Tests reported
5
Too few for a share
- Hill
- 5
- 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 Hill 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
Hill County, At a glance
Hill County at a glance
Predicted: EPA radon zone
EPA Zone 3: lower predicted potential
USGS geologic potential: Moderate across 55% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Hill County, 2008 to 2017, laboratory
CDC holds 5 reported tests for Hill County over the 2008 to 2017 laboratory totals, with a median of 0.1 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Hill County beside the counties around it is how this page reads it.
What these figures count
Only 5 tests were reported to CDC for Hill 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).
Hill County, Compared
Hill County radon figures, compared
Calculated by Radon411CDC's largest figure for Hill County rests on 5 tests over the 2008 to 2017 laboratory totals, 0 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 1.8 pCi/L, with a middle value of 0.1 pCi/L.
McLennan County, the one bordering county with a figure over the 2007 to 2016 laboratory totals, reported 17.1% of its tests at or above 4 pCi/L. Farther out, Tarrant County (55 miles away) at 10.6%, Dallas County (57 miles away) at 8.7% and Bell County (69 miles away) at 14.3% 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 Hill County in Zone 3, its lowest label: a predicted county average under 2 pCi/L. USGS geology rates 55% of the county's land moderate radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Hill County, Geology
The ground under Hill County
PredictedUSGS's geologic map splits Hill County: 54.9% of its land is moderate radon potential and 45.1% low. The map puts 54.9% of Hill County in the area it calls Cretaceous Gulfian series and 29.4% in East Texas Province, with one smaller area beside them. USGS gives the first a radon index of 10, in the moderate band (9 to 11), and the second 6, in the low band (5 to 8).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Cretaceous Gulfian series | Cretaceous sandstone, shale, limestone, siltstone. | Moderate | 10 | 54.9% |
| East Texas Province | Cretaceous through Quaternary marine sandstone, shale, chalk, limestone, siltstone, clay, and lignite. | Low | 6 | 29.4% |
| Central Texas/Gulf Coast Plain | Cretaceous through Quaternary marine sandstone, shale, chalk, limestone, siltstone, clay, and lignite. | Low | 7 | 15.7% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Hill County beside the ground around it
Across Texas 0.5% of the land is rated high; none of Hill County's is. Of the 6 counties that border it, none has as large a share of moderate-potential ground; Johnson County comes nearest at 54.0%.
The map rates the ground, not the air in any home.
Local help
Hill County, Local resources
Radon testing and mitigation in Hill 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
Hill County, Questions
Questions about radon in Hill County
Are radon levels high in Hill County?
Over the 2008 to 2017 laboratory totals, 0.0% of the radon tests reported to CDC for Hill County, Texas were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.1 pCi/L. McLennan County, the one bordering county with a figure over the 2007 to 2016 laboratory totals, reported 17.1% of its tests at or above 4 pCi/L.
Which counties border Hill County?
Hill County borders 6 counties: Ellis County, McLennan County, Bosque County, Johnson County, Navarro County and Limestone County.
Products
Hill County, Products
Testing a home in Hill County
No CDC figure names Hill County; the nearest county with one, McLennan County (30 miles away), reported 17.1% 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 Hill 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
EcoBlu plug-in digital radon monitor with a display
- C-NRPP 2024/25: Not included
- Plug-in
- 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
Hill County, Bordering counties
Counties bordering Hill County
Calculated by Radon411- Radon levels in Ellis CountyEPA zone 3
57.1%at or above 4 pCi/L
Median 11.0 pCi/L · 14 tests
- 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 Johnson CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 0.8 pCi/L · 14 tests
- Radon levels in Navarro CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 0.8 pCi/L · 6 tests
- Radon levels in Limestone CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 0.1 pCi/L · 2 tests
- Radon levels in Bosque CountyEPA zone 3
No CDC figure for 2007 to 2016; its page reads it against its own neighbours.
Hill County, Cities and towns
Cities and towns in Hill County
Hill County is growing: the Census Bureau puts it at 39,503 residents on July 1, 2025, up 9.8% from 35,965 in 2020. That works out to 41 people per square mile of land. Its largest town, Hillsboro, has 9,036 residents, 22.9% of the total. Together its 14 incorporated places hold 43.6% of those residents; the other 56.4% live outside any of them. CDC's 5 reported tests for 2008 to 2017 work out to 0.1 per 1,000 residents (2025 estimate), close to Texas' 0.1.
From Hillsboro to Aquilla, CDC publishes no figure by town: each reads Hill County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Hillsboro | 9,036 | +10.2% | 22.9% |
| Whitney | 2,134 | +7.1% | 5.4% |
| Itasca | 1,970 | +24.2% | 5.0% |
| Hubbard | 1,507 | +8.2% | 3.8% |
| Blum | 421 | +9.9% | 1.1% |
| Abbott | 377 | +6.8% | 1.0% |
| Mount Calm | 336 | +15.9% | 0.9% |
| Covington | 303 | +15.2% | 0.8% |
| Malone | 253 | +7.2% | 0.6% |
| Carl's Corner | 227 | +13.5% | 0.6% |
| Penelope | 196 | +8.9% | 0.5% |
| Bynum | 180 | +6.5% | 0.5% |
- Mertens
- Aquilla
14 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).
Hill County, Homes
Homes in Hill County
Of Hill County's 16,314 homes, 73% are detached houses, against 65% across Texas; 18% are mobile homes. Half of its homes were built before 1985, close to Texas' 1990: 23% date from before 1960 and 27% from 2000 or later. 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 | Hill County | Texas |
|---|---|---|
| Housing units | 16,314 | 11,890,808 |
| Detached houses | 73% | 65% |
| In buildings of 5 or more | 5% | 21% |
| Mobile homes | 18% | 7% |
| Built before 1960 | 23% | 13% |
| Built since 2000 | 27% | 37% |
| Middle year built | 1985 | 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.