Short-term kit
PicoCan short-term charcoal canister radon test
- Lab fee included
Method: Charcoal
In home: 48 to 96 hours
Locations and reports
Radon Levels in Marion County, Texas
EPA puts Marion 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
9.1%
Smith County, 61 miles
- Smith
- 9.1%
- Texas
- 10.4%
Share at 4+ pCi/L, 33 tests, 2007 to 2016
Ground above low
None
27.3 pts below Texas
- Marion
- 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 Marion 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
Marion County, At a glance
Marion 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 Marion County. Smith County, 61 miles away, is the nearest county with a figure over the 2007 to 2016 laboratory totals.
Marion County, Compared
Marion County radon figures, compared
Calculated by Radon411Marion 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 Smith County (61 miles away) at 9.1%, Collin County (131 miles away) at 7.7% and Dallas County (141 miles away) at 8.7%. 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 Marion 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.
Marion County, Geology
The ground under Marion County
PredictedUSGS's geologic map puts all of Marion County's mapped land in one class: low radon potential. All of it lies in the area the map calls East Texas Province, to which USGS gives a radon index of 6, in the low band (5 to 8).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| East Texas Province | Cretaceous through Quaternary marine sandstone, shale, chalk, limestone, siltstone, clay, and lignite. | Low | 6 | 99.6% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Marion County beside the ground around it
Across Texas 0.5% of the land is rated high; none of Marion 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
Marion County, Local resources
Radon testing and mitigation in Marion 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
Marion County, Questions
Questions about radon in Marion County
Are radon levels high in Marion County?
No CDC testing statistics are published here for Marion County, Texas yet. Of the 8 nearest counties with a figure, within 187 miles, the share of tests at or above 4 pCi/L runs from 0.0% to 17.1%.
Which counties border Marion County?
Marion County borders 5 counties: Harrison County, TX, Cass County, TX, Caddo Parish, LA, Morris County, TX and Upshur County, TX.
Products
Marion County, Products
Testing a home in Marion County
No CDC figure names Marion County; the nearest county with one, Smith County (61 miles away), reported 9.1% 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 Marion 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
MonitorX-Sense
XR0A-SR battery digital radon detector with a screen
- C-NRPP 2024/25: Not included
- Battery
- Screen
Method: Alpha spectrometry
First reading: Within 24 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Marion County, Bordering counties
Counties bordering Marion County
Calculated by Radon411- Radon levels in Caddo Parish, LAEPA zone 3
16.7%at or above 4 pCi/L
Median 1.2 pCi/L · 24 tests
- Radon levels in Harrison County, TXEPA zone 3
0.0%at or above 4 pCi/L
Median 0.2 pCi/L · 4 tests
- Radon levels in Cass County, TXEPA zone 3
0.0%at or above 4 pCi/L
Median 1.6 pCi/L · 1 test
- Radon levels in Morris County, TXEPA zone 3
0.0%at or above 4 pCi/L
Median 0.9 pCi/L · 3 tests
- Radon levels in Upshur County, TXEPA zone 3
0.0%at or above 4 pCi/L
Median 1.6 pCi/L · 4 tests
Marion County, Cities and towns
Cities and towns in Marion County
Marion County's population has barely moved since 2020: 9,896 residents on July 1, 2025 against 9,866 then, by the Census Bureau's estimates. That works out to 26 people per square mile of land. Jefferson, its one incorporated place, has 2,056 residents, 20.8% of the total. CDC publishes no radon test count for Marion County; across Texas its counts for 2007 to 2016 come to 0.1 tests for every 1,000 residents (2025 estimate).
Jefferson is the one incorporated place here; CDC publishes no figure by town, so it reads Marion County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Jefferson | 2,056 | +2.7% | 20.8% |
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).
Marion County, Homes
Homes in Marion County
Of Marion County's 5,609 homes, 67% are detached houses, against 65% across Texas; 29% are mobile homes. The homes are older than Texas' as a whole: half were built before 1981 (1990 for Texas), and 16% date from before 1960. Owners live in 77% of the occupied homes (Texas: 63%), so for most households a test and a fix are their own to order.
| Homes | Marion County | Texas |
|---|---|---|
| Housing units | 5,609 | 11,890,808 |
| Detached houses | 67% | 65% |
| In buildings of 5 or more | 1% | 21% |
| Mobile homes | 29% | 7% |
| Built before 1960 | 16% | 13% |
| Built since 2000 | 18% | 37% |
| Middle year built | 1981 | 1990 |
| Owner-occupied | 77% | 63% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.