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 Montgomery County, Texas
EPA puts Montgomery County in Zone 3, its lowest radon zone, and most reported tests there come back low, though 3.2% of 188 (2008 to 2017, laboratory totals) reached 4 pCi/L. Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Share at 4+ pCi/L
3.2%
7.0 pts below TX
- Montgomery
- 3.2%
- Texas
- 10.2%
188 tests, 2008 to 2017
Median result
0.8pCi/L
Below action level
- Montgomery
- 0.8 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
188
8th of 22 by tests
- Montgomery
- 188
- Harris
- 733
Reported to CDC before any fix, 2008 to 2017
EPA radon zone
Zone 3
Lower potential
- 1
- 2
- Zone 3
1 highest, 3 lowest
EPA predicts under 2 pCi/L indoors
Rank in Texas
14 of 22
Middle half
- Montgomery
- 3.2%
- Randall
- 69.0%
By share, of 22 with 30+ tests
Read a result for Montgomery County
Starts at Montgomery County's median, 0.8 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 0.8 pCi/L
Below 2 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is below 2 pCi/L, the level at which EPA says a fix should be considered. Montgomery County's median reported result, 2008 to 2017.
The data
Montgomery County, At a glance
Montgomery 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 Montgomery County, 2008 to 2017, laboratory
Under 2 pCi/L: 94%2 to 4 pCi/L: 3%4 pCi/L and above: 3%
Of 188 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 177 | 94.1% |
| 2 to 4 pCi/L | 5 | 2.7% |
| 4 pCi/L and above | 6 | 3.2% |
What these figures count
These are the 188 tests reported to CDC for Montgomery County over 2008 to 2017 (laboratory totals), many from homes being sold or already suspected of a problem: they describe the county's reported tests, not this house.
Measured: CDC tracking data. Figure above: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).
Montgomery County, Compared
Montgomery County radon figures, compared
Calculated by Radon411Only 6 of 188 radon tests reported for Montgomery County over the 2008 to 2017 laboratory totals reached 4 pCi/L (3.2%). The median result, 0.8 pCi/L, sits below 2, well under EPA's 4 pCi/L action level, and the top reported result was 14.9 pCi/L.
Across 138 Texas counties pooled together, 10.2% of tests reached that level, so Montgomery County runs 7.0 points below its state. Against the national pool of 35.7%, the gap is 32.5 points lower. Its place in the state: 14th of 22 Texas counties with 30 or more tests for the same period.
Zone 3 on EPA's map (predicted average under 2 pCi/L) and a 3.2% share point the same way here. Harris County, the one bordering county with a figure for the same period, reported 2.9%.
Below the action level, 177 tests (94.1%) came in under 2 pCi/L, against 80.3% statewide, and 5 tests (2.7%) fell between 2 and 4, against 9.6% statewide. USGS geology rates 100% of the county's land low radon potential.
CDC's ten-year totals for Montgomery County went from 91 tests (2005 to 2014) to 188 (2008 to 2017), the share going from 7.7% to 3.2%.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Montgomery County, Geology
The ground under Montgomery County
PredictedUSGS's geologic map puts all of Montgomery County's mapped land in one class: low radon potential. All 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 | 100% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Montgomery County beside the ground around it
Across Texas 0.5% of the land is rated high; none of Montgomery County's is. None of the 6 counties that border it has any moderate-potential ground either.
The map rates the ground, not the air in any home.
Local help
Montgomery County, Local resources
Radon testing and mitigation in Montgomery 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.
Listed radon professionals by town: Houston
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
Montgomery County, Questions
Questions about radon in Montgomery County
Are radon levels high in Montgomery County?
Over the 2008 to 2017 laboratory totals, 3.2% of the radon tests reported to CDC for Montgomery County, Texas were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.8 pCi/L. Of 22 Texas counties with 30 or more tests for the same period, 13 reported a higher share; pooled, the state comes to 10.2%.
Which counties border Montgomery County?
Montgomery County borders 6 counties: San Jacinto County, Walker County, Grimes County, Harris County, Liberty County and Waller County.
Products
Montgomery County, Products
Testing a home in Montgomery County
In Montgomery County, 3.2% of 188 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 10.2% pooled across Texas. 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 Montgomery 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
Corentium Home battery digital radon detector
- C-NRPP 2024/25: Approved
- Battery
- Screen
Method: Alpha spectrometry
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Montgomery County, Bordering counties
Counties bordering Montgomery County
Calculated by Radon411- Radon levels in San Jacinto CountyEPA zone 3
33.3%at or above 4 pCi/L
Median 1.7 pCi/L · 3 tests · 30.1 points above Montgomery County
- Radon levels in Harris CountyEPA zone 3
2.9%at or above 4 pCi/L
Median 0.4 pCi/L · 733 tests · 0.3 points below Montgomery County
- Radon levels in Walker CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 0.5 pCi/L · 7 tests · 3.2 points below Montgomery County
- Radon levels in Grimes CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 0.1 pCi/L · 1 test · 3.2 points below Montgomery County
- Radon levels in Liberty CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 1.2 pCi/L · 1 test · 3.2 points below Montgomery County
- Radon levels in Waller CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 0.1 pCi/L · 7 tests · 3.2 points below Montgomery County
Montgomery County, Cities and towns
Cities and towns in Montgomery County
Montgomery County is growing: the Census Bureau puts it at 781,194 residents on July 1, 2025, up 24.9% from 625,369 in 2020. That works out to 750 people per square mile of land. Houston, the largest place on its list (2,397,315 residents in all), extends beyond Montgomery County, so no share of the total is worked out for it. Testing is reported here more often than across the state: CDC's 188 reported tests for 2008 to 2017 come to 0.2 for every 1,000 residents (2025 estimate), against 0.1 for Texas.
From Houston to Woodloch, CDC publishes no figure by town: each reads Montgomery County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Houstonextends beyond Montgomery County | 2,397,315 | +4.3% | Counted whole |
| Conroe | 119,564 | +31.2% | 15.3% |
| Tomballextends beyond Montgomery County | 15,768 | +28.1% | Counted whole |
| Clevelandextends beyond Montgomery County | 9,936 | +32.6% | Counted whole |
| Magnolia | 8,095 | +166.5% | 1.0% |
| Willis | 7,652 | +19.1% | 1.0% |
| Shenandoah | 3,833 | +8.7% | 0.5% |
| Montgomery | 3,105 | +54.9% | 0.4% |
| Oak Ridge North | 2,991 | −2.1% | 0.4% |
| Panorama Village | 2,522 | −0.1% | 0.3% |
| Roman Forest | 2,347 | +32.6% | 0.3% |
| Splendora | 2,146 | +27.8% | 0.3% |
Places in Montgomery County with a city page: 1 of 1
- Patton Village
- Woodbranch
- Cut and Shoot
- Stagecoach
- Woodloch
17 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. “(part)” marks a place that extends into another county. Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025). A place that extends beyond Montgomery County is counted whole, so it has no share.
Montgomery County, Homes
Homes in Montgomery County
Of Montgomery County's 253,801 homes, 68% are detached houses, against 65% across Texas; 16% are in buildings of five or more homes. Much of Montgomery County is recent building: 58% of its homes have gone up since 2000 and the middle year built is 2003, against 1990 for Texas. 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 | Montgomery County | Texas |
|---|---|---|
| Housing units | 253,801 | 11,890,808 |
| Detached houses | 68% | 65% |
| In buildings of 5 or more | 16% | 21% |
| Mobile homes | 12% | 7% |
| Built before 1960 | 2% | 13% |
| Built since 2000 | 58% | 37% |
| Middle year built | 2003 | 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.