Short-term kitempowerDX
Standard Radon Test short-term mail-in radon test kit
- Lab fee included
Method: Passive sampler
In home: 48 to 96 hours
Locations and reports
Radon Levels in San Jacinto County, Texas
EPA puts San Jacinto County in Zone 3, its lowest radon zone, and only 3 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
7.1%
Montgomery County
- Montgomery
- 7.1%
1 of 5 neighbours have 30+ tests, 2007 to 2016
Nearest county
7.1%
Montgomery County, 28 miles
- Montgomery
- 7.1%
- Texas
- 10.4%
Share at 4+ pCi/L, 85 tests, 2007 to 2016
Ground above low
None
27.3 pts below Texas
- San Jacinto
- 0.0%
- Texas
- 27.3%
Share of land USGS rates moderate or high potential
Tests reported
3
Too few for a share
- San Jacinto
- 3
- 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 San Jacinto 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
San Jacinto County, At a glance
San Jacinto 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 San Jacinto County, 2008 to 2017, laboratory
CDC holds 3 reported tests for San Jacinto County over the 2008 to 2017 laboratory totals, with a median of 1.7 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). San Jacinto County beside the counties around it is how this page reads it.
What these figures count
Only 3 tests were reported to CDC for San Jacinto 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. Measured data period: 2008 to 2017.
San Jacinto County, Compared
San Jacinto County radon figures, compared
Calculated by Radon411CDC's largest figure for San Jacinto County rests on 3 tests over the 2008 to 2017 laboratory totals, 1 of them at or above 4 pCi/L, so each test moves its share by 33.3 points and no rank or comparison is drawn from it. Results reached as high as 5.2 pCi/L, with a middle value of 1.7 pCi/L.
Montgomery County, the one bordering county with a figure over the 2007 to 2016 laboratory totals, reported 7.1% of its tests at or above 4 pCi/L. Farther out, Harris County (52 miles away) at 3.1%, Brazos County (68 miles away) at 0.0% and Fort Bend County (81 miles away) at 3.4% 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 San Jacinto 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.
San Jacinto County, Geology
The ground under San Jacinto County
PredictedUSGS's geologic map puts all of San Jacinto County's mapped land in one class: low radon potential. 99.4% 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 | 99.4% |
| East Texas Province | Cretaceous through Quaternary marine sandstone, shale, chalk, limestone, siltstone, clay, and lignite. | Low | 6 | 0.6% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
San Jacinto County beside the ground around it
Across Texas 0.5% of the land is rated high; none of San Jacinto 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
San Jacinto County, Local resources
Radon testing and mitigation in San Jacinto 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
San Jacinto County, Questions
Questions about radon in San Jacinto County
Are radon levels high in San Jacinto County?
Over the 2008 to 2017 laboratory totals, 33.3% of the radon tests reported to CDC for San Jacinto County, Texas were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.7 pCi/L. Montgomery County, the one bordering county with a figure over the 2007 to 2016 laboratory totals, reported 7.1% of its tests at or above 4 pCi/L.
Which counties border San Jacinto County?
San Jacinto County borders 5 counties: Polk County, Walker County, Montgomery County, Liberty County and Trinity County.
Products
San Jacinto County, Products
Testing a home in San Jacinto County
No CDC figure names San Jacinto County; the nearest county with one, Montgomery County (28 miles away), reported 7.1% 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 San Jacinto 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
Corentium Home 2 battery digital radon monitor
- C-NRPP 2024/25: Not included
- Battery
- Bluetooth
- Screen, app
Method: Alpha spectrometry
Readings: Every 60 minutes
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
San Jacinto County, Bordering counties
Counties bordering San Jacinto County
Calculated by Radon411- Radon levels in Polk CountyEPA zone 3
100.0%at or above 4 pCi/L
Median 25.5 pCi/L · 1 test
- Radon levels in Montgomery CountyEPA zone 3
7.1%at or above 4 pCi/L
Median 0.6 pCi/L · 85 tests
- Radon levels in Walker CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 0.5 pCi/L · 7 tests
- Radon levels in Liberty CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 1.2 pCi/L · 1 test
- Radon levels in Trinity CountyEPA zone 3
No CDC figure for 2007 to 2016; its page reads it against its own neighbours.
San Jacinto County, Cities and towns
Cities and towns in San Jacinto County
San Jacinto County is growing: the Census Bureau puts it at 29,488 residents on July 1, 2025, up 7.1% from 27,542 in 2020. That works out to 52 people per square mile of land. Cleveland, the largest place on its list (9,936 residents in all), extends beyond San Jacinto County, so no share of the total is worked out for it. CDC's 3 reported tests for 2008 to 2017 work out to 0.1 per 1,000 residents (2025 estimate), close to Texas' 0.1.
From Cleveland to Point Blank, CDC publishes no figure by town: each reads San Jacinto County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Clevelandextends beyond San Jacinto County | 9,936 | +32.6% | Counted whole |
| Shepherd | 1,942 | −7.2% | 6.6% |
| Coldspring | 886 | +7.7% | 3.0% |
| Point Blank | 734 | +7.0% | 2.5% |
4 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 San Jacinto County is counted whole, so it has no share.
San Jacinto County, Homes
Homes in San Jacinto County
Of San Jacinto County's 14,487 homes, 71% are detached houses, against 65% across Texas; 23% are mobile homes. Half of its homes were built before 1992, close to Texas' 1990: 9% date from before 1960 and 36% from 2000 or later. Owners live in 84% of the occupied homes (Texas: 63%), so for most households a test and a fix are their own to order.
| Homes | San Jacinto County | Texas |
|---|---|---|
| Housing units | 14,487 | 11,890,808 |
| Detached houses | 71% | 65% |
| In buildings of 5 or more | 2% | 21% |
| Mobile homes | 23% | 7% |
| Built before 1960 | 9% | 13% |
| Built since 2000 | 36% | 37% |
| Middle year built | 1992 | 1990 |
| Owner-occupied | 84% | 63% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.