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 Tulare County, California
EPA puts Tulare County in Zone 2, its middle radon zone, and 23.8% of its 80 reported radon tests (2008 to 2017, laboratory totals) were at or above 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
23.8%
13.5 pts above CA
- Tulare
- 23.8%
- California
- 10.3%
80 tests, 2008 to 2017
Median result
1.7pCi/L
Below action level
- Tulare
- 1.7 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
80
23rd of 33 by tests
- Tulare
- 80
- Los Angeles
- 2,363
Reported to CDC before any fix, 2008 to 2017
EPA radon zone
Zone 2
Moderate potential
- 1
- Zone 2
- 3
1 highest, 3 lowest
EPA predicts 2 to 4 pCi/L indoors
Rank in California
4 of 33
Top quarter
- Tulare
- 23.8%
- El Dorado
- 30.3%
By share, of 33 with 30+ tests
Read a result for Tulare County
Starts at Tulare County's median, 1.7 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 1.7 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. Tulare County's median reported result, 2008 to 2017.
The data
Tulare County, At a glance
Tulare County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Tulare County is a
USGS geologic potential: Moderate across 73% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Tulare County, 2008 to 2017, laboratory
Under 2 pCi/L: 60%2 to 4 pCi/L: 16%4 pCi/L and above: 24%
Of 80 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 48 | 60.0% |
| 2 to 4 pCi/L | 13 | 16.3% |
| 4 pCi/L and above | 19 | 23.8% |
What these figures count
These are the 80 tests reported to CDC for Tulare 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).
Tulare County, Compared
Tulare County radon figures, compared
Calculated by Radon411Tulare County's 80 reported tests over the 2008 to 2017 laboratory totals had a middle value of 1.7 pCi/L and a maximum of 27.2 pCi/L, and 23.8% reached 4 pCi/L. California as a whole (56 California counties, pooled) comes to 10.3%: 13.5 points lower than here.
Among its state's counties it ranks 4th of 33 California counties with 30 or more tests for the same period. Statewide for the same period, El Dorado County reported the highest share (30.3%) and Sonoma County the lowest (0.8%).
Below the action level, 48 tests (60.0%) came in under 2 pCi/L, against 76.8% statewide, and 13 tests (16.3%) fell between 2 and 4, against 12.9% statewide. CDC's ten-year totals for Tulare County went from 81 tests (2005 to 2014) to 80 (2008 to 2017), the share going from 27.2% to 23.8%.
EPA's 1993 zone map puts Tulare County in Zone 2, a predicted county average between 2 and 4 pCi/L. USGS geology rates 73% of the county's land moderate radon potential.
Next door, the shares run from 11.0% in Fresno County to 11.6% in Kern County, with Kern County and Fresno County below Tulare County.
CDC also counts 7 tests taken after mitigation in Tulare County for the same period: tests in homes where a fix was already in.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Tulare County, Geology
The ground under Tulare County
PredictedUSGS's geologic map splits Tulare County: 72.8% of its land is moderate radon potential and 27.2% low. The map puts 72.8% of Tulare County in the area it calls Sierra Nevada and 27.2% in Great Valley. USGS gives the first a radon index of 9, in the moderate band (9 to 11), and the second 8, in the low band (5 to 8).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Sierra Nevada | Northern Sierra Nevada is underlain primarily by Paleozoic and Mesozoic metamorphic rocks. Granitic rocks predominate in the southern Sierrra Nevada , with lesser Mesozoic metamorphic rocks. | Moderate | 9 | 72.8% |
| Great Valley | Quaternary alluvial gravel, sand, silt, clay. | Low | 8 | 27.2% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Tulare County beside the ground around it
Across California 0.1% of the land is rated high; none of Tulare County's is. Of the 4 counties that border it, 1 has more high-potential ground, Inyo County the most at 1.0%.
The map rates the ground, not the air in any home.
Local help
Tulare County, Local resources
Radon testing and mitigation in Tulare County
- California Indoor Radon ProgramCalifornia Indoor Radon Program, run by California Department of Public Health, licenses or certifies radon professionals and offers free or discounted test kits, and answers questions about testing and mitigation in California.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
Discounted test kits can be purchased through our partner laboratory, Alpha Energy, for $14.95.
- Compare kits
- Professionals in California4 professionals are listed in California.
What California's program says
- Phone
- 1-800-745-7236
- Radonprogram@cdph.ca.gov
- Licensing of radon professionals
The Radon Program certifies all radon service providers operating in California.
What it means
Tulare County, Questions
Questions about radon in Tulare County
Are radon levels high in Tulare County?
Over the 2008 to 2017 laboratory totals, 23.8% of the radon tests reported to CDC for Tulare County, California were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.7 pCi/L. Of 33 California counties with 30 or more tests for the same period, 3 reported a higher share; pooled, the state comes to 10.3%.
Which counties border Tulare County?
Tulare County borders 4 counties: Kings County, Fresno County, Kern County and Inyo County.
Products
Tulare County, Products
Testing a home in Tulare County
In Tulare County, 23.8% of 80 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 10.3% pooled across California. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Tulare County; a long-term test tells the year-round average.
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
RadonScan-Plus USB-powered radon monitor with Wi-Fi
- C-NRPP 2024/25: Not included
- Plug-in
- Wi-Fi
- Alarm
- Screen, app
First reading: Within 5 minutes
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Tulare County, Bordering counties
Counties bordering Tulare County
Calculated by Radon411- Radon levels in Inyo CountyEPA zone 2
50.0%at or above 4 pCi/L
Median 4.0 pCi/L · 14 tests · 26.2 points above Tulare County
- Radon levels in Kern CountyEPA zone 2
11.6%at or above 4 pCi/L
Median 1.8 pCi/L · 121 tests · 12.2 points below Tulare County
- Radon levels in Fresno CountyEPA zone 2
11.0%at or above 4 pCi/L
Median 1.5 pCi/L · 100 tests · 12.8 points below Tulare County
- Radon levels in Kings CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 1.7 pCi/L · 2 tests · 23.8 points below Tulare County
Tulare County, Cities and towns
Cities and towns in Tulare County
The Census Bureau estimates 485,146 residents in Tulare County for July 1, 2025, 11,231 more than in 2020 (+2.4%). That works out to 101 people per square mile of land. Its largest town, Visalia, has 146,541 residents, 30.2% of the total. Together its 8 incorporated places hold 72.3% of those residents; the other 27.7% live outside any of them. CDC's 80 reported tests for 2008 to 2017 work out to 0.2 per 1,000 residents (2025 estimate), close to California's 0.2.
From Visalia to Woodlake, CDC publishes no figure by town: each reads Tulare County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Visalia | 146,541 | +3.3% | 30.2% |
| Tulare | 73,907 | +6.6% | 15.2% |
| Porterville | 63,088 | +0.1% | 13.0% |
| Dinuba | 25,949 | +4.6% | 5.3% |
| Lindsay | 12,578 | −0.6% | 2.6% |
| Farmersville | 10,326 | −0.6% | 2.1% |
| Exeter | 10,122 | −1.9% | 2.1% |
| Woodlake | 8,073 | +7.8% | 1.7% |
8 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).
Tulare County, Homes
Homes in Tulare County
Tulare County is a place of houses on their own lots: 75% of its 152,542 homes are detached single-family houses, against 57% across California. Half of its homes were built before 1983, close to California's 1976: 18% date from before 1960 and 26% from 2000 or later. 59% of occupied homes are lived in by their owner (California: 56%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Tulare County | California |
|---|---|---|
| Housing units | 152,542 | 14,532,683 |
| Detached houses | 75% | 57% |
| In buildings of 5 or more | 7% | 24% |
| Mobile homes | 6% | 4% |
| Built before 1960 | 18% | 27% |
| Built since 2000 | 26% | 18% |
| Middle year built | 1983 | 1976 |
| Owner-occupied | 59% | 56% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.