Short-term kit
Air Chek Short-Term radon test kit you hang, lab fee included
- Lab fee included
In home: 72 to 168 hours
Locations and reports
Radon Levels in Shasta County, California
EPA puts Shasta County in Zone 3, its lowest radon zone, and only 23 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
Share at 4+ pCi/L
12.1%
2.1 pts above CA
- Shasta
- 12.1%
- California
- 10.0%
33 tests, 2005 to 2014
Median result
0.8pCi/L
Below action level
- Shasta
- 0.8 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2005 to 2014
Tests reported
33
33rd of 34 by tests
- Shasta
- 33
- Los Angeles
- 2,302
Reported to CDC before any fix, 2005 to 2014
EPA radon zone
Zone 3
Lower potential
- 1
- 2
- Zone 3
1 highest, 3 lowest
EPA predicts under 2 pCi/L indoors
Rank in California
9 of 34
Top quarter
- Shasta
- 12.1%
- El Dorado
- 33.3%
By share, of 34 with 30+ tests
Read a result for Shasta County
Starts at Shasta 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. Shasta County's median reported result, 2005 to 2014.
The data
Shasta County, At a glance
Shasta 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 Shasta County, 2008 to 2017, laboratory
CDC holds 23 reported tests for Shasta County over the 2008 to 2017 laboratory totals, with a median of 2.0 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Shasta County beside the counties around it is how this page reads it.
What these figures count
Only 23 tests were reported to CDC for Shasta 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).
Shasta County, Compared
Shasta County radon figures, compared
Calculated by Radon41112.1% of its 33 tests over the 2005 to 2014 laboratory totals were at or above 4 pCi/L. That is 2.1 points above the 10.0% pooled from 54 California counties.
The newest figure, over the 2008 to 2017 laboratory totals, counts only 23 tests (21.7% at or above 4 pCi/L), too few to compare, so this reading uses the 33-test figure.
Ordered from highest share down, it comes 9th of 34 California counties with 30 or more tests for the same period. Nationally, every county with a figure for the same period pools to 36.0%; Shasta County sits 23.9 points below it.
Zone 3 on EPA's map (predicted average under 2 pCi/L) and a 12.1% share point the same way here.
Half the tests came in under 0.8 pCi/L and half over it; the single highest reached 37.3 pCi/L. The rest split 69.7% under 2 pCi/L and 18.2% from 2 to 4 (California: 77.8% and 12.2%).
CDC's ten-year totals for Shasta County went from 33 tests (2005 to 2014) to 23 (2008 to 2017), the share going from 12.1% to 21.7%.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Shasta County, Geology
The ground under Shasta County
PredictedUSGS's geologic map puts all of Shasta County's mapped land in one class: low radon potential. The map puts 52.9% of Shasta County in the area it calls Cascade Range and 40.2% in Klamath Mountains, with 2 smaller areas beside them. USGS gives the first a radon index of 8 and the second 6, both in the low band (5 to 8).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Cascade Range | Upper Tertiary and Quaternary extrusive rocks, mainly basalt and lesser andesite and rhyolite. | Low | 8 | 52.9% |
| Klamath Mountains | Metasedimentary and ultramafic metavolcanic rocks, and basalt. | Low | 6 | 40.2% |
| Great Valley | Quaternary alluvial gravel, sand, silt, clay. | Low | 8 | 6.5% |
| Northern Coast Ranges | Metamorphosed marine sedimentary rocks and ultramafic rocks. | Low | 6 | 0.5% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Shasta County beside the ground around it
Across California 0.1% of the land is rated high; none of Shasta County's is. Of the 6 counties that border it, 5 have more moderate-potential ground, Plumas County the most at 84.3%.
The map rates the ground, not the air in any home.
Local help
Shasta County, Local resources
Radon testing and mitigation in Shasta 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
Shasta County, Questions
Questions about radon in Shasta County
Are radon levels high in Shasta County?
Over the 2008 to 2017 laboratory totals, 21.7% of the radon tests reported to CDC for Shasta County, California were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.0 pCi/L. Of 34 California counties with 30 or more tests for the same period, 8 reported a higher share; pooled, the state comes to 10.0%.
Which counties border Shasta County?
Shasta County borders 6 counties: Tehama County, Trinity County, Siskiyou County, Plumas County, Lassen County and Modoc County.
Products
Shasta County, Products
Testing a home in Shasta County
In Shasta County, 12.1% of 33 tests reported to CDC over the 2005 to 2014 laboratory totals reached 4 pCi/L, against 10.0% pooled across California. 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 Shasta 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
RadonScan USB-powered radon monitor with a color screen
- C-NRPP 2024/25: Not included
- Plug-in
- Alarm
- Screen
First reading: Within 5 minutes
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Shasta County, Bordering counties
Counties bordering Shasta County
Calculated by Radon411- Radon levels in Plumas CountyEPA zone 2
33.3%at or above 4 pCi/L
Median 2.0 pCi/L · 24 tests · 21.2 points above Shasta County
- Radon levels in Siskiyou CountyEPA zone 3
18.2%at or above 4 pCi/L
Median 1.7 pCi/L · 11 tests · 6.1 points above Shasta County
- Radon levels in Tehama CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 1.5 pCi/L · 10 tests · 12.1 points below Shasta County
- Radon levels in Lassen CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 1.8 pCi/L · 2 tests · 12.1 points below Shasta County
- Radon levels in Trinity CountyEPA zone 3
No CDC figure for 2005 to 2014; its page reads it against its own neighbours.
- Radon levels in Modoc CountyEPA zone 3
No CDC figure for 2005 to 2014; its page reads it against its own neighbours.
Shasta County, Cities and towns
Cities and towns in Shasta County
Shasta County's population has barely moved since 2020: 181,648 residents on July 1, 2025 against 182,191 then, by the Census Bureau's estimates. That works out to 48 people per square mile of land. Redding alone is home to 94,092 of them, 51.8% of the total. Together its 3 incorporated places hold 63.5% of those residents; the other 36.5% live outside any of them. CDC's 33 reported tests for 2005 to 2014 work out to 0.2 per 1,000 residents (2025 estimate), close to California's 0.3.
From Redding to Shasta Lake, CDC publishes no figure by town: each reads Shasta County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Redding | 94,092 | +0.3% | 51.8% |
| Anderson | 11,131 | −1.7% | 6.1% |
| Shasta Lake | 10,208 | −1.5% | 5.6% |
3 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).
Shasta County, Homes
Homes in Shasta County
Of Shasta County's 79,748 homes, 70% are detached houses, against 57% across California; 11% are mobile homes. Half of its homes were built before 1982, close to California's 1976: 15% date from before 1960 and 18% from 2000 or later. 65% 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 | Shasta County | California |
|---|---|---|
| Housing units | 79,748 | 14,532,683 |
| Detached houses | 70% | 57% |
| In buildings of 5 or more | 8% | 24% |
| Mobile homes | 11% | 4% |
| Built before 1960 | 15% | 27% |
| Built since 2000 | 18% | 18% |
| Middle year built | 1982 | 1976 |
| Owner-occupied | 65% | 56% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.