Short-term kitFirst Alert
RD1 short-term charcoal radon test kit
- Lab fee included
Method: Charcoal
In home: 2 to 4 days
Locations and reports
Radon Levels in El Dorado County, California
EPA puts El Dorado County in Zone 2, its middle radon zone, and 30.3% of its 274 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
30.3%
20.0 pts above CA
- El Dorado
- 30.3%
- California
- 10.3%
274 tests, 2008 to 2017
Median result
1.6pCi/L
Below action level
- El Dorado
- 1.6 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
274
11th of 33 by tests
- El Dorado
- 274
- 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
1 of 33
Top quarter
- El Dorado
- 30.3%
- El Dorado
- 30.3%
By share, of 33 with 30+ tests
Read a result for El Dorado County
Starts at El Dorado County's median, 1.6 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 1.6 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. El Dorado County's median reported result, 2008 to 2017.
The data
El Dorado County, At a glance
El Dorado County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
El Dorado County is a
USGS geologic potential: Moderate across 100% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for El Dorado County, 2008 to 2017, laboratory
Under 2 pCi/L: 55%2 to 4 pCi/L: 15%4 pCi/L and above: 30%
Of 274 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 150 | 54.7% |
| 2 to 4 pCi/L | 41 | 15.0% |
| 4 pCi/L and above | 83 | 30.3% |
What these figures count
These are the 274 tests reported to CDC for El Dorado 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).
El Dorado County, Compared
El Dorado County radon figures, compared
Calculated by Radon411In El Dorado County, about 3 in 10 reported tests over the 2008 to 2017 laboratory totals (83 of 274) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 5.4 points lower. Across 56 California counties pooled together, 10.3% of tests reached that level, so El Dorado County runs 20.0 points above its state.
Of 4 neighbours with a figure, 1 reported a larger share at or above 4 pCi/L and 3 a smaller one; the spread is 7.4% (Placer County) to 37.0% (Douglas County, NV). By share, El Dorado County is 1st of 33 California counties with 30 or more tests for the same period.
Half the tests came in under 1.6 pCi/L and half over it; the single highest reached 39.0 pCi/L. Below the action level, 150 tests (54.7%) came in under 2 pCi/L, against 76.8% statewide, and 41 tests (15.0%) fell between 2 and 4, against 12.9% statewide.
Zone 2 on EPA's map (predicted average between 2 and 4 pCi/L) and a 30.3% share point the same way here. USGS geology rates 100% of the county's land moderate radon potential.
CDC's ten-year totals for El Dorado County went from 303 tests (2005 to 2014) to 274 (2008 to 2017), the share going from 33.3% to 30.3%.
Pooled shares: Radon411's sum of CDC's county counts for one period.
El Dorado County, Geology
The ground under El Dorado County
PredictedUSGS's geologic map puts all of El Dorado County's mapped land in one class: moderate radon potential. All of it lies in the area the map calls Sierra Nevada, to which USGS gives a radon index of 9, in the moderate band (9 to 11).
| 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 | 100% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
El Dorado County beside the ground around it
Across California 0.1% of the land is rated high; none of El Dorado County's is. Of the 5 counties that border it, none has as large a share of moderate-potential ground; Alpine County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
El Dorado County, Local resources
Radon testing and mitigation in El Dorado 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
El Dorado County, Questions
Questions about radon in El Dorado County
Are radon levels high in El Dorado County?
Over the 2008 to 2017 laboratory totals, 30.3% of the radon tests reported to CDC for El Dorado County, California were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.6 pCi/L. Of 33 California counties with 30 or more tests for the same period, none reported a higher share; pooled, the state comes to 10.3%.
Which counties border El Dorado County?
El Dorado County borders 5 counties: Placer County, CA, Amador County, CA, Alpine County, CA, Douglas County, NV and Sacramento County, CA.
Products
El Dorado County, Products
Testing a home in El Dorado County
In El Dorado County, 30.3% of 274 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 El Dorado County; a long-term test tells the year-round average.
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
View Plus radon and air quality monitor
- C-NRPP 2024/25: Approved
- Battery
- Wi-Fi, Bluetooth
- Screen, app
Method: Alpha spectrometry
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
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El Dorado County, Bordering counties
Counties bordering El Dorado County
Calculated by Radon411- Radon levels in Alpine County, CAEPA zone 2
63.2%at or above 4 pCi/L
Median 4.5 pCi/L · 19 tests · 32.9 points above El Dorado County
- Radon levels in Douglas County, NVEPA zone 1
37.0%at or above 4 pCi/L
Median 3.1 pCi/L · 1,617 tests · 6.7 points above El Dorado County
- Radon levels in Amador County, CAEPA zone 2
27.8%at or above 4 pCi/L
Median 2.3 pCi/L · 36 tests · 2.5 points below El Dorado County
- Radon levels in Sacramento County, CAEPA zone 3
7.7%at or above 4 pCi/L
Median 0.9 pCi/L · 194 tests · 22.6 points below El Dorado County
- Radon levels in Placer County, CAEPA zone 2
7.4%at or above 4 pCi/L
Median 1.1 pCi/L · 283 tests · 22.9 points below El Dorado County
El Dorado County, Cities and towns
Cities and towns in El Dorado County
The Census Bureau estimates 192,323 residents in El Dorado County for July 1, 2025, 1,086 more than in 2020 (+0.6%). That works out to 113 people per square mile of land. No town dominates: South Lake Tahoe, the largest, has 21,115 residents, 11.0% of the total. Together its 2 incorporated places hold 16.5% of those residents; the other 83.5% live outside any of them. Testing is reported here more often than across the state: CDC's 274 reported tests for 2008 to 2017 come to 1.4 for every 1,000 residents (2025 estimate), against 0.2 for California.
From South Lake Tahoe to Placerville, CDC publishes no figure by town: each reads El Dorado County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| South Lake Tahoe | 21,115 | −0.9% | 11.0% |
| Placerville | 10,685 | −0.3% | 5.6% |
2 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).
El Dorado County, Homes
Homes in El Dorado County
El Dorado County is a place of houses on their own lots: 80% of its 94,258 homes are detached single-family houses, against 57% across California. Half of its homes were built before 1983, close to California's 1976: 12% date from before 1960 and 22% from 2000 or later. Owners live in 76% of the occupied homes (California: 56%), so for most households a test and a fix are their own to order.
| Homes | El Dorado County | California |
|---|---|---|
| Housing units | 94,258 | 14,532,683 |
| Detached houses | 80% | 57% |
| In buildings of 5 or more | 7% | 24% |
| Mobile homes | 5% | 4% |
| Built before 1960 | 12% | 27% |
| Built since 2000 | 22% | 18% |
| Middle year built | 1983 | 1976 |
| Owner-occupied | 76% | 56% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.