Radon levels in Berkeley, California

LowEPA Zone 2

Predicted long-term basement average of 1.3 pCi/L (model estimate) across the 9 modeled ZIP codes in Berkeley - about 27% below the US average of 1.8, close to the California average of 1.5. Ranked #197 of 207 California cities on this site. Most of the city lies in Alameda County (its ZIPs also reach into 1 other county).

Test Berkeley, CA once anyway - radon varies house to house

The predicted basement average here is 1.3 pCi/L, below the EPA's 2 pCi/L "consider fixing" threshold. That's good news for the area - but the EPA still recommends every home be tested, because foundation cracks, soil pockets and ventilation make one house very different from its neighbor. One inexpensive kit settles it.

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Predicted (model estimate). The pCi/L figures on this page are long-term area averages from a peer-reviewed national model built on millions of real radon tests (2001-2021). They describe the typical home in this area - not your home, which can be several times higher or lower. The EPA radon zone is a separate, 1993 county-level classification. How the numbers work.

1.3 ± 0.07

pCi/L predicted basement mean (model SD)

0.7 ± 0.09

pCi/L predicted upstairs (above-ground) mean

1.2-1.4

range of ZIP-level basement predictions in the city

0%

of Berkeley ZIPs predicted ≥ 4 pCi/L (0% ≥ 2)

What this means for Berkeley

The typical Berkeley home is predicted below 2 pCi/L, the lowest band. That describes the average house; the ZIP-level predictions inside the city still span 1.2 to 1.4 pCi/L.

The city figure is not a separate estimate: it is the mean of the model's ZIP-code predictions, weighted by the share of the city's land in each ZIP (Census 2020 ZCTA-to-place relationship file). Note that the EPA classifies Alameda County as Zone 2 while the newer model predicts 1.3 pCi/L for Berkeley; where they disagree, we grade on the model but show both.

Comparable California cities: Sacramento (1.3), Pittsburg (1.3), Alameda (1.3), Paramount (1.3).

ZIP codes in Berkeley

ZIPs that overlap the city, largest share of its land first. Predicted basement and upstairs means are model estimates; ZIPs the model does not cover show a dash.

ZIPShare of cityBasementUpstairsGrade
9471020%1.4 ± 0.070.7Low
9470813%1.4 ± 0.060.8Low
9470212%1.3 ± 0.070.6Low
9470312%1.3 ± 0.070.6Low
9470711%1.3 ± 0.070.7Low
9470510%1.3 ± 0.070.6Low
947048%1.2 ± 0.070.6Low
947097%1.3 ± 0.070.6Low
947206%no model
947061%1.3 ± 0.070.6Low

Testing help in California

California's radon program page is at www.cdph.ca.gov; it lists testing and certified-mitigator guidance. EPA state radon contacts page. If a test comes back at 4 pCi/L or higher, mitigation typically costs $800-$2,500 installed; use EPA find-a-professional and read the mitigation guide.

Berkeley radon questions

Is radon high in Berkeley, California?
Low. Averaging the model's ZIP-code predictions across Berkeley (weighted by how much of the city each ZIP covers) gives a long-term basement mean of 1.3 pCi/L - about 27% below the US average of 1.8 and close to the California average of 1.5. That is below the EPA's 2 pCi/L "consider fixing" threshold, though individual homes still vary. Berkeley ranks 197 of 207 California cities on this site.
Which Berkeley ZIP codes have the highest radon?
Predictions for the 9 modeled ZIP codes in Berkeley range from 1.2 to 1.4 pCi/L in the basement. 0% of them are predicted at or above 4 pCi/L and 0% at or above 2. The city is fairly uniform, so the city-wide number is a reasonable guide for any neighborhood.
Should I test for radon in Berkeley?
Yes, once. The EPA recommends testing every home regardless of area. A short-term kit costs little and settles the question for your house; Berkeley's low predicted average describes the typical home, not yours.
What does EPA Radon Zone 2 mean for Berkeley?
Berkeley sits mainly in Alameda County, which the EPA classifies as Zone 2 - moderate potential (2-4 pCi/L). The zone map dates from 1993 and covers whole counties. The newer model's city average of 1.3 pCi/L does not line up with Zone 2, which is common - the EPA itself says high-radon homes exist in every zone. Neither replaces a test of your own home.

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