Is radon high in Florence-Graham, California?

Low. Averaging the model's ZIP-code predictions across Florence-Graham (weighted by how much of the city each ZIP covers) gives a long-term basement mean of 1.4 pCi/L - about 22% 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. Florence-Graham ranks 148 of 207 California cities on this site.

Which Florence-Graham ZIP codes have the highest radon?

Predictions for the 4 modeled ZIP codes in Florence-Graham range from 1.3 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 Florence-Graham?

Yes, once. The EPA recommends testing every home regardless of area. A short-term kit costs little and settles the question for your house; Florence-Graham's low predicted average describes the typical home, not yours.

What does EPA Radon Zone 2 mean for Florence-Graham?

Florence-Graham sits mainly in Los Angeles 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 1.4 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.

Radon levels in Florence-Graham, California

LowEPA Zone 2

Predicted long-term basement average of 1.4 pCi/L (model estimate) across the 4 modeled ZIP codes in Florence-Graham - about 22% below the US average of 1.8, close to the California average of 1.5. Ranked #148 of 207 California cities on this site. Most of the census-designated place lies in Los Angeles County.

Test Florence-Graham, CA once anyway - radon varies house to house

The predicted basement average here is 1.4 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.

Get a short-term test kit →Or track it with a continuous monitor

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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.

1.4 ± 0.06

pCi/L predicted basement mean (model SD)

0.8 ± 0.14

pCi/L predicted upstairs (above-ground) mean

1.3-1.4

range of ZIP-level basement predictions in the city

of Florence-Graham ZIPs predicted ≥ 4 pCi/L (0% ≥ 2)

What this means for Florence-Graham

The typical Florence-Graham home is predicted below 2 pCi/L, the lowest band. That describes the average house; the ZIP-level predictions inside the city still span 1.3 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 census-designated place's land in each ZIP (Census 2020 ZCTA-to-place relationship file). Note that the EPA classifies Los Angeles County as Zone 2 while the newer model predicts 1.4 pCi/L for Florence-Graham; where they disagree, we grade on the model but show both.

Comparable California cities: Santa Ana (1.4), Huntington Beach (1.4), Manteca (1.4), Rancho Cordova (1.4).

ZIP codes in Florence-Graham

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

ZIP	Share of city	Basement	Upstairs	Grade
90001	68%	1.4 ± 0.06	0.8	Low
90002	27%	1.4 ± 0.06	0.7	Low
90255	4%	1.4 ± 0.07	0.7	Low
90280	1%	1.3 ± 0.07	0.7	Low

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.

Florence-Graham radon questions

Is radon high in Florence-Graham, California?: Low. Averaging the model's ZIP-code predictions across Florence-Graham (weighted by how much of the city each ZIP covers) gives a long-term basement mean of 1.4 pCi/L - about 22% 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. Florence-Graham ranks 148 of 207 California cities on this site.
Which Florence-Graham ZIP codes have the highest radon?: Predictions for the 4 modeled ZIP codes in Florence-Graham range from 1.3 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 Florence-Graham?: Yes, once. The EPA recommends testing every home regardless of area. A short-term kit costs little and settles the question for your house; Florence-Graham's low predicted average describes the typical home, not yours.
What does EPA Radon Zone 2 mean for Florence-Graham?: Florence-Graham sits mainly in Los Angeles 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 1.4 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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