Is radon high in Glendale, Arizona?

Low. Averaging the model's ZIP-code predictions across Glendale (weighted by how much of the city each ZIP covers) gives a long-term basement mean of 1.7 pCi/L - close to the US average of 1.8 and close to the Arizona average of 1.7. That is below the EPA's 2 pCi/L "consider fixing" threshold, though individual homes still vary. Glendale ranks 24 of 27 Arizona cities on this site.

Which Glendale ZIP codes have the highest radon?

Predictions for the 12 modeled ZIP codes in Glendale range from 1.5 to 1.8 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 Glendale?

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

What does EPA Radon Zone 2 mean for Glendale?

Glendale sits mainly in Maricopa 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 1.7 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 Glendale, Arizona

LowEPA Zone 2

Predicted long-term basement average of 1.7 pCi/L (model estimate) across the 12 modeled ZIP codes in Glendale - close to the US average of 1.8, close to the Arizona average of 1.7. Ranked #24 of 27 Arizona cities on this site. Most of the city lies in Maricopa County.

Test Glendale, AZ once anyway - radon varies house to house

The predicted basement average here is 1.7 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.

1.7 ± 0.07

pCi/L predicted basement mean (model SD)

0.9 ± 0.08

pCi/L predicted upstairs (above-ground) mean

1.5-1.8

range of ZIP-level basement predictions in the city

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

What this means for Glendale

The typical Glendale home is predicted below 2 pCi/L, the lowest band. That describes the average house; the ZIP-level predictions inside the city still span 1.5 to 1.8 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 Maricopa County as Zone 2 while the newer model predicts 1.7 pCi/L for Glendale; where they disagree, we grade on the model but show both.

Comparable Arizona cities: Chandler (1.6), San Tan Valley (1.7), Queen Creek (1.7), Mesa (1.7).

ZIP codes in Glendale

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.

ZIP	Share of city	Basement	Upstairs	Grade
85308	19%	1.7 ± 0.06	1.0	Low
85301	15%	1.6 ± 0.07	0.7	Low
85302	10%	1.6 ± 0.07	0.8	Low
85303	9%	1.7 ± 0.06	0.9	Low
85305	8%	1.6 ± 0.07	1.0	Low
85307	8%	1.5 ± 0.07	0.7	Low
85304	7%	1.7 ± 0.07	1.0	Low
85355	7%	1.8 ± 0.06	1.1	Low
85306	6%	1.6 ± 0.08	0.9	Low
85309	6%	—	—	no model
85310	3%	1.7 ± 0.05	1.1	Low
85340	1%	1.8 ± 0.06	1.0	Low
85382	1%	1.8 ± 0.06	1.0	Low

Testing help in Arizona

Arizona's radon program page is at www.azdhs.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.

Glendale radon questions

Is radon high in Glendale, Arizona?: Low. Averaging the model's ZIP-code predictions across Glendale (weighted by how much of the city each ZIP covers) gives a long-term basement mean of 1.7 pCi/L - close to the US average of 1.8 and close to the Arizona average of 1.7. That is below the EPA's 2 pCi/L "consider fixing" threshold, though individual homes still vary. Glendale ranks 24 of 27 Arizona cities on this site.
Which Glendale ZIP codes have the highest radon?: Predictions for the 12 modeled ZIP codes in Glendale range from 1.5 to 1.8 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 Glendale?: Yes, once. The EPA recommends testing every home regardless of area. A short-term kit costs little and settles the question for your house; Glendale's low predicted average describes the typical home, not yours.
What does EPA Radon Zone 2 mean for Glendale?: Glendale sits mainly in Maricopa 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 1.7 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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