Radon levels in Stanislaus County, California

LowEPA Zone 3

Predicted long-term basement average of 1.4 pCi/L (model estimate) across 23 ZIP codes - about 23% below the US average of 1.8, close to the California average of 1.5. Ranked #54 of 58 California counties.

Test Stanislaus County, 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.

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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 ± 0.08

pCi/L predicted upstairs (above-ground) mean

1.2-1.6

range of ZIP-level basement predictions in the county

What this means for Stanislaus

The typical Stanislaus County home is predicted below 2 pCi/L, the lowest band. That is the best case an area can show - but it describes the average house, and the ZIP-level predictions within the county still span 1.2 to 1.6 pCi/L.

The 1993 EPA zone (3) and the 2001-2021 model agree for Stanislaus. County figures weight each ZIP by its 2010 Census population, so they describe where people live rather than empty land.

Comparable California counties: Marin County (1.4), San Joaquin County (1.4), Solano County (1.4), Humboldt County (1.4). The state's highest is Mono County at 2.7 pCi/L.

ZIP codes in Stanislaus County

Predicted basement and upstairs means by ZIP (model estimate). ZIPs whose land is mostly in this county.

ZIPBasementUpstairsGrade
953551.4 ± 0.060.7Low
953501.3 ± 0.060.8Low
953511.2 ± 0.060.7Low
953071.5 ± 0.060.8Low
953801.4 ± 0.060.8Low
953821.4 ± 0.060.8Low
953581.5 ± 0.060.7Low
953611.4 ± 0.050.8Low
953561.4 ± 0.060.8Low
953541.3 ± 0.070.8Low
953631.6 ± 0.070.8Low
953671.3 ± 0.060.8Low
953681.3 ± 0.060.7Low
953601.6 ± 0.060.9Low
953571.5 ± 0.060.8Low
953861.6 ± 0.060.9Low
953261.4 ± 0.060.8Low
953161.5 ± 0.060.9Low
953281.3 ± 0.070.7Low
953131.5 ± 0.060.9Low
953231.5 ± 0.060.8Low
952301.5 ± 0.060.9Low
953851.5 ± 0.060.8Low

If your test comes back at 4 pCi/L or higher

Mitigation is a routine job: a fan-driven pipe that vents soil gas from under the slab to above the roofline, typically $800-$2,500 installed (typical range; local quotes vary). Use certified professionals: EPA find-a-professional. Read the full mitigation guide.

Stanislaus County radon questions

Is radon high in Stanislaus County, California?
Low. The model predicts a long-term basement average of 1.4 pCi/L in Stanislaus County (about 23% 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. Ranked 54 of 58 California counties.
Should I test for radon in Stanislaus County?
Yes, once. The EPA recommends testing every home regardless of area, and the model's ZIP-level predictions in Stanislaus County already range from 1.2 to 1.6 pCi/L. A short-term kit costs little and settles the question for your house.
What does EPA Radon Zone 3 mean for Stanislaus County?
Zone 3 - low potential (< 2 pCi/L). The zone map dates from 1993 and classifies whole counties. The 2001-2021 model agrees with the zone here. Neither replaces a test of your own home.
How much does radon mitigation cost in Stanislaus County?
A standard active sub-slab depressurization system typically runs $800-$2,500 installed nationally; California quotes vary with foundation type (slab, crawlspace, basement), home size and local labor. Get two or three bids from certified mitigators listed by your state radon program or the EPA's find-a-professional page.

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