Radon levels in Shasta County, California

LowEPA Zone 3

Predicted long-term basement average of 1.6 pCi/L (model estimate) across 22 ZIP codes - close to the US average of 1.8, close to the California average of 1.5. Ranked #23 of 58 California counties.

Test Shasta County, CA once anyway - radon varies house to house

The predicted basement average here is 1.6 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.

1.6 ± 0.06

pCi/L predicted basement mean (model SD)

0.8 ± 0.08

pCi/L predicted upstairs (above-ground) mean

1.5-2.1

range of ZIP-level basement predictions in the county

What this means for Shasta

The typical Shasta 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 1.5 to 2.1 pCi/L.

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

Comparable California counties: Butte County (1.6), Tehama County (1.6), Colusa County (1.6), Santa Barbara County (1.6). The state's highest is Mono County at 2.7 pCi/L.

ZIP codes in Shasta County

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

ZIPBasementUpstairsGrade
960031.5 ± 0.070.8Low
960011.6 ± 0.060.8Low
960021.6 ± 0.060.8Low
960071.6 ± 0.060.8Low
960191.5 ± 0.070.7Low
960881.8 ± 0.060.8Low
960132.0 ± 0.061.0Low
960731.7 ± 0.060.9Low
960282.1 ± 0.071.0Moderate
960081.8 ± 0.071.0Low
960511.8 ± 0.070.8Low
960621.7 ± 0.060.9Low
960471.6 ± 0.070.8Low
960692.1 ± 0.071.1Moderate
960961.9 ± 0.071.0Low
960871.7 ± 0.060.9Low
960331.7 ± 0.070.9Low
960161.8 ± 0.070.8Low
960651.9 ± 0.071.0Low
960401.9 ± 0.070.9Low
960171.8 ± 0.080.9Low
960711.9 ± 0.070.9Low

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.

Shasta County radon questions

Is radon high in Shasta County, California?
Low. The model predicts a long-term basement average of 1.6 pCi/L in Shasta County (close to 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 23 of 58 California counties.
Should I test for radon in Shasta County?
Yes, once. The EPA recommends testing every home regardless of area, and the model's ZIP-level predictions in Shasta County already range from 1.5 to 2.1 pCi/L. A short-term kit costs little and settles the question for your house.
What does EPA Radon Zone 3 mean for Shasta 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 Shasta 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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