Is radon high in Placer County, California?

Low. The model predicts a long-term basement average of 1.6 pCi/L in Placer 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 31 of 58 California counties.

Should I test for radon in Placer County?

Yes, once. The EPA recommends testing every home regardless of area, and the model's ZIP-level predictions in Placer County already range from 1.4 to 2.5 pCi/L. A short-term kit costs little and settles the question for your house.

What does EPA Radon Zone 2 mean for Placer County?

Zone 2 - moderate potential (2-4 pCi/L). The zone map dates from 1993 and classifies whole counties. The newer model's predicted average of 1.6 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.

How much does radon mitigation cost in Placer 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.

Radon levels in Placer County, California

LowEPA Zone 2

Predicted long-term basement average of 1.6 pCi/L (model estimate) across 28 ZIP codes - close to the US average of 1.8, close to the California average of 1.5. Ranked #31 of 58 California counties.

Test Placer 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.

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.

1.6 ± 0.06

pCi/L predicted basement mean (model SD)

0.9 ± 0.07

pCi/L predicted upstairs (above-ground) mean

1.4-2.5

range of ZIP-level basement predictions in the county

What this means for Placer

The typical Placer 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 1.4 to 2.5 pCi/L.

Note that the EPA classifies Placer County as Zone 2 while the newer model predicts 1.6 pCi/L. The zone map predates two decades of test data; where they disagree, we grade on the model but show both. County figures weight each ZIP by its 2010 Census population, so they describe where people live rather than empty land.

Comparable California counties: Kern County (1.6), Monterey County (1.6), Madera County (1.6), Tulare County (1.6). The state's highest is Mono County at 2.7 pCi/L.

ZIP codes in Placer County

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

ZIP	Basement	Upstairs	Grade
95747	1.4 ± 0.06	0.7	Low
95648	1.6 ± 0.06	0.9	Low
95678	1.4 ± 0.06	0.7	Low
95765	1.4 ± 0.06	0.7	Low
95661	1.4 ± 0.06	0.8	Low
95603	1.6 ± 0.06	0.9	Low
95677	1.5 ± 0.06	0.8	Low
95746	1.5 ± 0.06	1.0	Low
95602	1.6 ± 0.06	0.9	Low
95650	1.7 ± 0.06	1.0	Low
95713	2.0 ± 0.05	1.3	Moderate
95658	1.8 ± 0.06	1.1	Low
95631	2.0 ± 0.06	1.4	Low
95722	1.9 ± 0.06	1.3	Low
96143	2.2 ± 0.06	1.6	Moderate
96145	2.5 ± 0.06	2.0	Moderate
95663	1.7 ± 0.06	1.0	Low
96146	2.2 ± 0.07	1.7	Moderate
95681	1.5 ± 0.06	0.9	Low
96140	2.2 ± 0.05	1.8	Moderate
95701	1.9 ± 0.06	1.1	Low
95703	1.8 ± 0.06	1.3	Low
96148	2.1 ± 0.06	1.6	Moderate
96141	2.3 ± 0.06	1.8	Moderate
95728	2.5 ± 0.06	1.9	Moderate
95714	2.0 ± 0.06	1.4	Moderate
95717	1.9 ± 0.07	1.1	Low
95715	2.4 ± 0.07	1.4	Moderate

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.

Placer County radon questions

Is radon high in Placer County, California?: Low. The model predicts a long-term basement average of 1.6 pCi/L in Placer 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 31 of 58 California counties.
Should I test for radon in Placer County?: Yes, once. The EPA recommends testing every home regardless of area, and the model's ZIP-level predictions in Placer County already range from 1.4 to 2.5 pCi/L. A short-term kit costs little and settles the question for your house.
What does EPA Radon Zone 2 mean for Placer County?: Zone 2 - moderate potential (2-4 pCi/L). The zone map dates from 1993 and classifies whole counties. The newer model's predicted average of 1.6 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.
How much does radon mitigation cost in Placer 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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