Is radon high in Los Angeles County, California?

Low. The model predicts a long-term basement average of 1.5 pCi/L in Los Angeles County (about 18% 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 38 of 58 California counties.

Should I test for radon in Los Angeles County?

Yes, once. The EPA recommends testing every home regardless of area, and the model's ZIP-level predictions in Los Angeles County already range from 1.3 to 2.1 pCi/L. A short-term kit costs little and settles the question for your house.

What does EPA Radon Zone 2 mean for Los Angeles 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 1.5 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 Los Angeles 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 Los Angeles County, California

LowEPA Zone 2

Predicted long-term basement average of 1.5 pCi/L (model estimate) across 274 ZIP codes - about 18% below the US average of 1.8, close to the California average of 1.5. Ranked #38 of 58 California counties.

Test Los Angeles County, CA once anyway - radon varies house to house

The predicted basement average here is 1.5 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.

1.5 ± 0.06

pCi/L predicted basement mean (model SD)

0.9 ± 0.09

pCi/L predicted upstairs (above-ground) mean

1.3-2.1

range of ZIP-level basement predictions in the county

What this means for Los Angeles

The typical Los Angeles 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 1.3 to 2.1 pCi/L.

Note that the EPA classifies Los Angeles County as Zone 2 while the newer model predicts 1.5 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: Yolo County (1.5), Mendocino County (1.5), Glenn County (1.5), Merced County (1.5). The state's highest is Mono County at 2.7 pCi/L.

ZIP codes in Los Angeles County

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

ZIP	Basement	Upstairs	Grade
90650	1.4 ± 0.06	0.7	Low
90011	1.3 ± 0.07	0.7	Low
91331	1.7 ± 0.06	0.9	Low
90201	1.3 ± 0.07	0.7	Low
90280	1.3 ± 0.07	0.7	Low
90805	1.4 ± 0.07	0.6	Low
90250	1.3 ± 0.06	0.7	Low
91342	1.7 ± 0.07	1.2	Low
90044	1.3 ± 0.06	0.8	Low
91744	1.4 ± 0.07	0.7	Low
90706	1.3 ± 0.06	0.7	Low
91706	1.4 ± 0.07	0.8	Low
90255	1.4 ± 0.07	0.7	Low
93550	1.8 ± 0.06	1.3	Low
91335	1.6 ± 0.07	1.2	Low
93535	1.8 ± 0.07	1.0	Low
91766	1.6 ± 0.06	0.9	Low
93536	1.8 ± 0.06	1.1	Low
91402	1.6 ± 0.07	0.9	Low
90262	1.3 ± 0.06	0.6	Low
90026	1.3 ± 0.06	0.8	Low
90022	1.4 ± 0.07	0.8	Low
90003	1.4 ± 0.06	0.8	Low
90019	1.3 ± 0.07	0.8	Low
90660	1.4 ± 0.06	0.8	Low
90640	1.5 ± 0.07	0.8	Low
90042	1.5 ± 0.07	0.8	Low
90037	1.4 ± 0.06	0.7	Low
90004	1.3 ± 0.06	0.7	Low
91770	1.4 ± 0.07	0.7	Low
91732	1.4 ± 0.07	0.7	Low
91343	1.6 ± 0.06	1.0	Low
91702	1.5 ± 0.06	1.0	Low
90731	1.3 ± 0.06	0.8	Low
90006	1.4 ± 0.07	0.8	Low
90813	1.3 ± 0.07	0.6	Low
90034	1.3 ± 0.06	0.8	Low
90745	1.4 ± 0.06	0.8	Low
90001	1.4 ± 0.06	0.8	Low
91605	1.6 ± 0.06	0.9	Low
90063	1.4 ± 0.06	0.8	Low
90066	1.3 ± 0.05	0.8	Low
90723	1.3 ± 0.06	0.7	Low
91745	1.5 ± 0.07	0.8	Low
90744	1.4 ± 0.07	0.7	Low
90221	1.3 ± 0.07	0.7	Low
91801	1.4 ± 0.07	0.7	Low
91344	1.6 ± 0.06	1.1	Low
91406	1.5 ± 0.08	1.0	Low
90002	1.4 ± 0.06	0.7	Low
91405	1.5 ± 0.07	0.9	Low
93551	1.8 ± 0.06	1.1	Low
91304	1.8 ± 0.06	1.4	Low
90703	1.5 ± 0.07	0.8	Low
90220	1.4 ± 0.06	0.7	Low
90018	1.4 ± 0.06	0.8	Low
90638	1.4 ± 0.07	0.7	Low
90033	1.4 ± 0.07	0.7	Low
90047	1.4 ± 0.06	0.8	Low
90046	1.4 ± 0.08	0.8	Low
91767	1.5 ± 0.06	0.9	Low
91352	1.8 ± 0.06	1.0	Low
90016	1.4 ± 0.06	0.7	Low
90247	1.4 ± 0.06	0.7	Low
90024	1.3 ± 0.06	0.8	Low
91765	1.7 ± 0.06	1.1	Low
90023	1.3 ± 0.06	0.8	Low
90032	1.5 ± 0.07	0.9	Low
90065	1.5 ± 0.07	0.7	Low
91748	1.6 ± 0.07	0.9	Low
90027	1.4 ± 0.08	0.7	Low
91306	1.6 ± 0.06	1.3	Low
90057	1.4 ± 0.07	0.9	Low
91606	1.5 ± 0.07	0.8	Low
91790	1.4 ± 0.06	0.8	Low
90043	1.5 ± 0.06	0.8	Low
90503	1.4 ± 0.06	0.8	Low
91733	1.4 ± 0.07	0.7	Low
90242	1.3 ± 0.06	0.7	Low
90501	1.4 ± 0.05	0.7	Low
91789	1.7 ± 0.06	1.0	Low
90241	1.4 ± 0.06	0.7	Low
90806	1.4 ± 0.06	0.7	Low
90025	1.3 ± 0.06	0.8	Low
90275	1.7 ± 0.06	1.4	Low
90059	1.4 ± 0.06	0.6	Low
90007	1.4 ± 0.06	0.8	Low
91016	1.5 ± 0.07	0.8	Low
90605	1.5 ± 0.06	0.9	Low
91387	1.8 ± 0.06	1.0	Low
90804	1.3 ± 0.07	0.7	Low
90278	1.5 ± 0.05	0.8	Low
90815	1.4 ± 0.07	0.7	Low
91367	1.8 ± 0.06	1.5	Low
90045	1.4 ± 0.05	0.8	Low
90604	1.4 ± 0.06	0.7	Low
90802	1.3 ± 0.07	0.7	Low
93534	1.6 ± 0.09	0.6	Low
90031	1.5 ± 0.07	0.7	Low
91401	1.5 ± 0.07	0.9	Low
90029	1.3 ± 0.07	0.7	Low
91776	1.4 ± 0.06	0.8	Low
90808	1.4 ± 0.07	0.7	Low
93552	1.7 ± 0.06	0.9	Low
91205	1.5 ± 0.07	0.7	Low
90005	1.4 ± 0.07	0.8	Low
91601	1.5 ± 0.07	0.8	Low
90036	1.4 ± 0.06	0.8	Low
91104	1.7 ± 0.06	1.2	Low
90810	1.4 ± 0.06	0.7	Low
90505	1.6 ± 0.07	0.8	Low
90301	1.4 ± 0.08	0.7	Low
91311	1.8 ± 0.06	1.4	Low
91001	1.9 ± 0.06	1.3	Low
91711	1.7 ± 0.06	1.1	Low
90049	1.6 ± 0.07	0.9	Low
90277	1.4 ± 0.06	0.8	Low
90266	1.5 ± 0.06	0.8	Low
90260	1.3 ± 0.07	0.7	Low
91321	1.8 ± 0.06	1.2	Low
91768	1.6 ± 0.06	0.9	Low
91722	1.5 ± 0.07	0.9	Low
91780	1.4 ± 0.06	0.7	Low
91340	1.6 ± 0.06	0.9	Low
91007	1.5 ± 0.06	0.8	Low
91326	1.6 ± 0.06	0.9	Low
91350	1.8 ± 0.06	1.2	Low
91750	1.8 ± 0.06	1.1	Low
91773	1.8 ± 0.06	1.1	Low
91206	1.6 ± 0.06	0.8	Low
91107	1.7 ± 0.06	1.1	Low
90062	1.4 ± 0.06	0.7	Low
91754	1.6 ± 0.06	0.9	Low
91355	1.8 ± 0.06	1.2	Low
91325	1.7 ± 0.06	1.2	Low
91791	1.6 ± 0.07	0.9	Low
90606	1.3 ± 0.06	0.7	Low
91351	1.8 ± 0.06	1.2	Low
90008	1.4 ± 0.06	0.8	Low
90504	1.4 ± 0.06	0.8	Low
90803	1.4 ± 0.06	0.7	Low
90601	1.6 ± 0.07	0.8	Low
90222	1.3 ± 0.07	0.6	Low
90230	1.4 ± 0.07	0.8	Low
91006	1.5 ± 0.06	0.8	Low
90712	1.4 ± 0.07	0.7	Low
90807	1.4 ± 0.06	0.7	Low
90012	1.4 ± 0.07	0.7	Low
91423	1.6 ± 0.07	1.5	Low
91792	1.5 ± 0.07	0.9	Low
91505	1.6 ± 0.07	0.8	Low
91746	1.5 ± 0.06	0.8	Low
91214	1.8 ± 0.06	1.1	Low
91803	1.4 ± 0.07	0.8	Low
91384	1.9 ± 0.05	1.4	Low
91731	1.3 ± 0.07	0.7	Low
91356	1.8 ± 0.06	1.4	Low
90302	1.4 ± 0.07	0.7	Low
91604	1.6 ± 0.07	1.2	Low
90038	1.3 ± 0.07	0.7	Low
91354	1.8 ± 0.06	1.3	Low
90028	1.3 ± 0.07	0.7	Low
90039	1.4 ± 0.08	0.7	Low
90035	1.4 ± 0.07	0.8	Low
90291	1.3 ± 0.06	0.7	Low
90304	1.5 ± 0.07	0.7	Low
91607	1.5 ± 0.07	0.8	Low
90713	1.3 ± 0.06	0.8	Low
91324	1.7 ± 0.06	1.2	Low
91042	1.6 ± 0.06	1.1	Low
91755	1.5 ± 0.07	0.8	Low
91103	1.8 ± 0.06	1.3	Low
90041	1.6 ± 0.07	0.8	Low
90270	1.3 ± 0.07	0.8	Low
90405	1.3 ± 0.06	0.7	Low
91316	1.7 ± 0.07	1.3	Low
90061	1.5 ± 0.06	0.8	Low
91303	1.7 ± 0.06	1.0	Low
90249	1.4 ± 0.06	0.7	Low
91724	1.7 ± 0.06	1.0	Low
90303	1.4 ± 0.06	0.8	Low
91010	1.5 ± 0.07	0.8	Low
90746	1.6 ± 0.06	0.8	Low
90240	1.5 ± 0.06	0.8	Low
91364	1.7 ± 0.06	1.5	Low
91741	1.7 ± 0.06	1.1	Low
90602	1.4 ± 0.06	0.7	Low
91302	1.7 ± 0.06	1.3	Low
91030	1.6 ± 0.07	0.9	Low
91301	1.7 ± 0.05	1.0	Low
90710	1.4 ± 0.05	0.7	Low
90064	1.6 ± 0.06	0.8	Low
91740	1.6 ± 0.06	1.0	Low
90274	1.7 ± 0.06	1.4	Low
91504	1.6 ± 0.06	0.9	Low
91411	1.5 ± 0.07	0.9	Low
90403	1.3 ± 0.06	0.8	Low
91307	1.8 ± 0.06	1.6	Low
91106	1.6 ± 0.06	0.9	Low
91775	1.5 ± 0.06	0.8	Low
90017	1.4 ± 0.06	0.8	Low
91403	1.6 ± 0.07	1.4	Low
90272	1.7 ± 0.07	1.0	Low
91202	1.6 ± 0.06	0.8	Low
91201	1.5 ± 0.07	0.8	Low
90068	1.5 ± 0.07	0.8	Low
90210	1.8 ± 0.18	0.9	Low
90292	1.3 ± 0.06	0.7	Low
90048	1.4 ± 0.07	0.8	Low
90404	1.3 ± 0.06	0.7	Low
90717	1.5 ± 0.06	0.8	Low
90732	1.5 ± 0.06	1.0	Low
91501	1.5 ± 0.07	0.9	Low
90069	1.4 ± 0.08	0.8	Low
91101	1.6 ± 0.06	1.1	Low
90715	1.4 ± 0.06	0.7	Low
91040	1.7 ± 0.06	1.1	Low
91011	1.7 ± 0.07	1.5	Low
91381	1.7 ± 0.06	1.2	Low
90603	1.5 ± 0.07	0.7	Low
91390	2.1 ± 0.06	1.6	Moderate
90254	1.4 ± 0.06	0.7	Low
90814	1.4 ± 0.06	0.7	Low
90015	1.3 ± 0.07	0.7	Low
91506	1.5 ± 0.07	0.8	Low
91345	1.8 ± 0.07	1.0	Low
91723	1.4 ± 0.06	0.8	Low
90265	1.7 ± 0.06	1.1	Low
90502	1.4 ± 0.06	0.7	Low
91602	1.5 ± 0.06	0.8	Low
90245	1.4 ± 0.05	0.8	Low
90701	1.4 ± 0.06	0.7	Low
91208	1.7 ± 0.06	1.4	Low
91204	1.6 ± 0.07	0.7	Low
90232	1.4 ± 0.06	0.7	Low
90670	1.5 ± 0.06	0.8	Low
90305	1.5 ± 0.06	0.7	Low
91436	1.6 ± 0.06	1.3	Low
90716	1.4 ± 0.06	0.7	Low
91108	1.6 ± 0.06	0.9	Low
91203	1.5 ± 0.07	0.7	Low
93543	1.8 ± 0.06	1.1	Low
90040	1.4 ± 0.06	0.7	Low
90402	1.6 ± 0.06	0.8	Low
90293	1.3 ± 0.06	0.7	Low
90013	1.3 ± 0.06	0.7	Low
90212	1.5 ± 0.06	0.7	Low
91502	1.5 ± 0.06	0.8	Low
91105	1.7 ± 0.06	1.1	Low
90755	1.4 ± 0.06	0.7	Low
91024	1.9 ± 0.06	1.4	Low
91207	1.7 ± 0.06	0.9	Low
90248	1.5 ± 0.07	0.7	Low
90077	1.8 ± 0.06	1.3	Low
90211	1.5 ± 0.06	0.8	Low
91020	1.6 ± 0.06	1.0	Low
93510	1.8 ± 0.06	1.3	Low
90056	1.5 ± 0.06	0.7	Low
93591	1.7 ± 0.07	0.9	Low
90014	1.4 ± 0.06	0.7	Low
90401	1.3 ± 0.06	0.8	Low
90290	1.9 ± 0.07	1.4	Low
90094	1.4 ± 0.07	0.7	Low
92397	2.0 ± 0.07	1.1	Low
90704	1.5 ± 0.06	0.9	Low
90021	1.6 ± 0.07	0.7	Low
90058	1.3 ± 0.07	0.7	Low
93532	2.1 ± 0.06	1.0	Moderate
90067	1.5 ± 0.07	0.7	Low
93553	2.0 ± 0.06	1.3	Moderate
91008	1.8 ± 0.06	1.0	Low
93544	1.9 ± 0.07	1.1	Low
91759	2.1 ± 0.06	1.1	Moderate
93563	2.0 ± 0.07	1.4	Low

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.

Los Angeles County radon questions

Is radon high in Los Angeles County, California?: Low. The model predicts a long-term basement average of 1.5 pCi/L in Los Angeles County (about 18% 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 38 of 58 California counties.
Should I test for radon in Los Angeles County?: Yes, once. The EPA recommends testing every home regardless of area, and the model's ZIP-level predictions in Los Angeles County already range from 1.3 to 2.1 pCi/L. A short-term kit costs little and settles the question for your house.
What does EPA Radon Zone 2 mean for Los Angeles 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 1.5 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 Los Angeles 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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