Out of 86 ZIP codes with data in California, these are the lowest-ranked areas for radon zone. See also: National ZIP Codes in EPA Radon Zone 1 | All California Rankings
| Statistic | Value |
|---|---|
| ZIP codes ranked | 86 |
| Lowest value | Zone 1 (highest potential) |
| Median value | Zone 1 (highest potential) |
| State | California |
86 Lowest-Ranked ZIP Codes
| Rank | ZIP Code | City | State | Radon Zone | Safety Score |
|---|---|---|---|---|---|
| 1 | 93012 | Camarillo | CA | Zone 1 (highest potential) | 43/100 |
| 2 | 93455 | Santa Maria | CA | Zone 1 (highest potential) | 43/100 |
| 3 | 93010 | Camarillo | CA | Zone 1 (highest potential) | 50/100 |
| 4 | 93117 | Goleta | CA | Zone 1 (highest potential) | 54/100 |
| 5 | 93036 | Oxnard | CA | Zone 1 (highest potential) | 56/100 |
| 6 | 93463 | Solvang | CA | Zone 1 (highest potential) | 56/100 |
| 7 | 93460 | Santa Ynez | CA | Zone 1 (highest potential) | 57/100 |
| 8 | 93013 | Carpinteria | CA | Zone 1 (highest potential) | 58/100 |
| 9 | 93101 | Santa Barbara | CA | Zone 1 (highest potential) | 58/100 |
| 10 | 93103 | Santa Barbara | CA | Zone 1 (highest potential) | 58/100 |
| 11 | 93105 | Santa Barbara | CA | Zone 1 (highest potential) | 58/100 |
| 12 | 93108 | Santa Barbara | CA | Zone 1 (highest potential) | 58/100 |
| 13 | 93109 | Santa Barbara | CA | Zone 1 (highest potential) | 58/100 |
| 14 | 93110 | Santa Barbara | CA | Zone 1 (highest potential) | 58/100 |
| 15 | 93111 | Santa Barbara | CA | Zone 1 (highest potential) | 58/100 |
| 16 | 93427 | Buellton | CA | Zone 1 (highest potential) | 58/100 |
| 17 | 93434 | Guadalupe | CA | Zone 1 (highest potential) | 58/100 |
| 18 | 93436 | Lompoc | CA | Zone 1 (highest potential) | 58/100 |
| 19 | 93437 | Lompoc | CA | Zone 1 (highest potential) | 58/100 |
| 20 | 93441 | Los Olivos | CA | Zone 1 (highest potential) | 58/100 |
| 21 | 93454 | Santa Maria | CA | Zone 1 (highest potential) | 58/100 |
| 22 | 93458 | Santa Maria | CA | Zone 1 (highest potential) | 58/100 |
| 23 | 93023 | Ojai | CA | Zone 1 (highest potential) | 59/100 |
| 24 | 93060 | Santa Paula | CA | Zone 1 (highest potential) | 59/100 |
| 25 | 93001 | Ventura | CA | Zone 1 (highest potential) | 61/100 |
| 26 | 93015 | Fillmore | CA | Zone 1 (highest potential) | 63/100 |
| 27 | 93022 | Oak View | CA | Zone 1 (highest potential) | 64/100 |
| 28 | 93041 | Port Hueneme | CA | Zone 1 (highest potential) | 65/100 |
| 29 | 93063 | Simi Valley | CA | Zone 1 (highest potential) | 65/100 |
| 30 | 93065 | Simi Valley | CA | Zone 1 (highest potential) | 65/100 |
| 31 | 91320 | Newbury Park | CA | Zone 1 (highest potential) | 66/100 |
| 32 | 91360 | Thousand Oaks | CA | Zone 1 (highest potential) | 66/100 |
| 33 | 91361 | Westlake Village | CA | Zone 1 (highest potential) | 66/100 |
| 34 | 93003 | Ventura | CA | Zone 1 (highest potential) | 66/100 |
| 35 | 93021 | Moorpark | CA | Zone 1 (highest potential) | 66/100 |
| 36 | 93033 | Oxnard | CA | Zone 1 (highest potential) | 66/100 |
| 37 | 91362 | Thousand Oaks | CA | Zone 1 (highest potential) | 67/100 |
| 38 | 91377 | Oak Park | CA | Zone 1 (highest potential) | 67/100 |
| 39 | 92101 | San Diego | CA | Zone 1 (highest potential) | 67/100 |
| 40 | 93004 | Ventura | CA | Zone 1 (highest potential) | 67/100 |
| 41 | 93030 | Oxnard | CA | Zone 1 (highest potential) | 67/100 |
| 42 | 93035 | Oxnard | CA | Zone 1 (highest potential) | 67/100 |
| 43 | 91319 | Newbury Park | CA | Zone 1 (highest potential) | — |
| 44 | 91358 | Thousand Oaks | CA | Zone 1 (highest potential) | — |
| 45 | 93002 | Ventura | CA | Zone 1 (highest potential) | — |
| 46 | 93005 | Ventura | CA | Zone 1 (highest potential) | — |
| 47 | 93006 | Ventura | CA | Zone 1 (highest potential) | — |
| 48 | 93007 | Ventura | CA | Zone 1 (highest potential) | — |
| 49 | 93009 | Ventura | CA | Zone 1 (highest potential) | — |
| 50 | 93011 | Camarillo | CA | Zone 1 (highest potential) | — |
| 51 | 93014 | Carpinteria | CA | Zone 1 (highest potential) | — |
| 52 | 93016 | Fillmore | CA | Zone 1 (highest potential) | — |
| 53 | 93020 | Moorpark | CA | Zone 1 (highest potential) | — |
| 54 | 93024 | Ojai | CA | Zone 1 (highest potential) | — |
| 55 | 93031 | Oxnard | CA | Zone 1 (highest potential) | — |
| 56 | 93032 | Oxnard | CA | Zone 1 (highest potential) | — |
| 57 | 93034 | Oxnard | CA | Zone 1 (highest potential) | — |
| 58 | 93042 | Point Mugu Nawc | CA | Zone 1 (highest potential) | — |
| 59 | 93043 | Port Hueneme Cbc Base | CA | Zone 1 (highest potential) | — |
| 60 | 93044 | Port Hueneme | CA | Zone 1 (highest potential) | — |
| 61 | 93061 | Santa Paula | CA | Zone 1 (highest potential) | — |
| 62 | 93062 | Simi Valley | CA | Zone 1 (highest potential) | — |
| 63 | 93067 | Summerland | CA | Zone 1 (highest potential) | — |
| 64 | 93093 | Simi Valley | CA | Zone 1 (highest potential) | — |
| 65 | 93094 | Simi Valley | CA | Zone 1 (highest potential) | — |
| 66 | 93099 | Simi Valley | CA | Zone 1 (highest potential) | — |
| 67 | 93102 | Santa Barbara | CA | Zone 1 (highest potential) | — |
| 68 | 93106 | Santa Barbara | CA | Zone 1 (highest potential) | — |
| 69 | 93107 | Santa Barbara | CA | Zone 1 (highest potential) | — |
| 70 | 93116 | Goleta | CA | Zone 1 (highest potential) | — |
| 71 | 93118 | Goleta | CA | Zone 1 (highest potential) | — |
| 72 | 93120 | Santa Barbara | CA | Zone 1 (highest potential) | — |
| 73 | 93121 | Santa Barbara | CA | Zone 1 (highest potential) | — |
| 74 | 93130 | Santa Barbara | CA | Zone 1 (highest potential) | — |
| 75 | 93140 | Santa Barbara | CA | Zone 1 (highest potential) | — |
| 76 | 93150 | Santa Barbara | CA | Zone 1 (highest potential) | — |
| 77 | 93160 | Santa Barbara | CA | Zone 1 (highest potential) | — |
| 78 | 93190 | Santa Barbara | CA | Zone 1 (highest potential) | — |
| 79 | 93199 | Goleta | CA | Zone 1 (highest potential) | — |
| 80 | 93254 | New Cuyama | CA | Zone 1 (highest potential) | — |
| 81 | 93429 | Casmalia | CA | Zone 1 (highest potential) | — |
| 82 | 93438 | Lompoc | CA | Zone 1 (highest potential) | — |
| 83 | 93440 | Los Alamos | CA | Zone 1 (highest potential) | — |
| 84 | 93456 | Santa Maria | CA | Zone 1 (highest potential) | — |
| 85 | 93457 | Santa Maria | CA | Zone 1 (highest potential) | — |
| 86 | 93464 | Solvang | CA | Zone 1 (highest potential) | — |
Methodology
This ranking is limited to EPA county-level radon zone classification. Zone 1 identifies the highest county-level potential category; it does not measure a home or establish whether any building is above an action level. Within Zone 1, ZIP codes are sub-ranked by Home Safety Score to organize area context.
Data sources: EPA Safe Drinking Water Information System (SDWIS), FEMA National Flood Insurance Program, EPA radon zone maps, EIA electricity rates, and Consumer Confidence Reports. Last updated: 2026-08-31.
Frequently Asked Questions
What is EPA Radon Zone 1?
Zone 1 is the EPA highest county-level radon-potential category. It is not a measurement for a home and cannot determine whether a building is above an action level. A home test is required for that decision.
Should I test for radon?
The EPA recommends testing all homes regardless of radon zone. A DIY test kit costs $15-40. Professional testing costs $150-250. If levels exceed 4 pCi/L, mitigation systems ($800-2,500) can reduce radon by up to 99%.
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