San Luis Obispo County, CA

ZIP 93405

In ZIP 93405, 6 of the 12 things we check have at least one part graded D or F.

• Drinking water: Atascadero Mutual Water Co has 2 contaminants at or over an EPA legal limit; 16 contaminants are above health goals, led by pfos at 9.7× California’s Public Health Goal.
• Closer to Superfund sites than 55% of U.S. neighborhoods, with no listed site within 10 miles of its center.
• Largest share of modeled toxic air from industry: Phillips 66 Co-Santa Maria Refinery (78%), mostly benzene.
• Fine particles (PM2.5) average 6.8 µg/m³; the WHO guideline is 5 and the EPA annual standard is 9.
• About 901,427 kg of agricultural pesticides are applied in the county each year.

Grades for ZIP 93405

• Superfund sites nearbyA to C
• Factories and industrial sitesA to C
• Oil and gas wellsA
• Parks and nature nearbyA to C
• Air qualityA to B
• Drinking water qualityB to F
• Pesticide useD to F
• Neighborhood health statusA to D
• Past wildfire impactsA to F
• Past flood impactsC
• Noise levelsA to D
• Radiation signalsB to D

Based on 9 census tracts · compiled October 25, 2026 · how each grade works and its sources

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