San Luis Obispo County, CA

ZIP 93422

In ZIP 93422, 6 of the 12 things we check have at least one part graded D or F.

• Drinking water: Atascadero State Hospital has 1 contaminant at or over an EPA legal limit; 13 contaminants are above health goals, led by pfos at 14× 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 (94%), mostly benzene.
• Fine particles (PM2.5) average 6.2 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 93422

• Superfund sites nearbyA to C
• Factories and industrial sitesA
• Oil and gas wellsA
• Parks and nature nearbyB to D
• Air qualityA
• Drinking water qualityD to F
• Pesticide useF
• Neighborhood health statusB to C
• Past wildfire impactsA to F
• Past flood impactsC
• Noise levelsA to D
• Radiation signalsC to D

Based on 9 census tracts · compiled September 10, 2026 · how each grade works and its sources

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