Sonoma County, CA

ZIP 95421

In ZIP 95421, 4 of the 12 things we check have at least one part graded D or F.

• Drinking water: Sea Ranch Water Company,the (Puc) meets every EPA legal limit; 10 contaminants are above health goals, led by lead at 109× California’s Public Health Goal.
• Closer to Superfund sites than 0% of U.S. neighborhoods, with no listed site within 10 miles of its center.
• Largest share of modeled toxic air from industry: Nick Barbieri Trucking LLC (96%), mostly xylene (mixed isomers).
• Fine particles (PM2.5) average 7.5 µg/m³; the WHO guideline is 5 and the EPA annual standard is 9.
• About 1,321,118 kg of agricultural pesticides are applied in the county each year.

Grades for ZIP 95421

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

Based on 3 census tracts · compiled September 10, 2026 · how each grade works and its sources

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