Napa County, CA

ZIP 94503

In ZIP 94503, 6 of the 12 things we check have at least one part graded D or F.

• Drinking water: City Of Vallejo-Lakes System meets every EPA legal limit; 10 contaminants are above health goals, led by lead at 45× 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: Valero Refining Co-Cali Fornia Benicia Refinery (38%), mostly nickel compounds.
• Fine particles (PM2.5) average 8.1 µg/m³; the WHO guideline is 5 and the EPA annual standard is 9.
• About 511,126 kg of agricultural pesticides are applied in the county each year.

Grades for ZIP 94503

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

Based on 6 census tracts · compiled September 10, 2026 · how each grade works and its sources

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