Contra Costa County, CA
ZIP 94531
In ZIP 94531, 7 of the 12 things we check have at least one part graded D or F.
- Drinking water: Diablo Water District meets every EPA legal limit; 14 contaminants are above health goals, led by arsenic at 893× California’s Public Health Goal.
- Closer to Superfund sites than 61% of U.S. neighborhoods, with no listed site within 10 miles of its center.
- Largest share of modeled toxic air from industry: Owens-Brockway Glass Container Inc Plant #22 (23%), mostly chromium compounds.
- Fine particles (PM2.5) average 9.3 µg/m³; the WHO guideline is 5 and the EPA annual standard is 9.
- About 98,092 kg of agricultural pesticides are applied in the county each year.
Grades for ZIP 94531
- Superfund sites nearbyA to D
- Factories and industrial sitesC to D
- Oil and gas wellsC to D
- Parks and nature nearbyB to D
- Air qualityC to F
- Drinking water qualityD
- Pesticide useC to D
- Neighborhood health statusA to C
- Past wildfire impactsA to C
- Past flood impactsB
- Noise levelsA to B
- Radiation signalsB to C
Based on 12 census tracts · compiled September 10, 2026 · how each grade works and its sources
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