Colusa County, CA

ZIP 95979

In ZIP 95979, 5 of the 12 things we check have at least one part graded D or F.

• Drinking water: City Of Williams meets every EPA legal limit; 8 contaminants are above health goals, led by lead at 77× 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: Johns Manville (54%), mostly styrene.
• Fine particles (PM2.5) average 8.3 µg/m³; the WHO guideline is 5 and the EPA annual standard is 9.
• About 916,603 kg of agricultural pesticides are applied in the county each year.

Grades for ZIP 95979

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

Based on 2 census tracts · compiled September 10, 2026 · how each grade works and its sources

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