San Bernardino County, CA

ZIP 92321

In ZIP 92321, 6 of the 12 things we check have at least one part graded D or F.

• Drinking water: Arrowhead Villas Mutual Service Company has 1 contaminant at or over an EPA legal limit; 13 contaminants are above health goals, led by lead at 106× California’s Public Health Goal.
• Nearest Superfund site: Newmark Ground Water Contamination, 7.2 miles away (2 within 10 miles).
• Largest share of modeled toxic air from industry: Sterigenics-Ontario Facility (86%), mostly ethylene oxide.
• Fine particles (PM2.5) average 8.6 µg/m³; the WHO guideline is 5 and the EPA annual standard is 9.
• About 52,223 kg of agricultural pesticides are applied in the county each year.

Grades for ZIP 92321

• Superfund sites nearbyA to D
• Factories and industrial sitesB to C
• Oil and gas wellsA to C
• Parks and nature nearbyB to C
• Air qualityB to D
• Drinking water qualityC to F
• Pesticide useB
• Neighborhood health statusC to F
• Past wildfire impactsF
• Past flood impactsC
• Noise levelsA
• Radiation signalsD

Based on 4 census tracts · compiled September 10, 2026 · how each grade works and its sources

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