San Bernardino County, CA

ZIP 92391

In ZIP 92391, 5 of the 12 things we check have at least one part graded D or F.

• Drinking water: Lake Arrowhead Csd has 2 contaminants at or over an EPA legal limit; 12 contaminants are above health goals, led by thallium at 5.2× California’s Public Health Goal.
• Nearest Superfund site: Newmark Ground Water Contamination, 7.3 miles away (2 within 10 miles).
• Largest share of modeled toxic air from industry: Sterigenics-Ontario Facility (84%), mostly ethylene oxide.
• Fine particles (PM2.5) average 7.3 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 92391

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

Based on 5 census tracts · compiled October 25, 2026 · how each grade works and its sources

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