San Bernardino County, CA

ZIP 91739

In ZIP 91739, 9 of the 12 things we check have at least one part graded D or F.

• Drinking water: Sheep Creek Water Company meets every EPA legal limit; 6 contaminants are above health goals, led by lead at 55× California’s Public Health Goal.
• Nearest Superfund site: Stringfellow, 7.6 miles away (2 within 10 miles).
• Largest share of modeled toxic air from industry: Sterigenics-Ontario Facility (78%), mostly ethylene oxide.
• Fine particles (PM2.5) average 13.8 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 91739

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

Based on 11 census tracts · compiled September 10, 2026 · how each grade works and its sources

Loading the full report, with every source…