Riverside County, CA

ZIP 92503

In ZIP 92503, 10 of the 12 things we check have at least one part graded D or F.

• Drinking water: Riverside, City Of has 2 contaminants at or over an EPA legal limit; 21 contaminants are above health goals, led by lead at 37× California’s Public Health Goal.
• Nearest Superfund site: Stringfellow, 2.8 miles away (2 within 10 miles).
• Largest share of modeled toxic air from industry: Sterigenics-Ontario Facility (48%), mostly ethylene oxide.
• Fine particles (PM2.5) average 10.1 µg/m³; the WHO guideline is 5 and the EPA annual standard is 9.
• About 1,172,577 kg of agricultural pesticides are applied in the county each year.

Grades for ZIP 92503

• Superfund sites nearbyC to F
• Factories and industrial sitesC to D
• Oil and gas wellsA to F
• Parks and nature nearbyC to F
• Air qualityC to F
• Drinking water qualityD to F
• Pesticide useD to F
• Neighborhood health statusB to D
• Past wildfire impactsA to C
• Past flood impactsC
• Noise levelsA to F
• Radiation signalsD

Based on 30 census tracts · compiled September 10, 2026 · how each grade works and its sources

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