Riverside County, CA
ZIP 92503
In ZIP 92503, 9 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; 18 contaminants are above health goals, led by pfhxs at 1.8× California Notification Level.
- Nearest Superfund site: Stringfellow, 2.8 miles away (2 within 10 miles).
- Largest share of modeled toxic air from industry: Sterigenics-Ontario Facility (56%), 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 nearbyB to D
- Air qualityC to F
- Drinking water qualityC to F
- Pesticide useC to F
- Neighborhood health statusA to C
- Past wildfire impactsA to C
- Past flood impactsC
- Noise levelsA to F
- Radiation signalsC to D
Based on 30 census tracts · compiled October 25, 2026 · how each grade works and its sources
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