Riverside County, CA

ZIP 92557

In ZIP 92557, 9 of the 12 things we check have at least one part graded D or F.

• Drinking water: Riverside Highland Water Company has 2 contaminants at or over an EPA legal limit; 18 contaminants are above health goals, led by pfos at 18× California’s Public Health Goal.
• Nearest Superfund site: March Air Force Base, 7.0 miles away (3 within 10 miles).
• Largest share of modeled toxic air from industry: Sterigenics-Ontario Facility (58%), mostly ethylene oxide.
• Fine particles (PM2.5) average 9.8 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 92557

• Superfund sites nearbyD
• Factories and industrial sitesD
• Oil and gas wellsB to C
• Parks and nature nearbyC to F
• Air qualityF
• Drinking water qualityD to F
• Pesticide useD
• Neighborhood health statusB to C
• Past wildfire impactsC to D
• Past flood impactsC
• Noise levelsA to D
• Radiation signalsC to D

Based on 13 census tracts · compiled September 10, 2026 · how each grade works and its sources

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