Plymouth County, IA

ZIP 51109

In ZIP 51109, 7 of the 12 things we check have at least one part graded D or F.

• Drinking water: Sioux City Water Supply has 2 contaminants at or over an EPA legal limit; 22 contaminants are above health goals, led by lithium at 19× the USGS health-based screening level.
• Closer to Superfund sites than 54% of U.S. neighborhoods, with no listed site within 10 miles of its center.
• Largest share of modeled toxic air from industry: Wilson Trailer Co (49%), mostly chromium.
• Fine particles (PM2.5) average 7.2 µg/m³; the WHO guideline is 5 and the EPA annual standard is 9.
• About 353,519 kg of agricultural pesticides are applied in the county each year.

Grades for ZIP 51109

• Superfund sites nearbyA to C
• Factories and industrial sitesB to C
• Oil and gas wellsA
• Parks and nature nearbyC to D
• Air qualityA to B
• Drinking water qualityC to F
• Pesticide useF
• Neighborhood health statusC to D
• Past wildfire impactsA
• Past flood impactsD
• Noise levelsA to D
• Radiation signalsD

Based on 4 census tracts · compiled September 10, 2026 · how each grade works and its sources

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