Asotin County, WA

ZIP 99403

In ZIP 99403, 8 of the 12 things we check have at least one part graded D or F.

• Drinking water: Pud #1 Of Asotin County meets every EPA legal limit; 10 contaminants are above health goals, led by lead at 78,354× California’s Public Health Goal.
• Closer to Superfund sites than 0% of U.S. neighborhoods, with no listed site within 10 miles of its center.
• Largest share of modeled toxic air from industry: Clearwater Paper Corp-Ppd & Cpd Idaho (76%), mostly formaldehyde.
• Fine particles (PM2.5) average 8.3 µg/m³; the WHO guideline is 5 and the EPA annual standard is 9.
• About 66,643 kg of agricultural pesticides are applied in the county each year.

Grades for ZIP 99403

• Superfund sites nearbyA
• Factories and industrial sitesB to D
• Oil and gas wellsA to C
• Parks and nature nearbyB to F
• Air qualityB to D
• Drinking water qualityD to F
• Pesticide useD to F
• Neighborhood health statusD to F
• Past wildfire impactsA to D
• Past flood impactsA
• Noise levelsA to B
• Radiation signalsC to D

Based on 7 census tracts · compiled September 10, 2026 · how each grade works and its sources

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