Walla Walla County, WA

ZIP 99363

In ZIP 99363, 5 of the 12 things we check have at least one part graded D or F.

• Drinking water: Westbourne Acres meets every EPA legal limit; 8 contaminants are above health goals, led by lead at 53× California’s Public Health Goal.
• Closer to Superfund sites than 59% of U.S. neighborhoods, with no listed site within 10 miles of its center.
• Largest share of modeled toxic air from industry: Tidewater Terminal Co Snake River Terminal (79%), mostly metham sodium (sodium methyldithiocarbamate).
• Fine particles (PM2.5) average 6.5 µg/m³; the WHO guideline is 5 and the EPA annual standard is 9.
• About 2,161,365 kg of agricultural pesticides are applied in the county each year.

Grades for ZIP 99363

• Superfund sites nearbyC
• Factories and industrial sitesD
• Oil and gas wellsA
• Parks and nature nearbyC
• Air qualityA
• Drinking water qualityB to F
• Pesticide useF
• Neighborhood health statusD
• Noise levelsA
• Radiation signalsD

Based on 1 census tract · compiled September 10, 2026 · how each grade works and its sources

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