Whitman County, WA

ZIP 99170

In ZIP 99170, 6 of the 12 things we check have at least one part graded D or F.

• Drinking water: Sleepy Hollow Apts has 2 contaminants at or over an EPA legal limit; 5 contaminants are above health goals, led by pfos at 6.4× California’s Public Health Goal.
• Nearest Superfund site: Grain Handling Facility at Freeman, 9.6 miles away.
• Largest share of modeled toxic air from industry: Spokane Industries (43%), mostly chromium.
• Fine particles (PM2.5) average 6.8 µg/m³; the WHO guideline is 5 and the EPA annual standard is 9.
• About 626,961 kg of agricultural pesticides are applied in the county each year.

Grades for ZIP 99170

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

Based on 3 census tracts · compiled September 10, 2026 · how each grade works and its sources

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