Okanogan County, WA

ZIP 98827

In ZIP 98827, 3 of the 12 things we check have at least one part graded D or F.

• Drinking water: Tonasket Water System meets every EPA legal limit; 6 contaminants are above health goals, led by arsenic at 529× California’s Public Health Goal.
• Nearest Superfund site: Silver Mountain Mine, 5.5 miles away.
• Fine particles (PM2.5) average 7.6 µg/m³; the WHO guideline is 5 and the EPA annual standard is 9.
• About 813,147 kg of agricultural pesticides are applied in the county each year.

Grades for ZIP 98827

• Superfund sites nearbyA
• Factories and industrial sitesA to C
• Oil and gas wellsA
• Parks and nature nearbyA to C
• Air qualityC
• Drinking water qualityC
• Pesticide useF
• Neighborhood health statusF
• Past wildfire impactsD to F
• Past flood impactsA
• Noise levelsA
• Radiation signalsB

Based on 2 census tracts · compiled October 25, 2026 · how each grade works and its sources

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