Matanuska-Susitna County, AK

ZIP 99623

In ZIP 99623, 5 of the 12 things we check have at least one part graded D or F.

• Drinking water: Wasilla Water System meets every EPA legal limit; 14 contaminants are above health goals, led by lead at 44× California’s Public Health Goal.
• Closer to Superfund sites than 62% of U.S. neighborhoods, with no listed site within 10 miles of its center.
• Largest share of modeled toxic air from industry: Crowley Palmer Facility (60%), mostly benzene.
• Fine particles (PM2.5) average 4.8 µg/m³; the WHO guideline is 5 and the EPA annual standard is 9.

Grades for ZIP 99623

• Superfund sites nearbyA to D
• Factories and industrial sitesA
• Oil and gas wellsA to C
• Air qualityA
• Drinking water qualityB to F
• Neighborhood health statusB to D
• Past wildfire impactsA to F
• Past flood impactsA
• Radiation signalsC to D

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

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