Calvert County, MD

ZIP 20678

In ZIP 20678, 3 of the 12 things we check have at least one part graded D or F.

• Drinking water: The Calverton School meets every EPA legal limit; 4 contaminants are above health goals, led by arsenic at 527× California’s Public Health Goal.
• Nearest Superfund site: Southern Maryland Wood Treating, 9.1 miles away.
• Largest share of modeled toxic air from industry: Waldorf Plant (40%), mostly lead.
• Fine particles (PM2.5) average 6.9 µg/m³; the WHO guideline is 5 and the EPA annual standard is 9.
• About 28,780 kg of agricultural pesticides are applied in the county each year.

Grades for ZIP 20678

• Superfund sites nearbyA to C
• Factories and industrial sitesA to B
• Oil and gas wellsA
• Parks and nature nearbyC
• Air qualityA to B
• Drinking water qualityA to C
• Pesticide useC to D
• Neighborhood health statusB to D
• Past wildfire impactsA
• Past flood impactsC
• Noise levelsA
• Radiation signalsB to D

Based on 7 census tracts · compiled October 25, 2026 · how each grade works and its sources

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