St. Mary's County, MD

ZIP 20630

In ZIP 20630, 4 of the 12 things we check have at least one part graded D or F.

• Drinking water: Piney Point Landings meets every EPA legal limit; 6 contaminants are above health goals, led by arsenic at 988× California’s Public Health Goal.
• Nearest Superfund site: Patuxent River Naval Air Station, 6.0 miles away.
• Largest share of modeled toxic air from industry: Stella-Jones Corp (70%), mostly arsenic compounds.
• Fine particles (PM2.5) average 6.5 µg/m³; the WHO guideline is 5 and the EPA annual standard is 9.
• About 64,785 kg of agricultural pesticides are applied in the county each year.

Grades for ZIP 20630

• Superfund sites nearbyC to D
• Factories and industrial sitesA
• Oil and gas wellsA
• Parks and nature nearbyC
• Air qualityA
• Drinking water qualityC to D
• Pesticide useF
• Neighborhood health statusC
• Past wildfire impactsA
• Past flood impactsD
• Noise levelsA
• Radiation signalsC

Based on 2 census tracts · compiled September 10, 2026 · how each grade works and its sources

Loading the full report, with every source…