Air Quality
Good
Water Violations
6
Air quality in Loudoun County is rated good with a median AQI of 43 (273 days measured in 2025). 2 community water systems serve the area, with 6 recent violations in the last 5 years.
Air Quality — Loudoun County (2025)i
AQSThe Air Quality Index measures how clean or polluted the air is on a given day. AQI is reported at the county level. A score of 0-50 is considered good; 51-100 is moderate; above 100 may be unhealthy for sensitive groups.
Median AQI
PM2.5 Daysi
107Ozone Daysi
165Drinking Wateri
SDWISPublic water systems registered to serve this area. Community systems (CWS) provide water to residents year-round. Violations indicate a system failed to meet federal drinking water standards.
Community Systemsi
2Active Systemsi
11Recent Violationsi
6Recent Violations (Last 5 Years)
FOXCROFT SCHOOL
Historical Violations (Over 5 Years Ago)
VIRGINIA TECH RESEARCH CENTER