Air Quality
Moderate
Water Violations
86
Active Contamination
1
Active Permits
7
Air quality in Larimer County is rated moderate with a median AQI of 54 (274 days measured in 2025). 12 community water systems serve the area, with 86 recent violations in the last 5 years. 1 contamination site are tracked, all with completed or ongoing remediation.
Air Quality — Larimer 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
37Ozone Daysi
236Drinking 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
12Active Systemsi
13Recent Violationsi
86Recent Violations (Last 5 Years)
Historical Violations (Over 5 Years Ago)
DEER MOUNTAIN CABINS
Industrial Monitoringi
Contamination Sitesi
Contaminated sites tracked by the EPA and state agencies. Superfund sites are the most seriously contaminated locations. Brownfields are former industrial properties being cleaned up for reuse. LUST sites have confirmed leaks from underground storage tanks.