Montana Tap Water Quality Report

Drinking water quality in Montana faces notable challenges, currently scoring below the national average with a composite safety score of 55.1/100 across 405 monitored ZIP codes. According to the EPA's Safe Drinking Water Information System, 3% of ZIP codes in the state have received a failing grade. These scores reflect historical struggles with aging infrastructure, localized contamination events, and recurring health-based violations that require active intervention by local utilities.

Over the past 5 years, water utilities in Montana have recorded a total of 2,102 violations, of which 431 were strictly health-based. While administrative and reporting violations are common nationwide, health-based violations mean that certain contaminants exceeded the EPA's Maximum Contaminant Levels (MCLs) at some point. Montana Department of Environmental Quality, which acts as the primary regulatory authority in the state, typically works closely with these utilities to issue boil water advisories or mandate infrastructure upgrades when these limits are breached.

One of the most pressing concerns for Montana residents is the elevated risk of lead exposure. EPA models and historical monitoring indicate that 60.7% of ZIP codes in Montana are classified as High or Very High risk for lead. This is frequently associated with older housing stock built before the 1986 federal ban on lead pipes and solder. Residents living in older homes should strongly consider having their tap water independently tested and utilizing a certified NSF/ANSI 53 water filter for drinking and cooking.