Wisconsin Tap Water Quality Report

The tap water quality in Wisconsin currently sits near the national average, registering a composite safety score of 65.6/100 across 898 monitored ZIP codes. While a significant portion of the state maintains adequate water quality and full compliance with federal standards, 1% of ZIP codes in Wisconsin have received a failing grade due to recent compliance issues. Monitoring data from the EPA indicates that while the majority of residents receive safe tap water, localized issues remain a challenge for several municipal systems.

The state's water infrastructure has experienced significant compliance hurdles recently, logging a staggering 816 health-based violations over the past 5-year monitoring window out of 5,281 total violations. When a state registers this volume of health-based violations, it often points to systemic challenges such as aging distribution networks, agricultural runoff affecting groundwater, or underfunded rural water systems. Wisconsin Department of Natural Resources is responsible for enforcing corrective actions and penalizing systems that repeatedly fail to meet safe drinking water standards.

One of the most pressing concerns for Wisconsin residents is the elevated risk of lead exposure. EPA models and historical monitoring indicate that 65.7% of ZIP codes in Wisconsin 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.