Sister Bay, WI vs Green Bay, WI

When comparing tap water quality between Sister Bay, WI and Green Bay, WI, Sister Bay currently holds a substantial 45-point lead in average WaterQ score, with a score of 96 out of 100 versus 51 for Green Bay. Sister Bay, WI carries an A grade while Green Bay, WI carries a D. A WaterQ score reflects an aggregate of EPA-reported violations, monitoring data, and compliance history across all public water systems serving each city, so a higher score generally indicates fewer recent violations and a stronger compliance record, though it does not guarantee that every tap in the city tests identically.

Green Bay, WI is the larger of the two, with 158,373 more residents than Sister Bay. Green Bay is served by 4 public water systems, compared with 1 in Sister Bay — a difference of 3 systems. A larger number of systems often reflects a more fragmented distribution network spanning multiple utilities, suburbs, or rural service areas, while a single large utility serving a big population can benefit from economies of scale in treatment and monitoring, but may also face more complex, aging infrastructure to maintain.

For residents of either Sister Bay or Green Bay, the most useful next step is to look up the specific water system that serves your address, since city-wide averages combine results from every system in the area. Visit the Sister Bay or Green Bay city pages below for a breakdown of local systems, recent violations, and contaminant-specific data, or browse WaterQ's contaminants directory to learn what each measured substance means for health.