By Brooke Hrdlicka, Paul Mathewson, Ph.D., & Kayla Rinderknecht, MPH, Clean Wisconsin
Summary
Everyone deserves clean, safe drinking water. In Wisconsin, about two-thirds of people get their drinking water from public water systems. Here we explore health-based violations in public water systems to better understand how common health-based violations are at public water systems in Wisconsin, which contaminants have been found at unsafe levels, and what violations are most common.
Key takeaways:
- The vast majority of community water systems in the state have not had any health-based drinking water violations since 2015.
- 23% of active community water systems have had a health-based drinking water violation since 2015.
- These systems serve 807,000 residents, about 15% of the state’s population.
- 7% of community water systems have had a maximum contaminant level violation (MCL), meaning that contaminant concentrations in the drinking water exceeded health-based standards.
- 18% of community water systems have had a treatment technique violation, meaning that the safety of the drinking water could not be ensured.
- MCL violations were most common for radionuclides, nitrates, arsenic, and disinfection byproducts.
- Systems in rural, lower-income areas of the state are more likely to have drinking water violations.
- 37% of rural, low-income systems had health-based violations compared to 20-23% of other systems.
- Rural, low-income systems had 0.85 violations per system compared to 0.23-0.46 for other systems.
- Health-based violations tended to be lower in systems serving higher percentages of non-white residents.
- This highlights the opportunity for targeted interventions to support rural, low-income systems to significantly improve overall water quality and health equity in the state.
