Public Water Systems

The Safe Drinking Water Act defines a public water system as a system that provides drinking water to at least 15 service connections, or regularly serves an average of at least 25 individuals daily at least 60 days out of the year. There are four types of public water systems in Wisconsin:

  • Municipal community systems, like cities, towns, and villages, serve people where they live.
  • Other-than-municipal community systems, like mobile home parks, subdivisions, apartment buildings, and condominiums, serve people where they live.
  • Non-community, non-transient systems, like schools, daycare centers, and factories, serve people where they work and learn.
  • Non-community transient systems, like restaurants, taverns, campgrounds, parks, motels, and gas stations. serve people where they eat, drink, and play.

The Safe Drinking Water Act requires that public water systems test for contaminants regularly and take action if contaminant levels are too high. In Wisconsin, the Department of Natural Resources (DNR) regulates public water systems to ensure that they are following these requirements. While most drinking water in Wisconsin is safe to drink, it is important to learn about the quality of your drinking water and follow any actions recommended by the public water system.

Public Water System Users Should Learn About the Quality of Their Water

  • The Safe Drinking Water Act requires that public water systems develop a report each year. This consumer confidence report describes where the drinking water comes from, what contaminants are detected and their potential health effects, and if there are any standards violations. This infographic explains how to interpret a consumer confidence report.
  • Each year, the DNR publishes a report that summarizes how public water systems in the state are doing and highlights efforts taken by systems to provide safe drinking water.
  • In 2019, they found that more than 99% of Wisconsin's public water systems provided water that met all of the health-based drinking water standards.
  • You should contact your water utility if you are experiencing issues with your drinking water's color, taste, or odor.

Public Water Systems Will Issue a Public Notice if the Water Poses a Health Risk

  • Drinking water can sometimes have unsafe levels of contaminants. If these levels pose a health risk, the public water system will issue a public notice. It is important to follow the instructions in the notice to protect yourself and your family.
  • A Boil Water Notice, P-44589 (PDF) is issued when certain indicator bacteria are found in the water. These bacteria indicate that pathogens may be present in the water. If you or a family member experiences diarrhea, cramps, or nausea during a boil water notice, call your doctor and local health department. Note, however, that these symptoms may be caused by factors other than unsafe water.
  • A "do not drink" or "flush only" notice is issued when levels of a chemical are too high. The actions recommended by the notice may apply to certain populations (like infants or pregnant women) or to everyone.
    • If a "do not drink" notice is issued, the water is not safe to use for cooking or preparing food but can be used for washing hands and showering.
    • If a "flush only" notice is issued, the water is not safe to use for drinking, preparing food, washing hands, showering, or other activities that result in contact with the water, but can be used to flush toilets. Flush-only advisories are rare in Wisconsin.

Source: Public Water Systems | Wisconsin Department of Health Services