According to the Center for Disease Control (CDC), the United States has one of the safest drinking water supplies in the world. Most Michigan residents’ water is likely meeting chemical and biological safety standards.

However, contamination can (and does) occur. It is essential for you to understand how it happens and what types of pollution may be present in your system.

In public water systems, contamination may occur in the water source or the distribution system. If the water utility is drawing water from groundwater sources, contamination risk is similar to that of a private well. If the water utility is drawing from a surface water source, biological and chemical contaminants may be introduced through several routes, including runoff from agricultural and urban surfaces, industrial processes, and sewer overflows.

While many contaminants are removed during the water treatment process, water that is not properly treated or that is distributed through poorly maintained pipes may still contain potentially harmful contaminants.

There is also a growing number of emerging contaminants, which are chemicals used in everyday life but for which health and environmental impacts are not fully understood.

According to the CDC, the most common outbreak-causing biological contaminants in public water systems include:

The most common types of outbreak-causing chemical contaminants are copper and excess fluoride. Recently, lead has also risen to the national spotlight as excess concentrations were found to be leaching out of distribution pipes in Flint, Michigan.

There is a growing concern in Michigan surrounding disinfection by-products, especially related to total trihalomethanes.


PFAS is an emerging contaminant that is appearing in public and private water sources across Michigan. It is is a broad category of organic chemicals that have been used for an assortment of industrial and consumer products since the 1950s. Find Out More About PFAS



If you would like to find learn more about your water utility’s treatment process and how well the utility meets compliance, obtain a copy of your Consumer Confidence Report (CCR), which should be sent to you once per year or made available online.