Drinking Water

Girl drinking from an outside water fountain

Drinking water that is piped into your home, school, or office comes from either the public water supply or a private well. Knowing about issues that can affect water quality is important for good health.

Drinking water comes from either surface water, such as lakes, or groundwater. Some Wisconsin communities along Lake Superior, Lake Michigan, and Lake Winnebago use surface water as their drinking water source.

Most residents use groundwater for their drinking water

Both public systems and private well owners can have groundwater as their drinking water source. The Wisconsin Department of Natural Resources (DNR) estimates that two-thirds of Wisconsin residents use groundwater as their drinking water source.

Groundwater is part of the water cycle. When it rains or when snow melts, water seeps into pores and cracks in the soil and is stored underground in aquifers. Aquifers are underground groupings of rock that allow water to move. They are not underground rivers or lakes.

There are four major types of aquifers in Wisconsin that can become contaminated (unsafe) when pollution enters them from things such as septic tanks, pesticides, fertilizers, or natural rocks. We have information on the more common concerns in private wells to protect you and your family.


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Last Revised: June 14, 2018