Drinking Water Information & Concerns

Drinking Water Information

The water that you drink comes from either a public water system or a private well.

In Wisconsin, drinking water comes from either a lake or groundwater. Some Wisconsin communities along Lake Superior, Lake Michigan, and Lake Winnebago use these lakes as their drinking water source.

Groundwater

About 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.

Potential Issues

Knowing about issues that can affect your drinking water's quality is important for good health.

The Wisconsin Department of Health (DHS) has more information and resources for people that get their drinking water from a public water system and for people that get their water from a private well. DHS offers additional information on some common drinking water concerns and steps you can take to protect yourself and your family.

ource: Drinking Water | Wisconsin Department of Health Services

Drinking Water Concerns

While most Public Water Systems and private wells in Wisconsin provide safe drinking water, some may contain chemicals that can affect our health. Following is information on the chemicals most commonly found in Wisconsin's drinking water.

Nitrate in Private Wells

Nitrate is one of the most common groundwater contaminants in Wisconsin.

Nitrate is a molecule that is naturally found in plants and animals. Nitrate can enter groundwater from fertilizers and animal and human waste. Some studies estimate that at least 10% of private wells in Wisconsin have high levels of nitrate. If you have a private well, we recommend that you test your well for nitrate every year and take action if levels are high (P-02128 - English, Spanish, Hmong)

High levels of nitrate in drinking water can affect everyone.

Blue Baby Syndrome (methemoglobinemia)

  • Nitrates can affect how our blood carries oxygen. Nitrate can turn hemoglobin (the protein in blood that carries oxygen) into methemoglobin. High levels can turn skin to a bluish or gray color and cause more serious health effects like weakness, excess heart rate, fatigue, and dizziness. Nitrate can affect babies more seriously because their bodies interact with nitrate differently. 
  • When nitrate levels are high, water should not be given to babies less than 6 months old or used to make infant formula.

Birth Defects

  • High levels of nitrate in drinking water may cause neural tube defects (a type of birth defect). The neural tube turns into the brain and spine in an unborn baby. Neural tube defects can occur very early in pregnancy. 
  • When nitrate levels are high, women who are or may become pregnant should immediately stop using the water for drinking and preparing foods that use a lot of water.

Thyroid Disease

  • High levels of nitrate in drinking water may increase the risk of thyroid disease. Nitrate can affect how the thyroid functions by blocking the uptake of iodine. The thyroid needs iodine to make hormones. Low levels of thyroid hormone levels can cause fatigue, weight gain, dry skin, hair loss, and goiters (enlarged thyroid).
  • When nitrate levels are high, everyone should avoid long-term use of water for drinking and preparing foods that use a lot of water.

Colon Cancer

  • High levels of nitrate in drinking water may increase the risk of colon cancer. Nitrate may enhance the cancer potential of other compounds or may turn into cancer-causing chemicals like the body. Nitrate in drinking water has not been shown to increase the risk of other kinds of cancer.
  • When nitrate levels are high, everyone should avoid long-term use of water for drinking and preparing foods that use a lot of water.

Source: Drinking Water | Wisconsin Department of Health Services