Door County Groundwater

Although Door County is surrounded by the waters of Lake Michigan and Green Bay, the primary source of drinking water for nearly all county residents and visitors is groundwater. Due to the geology of the county, groundwater resources are readily impacted by land use and surface activities. 

Door County’s bedrock is made up of what is referred to as a karst landscape, this is limestone-based bedrock that has been highly modified by water over thousands of years creating solution features such as crevices, sinkholes and caves. The result is a highly fractured bedrock aquifer, the “container” that holds our drinking water. This cracked and creviced bedrock, coupled with a very thin layer of soil to provide a “buffer” from surface activities, results in a very vulnerable resource that tens of thousands of people rely on.Karst Cross Section

Emerging Contaminants January 23, 2024 County Board Presentation (PDF)


Well Water Test Kits

"An estimated 34 million Americans get their water from private ground water wells, which are not subject to EPA regulations. Private ground water wells can provide safe, clean water. However, contamination that can cause sickness also can occur in well water.

If you have a well, you should take steps to protect it and have the water tested annually to make sure your water is safe."  - Centers for Disease Control (CDC)

Click on Well Water Test Kit link on the left for more information.

Well Data

Link to the Wisconsin Department of Natural Resources well data information.

Well Water Quality Viewer

Link to the UW-Stevens Point Well Water Quality Viewer - Private Well Data for Wisconsin