Private well owners are not required to test their water quality. Yet the Division of Public Health urges well owners to test because so many wells are contaminated:
• One-third have detectable pesticide residues (DATCP estimate), with higher frequencies in agricultural areas.
• 9 to 11 percent exceed the drinking water standard for nitrates, 90 percent of which come from agriculture.
• About one-quarter are contaminated with coliform bacteria.
Resources for private well owners
Wisconsin Well Water viewer — Explore data on private well contamination statewide, from the University of Wisconsin-Extension/UW-Stevens Point Center for Watershed Science and Education. Goes down to township level. Does not show trends over time.
FAQ and more resources for well owners from CWSE.
Manure contamination of wells — Division of Public Health publication
Labs certified to test for bacteria, by county
Labs certified to test for other contaminants
More reading: Kewaunee County list of resources (many relevant statewide)
New baby well testing program: Local health departments can test the wells of low-income families with new babies for free. A state program that funds tests of total coliform, E. coli and nitrates draws about 2,000 participants a year, said Chuck Warzecha, environmental and occupational health director at the Wisconsin Department of Health Services. A list of contacts for local health departments is here.
Learn more about karst
Avoid That Sinking Feeling — Kewaunee County brochure.
Living with Karst — National brochure from federal agencies and cave associations.
Final report of the Northeastern Karst Task Force (2007)
Karst map of Wisconsin from the Wisconsin Geological and Natural History Survey