The Marathon County Public Health Laboratory provides convenient, reliable, and reasonably priced water testing services to the citizens of Marathon County and surrounding counties, with the goal of safer water supplies. The lab is involved in monitoring public drinking water supplies which include municipal community water systems and those involved in our Department of Natural Resources (DNR) transient non-community water (TNC) systems program.

Water Testing Laboratory Hours (Effective July 1, 2019)
Monday-Thursday, 8:00 a.m. - 4:30 p.m.,
Friday, 8:00 a.m. - 3:00 p.m.

Clean, safe drinking water is one of the most important elements of good health. Testing well water on an annual basis is one of the easiest things a private well owner can do to take care of their health and the health of their loved ones. It’s estimated that 20-25% of Wisconsin wells have bacterial contamination, so Marathon County Health Department advises all private well owners to have their well water tested for coliform bacteria. If there are infants under six months of age or women of childbearing age drinking the water, it should also be tested for nitrates.

Tests for Drinking Water from Private Wells

Test Result Information

Arsenic Coliform Bacteria
Copper Hardness, pH, Alkalinity
Iron Nitrate

How do I test my private well drinking water? How often do I need to test?

To test your private well water, obtain a water sample bottle, instructions, and a lab submission form from the Marathon County Health Department Laboratory.  Results will be ready within one week.  Most Wisconsin wells provide safe water.  However, bacterial and chemical contaminants can pollute ground water in a variety of ways.  Common tests include coliform bacteria, nitrates, and fluoride.  Every private well should be tested annually and whenever there are changes in taste, color, odor or appearance.  Contact Marathon County Health Department to find more information by calling (715) 261-1900.

Additional Information: Drinking Water

Additional Information: Water Quality Issues

Well Water Sampling Instructions Well Chlorination Procedure









If you would like more information or have questions about water testing,please contact Cheryl or Deanna by calling 715-261-1908.

For directions to Marathon County Health Department, use this map.



Help us improve this website - take our survey