Drinking Water: Private Wells

About 30 percent of Wisconsin residents get their drinking water from private wells.

What is a private well?

A well for drinking water.

A private well is a way to access groundwater. A well is “private” if it has fewer than 15 connections and serves fewer than 25 people.

A single person or an entity can own a private well. Examples include a small business, mobile home, or school.

Unlike public water systems, the owner of a private well is in charge of protecting and maintaining the well.

How do I maintain my well?

A private well needs regular maintenance and inspection. You want to make sure it’s working correctly. Here are ways to protect your well:

  • Avoid damaging the well casing. See Learn About Private Water Wells for a diagram of the parts of a well.
  • Keep the area around the well clean and safe.
  • Make sure the ground slopes away from the well.
  • Make sure your well cap is secure and in good condition. It shouldn’t have cracks, holes, or other damage.
  • Work with licensed professionals and keep records of all well work and testing. For a list of professionals, see Well and Heat Exchange Contractors.

When should I test my private well and what should I test for?

Private well users should test their private well for:

Well users may want additional testing for additional substances depending on where they live and how the land around the well is used. These substances are described below. The Department of Natural Resources (DNR) Drinking Water Tests for Private Wells fact sheet (PDF) has more information on which tests to conduct and when.

Wisconsin's Well Testing Access Program (WellTAP)

Through WellTAP, well users may be eligible for no-cost testing through their local or Tribal health department. To qualify for WellTAP:

  • The well must serve someone who is pregnant, a child 12 or under, or a person with weakened immune system,
  • The well must serve your primary residence, and
  • A financial or other burden prevents you from testing on your own.

To learn more about the program and to find out if you are eligible, contact your local health department or tribal health center.

What substances could be in my well water?

While most private wells in Wisconsin provide safe drinking water, some may contain substances that can affect our health. Many of these substances do not affect the color, smell, or taste of the water. Because of this, we recommend that all well users test their well water regularly. When testing, it is best to use a Wisconsin certified lab.

These substances may be found in a private well in Wisconsin:

What can I do if there are contaminants in my water?

Short-term options

  • If your water contains elevated levels of a contaminant, you should use a different source of water for drinking, making baby formula, and preparing foods that take up a lot of water (like oatmeal, rice and gelatin).
  • Options for different water include bottled water, water from a well without issues, and water from a public system.
  • Information on how to address specific contaminants can be accessed above or from our chemicals list.

Long-term options

  • One option is to drill a new well to access water that is not affected. Because this can be a complex process, it is best to work with your regional private well specialist.

    The DNR well compensation grant program provides funding to address contamination in private water supplies for eligible landowners, renters, and business owners.

  • Another option is to install a certified treatment device. Using a certified device is important because it means the device has met a set of voluntary manufacturing and performance standards.

    Our Water Treatment Devices for Private Well Contaminants fact sheet, P-45012 (PDF) has more information on which the types of treatment devices available for many of the contaminants listed above.

Related topics

Our chemical page has information on the other substances that we can be exposed in drinking water, air, and soil.

We also have information on steps to take if your private wells has been impacted by a manure spill or by flooding.

DNR has a list of certified professionals that can help inspect wells and address issues.

The University of Wisconsin's How to Read Your Private Well Water Lab Report Guide (PDF) describes the different sections of a lab report, defines the terms used, and provides a step-by-step guide on how to determine if the results indicate a public health issue.


Questions? Can't find what you're looking for? Contact us at dhsenvhealth@wi.gov.

Last revised December 17, 2024