Water Testing

While many private wells provide quality water that is safe for you, your family, and pets, you should regularly test your well because it may have one or more water quality problems. Some contaminants can be seen or tasted while others require testing to detect. 

Private well owners are responsible for testing and maintaining their well. Unlike public water systems, private well owners are not required to regularly test their wells or correct water-quality problems. It is your choice to decide which test to do and actions to take.

There are a few essential tests that should be performed routinely on every private well. Homeowners should routinely test their well. You may decide to test more often if your previous results were unsafe.

Water Test Kit QR code
Southeastern Minnesota Water Analysis Laboratory (SEMWAL):
  • CLICK HERE to visit the SEMWAL webpage and order a test kit!

Three Routine Tests for Every Well Owner

Everyone is potentially at risk from the three most common contaminants in Minnesota well water.

  1. Bacteria - Every well should be tested once a year, and when you notice a change in taste, color, or smell.
  2. Nitrate - Every well should be tested once a year, and before the well will be used by a woman who is or may become pregnant or if an infant under the age of 1 is in the household
  3. Arsenic - Test for arsenic at least once. Arsenic occurs naturally in rocks and soil across Minnesota and can dissolve into groundwater. Arsenic levels can vary between wells, even within a small area. Visit the MN Department of Health webpage for more information: https://data.web.health.state.mn.us/web/mndata/arsenic_wells


Southeastern MN Water Analysis Lab
phone: 507-328-7495

MN Dept of Health - Well Management
phone: 651-201-4600 or 877-383-9808
fax: 877-434-9853

Additional Testing for Private Well Owners

You may consider additional testing to look for:

  • Geologically occurring contaminants in the rock and soil that may enter your well.
  • Human caused contaminants from land-use, your plumbing materials, or other sources of pollution near your well.


  • Manganese - Test once for manganese, especially if you have an infant in the home or notice brown or black staining or black sediment in your water.
  • Fluoride - Test for fluoride if you have an infant in the household or when you move into a home with a well. Your dentist and pediatrician will use this information to decide how much additional fluoride to recommend.

Human & Geologic

  • Chloride - Test annually to monitor for noticeable increases above background levels (1- 5mg/L across much of MN).                                                  Higher levels of chloride indicate contamination by human activities, including potassium chloride fertilizer application on crops, road salt application, water softener discharge, human or animal waste disposal, and leachate from landfills.


  • Lead & Copper - Test once every five years or if the water will be used by a pregnant woman or infant. Lead and copper may be in your water from the plumbing materials used in your home.
  • Pesticides - Consider this test if your home is within ¼ mile of agricultural fields or areas where pesticides are manufactured, stored, or mixed.
  • VOCs - Volatile organic compounds (VOCs), testing is recommended for homes within ¼ mile of a landfill, industrial site, gas station or other underground tank, and especially if you smell chemical or fuel odors in the home.

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