Minnesota well water testing: MDH recommendations
Short answer: The Minnesota Department of Health recommends testing your well every year for coliform bacteria and nitrate, and at least once for arsenic, lead and manganese. Test water from the faucet you use for drinking and cooking, after any treatment, and use an accredited laboratory or your county's well testing service.
The U.S. Geological Survey estimated that about 1.18 million people in Minnesota supplied their own household water in 2015. USGS says the most common source of self-supplied water is a well. [source] [source]
What to test and how often (MDH)
| Contaminant | How often |
|---|---|
| Coliform bacteria | Every year |
| Nitrate | Every year |
| Arsenic | At least once |
| Lead | At least once |
| Manganese | At least once |
Test water from a faucet you use for cooking and drinking, and if you treat your water, test it after treatment. Testing is especially important if babies or young children drink the water. [source]
Arsenic and new wells
Since August 2008, well contractors have tested each newly drilled well for arsenic and shared the results with the owner and MDH. MDH says to use an accredited laboratory, or ask your county environmental or public health services whether they offer well testing. [source]
Find a lab
Use MDH's accredited laboratory search. [source]
County guides
No county pages for this state yet. Your local health department is the first stop, per EPA guidance. [source]
FAQ
What should Minnesota well owners test for?
The Minnesota Department of Health recommends testing your well every year for coliform bacteria and nitrate, and at least once for arsenic, lead and manganese. Test water from the faucet you use for drinking and cooking, after any treatment, and use an accredited laboratory or your county's well testing service.
Are new Minnesota wells tested for arsenic?
Yes. MDH says that since August 2008, well contractors test each newly drilled well for arsenic and share the results with the owner and MDH.
Sources
- USGS – Estimated Use of Water in the United States, County-Level Data for 2015 (domestic self-supplied population) (accessed 2026-10-23)
- USGS – Domestic Water Use (accessed 2026-10-23)
- Minnesota Dept. of Health – Well Testing, Results, and Options (accessed 2026-10-23)
- Minnesota Dept. of Health – Arsenic in Well Water (accessed 2026-10-23)
- Minnesota Dept. of Health – Accredited laboratory search (accessed 2026-10-23)
- US EPA – Protect Your Home's Water (accessed 2026-10-23)
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