Private well guide

Well Water in Minnesota: Testing, Rules, Labs and Licensed Contractors

470,764 households in Minnesota get their water from a private well. Here is what the state requires, where to get it tested, and who is licensed to work on it.

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232Licensed contractorschecked against state records

28Certified labsfrom the state certified list

86Counties covered

470,764Households on wells21% of households (est.)

About one in five Minnesota homes is on a private well, and the state regulates the well tightly and the water hardly at all. The Department of Health licenses the contractor, requires a bacteria, nitrate and arsenic test on every new well, and files the well record. After that, the schedule is yours. Arsenic, nitrate and manganese are the reasons to keep it.

What comes out of the ground in Minnesota

Roughly one Minnesota well in ten exceeds the arsenic standard, most of them in the west-central and northwest glacial aquifers. Nitrate follows farmland: the karst counties of the southeast and the central sands around Stearns, Benton and Wadena are the hot spots. Manganese is widespread enough that MDH added it to the recommended first test. Radium and radon occur in the deep sandstone aquifers of the east-central and southeast counties, and PFAS has turned up in wells in the east metro and near airports and fire training sites. MDH recommends coliform every year, nitrate every other year, and arsenic, lead and manganese at least once.

Chapter 4725: what the contractor must do and what is on you

Before drilling, the licensed well contractor files a well notification with MDH. When the well is done, the contractor must have it tested for coliform bacteria, nitrate and arsenic and give you the results; the well record then goes into the Minnesota Well Index, which is public. When a property changes hands, Minnesota requires a well disclosure statement in the purchase agreement and a well disclosure certificate filed with the deed listing every well and whether it is in use, not in use or sealed. No water test is required at sale, though lenders usually want one.

At a glance

Water test for a new wellRequired

The licensed well contractor must have every new well tested for coliform bacteria, nitrate and arsenic before it is put into service, and must file a well notification with MDH before drilling. Results go to the owner and to MDH.

Water test when a home is soldNot required statewide

No water test is required, but Minnesota requires a Well Disclosure Statement in the purchase agreement and a Well Disclosure Certificate filed with the deed listing every well on the property and whether it is in use or sealed.

What the state recommends

MDH recommends testing for coliform bacteria every year, nitrate every other year (every year if an infant or pregnant woman drinks the water), and arsenic, lead and manganese at least once. Retest after any repair, flooding or change in taste, color or odor.

Free or low-cost testingAvailable

The Minnesota Department of Agriculture and many counties and soil and water conservation districts run free or low-cost nitrate screening clinics; several county health departments run accredited labs that accept homeowner samples.

MDH-accredited labs that take homeowner samples

MDH accredits labs under the Safe Drinking Water Program, and the list below is limited to labs that told MDH they accept samples from private homeowners. County health department labs and soil and water conservation districts run the cheapest bacteria and nitrate tests; the commercial labs in the metro handle metals, radiological and PFAS panels.

28 certified labs