Water Contamination: What You Should Know About MN Well Water

water contamination in MN Well Water

The Minnesota Department of Health recently reported finding higher-than-average quantities of various chemical pollutant water contamination in Minnesota’s well water. MPR reported concentrations of nitrate, arsenic, and bacteria. The Minnesota Department of Health recently tightened well water safety guidelines to respond to heightened levels of the dangerous Perfluorochemicals PFOA and PFOS. These contaminants primarily affect private wells in the East Metro area, but the new regulations imposed by the MN Health Department will affect public supply wells in Cottage Grove, Oakdale, Woodbury, and St. Paul Park.

So: what’s is this water contamination? How did it get there? Why is it concerning? Can it affect me? And what can we do about it? Here’s all the information you should know about each of the contaminants polluting Minnesota’s well water.


Fertilizer seepage creates nitrate water contamination


What It Is

Nitrate is a natural ionic compound formed when nitrogen combines with oxygen or ozone.  Plants and animals produce it naturally, and it’s a crucial part of the fertilizing process. Industrial and automobile exhaust also produce it.

How Did It Get Into The Water

Nitrogen is the active ingredient in most fertilizer. Bacteria in soil convert introduced nitrogen into nitrate, which is easier for plants to absorb. During periods of heavy rainfall or over-irrigation, nitrate seeps down through soil and into groundwater before plants have a chance to absorb it.

Most of the nitrate in Minnesota’s well water seeped down from fertilizer. Consequently, nitrate water contamination is particularly widespread in parts of Minnesota with prevalent agriculture. Water seeps into sandy soil more easily than densely packed soil, so the sandy soil in central Minnesota, especially northwest of the Twin Cities, may be particularly nitrate prone.

Why It’s Concerning

When people drink too much nitrate, the digestive system transforms it into NITRITE–with an “i” instead of an “a”. No, we don’t know why they named it that. We’re plumbers, not scientists. Nitrite-with-an-”i” oxidizes iron in red blood cells, forming methemoglobin. Too much methemoglobin affects blood’s ability to carry oxygen, resulting in a condition called methemoglobinemia. Methemoglobinemia doesn’t affect most adults, but it’s sometimes called “blue baby syndrome” because it harms a baby’s ability to get oxygen.

Nitrate only becomes a problem in quantities above the established health risk level of 10 mg/L. Unfortunately, the MN Department of Health found unsafe nitrate concentrations in about 12% of Minnesota’s well water. So far, nitrate water contamination has affected Bemidji, the East Metro, and parts of northwest and central Minnesota.

What Can I Do?

If you’re worried about nitrate water contamination, contact your local health department. Several filtration and treatment procedures, such as those used by municipal water systems, can remove nitrates from water. You can also have a reverse osmosis water filtration system installed to purify your well’s drinking water.

The state health department recommends testing your well water tested for nitrate 1-2 times per year. Be particularly wary of nitrate if you are pregnant, plan to become pregnant, or have a baby.  

Arsenic, a heavy metal element that may cause water contamination


What It Is

Arsenic is a heavy metalloid element naturally found in the earth’s crust. Arsenic is widely distributed in air, soil, and water and combines with both organic and inorganic substances to form compounds. Industrial companies use arsenic to strengthen copper or lead alloys and make pigment, paper, adhesives, and paper. We used to use it in pesticides and weed killers, as well. In high enough concentrations, arsenic is a deadly poison.

How Did It Get Into the Water

Arsenic occurs naturally in rocks and soil. The heavy metal dissolves into groundwater when the water erodes rock and soil it comes into contact with. It may also seep out of industrialized areas or from the residue of old pesticides.

Why It’s Concerning

Arsenic is a known carcinogen. Prolonged exposure may cause chronic arsenic poisoning, which can lead to stomach and skin cancer. Other consequences of long-term exposure include skin pigmentation changes, skin lesions and hyperkeratosis (hard patches on the palms and the soles of your feet). Early long-term effects like these manifest after about five years of exposure to dangerous levels of arsenic. There is some evidence to suggest that arsenic exposure may lead to adverse pregnancy outcomes and child health problems.

The MN Department of Health doesn’t know how much arsenic will produce negative effects, and people may differ in their individual susceptibility. The EPA’s standard Maximum Contaminant Level (MCL) for arsenic in drinking water is 10 micrograms per liter.

What Can I Do

Have your well water tested for arsenic at least once a year. Water filtration systems such as the reverse osmosis can filter potentially dangerous amounts of arsenic out of your water.

Conventional systems like water softeners and activated carbon filters can’t remove arsenic water contamination all on their own, and boiling your water won’t help either. You could attempt to invest in a new well if you’re unwilling to purchase a filtration system.

PFC water contamination

Perfluorochemicals (PFCS)

What They Are

PFCs are a type of manmade chemicals once used to make heat, oil, stain, and water resistant materials like non-stick cookware. The same properties that make them ideal for creating resistant products unfortunately make them very long-lasting in the environment. PFCs virtually never break down and can travel long distances in water or the air.

The specific PFCS present in Minnesota water, perfluorooctanoic acid (PFOA) and perfluorooctanoic sulfonate (PFOS), were also used to make resistant materials. In 2016, the EPA released a Health Advisory on PFOA and PFOS and estimated the safe consumption levels of the combined PFCS at 70 parts per trillion.

How Did It Get In The Water

In Minnesota, the recent influx of PFCs affected water systems in Bemidji and Washington County in the east metro of the Twin Cities the most. PFCs were introduced in Washington county when waste products from 3M’s PFC manufacturing facilities were dumped in Washington county landfills and seeped into the groundwater from there. PFCs got into Bemidji’s public and private groundwater when firefighting foam used in training exercises at the Bemidji Regional Airport was absorbed into the ground.    

It’s not uncommon for PFCs to enter groundwater this way. Heavy industry and manufacturing runoff is responsible for originally introducing much of the PFC contamination present in the environment today.

Why It’s Concerning

Some studies have found links between higher PFC levels and high cholesterol, changes to liver function, reduced immune response, thyroid disease, and even kidney and testicular cancer. These studies are not conclusive, however, and research is ongoing. PFCs may also affect fertility, hormone levels, cholesterol, and the immune system.

PFOA and PFOS are primarily concerning for their possible effect on developing fetuses and infants. PFCs never break down in the body and mothers may pass them to fetuses or infants via breastfeeding. In utero or infant exposure to PFCs can have adverse effects on the baby’s weight and growth, and may cause learning or behavior disorders.

What You Can Do

Fish caught from contaminated rivers and lakes may contain high PFC concentrations. Consider limiting local fish consumption. Use reverse osmosis or an activated carbon water filtration system to treat all well water before consuming or using. Consider temporarily switching to bottled water or filtered tap water until you can have a treatment system installed.


If you’re worried about the safety or quality of your drinking water, give us a call. We can do water quality tests and make recommendations on protecting yourself and your family.

We also offer reverse osmosis water filtration system installations for private wells and water systems connected to city supplies. Filtering your water right before you drink it is the best way to prevent contaminants. Even if you depend on a well for all your water uses, you don’t have to fear contamination. You have options–including us!

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