Arsenic Found in Nearly Half of Minnesota Private Wells

State testing revealed that contamination has persisted in wells installed since 2008.

Updated on Sept. 21, 2026 in Cancer

Flat gouache-painted editorial illustration of a brass outdoor water spigot embedded in gravelly soil, symbolizing regional water quality issues. — State data confirms that nearly half of all private wells installed in Minnesota since 2008 contain levels of arsenic that pose long-term health risks. AI Illustration. Upload story photo >

Live Poll

Should local governments provide more financial assistance to help private well owners treat contaminated water?

Data gathered through 2021 showed that arsenic is present in nearly 50% of new private wells in Minnesota. Approximately 20% of the state population relies on these private water sources for their daily drinking water.

Why it matters

High costs for professional water filtration systems, which can exceed $5,000 per home, prevent many residents from effectively removing these contaminants. This leaves many households consuming water with levels that may pose long-term health risks.

Nearly half of the 65,000 wells sampled by state officials contained arsenic levels exceeding two micrograms per liter. High concentrations topping 10 micrograms per liter are particularly prevalent in central and northwestern Minnesota.

The players

Minnesota Department of Health

This state agency is responsible for protecting, maintaining, and improving the health of all Minnesotans through public health initiatives and environmental oversight.

The details

Arsenic entered the local soil approximately 14,000 years ago via glacial deposits, making it a naturally occurring feature of the regional landscape. While reverse osmosis systems can filter out lead, manganese, nitrate, and coliform bacteria alongside arsenic, their high installation cost remains a significant barrier for many well owners.

Glacial deposits introduced arsenic to Minnesota soil 14,000 years ago.
The Minnesota Department of Health conducted well sampling from 2008 to 2021.

The Big Picture

This situation highlights a gap in public health protection as private well quality remains outside the strict regulatory enforcement standards of the 1974 Safe Drinking Water Act. It underscores the ongoing challenges of managing groundwater quality in regions with naturally occurring mineral deposits.

Residents relying on private wells should consider professional water testing and evaluate the feasibility of installing reverse osmosis filtration. High initial costs require families to plan for significant upfront maintenance expenses to ensure their water is free from arsenic and other heavy metals.

The takeaway

Because arsenic is a naturally occurring element in Minnesota soil, it will not become less common in the state's groundwater over time. Residents must prioritize regular testing to understand the specific safety of their home water supply.