United States Last reviewed: August 28, 2026

Minnesota Tap Water Quality

Q: Is tap water safe to drink in Minnesota?

Yes: Minneapolis, St. Paul, and the large systems meet all EPA standards. In the karst southeast, private wells need regular nitrate testing.

Q: What did 3M do to Minnesota's water?

Decades of PFAS disposal in east-metro landfills contaminated a large aquifer area. Minnesota's 2018 settlement with 3M ($850 million) funds new treatment plants and alternative supplies for affected communities.

Q: Why is southeast Minnesota's groundwater vulnerable?

Karst limestone lets surface water and farm runoff reach aquifers quickly, so nitrate and bacteria appear in wells faster than in most geology; the region is a state testing priority.

about 960

Community water systems

City reports on this site

Tracked contaminants

August 28, 2026

Data reviewed

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Overview

Minneapolis and St. Paul both treat Mississippi River water with modern multi-barrier plants (softening included), and the Twin Cities supply meets all federal standards. Outstate systems split between groundwater and surface sources.

Minnesota's east-metro PFAS story is foundational: 3M's disposal sites contaminated groundwater under Oakdale, Woodbury, Cottage Grove, and neighboring suburbs, producing an $850 million settlement now funding treatment plants across the area. Farm-country nitrate in the karst southeast and central sands is the other standing concern.

Common Contaminants in Minnesota

PFAS

The east-metro 3M plume is among the world's most studied; settlement-funded treatment now covers affected suburbs, and statewide monitoring continues

Nitrate

Karst southeast Minnesota and the central sands show rising nitrate in wells; the state faces EPA pressure over the karst region's private wells

Manganese

Naturally elevated in some groundwater systems; Minnesota issues health-based guidance for infants

Violations & Compliance

Twin Cities systems hold strong compliance records. Violations cluster in small groundwater systems (nitrate, occasional radium), and the karst region's private wells are a recognized public-health gap outside federal jurisdiction.