Minnesota Tap Water Quality
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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
The east-metro 3M plume is among the world's most studied; settlement-funded treatment now covers affected suburbs, and statewide monitoring continues
Karst southeast Minnesota and the central sands show rising nitrate in wells; the state faces EPA pressure over the karst region's private wells
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.
Water Hardness in Minnesota
Very hard, typically 180–350 mg/L. Groundwater across Minnesota is very hard; Minneapolis and St. Paul soften their Mississippi River supply at the plant, so city tap water tests softer than the raw source.
Hardness affects taste, limescale, and soap — not safety. Compare levels across all cities or read the water hardness guide.
City Water Reports in Minnesota
Frequently Asked Questions
Sources & References
The safety rating and guidance on this page draw on the following sources. See our full methodology.
- •US EPA Safe Drinking Water Act regulations
- •EWG Tap Water Database
- •The utility's most recent Consumer Confidence Report (CCR)
- •WHO Guidelines for Drinking-water Quality