From the Mississippi to Lake Superior
Minneapolis and St. Paul both treat Mississippi River water and soften it, leaving it moderately hard. Duluth pulls very soft water from Lake Superior that stays frigid nearly all year. Rochester and many suburbs rely on wells, and that groundwater is often quite hard, so tanks there gather sediment fast. Statewide, deep-winter inlet water near freezing is what makes undersized heaters run short in January.
DLI licensing, local permits and costs
The Minnesota Department of Labor and Industry licenses plumbers and is the permit office for many communities, while larger cities such as Minneapolis and St. Paul issue their own. Across the state, most repair visits fall between $175 and $650, and swapping a 40 or 50 gallon gas tank usually lands from $1,500 to $3,200 installed; read more on water heater replacement.