Manganese in Drinking Water

Manganese naturally occurs in drinking water and can be found in rocks and soil. The Minnesota Department of Health has developed guidance levels for manganese in drinking water. Safe drinking levels for manganese in drinking water for infants one year old and younger who drink tap water or drink formula made from tap water is 100 micrograms per liter (ug/L) or less. Infants one year old and younger who never drink tap water or formula made from tap water and everyone in your household over one year old a safe level of manganese in the drinking water is 300 micrograms per liter (ug/L) or less. The guidance levels set by the Minnesota Department of Health were set in 2018 and are not required to be met by the public water systems. Public water systems are not required to treat for manganese within drinking water as it is not a primary drinking water standard.

Health effects of elevated manganese

Children and adults who drink water with levels of manganese above the guidance level for a long duration may have problems with memory, attention, and motor skills. Infants one year old and younger may develop learning and behavior problems if they drink water levels of manganese above the guidance level.

The City of Northfield in conjunction with the Minnesota Department of Health, took samples for the Fourth Unregulated Contaminants Monitoring Rule (UCMR 4). These samples are required for all public water systems serving over 10,000 people by the United States Environment Protection Agency. As part of the analysis, manganese is being analyzed within the drinking water. Samples were taken for the UCMR 4 in 2019 and additional manganese samples were taken in 2020. The results are listed in the table.

With most of the wells having manganese levels over 100 ug/L, the City will be conducting a drinking water system study in 2021 to review options for lowering the manganese level.

If residents have children under the age of one year old that drink tap water, they should consider different options for drinking water for these children. Listed below are different options that homeowners can remove manganese at their home.

Ways homeowners can remove manganese at their home

• Use of a carbon filter.
• Use of distilled water or a distillation system.
• A water filtration system.
• A reverse osmosis water system.
• Use of a water softener.

Related information on manganese

Information from the Minnesota Department of Health:

MDH general manganese information

MDH Quick Fact Sheet

Information about home water treatment systems

MDH Toxicology Summary for Manganese