Manganese Fact Sheet

Dear Public Water System,

 We are contacting you due to your systems’ recent manganese detection above 0.1 mg/L (0.1 parts per million) collected 4/20/2026 with results of 0.29 mg/L.  Although this is not a violation, we strongly recommend that you take action based on EPA’s Manganese lifetime health advisory and NHDES’ Environmental Health Program’s assessment of or recent research, as these levels may pose a health concern for direct consumption by infants less than 12 months old.  Making formula or foods with water containing manganese levels above 0.1 mg/L can increase an infant’s risk of health problems such as impaired motor function and learning, as well as harm to their nervous system.  Long-term, it is not advisable to consume water containing manganese above 0.3 mg/L even by the general population.  Infants up to 12 months of age should not be given water with manganese above 0.3 mg/L for any more than 10 days per year, as they cannot eliminate manganese as efficiently as older children and adults, resulting in higher exposure.  For more information about the health effects of manganese, particularly the potential neurotoxic effects on children, please see NHDES Fact Sheet ARD-EHP-15, Manganese: Health Information Summary.

Treatment to remove manganese above 0.1 mg/L should be installed or an alternate source of drinking water, such as bottled water, should be used for formula-fed infants. For assistance in evaluating treatment options, please see NHDES Fact Sheet DWGB-3-8 Iron and/or Manganese in Drinking Water and contact [email protected].