What to do if manganese is high

Manganese is common in groundwater and matters most for infants.

Why it matters: Occurs naturally in some areas. High levels can harm how a child’s brain and behaviour develop; babies fed formula made with well water face the greatest risk. Also stains fixtures and laundry. ^{[Health Canada],[US EPA]}
US limit: Not on the EPA list of enforceable limits; Health Canada’s limit is 0.12 mg/L. ^{[US EPA],[Health Canada]}
Canada limit: 0.12 mg/L (aesthetic objective 0.02 mg/L). ^{[Health Canada]}

1. Right away

Babies fed formula face the greatest risk, so mix formula with water from another source. ^{[Health Canada]}
Boiling does not remove chemicals. ^[CDC]

Distillation (NSF/ANSI 62) is certified for manganese; reverse osmosis (NSF/ANSI 58) now covers it but certified units may not be available yet. NSF/ANSI 42 filters address taste and staining only. Removing iron first helps. ^{[Health Canada],[Health Canada]}
Choose a treatment system certified to the NSF/ANSI standard for your specific contaminant, then have an accredited lab test the water going into and coming out of it to confirm it works. ^{[Health Canada]}

Who to call: in the US, contact your county or state health or environment agency (EPA lists them by state). In Canada, contact your local public health office or the provincial drinking-water authority. ^{[US EPA],[CDC],[Health Canada]}

General information, not medical advice.