Water Test Results Centre
How to read a manganese result.
Black or brown staining, the 0.12 mg/L health-based value, and why manganese is often paired with iron treatment.
Unit
Usually mg/L or µg/L. 0.12 mg/L = 120 µg/L.
Canadian reference
Health Canada’s maximum acceptable concentration for manganese is 0.12 mg/L. An aesthetic objective of 0.02 mg/L is often cited for staining.
Possible sources
Groundwater and some surface supplies; often travels with iron. Infant formula prepared with high-manganese water is a specific concern.
What one result cannot conclude
- A result below the MAC is not a staining guarantee.
- Manganese speciation and pH change which media will work.
Sensible follow-up testing
- Retest if the first result is close to 0.12 mg/L.
- Include iron, pH and hardness in the same panel used for design.
Source correction
You generally cannot remove manganese from a well aquifer. Treatment and, where relevant, an alternate drinking supply for infants are the practical steps.
Certification questions
Ask whether a proposed filter has a manganese reduction claim for the expected influent level — not only an iron claim.
Treatment options
Oxidation and catalytic media trains that also handle iron are common. Confirm with paired samples after install.