Manganese in Water: Understanding Risks and Solutions

You may have noticed blackish deposits around your faucets or dark brown stains on your sanitary facilities. These signs can sometimes indicate the presence of manganese in the water. Should you be concerned? Not necessarily.

In this guide, discover why manganese appears in drinking water, in which situations it warrants particular attention, and what solutions effectively eliminate it.

What is manganese in water?

Origin of manganese in water

Manganese (Mn) is one of the most abundant elements in the Earth's crust. Like iron, it is naturally present in soil metals. Its presence in water primarily results from the chemical alteration of rock minerals and soil leaching. Under certain conditions, these processes favor its dissolution and transfer to groundwater and surface waters.

Good to know: Manganese accounts for approximately 0.1% of the Earth's crust.

Dissolved manganese and oxidized manganese

In water, manganese is present either in dissolved form (Mn²⁺), invisible to the naked eye, or in oxidized form MnO₂, consisting of solid particles.

Why is manganese found in drinking water?

Natural causes

In groundwater, when the environment is poor in oxygen, manganese naturally present in rocks and soils can dissolve. It then becomes soluble and ends up in aquifers that supply drinking water.

Regarding surface waters, concentrations can also vary seasonally. In summer, the thermal stratification of lakes and reservoirs can cause a lack of oxygen in the deep layers. This phenomenon promotes the dissolution of manganese present in sediments. In autumn, when water masses mix again, this manganese is recirculated in the water column and can reach catchment areas.

Distribution networks

In addition to natural phenomena, the pipes themselves can be a source of secondary contamination. In distribution networks, manganese can gradually accumulate on pipe walls. Following pressure variations or work on the network, these deposits can detach and cause temporary discoloration of the water or an increase in its turbidity (Wu et al., 2025).

Is manganese in water dangerous?

Effects of manganese on health

Manganese is a trace element naturally present in your daily diet. It is involved in energy metabolism, the formation of connective tissues, and the protection of your cells against oxidative stress as an enzymatic cofactor. It is found in whole grains, oilseeds, green vegetables, and tea, among others.

In healthy adults, the digestive system effectively regulates the absorption of manganese from food. This is why cases of poisoning linked to this sole route of exposure are very rare. At-risk situations mainly concern chronic occupational exposure through inhalation (welding, metallurgy, etc.) and, more rarely, specific medical contexts, such as prolonged parenteral nutrition.

Good to know: 3 mg/day represents the adequate manganese intake for an adult according to EFSA.

Manganese and toxicity at high doses

Drinking water, however, represents a separate exposure pathway.

Health Canada (2023) particularly highlights the vulnerability of infants exposed to manganese present in the water used for reconstituting infant formula. At this age, exposure can be higher relative to body weight, and elimination mechanisms are still immature.

Several studies have shown associations between high concentrations of manganese in water and certain neurodevelopmental effects in children. These include a decline in cognitive performance, behavioral disorders, and impaired short-term memory.

In healthy adults, a one-time exposure to water slightly above the quality threshold does not pose a proven danger.

However, chronic and prolonged consumption at very high doses has been associated with Parkinsonian-type neurological disorders in people over 50 according to the Quebec National Institute of Public Health (INSPQ, 2021).

What are the manganese standards in water?

French and European standards

The quality reference for manganese in drinking water is set at 50 µg/L (i.e., 0.05 mg/L) in the European Union, in accordance with Directive (EU) 2020/2184.

In France, the National Agency for Food, Environmental and Occupational Health Safety (ANSES) has established a maximum admissible health value of 60 µg/L to complement this framework.

Why these standards exist

These two values do not serve the same purpose.

The 50 µg/L set at the EU level corresponds to a drinking water quality management value. It aims to guarantee water that is acceptable from a health and organoleptic (taste, color, deposits) perspective, without directly being a toxicity threshold. In case of exceedance, authorities and network managers assess the situation and, if necessary, implement corrective measures.

The health value of 60 µg/L responds to a public health protection logic. Calculated from the most restrictive scenario (that of infants aged 1 to 4 months), it is considered protective for the entire population according to ANSES.

The agency specifies that this maximum admissible health value cannot be exceeded for children aged 0 to 3 years old inclusive. For subsequent age groups, higher management aid values (from 190 to 370 µg/L depending on age) have been defined. They allow health authorities to adapt measures proportionally rather than alarming the entire population.

How do you know if your water contains manganese?

Visible signs in the water

Several indicators can suggest the presence of high concentrations of manganese in tap water:

• blackish or brown deposits in your sinks, toilets, bathtubs, or washing machines;
  
• brownish or yellowish discoloration of the water, especially after a period of inactivity;
  
• metallic or slightly bitter taste at the tap;
  
• persistent stains on your laundry after washing.
  

These signs can sometimes appear well before the reference threshold is reached.

Analyses and controls

If you are connected to the public network, you can consult the results of sanitary controls carried out by the Regional Health Agency (ARS). They are generally accessible online on the Ministry of Health's portal or displayed at the town hall. This data is your primary reliable source of information on the manganese content of your water.

You can use rapid test kits (strips or chemical reagent photometers) to obtain a first estimate. Their accuracy varies depending on the methods used and generally remains insufficient for a reliable evaluation.

If in doubt, contact an accredited laboratory to carry out a complete physico-chemical analysis. This is the only approach that guarantees a precise and quantified result.

How to remove manganese from water?

Treatments used by drinking water networks

To remove manganese from water before distribution, drinking water suppliers mainly use oxidation-filtration processes. This technique involves transforming dissolved manganese into solid particles using an oxidizing agent (chlorine, ozone, or potassium permanganate), then retaining them by filtration through sand or multi-layer materials.

Solutions for individuals

To reduce or eliminate manganese from water, you can intervene at two levels.

At the point of use

An under-sink reverse osmosis filter can help reduce manganese concentration daily. You can also use an ion-exchange resin filter pitcher, provided the cartridges are replaced periodically. However, avoid activated carbon filters not suitable for removing dissolved manganese (Carrière et al., 2011).

At the general water inlet

To treat all the water in your home, a manganese removal system such as a green sand filter is often recommended. This is one of the best options to protect all your installations. However, it requires a significant initial investment and regular maintenance.

Manganese in water: case of wells and boreholes

If your home is supplied by a private well or borehole, be vigilant: groundwater is often naturally richer in manganese than network water, depending on the local geological context.

In France, any well or borehole intended for domestic use must be declared to the town hall and registered via a national online procedure (DUPLOS) according to the Gers Prefecture (2026).

If an analysis reveals a manganese content exceeding 50 µg/L in your water, it is recommended to:

• not use this water to prepare baby bottles;
• install an appropriate treatment system (manganese removal filter or reverse osmosis);
• have the water quality regularly re-evaluated by an approved laboratory.

FAQ — Manganese in water

Is manganese in tap water dangerous?

In the vast majority of cases, tap water in France complies with the quality standard set at 50 µg/L. At these concentrations, it does not pose a health hazard to a healthy adult. Risks mainly appear in cases of prolonged exposure to high levels.

What is the standard for manganese in drinking water?

In France, the quality reference is 50 µg/L. ANSES retains a maximum admissible health value of 60 µg/L.

How to remove manganese from your water?

By oxidation followed by filtration (standard industrial process), by a domestic manganese removal device, or by reverse osmosis. The choice of process depends on the concentration present in your water and its origin (public network or private well).

Does manganese give water a taste?

Yes. Above approximately 100 µg/L, it can give your water a metallic or slightly bitter taste. Changes in color and turbidity often appear at much lower concentrations.

Can you drink water rich in manganese?

If you are a healthy adult, a one-time exposure to a concentration slightly above the quality reference does not pose a proven risk. However, caution is advised if you have infants or young children, as soon as the content exceeds 50 µg/L.

Is manganese in water dangerous for babies?

This is the most vulnerable group. Infants absorb proportionally more manganese, eliminate it less efficiently, and their brains are still developing. If the water you use to prepare formula contains excess manganese, it could increase the risk of neurodevelopmental effects according to available data.

What is the difference between iron and manganese in water?

Iron and manganese are often present together in groundwater because they share similar geochemical conditions. Iron causes a reddish discoloration and a pronounced metallic taste; manganese generates darker deposits (black or dark brown) and can have a neurological impact at high doses.

What to remember

At concentrations typically observed in drinking water in accordance with current standards, no concerning health effects have been identified for the general population.

If your water exceeds the quality reference, you should be vigilant, especially if infants or young children are involved.

Warning signs (black deposits, discolored water, metallic taste) are indicators not to be ignored. If in doubt, contact an accredited laboratory for a reliable and thorough analysis.

Finally, do not confuse normal dietary intake with excessive exposure from contaminated water. Some dietary supplements or rehydration solutions contain manganese in appropriate and strictly controlled nutritional doses, which are unrelated to the situations discussed in this guide.

Bibliography

Obeng, S. K., Kulhánek, M., Balík, J., Černý, J., & Sedlář, O. (2024). Manganese: From Soil to Human Health-A Comprehensive Overview of Its Biological and Environmental Significance. Nutrients, 16(20), 3455. https://doi.org/10.3390/nu16203455

Bouchard, M. F., Sauvé, S., Barbeau, B., Legrand, M., Brodeur, M. È., Bouffard, T., Limoges, E., Bellinger, D. C., & Mergler, D. (2011). Intellectual impairment in school-age children exposed to manganese from drinking water. Environmental health perspectives, 119(1), 138–143. https://doi.org/10.1289/ehp.1002321

Schullehner, J., Thygesen, M., Kristiansen, S. M., Hansen, B., Pedersen, C. B., & Dalsgaard, S. (2020). Exposure to Manganese in Drinking Water during Childhood and Association with Attention-Deficit Hyperactivity Disorder: A Nationwide Cohort Study. Environmental health perspectives, 128(9), 97004. https://doi.org/10.1289/EHP6391

Agence nationale de sécurité sanitaire de l'alimentation, de l'environnement et du travail. (2018). Détermination d'une valeur sanitaire maximale admissible pour le manganèse dans l'eau destinée à la consommation humaine (Saisine n° 2016-SA-0203). https://www.anses.fr/fr/system/files/EAUX2016SA0203.pdf

Wu, Y., Jia, Y., Hu, Z., Yuan, Y., & Zhang, Y. (2025). Manganese in drinking water distribution systems: A comprehensive review on the occurrence, migration transformation mechanisms, and control strategies. Critical Reviews in Environmental Science and Technology, 55(15), 1222–1247. https://doi.org/10.1080/10643389.2025.2503391

Santé Canada. (2023). Le manganèse dans l’eau potable. Gouvernement du Canada. https://www.canada.ca/fr/sante-canada/services/sante-environnement-milieu-travail/rapports-publications/qualite-eau/manganese-dans-eau-potable.html 

Institut national de santé publique du Québec. (2021). Le manganèse dans l’eau potable : foire aux questions. https://www.inspq.qc.ca/eau-potable/manganese/foire-aux-questions 

Arrêté du 11 janvier 2007 relatif aux limites et références de qualité des eaux brutes et des eaux destinées à la consommation humaine. (2007, 6 février). Journal officiel de la République française, n° 31. https://www.legifrance.gouv.fr/loda/id/JORFTEXT000000465574/

Carrière, A., Brouillon, M., Sauvé, S., Bouchard, M. F., & Barbeau, B. (2011). Performance of point-of-use devices to remove manganese from drinking water. Journal of Environmental Science and Health, Part A, 46(6), 601–607. https://doi.org/10.1080/10934529.2011.562852 

Préfecture du Gers. (2026, 17 avril). Obligations pour les particuliers – Puits, forages ou ouvrages de prélèvements d’eau inférieurs à 1000 m³ pour usage domestique. Les services de l’État dans le Gers. https://www.gers.gouv.fr/Actions-de-l-Etat/Environnement/Gestion-de-l-eau/Puits-forages-ou-ouvrages-de-prelevements-d-eau/Puits-forages-ou-ouvrages-de-prelevements-d-eau-inferieurs-a-1000-m3-pour-usage-domestique/Obligations-pour-les-particuliers