At a glance
| Chemical family | Transition metal (Mn). An essential trace nutrient (needed for enzymes and bone) that is neurotoxic in excess — the same essential-but-toxic pattern as copper. Naturally abundant in soil and groundwater. |
| CAS number | 7439-96-5 (elemental manganese) |
| Classification | Not classified as a carcinogen. EPA secondary (aesthetic) drinking-water standard 0.05 mg/L; Lifetime Health Advisory 0.3 mg/L; short-term (1-day/10-day) advisory 1.0 mg/L (but use 0.3 for infants). WHO health-based value 0.08 mg/L. The hazard endpoint is neurological, especially developmental. |
| Where you encounter it | Naturally-occurring in groundwater — private wells in manganese-rich geology are the main high-exposure route; also surface water and, at trace levels, most municipal supplies. Dietary manganese (grains, tea, leafy greens) is the normal, generally benign source. A gasoline additive (MMT) is a minor ambient air source in some regions. |
| Sleep micro environment relevance | Indirect — an ingestion exposure via drinking water, on the Atlas as part of the tap-water picture and because the developmental concern overlaps the parent/infant audience the water hub serves. |
| Activated carbon capture | Not reliably removed by a standard carbon filter. Removal uses oxidation-filtration (e.g. manganese greensand), ion-exchange softening, or reverse osmosis for point-of-use drinking water. Inferred from standard manganese water-treatment engineering; dissolved Mn is not adsorbed by ordinary carbon |
Regulatory & certification status
Manganese is unusual in US regulation: it has an aesthetic standard and health advisories, but no enforceable primary limit. The rows below untangle the numbers.
| United States | EPA sets a secondary (non-enforceable, aesthetic) standard of 0.05 mg/L for the staining and taste, and health advisories: a Lifetime Health Advisory of 0.3 mg/L and a short-term (1-day and 10-day) advisory of 1.0 mg/L — with the instruction to use 0.3 mg/L even short-term when infants under six months drink the water. There is no enforceable MCL; manganese is on EPA's Contaminant Candidate List. Regulatory — US EPA |
| World Health Organization | WHO's 2021 review set a health-based value of 0.08 mg/L (80 µg/L) for manganese in drinking water, noting that this is below the level at which staining and taste problems typically appear. Regulatory — WHO |
| International | Health Canada sets a maximum acceptable concentration of 0.12 mg/L for manganese (with an aesthetic objective of 0.02 mg/L), explicitly citing the neurodevelopmental evidence — one of the first jurisdictions to set a health-based manganese limit. Regulatory — Government of Canada |
| The 72-hour test window | Not applicable. Manganese is a waterborne ingestion exposure detected by a standard water lab test, unrelated to the VOC-emission chamber tests used for mattresses and foam. Inferred — from the ingestion-via-water route versus the material/VOC focus of product emissions testing |
What it is
Manganese is a common transition metal and a genuine nutrient — your body uses small amounts for enzymes involved in metabolism, bone formation, and antioxidant defense, and ordinary dietary manganese (from grains, nuts, tea, and leafy vegetables) is well-regulated by the body and generally not a concern. The problem is excess, and specifically excess by the drinking-water route, because manganese absorbed from water appears to be handled differently than manganese from food, and because the developing brain is sensitive to it.
At high chronic exposure, manganese is a recognized neurotoxicant. The classic severe form is manganism, a Parkinson's-like movement and mood disorder documented in miners and welders with heavy inhalation exposure. The drinking-water concern is subtler and centers on children: several studies associate elevated water manganese with lower cognitive scores and attention or behavioral effects in kids. Infants are the most sensitive group — they absorb more manganese and excrete less, and formula made with high-manganese water is a specific concern.
In the water itself, the first thing most people notice is not health but housekeeping: manganese oxidizes to black or brown deposits that stain sinks, tubs, toilets, and laundry, and gives water a metallic, off taste. That aesthetic nuisance is what the 0.05 mg/L secondary standard targets — and, usefully, it often flags the presence of manganese before anyone thinks to test for the health endpoint.
Where you encounter it
From private wells
The dominant high-exposure route. Manganese is naturally abundant in the earth's crust and dissolves into groundwater, so private wells — especially in manganese-rich geology and in low-oxygen (reducing) aquifer conditions — can carry manganese well above the health-advisory level. Because private wells aren't tested by anyone but the owner, a high-manganese well can go unrecognized for years, flagged only by staining.
From municipal water (usually low)
Public systems generally keep manganese low, both because it's monitored and because utilities remove it to avoid the staining complaints. Occasional "dirty water" or discoloration events in distribution systems can involve manganese deposits dislodging from pipes, but sustained high levels are uncommon on treated municipal supplies.
From diet (the benign majority)
Most manganese intake is dietary and normal — whole grains, nuts, tea, and leafy greens are rich in it, and the body regulates absorption. This dietary manganese is not the concern; the water-route excess is, which is why the distinction matters when people worry about "too much manganese."
What the research says
The children's-IQ evidence
Bouchard and colleagues (2011) in Environmental Health Perspectives studied school-age children in Quebec and found that those exposed to higher manganese concentrations in drinking water scored significantly lower on IQ testing, with a dose-response relationship. Peer-reviewed This and related studies of attention and behavior are the basis for treating water manganese as a developmental-neurotoxicity concern rather than a purely aesthetic one, and they informed Health Canada's decision to set a health-based limit.
The high-dose neurotoxicity
The ATSDR Toxicological Profile for Manganese documents the well-established high-dose neurotoxicity, including occupational manganism, and the toxicokinetics that make infants and young children more susceptible. Regulatory The occupational evidence is old and firm; the lower-dose developmental evidence is newer and is what's driving guideline changes.
What helps
On a well, test for manganese — and act on 0.3 mg/L, sooner if infants drink it. Manganese is a cheap addition to a standard well-water panel. If a young child or infant is in the home, treat the water or use an alternative source for drinking and formula above the health-advisory level.
For drinking water, reverse osmosis is the straightforward fix. Point-of-use RO removes manganese along with most other contaminants. For whole-house staining, oxidation-filtration (manganese greensand) or an ion-exchange softener addresses it at higher flow.
Don't make infant formula with high-manganese water. If your water exceeds the health advisory, use treated or low-manganese water for formula preparation until the well is remediated.
What does NOT help
- Boiling. Manganese is a dissolved metal; boiling concentrates it as water evaporates, exactly as with nitrate and other dissolved contaminants.
- Standard carbon pitcher filters. They don't reliably remove dissolved manganese. Verify a system rated for manganese.
- Worrying about dietary manganese. Food manganese is normal and body-regulated; the concern is the water-route excess, not tea or whole grains.
- Assuming clear water is low-manganese. Dissolved manganese can be colorless until it oxidizes; the staining may lag the exposure. Test rather than eyeball it.
Open questions
- The precise dose-response for neurodevelopmental effects at low water-manganese levels, and whether a threshold exists, is still being characterized. Speculation re: low-dose threshold; the high-dose neurotoxicity is established
- Why water-route manganese appears more concerning than dietary manganese at similar intakes — differences in absorption and the co-presence of iron — is an active question. Speculation
- Whether the US will move from advisories toward an enforceable manganese standard, as Canada and WHO have tightened, is a live regulatory question. Inferred from the drinking-water rulemaking trajectory
Where you meet Manganese across your home
The same compound turns up in more than one place you live. Here's where it shows up in Embr — each links to the full breakdown for that part of your home.
Citations
- US Environmental Protection Agency. Secondary standard 0.05 mg/L; Lifetime Health Advisory 0.3 mg/L; short-term 1.0 mg/L (0.3 for infants). epa.gov Regulatory
- Agency for Toxic Substances and Disease Registry (2012). Toxicological Profile for Manganese. atsdr.cdc.gov Regulatory
- World Health Organization (2021). Manganese in Drinking-water — health-based value 80 µg/L. who.int Regulatory
- Bouchard MF, Sauvé S, Barbeau B, et al (2011). Intellectual impairment in school-age children exposed to manganese from drinking water. Environmental Health Perspectives, 119(1):138-143. DOI 10.1289/ehp.1002321 Peer-reviewed
Frequently asked questions
Is manganese in well water dangerous?
At typical levels it's mostly a nuisance — manganese stains fixtures and laundry black-brown and gives water a metallic taste, which is what the EPA's aesthetic standard of 0.05 mg/L addresses. The health concern kicks in at higher concentrations: manganese is an essential nutrient in small amounts but a neurotoxicant in excess, and the EPA sets a lifetime health advisory of 0.3 mg/L. The clearest concern is for infants and young children, whose developing brains are more vulnerable and who absorb and retain more manganese than adults. Private wells in manganese-rich geology can exceed these levels, and no one tests them for you.
What level of manganese is safe in drinking water?
The EPA's secondary (aesthetic) standard is 0.05 mg/L, set because manganese stains and tastes metallic above that. For health, the EPA lifetime health advisory is 0.3 mg/L, and it advises using that same 0.3 mg/L value even for short-term exposure when infants under six months are drinking the water. The WHO's health-based value is 0.08 mg/L (80 µg/L). Practically: below ~0.05 mg/L it's a non-issue; between there and 0.3 it's mainly aesthetic with a caution for infants; above 0.3 mg/L, treat it.
Does manganese affect children's development?
There is credible evidence it can, at elevated levels. A 2011 Canadian study found that school-age children exposed to higher manganese in drinking water scored lower on IQ tests, and other research links early-life manganese exposure to attention and behavioral effects. Manganese is a recognized neurotoxicant at high doses — occupational overexposure causes "manganism," a Parkinson's-like condition — and children are more susceptible because they absorb more and their brains are still developing. This is why the infant caution exists and why a high-manganese well is worth treating.
How do I remove manganese from water?
It depends on the level and form. For staining-level manganese, oxidation-filtration systems (like manganese greensand) and ion-exchange water softeners can remove it. For drinking water specifically, reverse osmosis removes manganese along with most other contaminants and is the straightforward point-of-use choice. A standard carbon pitcher does not reliably remove dissolved manganese. If your well is high in manganese, test to confirm the level and form, then choose a system rated for it.
Related compounds
Embr researches the chemistry of where you live — including the water you drink. See the methodology page for how this Atlas tags claims by evidence strength, the tap-water hub for the other things in your water, and water filters compared for how to remove manganese.
Last reviewed 2026-07-12. If you find a factual error, contact us.