Manganese

WTR

100 ppb the health line, set for bottle-fed infants

Staining and taste start around 50 ppb. The modern health values sit in an 80 to 120 ppb band, about two-fold higher than the staining line.

Emerging evidence

Stasis Home Research Every claim on this page is graded against peer-reviewed health research and linked to its primary source.Updated August 2026

Manganese is a groundwater metal with two lines that used to sit far apart and no longer do. Above 50 ppb, or parts per billion, it stains fixtures and laundry black to brown and tastes bitter and metallic. At 100 ppb, Minnesota's health-based value for bottle-fed infants is crossed. The nervous system is the organ of concern and infants are the sensitive group, so this number reaches you first if you are preparing formula.

Manganese: what is it, and where does it come from?

Manganese is a naturally occurring metal and an essential dietary nutrient, so your body needs a small amount each day. In drinking water it is a groundwater signal: it dissolves out of manganese-bearing minerals in the aquifer, so it shows up in the local-groundwater fraction of a supply and is usually absent in any imported surface-water fraction. Nothing your home's plumbing does creates it and no disinfection process leaves it behind; it comes out of the aquifer. Manganese also accumulates in distribution mains and is released in episodes after main breaks, flushing, or a change in water chemistry, so a sample taken during a brown-water episode and a sample taken on a normal day are two different measurements. Nobody put it there. It is geology, and it is not a utility failure.

Manganese: why does it matter?

The central nervous system is the target organ. The settled part of that is occupational: workers who chronically inhale high manganese dust develop manganism, a syndrome of cognitive and motor changes that clinically resembles Parkinson's disease. That evidence is inhalation-route and it is not the basis for any drinking-water number. The drinking-water values come from a thinner developmental picture. A rat-pup study found hyperactivity, disinhibition, and spatial learning and memory deficits, and it is the starting-point study underneath three of the four modern agency values. Human studies support the direction rather than the exact number: 362 Quebec children on groundwater showed a 6.2-point IQ difference between the lowest and highest exposure groups, and a Danish cohort of 643,401 children found elevated risk of the inattentive type of attention-deficit disorder above 100 ppb. Every agency that read this evidence after 2019 moved its number down, and they landed close together: WHO at 80 ppb, Minnesota at 100, Health Canada at 120, each of them derived on the bottle-fed infant, who takes in more water per kilogram of body weight, absorbs more manganese, and excretes less of it. EPA's 300 ppb lifetime advisory is the outlier on that list. It was derived in 2004 from adult dietary intake, its derivation contains no developmental study and no infant, and no agency has re-derived it since. What that changes is the old story. When the staining line and the health line sat six-fold apart, it was fair to say you would hate the taste long before the dose mattered. They are now about two-fold apart and that sentence no longer holds.

Minnesota adopted 100 ppb into rule in November 2023 as a short-term health-based value protective of bottle-fed infants under one year, the most sensitive population. It derived no chronic value, pointing instead to EPA's 300 ppb advisory for older children and adults.Minnesota Department of Health, Toxicological Summary for Manganese (short-term health-based value 100 µg/L, protective of bottle-fed infants under one year; adopted as rule November 2023)
A benchmark analysis pooling 630 Canadian children put the drinking-water manganese concentration associated with a 1 percent drop in Performance IQ at 133 ppb, with a lower credible bound of 78 ppb. Girls were more sensitive than boys at every benchmark.Kullar et al., 2019 (Environment International 130:104889), benchmark concentration analysis of 630 Canadian children: 1% Performance IQ decrement at 133 µg/L, lower credible bound 78 µg/L
A nationwide cohort of 643,401 Danish children born between 1992 and 2007 reported elevated risk of the inattentive subtype of attention-deficit hyperactivity disorder above 100 ppb of manganese in drinking water.Schullehner et al., 2020 (Environmental Health Perspectives 128(9):097004, DOI 10.1289/EHP6391), 643,401 Danish children: elevated risk of the inattentive ADHD subtype above 100 µg/L in drinking water
California cut its manganese notification level from 500 ppb to 50 ppb and its response level from 5,000 ppb to 200 ppb on June 2, 2026. Above the response level a community water system must tell customers within 30 days to use bottled water for infant formula or otherwise reduce exposure.California SWRCB, Division of Drinking Water, Notification and Response Level Issuance for Manganese, signed final 2026-06-02 (notification level 0.05 mg/L on a running annual average; response level 0.20 mg/L on a single confirmed detection)
EPA's 50 ppb secondary standard is set on consumer acceptance, not health: the effects it names above that level are black to brown color, black staining, and a bitter metallic taste. EPA states plainly that it does not enforce secondary standards.US EPA, Secondary Drinking Water Standards: Guidance for Nuisance Chemicals (manganese 0.05 mg/L; black to brown color, black staining, bitter metallic taste; EPA does not enforce secondary standards)
The counterweight: a meta-analysis of 55 studies covering 13,388 subjects found a significant association between hair manganese and lower Full Scale IQ, while its blood and drinking-water analyses were not significant, and WHO judges this epidemiology to be of limited utility for risk assessment on its own, supporting the animal findings qualitatively rather than setting the numbers.Liu et al., 2020 (Environmental Health 19:104), meta-analysis of 55 studies and 13,388 subjects: hair manganese associated with lower Full Scale IQ, blood and drinking-water analyses not significant

Manganese: what do we grade it against?

Manganese has a health-based level but no enforceable legal limit. The health-based level for Manganese, staining and taste (ppb) is 50 (black to brown color, black staining, bitter metallic taste above this; a consumer-acceptance guideline EPA states it does not enforce, and never a health finding), from US EPA, Secondary Drinking Water Standards. The table below lists every level on this page next to the source that set it.

Where the health research draws the line, versus the legal limit.
Contaminant	Health-based level	Source (health-based)
Manganese, staining and taste (ppb)	50 black to brown color, black staining, bitter metallic taste above this; a consumer-acceptance guideline EPA states it does not enforce, and never a health finding	US EPA, Secondary Drinking Water Standards
Manganese, California notification level (ppb)	50 a state advisory line on a running annual average, effective 2026-06-02; California set it here to line up with the staining standard and the bottled-water limit, not because 50 is its health-derived number, which is 20	California SWRCB, Division of Drinking Water, manganese notification and response level issuance, 2026-06-02
Manganese, WHO provisional guideline (ppb)	80 protective of bottle-fed infants; provisional because of the 1,000-fold composite uncertainty factor in its derivation	WHO, Guidelines for Drinking-water Quality, manganese fact sheet
Manganese, the health line we flag on (ppb)	100 Minnesota's short-term health-based value, adopted into rule in 2023 and protective of bottle-fed infants under one year; short-term is the agency's own word, so this is not a long-term-average line	Minnesota Department of Health, Toxicological Summary for Manganese
Manganese, Health Canada maximum (ppb)	120 health-based maximum acceptable concentration, set in 2019 for infants fed formula prepared with tap water	Health Canada 2019, via the British Columbia Drinking Water Officers' Guide
Manganese, California response level (ppb)	200 on a single confirmed detection; above it a community water system must tell customers within 30 days to use bottled water for infant formula or otherwise reduce exposure	California SWRCB, Division of Drinking Water, manganese notification and response level issuance, 2026-06-02
Manganese, EPA lifetime health advisory (ppb)	300 covers children over one year and adults; derived in 2004 from an adult dietary intake level, with no developmental study and no infant in the derivation, and not re-derived since. A health advisory is not an enforceable standard	US EPA, Drinking Water Health Advisory for Manganese, 2004
Measured example: Southern California groundwater (ppb)	~48 two Orange County districts read right at California's notification level, at about 60 percent of the WHO guideline and about half the 100 ppb infant line	La Palma + Huntington Beach CCRs (groundwater)

Health-based levels come from peer-reviewed research and government risk scientists working without cost constraints, while legal limits are enforceable compromises. Your report grades to the health column.

What helps against Manganese?

7 approaches below reduce Manganese in a home, ordered from the most direct fix to the smallest change in habit. The most direct is Reverse osmosis at the kitchen tap (NSF/ANSI 58). Each entry also names what it cannot do, because no single fix covers every exposure route.

Direct fixes

Reverse osmosis at the kitchen tap (NSF/ANSI 58)
WHO calls reverse osmosis the most effective and reliable point-of-use treatment for manganese. It is the fix that matters most for the formula case, because formula is prepared at one tap, and it is the same under-sink unit already used for other source-water concerns.

Bigger retrofits

Oxidation followed by filtration at the point of entry
The dedicated whole-house method and the one utilities themselves use: dissolved manganese is oxidized to an insoluble form and filtered out, classically on manganese greensand. This is the right answer when black staining throughout the home is the complaint.
Ion-exchange water softener
A softener's cation-exchange resin removes dissolved manganese along with hardness, so if you install one for hard groundwater you get manganese reduction with it. Manganese and hardness travel together in hard-groundwater systems. WHO rates point-of-use ion exchange as moderately effective.

Free and behavioral

Activated carbon pitcher or block
Useful for taste and chlorine.
No agency source credits carbon filtration with manganese removal. A carbon pitcher or block is not a manganese solution and must not be treated as one.
Do not boil it off
Boiling is the reflex and it is the wrong move here. British Columbia's guidance states that boiling water may increase the concentration of dissolved manganese in drinking water and is not recommended.
An alternate source for infant formula, above the health line
At or above 100 ppb, a household preparing infant formula should consider an alternate water source or point-of-use reverse osmosis for the water that goes into the bottle. At or above 200 ppb that stops being a suggestion: California directs systems to tell customers to use bottled water for formula. British Columbia issues its version lower, at Health Canada's 120 ppb maximum, where its public notice fires and says infants should not consume tap water or formula prepared with tap water above that level and that an alternate source such as bottled water should be used. Below 100 ppb no agency asks for anything, and neither do we.
Test the well when staining or a rotten-egg smell shows up
Manganese, iron, and hydrogen sulfide are the common nuisance trio in private-well groundwater, and they tend to travel together. A one-time well test tells you which you actually have and at what level, so you treat the real problem instead of guessing. Utility Consumer Confidence Reports do not cover private wells, so if you are on a well you are the only one who can order the test.

See how well each fix works

Method

Water softeners

We used to say manganese was a staining and taste problem you would notice long before it mattered to your health. That was true when the two lines sat six-fold apart. They no longer do. Since 2019, WHO, Health Canada, Minnesota and California have all set or cut their manganese numbers downward, and the modern health values land in an 80 to 120 ppb band, roughly two-fold above the 50 ppb staining line. So what is true depends on where your number falls. Below 50 ppb there is nothing here. Between 50 and 100 ppb this is a staining and taste finding, worth fixing if brown laundry or a metallic edge bothers you, and it is not a health exceedance. Between 100 and 200 ppb it becomes a health conversation for one household in particular, the one preparing infant formula. Above 200 ppb the agency instruction is to use another source for formula water. What we will not do is run the correction in the other direction. Manganese is an essential nutrient, and the evidence underneath the modern values is one animal study plus human epidemiology the agencies themselves call of limited utility for setting numbers. We say that here rather than only in the footnotes. It is also fixable: reverse osmosis at the tap, oxidation-filtration or a softener for the whole house. Carbon does not touch it, and boiling makes it worse.

Common questions about Manganese

Is the manganese in my tap water dangerous?

It depends on the number, and the bands are narrower than they used to be. Below 50 ppb there is no finding. Between 50 and 100 ppb it is a staining and taste issue and not a health one. At or above 100 ppb, Minnesota's health-based value for bottle-fed infants under one year has been crossed, and the household that acts on that is one preparing formula. At or above 200 ppb, California directs systems to tell customers to use bottled water for infant formula. For children over one year and adults, the reference is EPA's 300 ppb lifetime advisory, which is a 2004 number derived from adult dietary intake.

Is manganese a health problem, or just a staining one?

Health Canada set a health-based maximum of 120 ppb in 2019, WHO reinstated a provisional guideline at 80 ppb, Minnesota adopted 100 ppb into rule in 2023, and California cut its notification level from 500 ppb to 50 ppb and its response level from 5,000 ppb to 200 ppb on June 2, 2026. EPA's 300 ppb is a 2004 adult dietary figure nobody has re-derived. Against the current values, a reading near 50 ppb is at about half the health line rather than a sixth of it.

Should I worry about manganese for my baby?

This is the whole health question for manganese. Every modern agency value, WHO's 80 ppb, Minnesota's 100 ppb, Health Canada's 120 ppb, is derived on a bottle-fed infant, because an infant drinks far more water per kilogram of body weight than an adult, absorbs more manganese, and excretes less of it. At or above 100 ppb, use an alternate source or point-of-use reverse osmosis for the water that goes into formula. At or above 200 ppb, California directs systems to advise using bottled water for infant formula. British Columbia's instruction fires lower, at Health Canada's 120 ppb maximum, where its public notice says infants should not consume tap water or formula prepared with tap water and that an alternate source should be used. Below 100 ppb no agency asks for anything and we are not going to invent a worry.

What causes the black or brown staining on my fixtures and laundry?

Manganese above the 50 ppb staining line. EPA describes the effects above that level as black to brown color, black staining, and a bitter metallic taste. If the staining comes and goes rather than staying constant, the cause is often manganese that has built up in the distribution main being released after a break, a flush, or a change in water chemistry. A whole-house oxidation-filter is the dedicated fix when staining is the complaint.

Will my carbon pitcher remove manganese?

No. No agency source credits carbon filtration with manganese removal, so a carbon pitcher or block is the wrong tool here. Reverse osmosis at the tap, a whole-house oxidation-filter, or an ion-exchange softener are the options that work. Boiling is worse than useless: British Columbia's guidance says boiling may increase the concentration of dissolved manganese and is not recommended.

My well water has orange stains or a rotten-egg smell, what is that?

That is usually iron or hydrogen sulfide, the two nuisance parameters that most often travel with manganese in private-well groundwater. Iron leaves orange to red-brown stains on fixtures and laundry and a metallic taste. Hydrogen sulfide is the rotten-egg gas, noticeable by smell at very low levels. Iron sits on the EPA's secondary standards, the non-enforceable guidelines set for taste, color, and staining rather than health. Hydrogen sulfide you can smell well below any level that would concern your health. At the concentrations wells usually show, both are a nuisance rather than a toxicity problem. The same oxidation-and-filtration approach that handles manganese generally handles iron and sulfur too, and a one-time well test tells you which of the three you have and at what level.