Manganese in Water

The short answer

Manganese is a natural element in rocks and soil, and EPA's health advisory for manganese says it occurs naturally in many surface and ground water sources. Your body needs a little of it. The Minnesota Department of Health puts it plainly: your body needs some manganese to stay healthy, but too much can be harmful.

Two EPA numbers frame every manganese result, and they do different jobs:

• The secondary standard is 0.05 mg/L^[2]. It is a non-enforceable guideline for color, staining and taste. EPA lists black to brown color, black staining and a bitter metallic taste as the effects you can notice above it.
• The lifetime health advisory is 0.3 mg/L^[1]. EPA says it will protect against concerns of potential neurological effects. It is guidance, not a legally enforceable federal standard.

Infants are the group to think about first. For babies younger than six months, EPA advises using the lifetime advisory even for a short exposure, because young infants may absorb more manganese and excrete less.

A private well has no one checking it for you. Penn State Extension notes that private water systems serving individual homes are not subject to state or federal drinking water standards, and MDH says you may want to test for manganese, especially if infants drink your tap water. If the lab doesn't detect manganese, no treatment is needed based on that result. Our manganese water test guide explains who should test, how to take the sample and what your result means.

Manganese levels and what to do

The table below lines up both federal benchmarks for manganese with what a result at each level means for your household. The values come from our versioned benchmark data, which records EPA's figures and the date we last checked them. Our guide on how to read your lab report explains the units and terms you will see on it.

How the two benchmarks work together

The secondary standard is the lower of the two values. EPA's health advisory recommends reducing manganese to the secondary standard or below to make the water more acceptable to consumers, and says that standard is based on staining and taste. It is not a federally enforceable regulation.

The lifetime health advisory is higher, and it is about health. EPA describes health advisories as technical guidance for officials, and says they are not to be construed as legally enforceable federal standards. So a result between the two values usually means stains and taste problems, while a result above the advisory is a health question to take up with your local health department.

Babies younger than six months

EPA's advisory also gives short-term values for children. But for infants younger than six months, EPA advises using the lifetime advisory even for an exposure of 10 days^[1]. Its reasons are differences in manganese content between breast milk and formula, and the possibility that young infants absorb more manganese and excrete less. The advisory sets no separate value for infants; it points to the lifetime advisory instead.

Some states go further. The Minnesota Department of Health has its own manganese guidance values, with a stricter one for households where an infant drinks tap water or formula made with it. Ask your state or local health department whether it has guidance for your area.

Health effects of manganese in drinking water

The nervous system. EPA's health advisory says that although manganese is an essential nutrient at low doses, chronic exposure to high doses may be harmful, and that the nervous system is the primary target. EPA also says the data linking manganese taken by mouth to toxic effects are limited. Many reports of harm come from breathing manganese at work, not from drinking water. EPA says the lifetime advisory is estimated to be an intake for the general population that is not associated with adverse health effects.

What MDH describes. The Minnesota Department of Health says children and adults who drink water with high levels of manganese for a long time may have problems with memory, attention and motor skills. It says infants, babies under one year old, may develop learning and behavior problems if they drink water with too much manganese.

Who may be more sensitive. EPA names groups that may absorb more manganese or excrete less: the very young, the elderly, and people with liver disease.

Food and water. Food is the main source of manganese for most people, according to EPA and the U.S. Geological Survey. MDH explains that many foods can block manganese from getting into the body, but water does not, so your body can more easily absorb manganese from water.

Cancer. EPA's advisory found no studies linking exposure to elevated inorganic manganese with cancer in humans, and says there are little data to suggest it causes cancer.

A water test measures manganese in your water, not in anyone's body. If you have health concerns, or a baby in your home has been drinking the water, talk to a health professional and bring your lab report.

Where manganese in water comes from

Mostly natural. EPA's health advisory says manganese occurs naturally in many surface and ground water sources and in soils that may erode into them. It adds that groundwater with little oxygen often contains elevated levels of dissolved manganese.

Sometimes human activity. EPA says human activities are also responsible for much of the manganese contamination in water in some areas. It names industrial discharges, landfill and soil leaching, and underground injection as the main sources of releases to surface and ground water. Penn State Extension adds that in Pennsylvania's coal mining regions, manganese can also come from deep and surface mining.

How common it is. The U.S. Geological Survey sampled domestic wells across the country and detected manganese in about half of them. It found manganese above EPA's secondary standard in 21 percent^[6] of wells, and above a USGS health-based screening level in about 5 percent^[6]. High levels showed up most often in glacial aquifers, in sandstone aquifers in Pennsylvania and West Virginia, and in some coastal-plain aquifers in Louisiana and Texas. USGS linked high manganese to water with low dissolved oxygen and low pH.

Often with iron. Penn State Extension says iron and manganese often occur together in groundwater, but manganese usually occurs at much lower concentrations. Our guide to iron in water covers that metal. Both can look clear at the tap and then form stains or particles once the water meets air: orange-brown for iron, black for manganese.

When to test and retest for manganese

You can't rely on stains alone. EPA lists black staining as an effect noticeable above the secondary standard, but the health advisory is higher, so stains can't tell you which side of the advisory your water is on. Only a lab result can.

Test or retest in these situations:

• Before a baby drinks the water. MDH says you may want to test for manganese, especially if infants drink your tap water. EPA's infant advice makes this the most important time to know your level.
• To confirm a high result. If manganese was near or above the health advisory, retest with a state-certified lab before you decide on treatment.
• When you see black stains or notice a metallic taste. Penn State Extension advises testing if you notice these signs, and using an accredited lab for an overall treatment plan.
• After you install treatment. MDH says to test the treated water to make sure the treatment works, and to follow the maker's cleaning and maintenance advice.

Use an accredited lab, as MDH advises. You can build a test plan that covers manganese and the other tests your well needs, and our well water testing guide explains the yearly well check.

How to lower manganese in your water

Start with a confirmed result from a state-certified lab. What you do next depends on what it shows, and "no treatment needed" is a real outcome.

If manganese was not detected, or is below the secondary standard, no treatment is needed based on that result.

If it is above the secondary standard but below the health advisory, the issue is stains and taste. Whether to treat is your choice.

If a confirmed result is near or above the health advisory, talk to your local or state health department about what it means for your household. If a baby younger than six months drinks the water, ask about another water source for the baby while you work out a fix.

In summary, the treatments that MDH and Penn State Extension describe include:

• Water softeners. MDH says a study in Dakota County found water softeners can be an effective way to reduce manganese in drinking water. Penn State Extension says conventional softeners are sometimes effective for small amounts of manganese.
• Oxidizing filters. Penn State Extension says properly maintained manganese greensand filters are extremely efficient for moderate levels of iron and manganese, but need regular regeneration and backwashing. It says birm filters remove manganese with highly variable efficiency.
• Oxidation followed by filtration. Penn State Extension says this is the most effective approach when combined iron and manganese are high, but that chlorine is not recommended as the oxidant for very high manganese.

Penn State Extension also says polyphosphate addition is generally ineffective for manganese. MDH advises choosing a unit certified by NSF, UL or the Water Quality Association for the contaminant you want removed, where a certification exists, and checking that any installer is licensed. Retest the treated water with a certified lab after installation, and keep up the maintenance: MDH warns that an unmaintained unit can make water quality worse.