The greatest exposure of humans to manganese is from food. Vegetarians, who consume foods rich in manganese such as grains, beans and nuts, as well as heavy tea drinkers, may have a higher intake of manganese than the average person. The exposure to manganese is typically lower from water than from food.

Certain occupations, like welding or working in a factory where manganese is used, can lead to breathing air with high manganese levels.

Adverse health effects may be caused by either inadequate intake or overexposure, however, manganese deficiency is rare. Some epidemiology studies suggest an association between elevated levels of manganese in drinking water with poorer memory, attention and motor function, as well as increased hyperactivity.

Manganese occurs naturally and is widely distributed in the environment. It is often present at low levels in natural waters. The best way to know if manganese is found in your source water or treated drinking water is to contact your water utility or state public health agency. Depending on the source of your water and geology of your water supply, your utility may be more susceptible to high levels of manganese.

If you get your drinking water from a private well and you suspect a problem, or have stains on your plumbing fixtures and laundry (which may be a sign of high manganese levels), you should have your water tested for manganese by a certified laboratory. You can find information on how to sample for manganese and where to send samples for analysis by contacting your state water laboratory certification officer (visit the U.S. Environmental Protection Agency's drinking water lab certification page). Additional information about well water testing from EPA is available on their private drinking water well page.

EPA has established National Secondary Drinking Water Regulations that set non-mandatory “secondary maximum contaminant levels” for 15 contaminants; manganese is one of these contaminants. Water systems use these secondary maximum contaminant levels (SMCLs) as guidelines to manage their drinking water for aesthetic considerations, such as for taste, color and odor. Manganese has a SMCL of 0.05 milligram/liter to control for color and metallic taste.

In 2004, EPA issued a drinking water health advisory for manganese. Health advisories are non-regulatory levels of contaminants to assist public health professionals. Negative health impacts are not anticipated at these concentrations.

EPA provided both short-term and lifetime advisory levels for manganese. One-day and ten-day exposure advisory values for most individuals is the same -- one milligram/liter. EPA suggests that 0.3 milligram/liter be used both as a lifetime advisory value and as a guide for short-term exposures for infants younger than six months of age.

Regulators, utility managers and public health officials use health advisories as they consider what management practices are necessary and when to take additional actions when manganese is found at elevated levels.

The Safe Drinking Water Act (SDWA) requires EPA to publish a list of substances that could potentially be of concern and warrant further study. This is known as the Contaminant Candidate List (CCL) and it is prepared every five years. Manganese was included on the first CCL in 1998; it was not on either of the next two CCLs, but it did return in the latest CCL in 2016 based on new health effects information and additional occurrence data.

Under the SDWA, EPA is also required once every five years to issue a new list of up to 30 unregulated contaminants to be monitored by public water systems. This is known as the Unregulated Contaminant Monitoring Rule. Manganese is included in the fourth round of UCMR (UCMR4). Testing for UCMR4 starts in January 2018 and will continue through December 2020. The data from this nationwide monitoring will inform and support EPA’s decisions on regulatory actions to protect public health.

Filtration or water softeners have been shown to be effective at removing manganese from water supplies depending on the state of manganese in your water (precipitated vs. un-precipitated).

NSF International, the Water Quality Association, Underwriters Laboratories and CSA International all certify home treatment products for removal of contaminants. Unfortunately, current certification does not certify products for home treatment device manganese reduction claims. If a home treatment device is used, it is very important to follow the manufacturer's operation and maintenance instructions carefully to make sure the device functions properly.

Bottled water in the United States is regulated by the U.S. Food and Drug Administration and is required to meet standards equal to EPA’s tap water standards. There are also individual state standards established for bottled water. However, in most cases, contacting the bottled water manufacturer for information about manganese levels in the water is a good idea.