Manganese and Drinking Water
Manganese is a common, naturally-occurring element found in rocks, soil, water, air and food. Manganese is an essential element and is needed to form healthy bones, produce glucose and heal wounds. Small amounts of manganese are part of a healthy diet. Grains, beans, nuts, seeds, leafy vegetables and teas are rich in manganese. Manganese is naturally found in breastmilk and included in infant formula to ensure proper development. Although the primary source of exposure to manganese is food, drinking water can increase the overall dietary intake of manganese. High levels of manganese can affect our health. Learn more about manganese and your health at Wisconsin Department of Health Services (DHS).
Unsafe Levels of Manganese in drinking water
Manganese may be in your water if it has a rust color, causes staining of faucets, sinks or laundry, or if it has an off taste or odor. Wisconsin has set a groundwater quality enforcement standard for manganese of 300 micrograms per liter (µg/L). The US Environmental Protection Agency (EPA) has also set a lifetime health advisory level of 300 µg/L.
According to DHS, studies among people indicate that exposure to high levels of manganese can affect the nervous system. Also, studies in research animals suggest that high levels of manganese may also affect reproduction and impact the kidneys. People over the age of 50 and infants less then six months old are the most sensitive to these effects. In older adults, high levels of manganese may cause a disorder similar to Parkinson’s disease. In infants, exposure to high levels of manganese may affect brain development and impact learning and behavior. Some studies among people indicate that people with certain medical conditions (iron-deficiency anemia, liver disease) may also be more sensitive to the effects of manganese.
The groundwater enforcement standard and US EPA health advisory level are intended to protect against these effects. According to DHS, manganese levels over 300 µg/L pose an immediate health risk for sensitive groups. When manganese levels are above 300 µg/L, people over the age of 50 and infants less than 6 months old should stop using the water for drinking and preparing foods and beverages that use a lot of water. Manganese at these levels also pose a long-term health risk for everyone. Everyone should avoid long-term use of the water for drinking and preparing foods and beverages that take up or use a lot of water.
There are rare occasions when manganese concentrations in groundwater exceed 1000 µg/L and no one should drink the water. US EPA has determined that concentrations above this level pose an immediate health risk to all consumers.
In addition to the groundwater and health advisory standards, the US EPA has established a secondary water quality standard of 50 µg/L. Manganese concentrations greater than 50 µg/L in drinking water causes esthetic issues related to taste and color.
Manganese in Public Drinking Water Systems
All public water systems except for transient non-community water systems are required to monitor at least once every nine years for manganese. You can contact your water utility directly or you can look up sample results reported by your water utility in the DWS Portal.
If a public water system reports manganese concentrations greater than the US EPA health advisory level and the groundwater standard of 300 µg/L, the DNR will require the system to post a public notice informing consumers of the water quality. DNR will also work the with system to suggest steps to reduce exposure to drinking water with elevated manganese.
A public drinking water system with concentrations exceeding the secondary standard of 50 µg/L may be required to address the concentrations especially if customers report esthetic issues related to the water quality.
Manganese in Private Drinking Water Systems
For private residential wells, there is no state or federal requirement that you stop using your water, regardless of the manganese level. However, if your manganese level is equal to or greater than 300 µg/L, DHS recommends that you stop using your water for drinking or food preparation and find an alternative safe source of drinking water.
What to do about high manganese levels in your well
There are some options for well owners when well water tests high for manganese:
- bottled water,
- treatment device or
- alternative safe source/drilling a new well.
Approved manganese treatment devices
The Department of Safety and Professional Services (DSPS) approves devices for treating water. Two categories of devices are defined, Point of Use (POU) and Point of Entry (POE). POU devices are used to treat water at the point of use such as a single tap. POE treatment systems treat all the water entering the home. All types of systems must be properly installed and maintained to reliably remove the manganese from your drinking water.
To access the DSPS list of water treatment devices go to:
- https://esla.wi.gov/verifylicense, choose plumbing products, then from the Select Credential/Permit Type dropdown choose water treatment device.