How Canada Regulates Manganese in Drinking Water

March 9, 2021
How Canada Regulates Manganese in Drinking Water

Canada has always been an active proponent of environmental sustainability. In 1970, responding to calls for action to protect the quality and distribution of its water, Canada passed the Canada Water Act; the following year, the Canadian Department of the Environment was established.

While the federal government of Canada has some responsibilities in regard to water that include fisheries and navigation, individual provinces are actually responsible for the day-to-day management of their water resources.

New Health Canada Guidelines

Health Canada is a federal department responsible for “helping Canadians maintain and improve their health.” With the Federal-Provincial-Territorial Committee on Drinking Water (CDW), these entities establish draft guidelines for maintaining the quality of drinking water based on the most recent scientific research. Once drafted, these guidelines proceed through what can be a years-long process to potential changes in existing guidelines.

In 2019, Health Canada responded to new research by updating Canadian Drinking Water Guidelines. Included in the new guidelines was a maximum acceptable concentration (MAC) level for manganese in drinking water supplies where none had existed before. The new MAC for drinking water was set at 0.12 mg/L.

In addition, because manganese causes aesthetic concerns due its propensity to create water discoloration that can stain laundry and other items, an additional aesthetic objective was set at 0.02 mg/L. This new guideline value, one of the lowest in the world, is lower than the 0.3 mg/L maximum contaminant level (MCL) guidelines of the U.S.

Following the announcement of the new national guidelines, provincial governments alerted their citizens of the need to test their drinking water. In Nova Scotia, for example, where 40 percent of households access private wells for their drinking water, citizens were urged by the chief medical officer of health to test their well water regularly in order to prevent exposure to bacteria and chemicals.

So, why did the guideline change? Until recently, manganese was considered merely a nuisance chemical. The new MAC for manganese was based on new research about the risks of manganese toxicity, including potential impacts on memory, motor function, attention spans and the neurological development of infants and young children.

Applying the Guidelines

Following the announcement, Health Canada issued recommendations for applying the manganese guidelines, including:

  • Sampling water sources in periods when manganese is most likely to be elevated;
  • Frequent monitoring of surface water and water treated water by utilities to remove manganese; and
  • Monitoring within the distribution system and at consumer taps for systems where manganese is or was historically present in the course water.

Monitoring for manganese is recommended primarily at consumer taps with a portion of samples collected from sites located near the treatment plant. Homeowners with private wells are also encouraged to have their water tested annually to ensure that the water supply is below the MAC.

Removing Manganese

In Canada, private wells and many small drinking water systems rely on certified products to meet requirements for drinking water. In 2019, the Canadian Water Quality Association produced a standard for these products that allow their manufacturers to certify their health-based manganese removal claims. It is hoped that this new standard will help companies address the growing concerns about the potential threat that manganese poses in Canada and other countries.


Photo by DD Images -

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