Prioritization Process for the Development of Guidelines for Canadian Drinking Water Quality

Health Canada leads the development of the Guidelines for Canadian Drinking Water Quality, in close collaboration with the provinces, territories and other federal departments through the Federal-Provincial-Territorial Committee on Drinking Water (CDW).

On this page

  • Background
  • Prioritization Process
  • Prioritization of chemical contaminants
  • Prioritization of microbiological and radiological contaminants
  • Additional Information

Background

The prioritization process for the development of the Guidelines for Canadian Drinking Water Quality for contaminants takes into consideration the Canadian context and examines many sources of information, including:

  • updates in the scientific literature;
  • new international limits and reviews; and
  • input and data from the provinces, territories and other federal departments

Health Canada has developed over 100 Guidelines for Canadian Drinking Water Quality that recommend maximum levels for microbiological, chemical and radiological contaminants in drinking water. These maximum levels are designed to protect Canadians such that, over a lifetime, drinking water containing contaminants at or below these maximum levels should not result in an increased health risk. Many more contaminants exist, but not all of them are found, or expected to be found, in Canadian drinking water

Health Canada is committed to keeping pace with new science to ensure that contaminants of emerging concern from a drinking water perspective, that do not currently have guidelines are considered for assessment. Health Canada also recognizes the importance of ensuring existing guidelines are updated to reflect advances in the scientific literature and risk assessment methodologies, as well as assessments by other international jurisdictions. To this end, Health Canada has a process for prioritizing the revision of existing guidelines and for the development of new guidelines on a periodic basis.

Prioritization Process

Starting in 2005, a prioritization process for developing Guidelines for Canadian Drinking Water Quality is undertaken approximately every 4 to 5 years. At any time during the process, Health Canada, in collaboration with the provinces, territories, and other federal departments, can amend the prioritized list of contaminants if issues arise that require immediate attention.

There are different processes for prioritizing chemical contaminants and for prioritizing microbiological and radiological contaminants.

Prioritization of chemical contaminants

Health Canada compiles an initial list of chemical contaminants for prioritization that includes:

  • those with guidelines developed more than 6 years ago;
  • those with new scientific information from provinces, territories and other federal departments (e.g., water monitoring data, specific requests, and Canadian sales and use reports for pesticides);
  • input and requests from provinces, territories and other federal departments;
  • new international scientific reviews; and
  • updates to drinking water quality standards and guidelines set out by foreign governments or international agencies, notably the World Health Organization.

The chemical contaminants on the initial list are reviewed and ranked for their potential risks to human health (referred to as the health risk ranking) based on:

  • examination of scientific information;
  • input from other federal departments;
  • new international limits and reviews; and
  • the potential for a contaminant to be in drinking water based on its chemical and physical properties.

Contaminants that can potentially be present in drinking water at levels which may be a risk to health are given a higher ranking. Any contaminant for which there have been improvements in scientific information that may affect the basis of the guidelines are also given a higher ranking. The health risk ranking is further refined by two additional considerations:

  1. Treatment and measurement methods
  2. The availability of measurement and treatment methods for chemical contaminants is considered so that contaminants can be reliably and accurately measured or removed when they are found in drinking water at or above the guideline values.

    If improved treatment technologies or measurement methods for chemicals with existing guidelines are identified, these contaminants may be given a higher ranking.

  3. Provincial, territorial and federal departments' needs
  4. Provinces, territories and federal departments have specific assessment needs for potential drinking water contaminants within their jurisdictions. For example, a province may have an industrial or farming activity that may impact drinking water quality, and a chemical may be given a higher ranking as a result.

    Provinces, territories and some federal departments also have water monitoring programs. They help determine the likelihood and magnitude of exposure to contaminants through drinking water.

Prioritization of microbiological and radiological contaminants

Microbiological contaminants are always on Health Canada's priority list because these contaminants pose greater and more immediate health risks than chemical contaminants in drinking water. New and updated evidence is reviewed on an ongoing basis.

For radiological contaminants, Health Canada continuously monitors any scientific developments to determine if the guidelines need to be revisited. The current guideline values were developed based on the recommendations of the International Commission on Radiological Protection, an independent organization designed to advance the science of radiological protection to increase public protection.

Additional Information

If you are interested in learning more about the Prioritization Process for the Development of Guidelines for Canadian Drinking Water Quality, or have information to provide, please contact us at hc.water-eau.sc@canada.ca.

If you would like to get the latest news and information about Health Canada's activities in the area of drinking water, you can subscribe to our mailing list.

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