Drinking water guidelines

Safe drinking water is everybody's business. Managing drinking water supplies properly, from the source water to the consumer's tap, takes a great deal of knowledge and coordination among multiple stakeholders--from governments and businesses, to individuals like you and me.

A shared responsibility

In Canada, the responsibility for making sure drinking water supplies are safe is shared between the provincial, territorial, federal and municipal governments. The day-to-day responsibility of providing safe drinking water to the public generally rests with the provinces and territories, while municipalities usually oversee the day to day operations of the treatment facilities.

Health Canada's Water Quality and Health Bureau plays a leadership role in science and research. Its mandate and expertise lies in protecting the health of all Canadians by developing the Guidelines for Canadian Drinking Water Quality in partnership with the provinces and territories. These guidelines are used by every jurisdiction in Canada and are the basis for establishing drinking water quality requirements for all Canadians.

Health Canada is recognized as a World Health Organisation/Pan American Health Organisation (WHO/PAHO) Collaborating Centre for Water Quality, and participates in the development of  WHO guidelines for drinking water. The Bureau also works closely and shares information with other government agencies such as the  United States Environmental Protection Agency.

The multi-barrier approach

The best way to make sure drinking water supplies are kept clean, safe and reliable is to take a preventive risk management approach. This means understanding each water supply from its beginning in nature to where it reaches you, the consumer. This understanding--about the water's characteristics, the ways it could become contaminated, and the type of treatment it needs--comes from collecting and studying data.

The drinking water supply can be broken down into three parts: the source water, the drinking water treatment system, and the distribution system which carries the treated water to homes, businesses, schools, and other buildings. The plumbing inside your home is an extension of the distribution system.

As drinking water travels on its journey to you, it can become contaminated in many ways. The multi-barrier approach to managing drinking water supplies is a preventive risk management approach that identifies all known and potential hazards and makes sure barriers are in place to reduce or eliminate the risk of contamination.

Drinking water guidelines

In order to know whether their drinking water management program is working, drinking water authorities need to have benchmarks for water quality. These benchmarks come in the form of drinking water guidelines. Guidelines make it possible for drinking water to be tested at various points along its journey and analysed to determine whether it is safe to drink. The Guidelines for Canadian Drinking Water Quality are established by the Federal-Provincial-Territorial Committee on Drinking Water and published by Health Canada.

The guidelines for some contaminants, like E.coli which indicates the presence of microbiological pathogens, are very clear and should never be exceeded because people will become sick soon after drinking contaminated water. Others, like many of the chemical guidelines, are based on the best available science and give a good indication of health effects that might be seen in some people if we consume high amounts of the chemical in drinking water over a period of decades.

Products and materials that come into contact with drinking water

Another way that drinking water can become contaminated is by the products and materials with which it comes into contact. Water is a solvent and can leach metals and other chemicals from pipes, fittings, fixtures, and other products. Health Canada works with national and international standards-setting organizations to develop health-based performance standards for these products and materials to make sure they are not contributing harmful contaminants to your drinking water.