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Fluoridation of drinking water


Fluorides are fluorine salts naturally present in the environment. Among other places, they are found in soil, minerals, air, streams and plants.

Fluorides can also be naturally present in drinking water. In sufficient quantity, they have recognised beneficial effects on dental health, particularly in preventing cavities.

Fluoridation is the addition of fluoride to drinking water so that the right amount of it is present to prevent tooth decay.

Fluoridation improves the mineral composition of water without changing its taste, smell and appearance.

Preventing cavities

Fluorides reduce the effect of bacteria that cause cavities and make teeth more resistant to their action. Fluoridation of water generally reduces cavities in the population by 20 to 40%.

As a consequence, fluoridation of drinking water helps improve the health of teeth and maintain good overall wellness. It also has the benefit of significantly reducing cavities treatment needs and thus, personal spending on dental care.

In Quebec, the concentration of fluoride in drinking water that is ideal to obtain the best possible protection against tooth decay is regulated at 0.7 mg per litre.

Health effects

Fluoridation of drinking water is a measure to prevent tooth decay that has been studied for over 65 years.

The national and international medical and scientific community acknowledge that fluoridation is efficient, safe and cost-effective. The most important national and international scientific organisations, including medical, dental and pediatric associations in Quebec, Canada and the United States, also support water fluoridation.

In Canada, the concentration of fluoride in drinking water must not exceed 1.5 mg per litre. Drinking water that does not contain more than 1.5 mg of fluoride per litre is not a health risk.

Health measure for the community

Fluoridation of water is an excellent preventive measure because the entire population reaps the benefits simply by drinking tap water. Studies show that a population’s oral health is better in areas where water is fluoridated than in those where it is not.

According to the United States Centers for Disease Control and Prevention, fluoridation of drinking water is one of the 10 most important preventive public health measures of the 20th century.

Effects on the environment

The fluoridation of drinking water has no known effect on the environment and aquatic life.


Over 400 million people worldwide have access to naturally or voluntarily fluoridated water. In Ontario and the United States, municipal water supply systems provide fluoridated water to over 70% of the population.

Quality control

As part of the Quebec program for the fluoridation of drinking water (Programme québécois de fluoration de l’eau potable), the ministère de la Santé et des Services sociaux has entrusted the Laboratoire de santé publique du Québec (LSPQ) with the responsibility of monitoring water fluoridation quality for municipalities participating in the program.

The LSPQ verifies the quality of products that the municipalities use to fluoridate drinking water, as well as the concentration of fluoride in it. Participating municipalities must conduct daily and monthly analysis of their water to monitor the quantity of fluoride it contains. They must also submit samples to the LSPQ for analysis.

Last update: July 5, 2017


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