"Community water fluoridation (CWF) is a process of adjusting fluoride levels in the public water supply to a level that prevents dental caries... According to the 2010 Health Canada Guidelines for Drinking Water Quality,7 the maximum acceptable concentration of fluoride in drinking water is 1.5 ppm (parts per million or mg/L), while the optimal level of fluoride in drinking water is 0.7 ppm. Municipalities with fluoridated drinking water adjust fluoride levels to fall within this Health Canada range, as well as within their own provincial or territorial guidelines."
Canadian Agency for Drugs and Technology in Health

The majority of Canadians (88.9%) receive their water from municipal water supplies (from water piped into their homes), while 10.5% of Canadians get their water from private wells, and the remainder (0.6%) have their water hauled in (e.g., water trucked into the community). CWF is only available to Canadians who drink from municipal water supplies and, as of 2017, roughly 39% of Canadians have access to fluoridated water. However, in 2007, this estimate was 45% of the population. This decrease is most likely the result of several large Canadian cities having discontinued water fluoridation.

Under the Fluoridation Act of Ontario, the council of a municipality may enact a bylaw to establish, maintain and operate a fluoridation system in connection with the waterworks system.

Decisions regarding CWF programs are complex, with many stakeholders and issues to consider. While most public health and oral health organizations, and about 60% of the Canadian public, view CWF as an effective, safe, and equitable means of improving and protecting the oral health of populations, CWF is a controversial topic, with strong feelings both in favour of and against water fluoridation. Additionally, implementing CWF programs requires a multi-level process, with involvement and different roles and responsibilities from all levels of government. Regulators are often different from those who decide whether CWF programs will be started (or stopped), who in turn are often different from those who pay for oral health care.