Fluoride by City - Ontario, Canada

Understanding Fluoridation

Fluoride can be present in Canadian drinking water in two ways: some municipalities add it as part of community water fluoridation, and it also occurs naturally in some groundwater sources, where levels can vary widely depending on local geology. The chart above focuses on added fluoride, showing whether each municipality currently fluoridates its water, has never fluoridated, or has discontinued the practice. Because the decision to fluoridate is made at the local level, practices vary from one community to the next. The target for fluoridated water is 0.7 mg/L, well below the Health Canada maximum acceptable concentration (MAC) of 1.5 mg/L. Keep in mind that a community without added fluoride may still have some naturally occurring fluoride, particularly in private wells and groundwater supplies, so testing is the only way to know your actual level. This matters when selecting treatment, since common options such as standard carbon filters and water softeners do not remove fluoride, while reverse osmosis, activated alumina, and distillation can. Knowing your municipality’s fluoridation status, along with any naturally occurring fluoride in your source water, helps individuals and organizations make informed decisions about water treatment, maintenance, and risk management.