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Fluoride in the Drinking Water

Tooth decay is the single most common disease in children. Municipalities add controlled levels of fluoride to our drinking water supply to help in the prevention of tooth decay. Learn about fluoridation here.

What is water fluoridation and why is it so important?

Water fluoridation is the process of adjusting the natural level of fluoride in our municipal water supply to a level that will optimize dental benefits. Fluoride additives meet the standard of quality before being added to water at the recommended levels.

Water fluoridation is important because:

  • Research has shown that fluoride in drinking water reduces the number of cavities in children and youth
  • Tooth decay is the most common chronic disease in children (five times more common than asthma and seven times more common than hay fever!)

Water fluoridation in Halton

Public water systems

  • Halton Region's Certified Water Treatment Operators add and monitor fluoride in our water supply
  • When fluoride is added to the water supply it is maintained at the Ontario Ministry of the Environment recommended levels of 0.5-0.8 parts per million (ppm) for optimal tooth decay prevention.
  • Fluoridation does not occur in the older section of Milton, although the groundwater based system contains natural fluoride of 0.1 parts per million (ppm) to 0.15 ppm.
  • Natural fluoride levels in Halton region are too low for the prevention of tooth decay.
  • Any municipal supply of drinking water in Halton Region is safe to use for the preparation of infant formula, whether fluoride is added to the water supply or not.
  • Most water filters do not remove fluoride from municipal drinking water.

Private well water

  • Halton Region does not treat or add anything to private well water.
  • Well water fluoride levels can vary substantially.
  • Well owners must maintain and test their well water for bacteria. A private laboratory will test your water to assess fluoride levels as well. Find out how to have your well water tested.

Organizations that support water fluoridation

A number of reviews on the effectiveness of water fluoridation have been conducted over the last 10 years. Over 90 dental and public health organizations support fluoridation, including:

  • The World Health Organization
  • Health Canada
  • The Canadian and American Dental Associations
  • The Canadian Public Health Association
  • The U.S. Centers for Disease Control and Prevention (CDC)

Information about water fluoridation:

Are there any health risks associated with water fluoridation?

  • A 2018 review conducted by Public Health Ontario reaffirmed the safety of optimally fluoridated drinking water.
  • Long term consumption of fluoride taken in excessive amounts (levels greater than 4 ppm), can cause skeletal fluorosis or osteoporosis.
  • Fluorosis occurs when too much fluoride is swallowed during the important tooth formation years (0-6 for front teeth). Sources of fluoride also include toothpaste and fluoride supplements.
  • In mild cases, fluorosis appears as white flecks on the tooth surface.