Southwestern Public Health

Oxford – Elgin – St. Thomas

Elgin St. Thomas Site
Administrative Office
1230 Talbot Street
St. Thomas, ON
Woodstock Site
410 Buller Street
Woodstock, ON
N4S 4N2

December 7, 2020

Health Advisory

Fluoride in drinking water in Oxford County


Fluoride is naturally present at varying levels in Oxford County water sources. Oxford County’s municipal water systems include groundwater from underground aquifers. Oxford County does not add fluoride to the treated municipal drinking water provided to its serviced customers.

Water that contains fluoride up to 2.4 mg/L is considered acceptable to drink by the Ontario Ministry of the Environment, Conservation and Parks. The bacteriological safety of municipal drinking water is not affected by fluoride levels, meaning the water is safe to drink.

Notice of fluoride levels
When fluoride levels are in the range of 1.5 – 2.4 mg/L, the Ontario Ministry of Health recommends heightened public awareness to educate people on how to control too much exposure from other sources of fluoride, such as food and toothpaste. This is to protect against dental fluorosis in young children.

Accordingly, this Health Advisory is to advise residents, health care professionals and other users of the municipal drinking water system that fluoride levels in the following Oxford County communities have tested above the Maximum Acceptable Concentration (MAC) of 1.5 mg/L.


Fluoride levels*

Maximum Acceptable Concentration (MAC)

 Fluoride range which is still acceptable to drink**


1.7 mg/L

1.5 mg/L

1.5 – 2.4 mg/L


0.8 – 2.1 mg/L


1.6 mg/L

Oxford South

0.1 – 1.7 mg/L

* Oxford County is required to test for fluoride samples in municipal drinking water every five years.

** Children seven years of age and younger are at greater risk of dental fluorosis (mottling and discolouration of the teeth). If young children are in the household, cut back on other sources of fluoride to prevent fluorosis. For example, use non-fluoridated toothpaste, used bottled water for baby formula (after it has been boiled and cooled).

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Fluorosis is a dental condition caused by exposure to fluoride while teeth are forming in the gums (usually ages 0-6 years). Fluorosis can cause small white flecks on teeth or larger white areas or, at higher fluoride levels, pitting or brown areas. Fluorosis is cosmetic, not a health condition.

Drinking water below the maximum acceptable concentration of 1.5mg/L will protect against moderate dental fluorosis in children while helping to protect against cavities. However, it is difficult to predict if fluorosis will occur and what it will look like. The following recommendations are intended to minimize the effects of fluoride in the water system if levels are above 1.5mg/L:

1. Water treatment. Use a home treatment system to remove or reduce the fluoride content if there are young children in the home. Only reverse osmosis and distillation processes remove fluoride. Charcoal filters do not remove fluoride.

2. Use other sources of water. If it is not possible to use a home treatment system, consider using water from another source with a lower fluoride level (e.g., non-fluoridated, bottled water) for drinking, cooking, mixing juices or making baby formula, especially when there are young children in the home. Bottled water, like tap water, must be sterilized when used to make baby formula.

3. Non-fluoride toothpaste. Consider using non-fluoride toothpaste for children up to and including 6 years of age, or no toothpaste for children up to 3 years of age, especially for children who may swallow toothpaste. Parents should only use a small amount of toothpaste (pea-size or a smear) regardless of fluoride levels in the water and should always supervise the amount of toothpaste being used.

4. Don’t use fluoride supplements. Fluoride supplements should not be used in areas with naturally occurring fluoride.

5. Consult with your dentist. A fluoride treatment at the dentist is not likely to contribute to fluorosis; however, parents should discuss the use of any dental products with their dentist.

Fluoride levels in non-municipal drinking water (private wells)
Some private wells in Oxford County may also contain naturally occurring fluoride levels above the recommended level of 1.5 mg/L. Public Health recommends regular testing of well water: three times a year for bacteria and once a year for fluoride and nitrates.

More information
If you have questions about fluoride in your drinking water, please consult your health care professional, or call Southwestern Public Health at 519-421-9901, ext. 3410, toll-free 1-800-922-0096. More information is available online at

Dr. Joyce Lock Medical Officer of Health
1-800-922-0096, ext.1255

Staff contact for information:
Amy Pavletic, Program Manager
1-800-922-0096, ext. 3407

*See original pdf at

*See also Dec 8, 2020, Southwestern public health issues fluoride and sodium reminder for Oxford County