Guidelines for Canadian Drinking Water Quality: Guideline Technical Document – Fluoride

Low levels of fluoride occur naturally in most sources of drinking water in Canada. Fluoride can occur naturally in surface waters from the deposition of particulates from the atmosphere and the weathering of fluoride-containing rocks and soils, and in groundwater from leaching from rock formations. The maximum acceptable concentration (MAC) for fluoride in drinking water is 1.5 mg/L.