What is the recommended concentration of fluoride in community drinking water as established by the U.S. Public Health Service?

The U.S. Public Health Service updated its recommendation in 2015 to a single optimal fluoride concentration of 0.7 mg/L (ppm) for community water fluoridation. This replaces the previous range of 0.7 to 1.2 ppm that varied by climate (since people in warmer climates were expected to drink more water). The 0.7 ppm level is designed to maximize caries prevention while minimizing the risk of dental fluorosis. Community water fluoridation at this concentration has been shown to reduce dental caries by approximately 25% across all age groups.