On January 7th, 2011 the U.S. DHHS recommended setting the level of fluoride in drinking water to the lowest end of the current optimal range (0.7 to 1.2 ppm). EPA is initiating a review of the maximum amount of fluoride allowed in drinking water based on scientific assessments of health effects from too much fluoride. MCL (Maximum Contaminant Level) is the legal threshold limit on the amount of a substance allowed in public water systems. EPA sets the MCL to address adverse health effects. Current MCL for fluoride is 4 mg/L. The EPA is unsure if they will revise the MCL. U.S. DHHS is strictly concerned with the standard for optimal oral health which is 0.7 to 1.2 ppm.
Dr. Dale Stephenson