What is the primary Maximum Contaminant Level (MCL) for fluoride in drinking water?

The primary Maximum Contaminant Level (MCL) for fluoride in drinking water is set at 4.0 mg/L. This limit is based on health considerations, specifically aiming to protect consumers from adverse effects that can occur at higher fluoride concentrations, such as dental and skeletal fluorosis. The U.S. Environmental Protection Agency (EPA) established this standard to mitigate the risk of excessive fluoride exposure, as it can lead to serious health complications.

Fluoride is commonly added to municipal water supplies for its dental health benefits; however, maintaining levels below the MCL is crucial for the safety of the water supply. It's also important to be aware that certain fluoride levels above the MCL can lead to negative health outcomes, hence the establishment of this threshold by regulatory agencies. The correct understanding of these limits is essential for water operators to ensure public health and compliance with federal regulations.