Fluoride is added to drinking water across the U.S., but residents of some states are considerably more likely to be drinking fluoridated water than others, according to data from the U.S. Centers for Disease Control and Prevention ( CDC)

For years, local water authorities have considered the addition of low concentrations of fluoride to drinking water a public health achievement. The Centers for Disease Control and Prevention recommends it, citing evidence showing that fluoride prevents cavities in children — the No. 1 chronic disease in kids.

The Centers for Disease Control call the addition of fluoride in water one of the biggest medical advances in the 20th century, noting that it led to healthier teeth.

The water you drink might be different after the next president takes office. Robert F. Kennedy Jr. is expected to have a spot in the Trump administration, and he wants public water systems to remove fluoride.