Our drinking water comes from local reservoirs like Lake Ray Hubbard and contains natural minerals. Fluoride is added to promote dental health by strengthening tooth enamel and preventing cavities. The benefits of fluoride in drinking water have been studied since the early 1900s, when high fluoride levels in some areas led to staining but low levels prevented cavities. Since 1945, many cities across the US have added fluoride to their water, and over 75% of Americans now have access to fluoridated water. However, over 100 million still do not, so increasing access to fluoridated water remains a public health goal.