From the cited article ...

... Most communities in the U.S. add fluoride to the tap water. It has been common practice for nearly 80 years to protect against tooth decay and cavities, and it's considered a major achievement in public health. The Centers for Disease Control and Prevention says research shows that community water fluoridation reduces cavities by around 25%. ...

This week, government scientists published a paper in the medical journal JAMA Pediatrics that has added to the debate. It is the analysis behind a 300-page report released last August from the National Toxicology Program, part of the National Institutes of Health.

That report concluded with "moderate confidence" that there may be a link between high levels of fluoride exposure and lowered IQ. This could indicate possible neurodevelopmental harms to pregnant people or young children, when they are exposed to drinking water containing at least 1.5 milligrams of fluoride per liter -- a level more than twice what's recommended (0.7 mg/L) for the U.S. water supply. ...

OK, so I have to ask, what drinking water has a floride level higher than the higher than the ... when they are exposed to drinking water containing at least 1.5 milligrams of fluoride per liter -- a level more than twice what's recommended (0.7 mg/L) for the U.S. water supply. ...

And, if those suppliers of such water, why are they seeming to ignore the Federal recommendations?