As for efficacy, the same (or greater) benefits to enamel hardness can be obtained from using fluoride toothpaste anyway, I do not see the urgency for this. They've stopped fluoridating their water in Scandinavia for years now.
Note that Scandinavia has naturally high fluorine levels in their groundwater:
> In Sweden, fluoride concentrations in drinking water from water treatment plants have been reported to mostly range between 0 and 1.5 mg/L, with a maximum level of 4.1 mg/L, while in private wells in South-Eastern Sweden, it was found that 24% out of about 4,800 wells exceed 1.5 mg/L. In Norway, a study from 2017 found that 4 of 201 waterworks had fluoride concentrations exceeding guideline value of 1.5 mg F/L. In a study from Western Norway, the fluoride concentration in selected wells ranged from 0.51 to 8.0 mg F/L, and drinking water was the only dietary variable associated with increased risk of dental fluorosis. In Denmark, analyses of drinking water show most sources being low and below 1.5 mg F/L.
https://pmc.ncbi.nlm.nih.gov/articles/PMC10770722/
The US targets 0.7 mg/L.
Many European countries also choose to add fluorine to milk and/or salt instead of water.
The only difference is that it's rather harder to avoid fluorinated water than iodized salt if one is so inclined, which raises the bar for proof of efficacy and preponderance evidence that it does not cause harm (which has been provided by others in this thread).
Fluoridation started in US water supplies 80 (eighty) years ago. The people who set that "dangerous precendent" are all dead now. Seems like we've done OK with that "unchecked potential for great harm".
I mean, come on. Even as a libertarian argument this seems tone deaf in a month where we're literally rolling back the fourth amendment.