Fluoride is actually way more effective in the topical route instead of being added to the city water supplies, both efficiency-wise and economically speaking. ~99% of fluoride added to the water goes straight down the drain and this can be MILLIONS in useless spending for cities when toothpaste costs what $3 MAX?

Another interesting thing to note is that some people (like those with kidney disease) drink more water and thus are more exposed. Not to mention the shower being a huge source of fluoride. The skin is the largest organ. And fluoride is stored in calcifying tissues https://www.ncbi.nlm.nih.gov/pubmed/?term=pineal+fluoride+calcium like the bones and the pineal gland.

Most cities add chlorine to deal with bacteria. Fluoride is mostly added to water because toxic waste corporations would have to spend money disposing of....Y'know, because it's so toxic it can't be allowed into the environment... Anyhoo, it's a Multi-Billion $ toxic waste industry now, thanks to the propaganda that everybody is now very familiar with. It was sold as poison initially though and it's still sold as poison to this day, I know people in the pest control industry who confirm this reluctantly.