City water is regulated to greater degree than bottled water so the fluoride is usually kept at .1ppm which is just enough. The other problem with bottled water is that many of them are acidic which is bad for your teeth. Check out this link for information on bottled water vs tap water. https://www.alkalinewaterplus.com/analyzing-comparing-brands-of-bottled-water/ In general, Dr. Booth recommends drinking filtered tap water when ever possible and just bottled water just for convenience. Fiji and Evian are two brands of bottled water with neutral or better pH.