… According to the data obtained through a public records request, the highest fluoride reading in more than five years was taken in San Carlos in August 2024.  The reading registered 1.1 milligrams of fluoride per liter, just .01 milligrams less than the state threshold allows. Meanwhile, the lowest reading also occurred in 2024 but less than 10 miles away in Kensington, where in April 2024, city water testers found just .22 milligrams of fluoride per liter. Despite the U.S. Health Department’s recommendation to lower fluoride levels to a uniform .7 milligrams per liter, California has stuck with the acceptable range of .7 to 1.2 milligrams per liter. When looking strictly at drinking water in San Diego, the city has barely managed to stay within that range. In fact, the data shows that fluoride levels have increased on average since 2019.