As a general rule, the only fresh water with high levels of fluoride (other than waters polluted by fluoride-emitting industries) is water derived from deep wells. Rather than being something to celebrate, high levels of naturally occurring fluorides have wreaked havoc on tens of millions of people’s health around the world. People consuming water with naturally high levels of fluoride have been found to suffer serious health ailments including disfiguring tooth damage, bone disease, ulcers, reduced IQ, thyroid disease, and infertility. Because of this, international organizations like UNICEF assist developing nations in finding ways of removing fluoride from the water.
Thankfully, most fresh water supplies contain very low levels of fluoride. The average level of fluoride in unpolluted fresh water is less than 0.1 ppm, which is about 10 times less than the levels added to water in fluoridation programs (0.7 to 1.2 ppm). The frequent claim, therefore, that “nature thought of fluoridation first” does not withstand scrutiny.