Having fluoride in most drinking water and crop irrigation systems for decades means most people have fluoride accumulated in the tissues of their body, even if it’s in small daily doses that are considered “safe”. Accumulation is the key word.
Avoiding it and getting it out should be a priority, since fluoride creates serious health problems including DNA damage, cancer, thyroid disruption, Alzheimer’s disease, hormone disruption, and pineal gland dysfunction.
There are two types of fluorides that can contaminate water. Calcium fluoride is common in water from wells, sometimes even if fed by aquifers. It’s not as toxic as the waste material for phosphate mined fertilizer or aluminum plants that’s added into water supplies.