Water treatment is the process by which public drinking water is treated to make it safe to drink. The most common example is water chlorination, which kills certain bacteria and other microbes that may harm people .
Water fluoridation, on the other hand, does not treat the water itself. Rather, fluoridation uses the water supply to treat people. This is a fundamental and radical difference , which raises many ethical objections  and violates numerous principles of consent .
Opponents of fluoridation argue that the public water supply is not an appropriate vehicle for delivering mass treatment to the population. Consent cannot be obtained from all individuals, dose cannot be controlled, and proper biomonitoring is hugely problematic [5-6].
 Wikipedia, Water chlorination.
 Fluoridation as a practice, Overview.
 Fluoridation and ethics, Overview.
 Final Nails in the Ethical Coffin of Water Fluoridation, Consent principles.
 Measures of Exposure, NRC
 Sources of fluoride, FAN