Most Americans aren't aware that there's controversy over whether or not fluoride should be added to the public water supply; it rarely gets discussed in the mainstream media. Most first world countries no longer add the substance. In Western Europe this figure is well over 90%. This contrasts America where approximately 73.9% of Americans are “served” fluoridated water. Compared to other states, a high proportion of Minnesota residents, approximately 98.8%, are provided fluoridated water.
Proponents of adding fluoride say it fights tooth decay and is safe. According to the Centers for Disease Control and Prevention:
Water fluoridation prevents tooth decay mainly by providing teeth with frequent contact with low levels of fluoride throughout each day and throughout life. Even today, with other available sources of fluoride, studies show that water fluoridation reduces tooth decay by about 25 percent over a person's lifetime.
Community water fluoridation is not only safe and effective, but it is also cost-saving and the least expensive way to deliver the benefits of fluoride to all residents of a community. For larger communities of more than 20,000 people, it costs about 50 cents per person to fluoridate the water. It is also cost-effective because every $1 invested in this preventive measure yields approximately $38 savings in dental treatment costs.
It's pretty much undisputed that fluoride can help prevent tooth decay but there’s mounting evidence that fluoride can cause some serious harm including depressing children's IQ. From the Harvard School of Public Health:
For years health experts have been unable to agree on whether fluoride in the drinking water may be toxic to the developing human brain. Extremely high levels of fluoride are known to cause neurotoxicity in adults, and negative impacts on memory and learning have been reported in rodent studies, but little is known about the substance’s impact on children’s neurodevelopment. In a meta-analysis, researchers from Harvard School of Public Health (HSPH) and China Medical University in Shenyang for the first time combined 27 studies and found strong indications that fluoride may adversely affect cognitive development in children. Based on the findings, the authors say that this risk should not be ignored, and that more research on fluoride’s impact on the developing brain is warranted.
It seems obvious that the risks of water fluoridation outweigh any benefits and that the practice should be discontinued immediately.
There's a number of ways people can avoid consuming fluoridated water. Purchasing an appropriate water filter appears to be the most practical.