A disturbing Harvard University review funded by the National Institutes of Health (NIH) has concluded that children who live in areas with highly fluoridated water have IQ scores that are “significantly lower” than those who live in low-fluoride areas. 
This study is however just the tip of the iceberg. Over 23 human studies and over 100 animal studies have linked fluoride to brain damage. Yet despite the significant volume of evidence against it – that has been mounting for over 50 years – fluoride is still added to 70 percent of U.S. public drinking water supplies  “to promote dental health”.
The neurotoxicity of low-level fluoride in water has been known about for over half a century. In 1944, the Journal of the American Dental Association wrote “Drinking water containing as little as 1.2 ppm fluoride will cause developmental disturbances. We cannot run the risk of producing such serious systemic disturbances. The potentialities for harm outweigh those for good.”
Fluoridation of water has also been linked to cancer for over half a century. Dr. Dean Burk, one of the 1937 co-founders of the US National Cancer Institute (NCI), denounced water fluoridation in the strongest possible terms, calling it “Public murder on a grand scale.” He stated that the fluoridation of water causes cancer and that the research was “one of the most conclusive bits of scientific and biological evidence that I have come across in my 50 years in the field of cancer research…. It should be the end [of fluoridation of drinking water] by Federal Law known as the Delaney Amendment, which says that anything found to induce cancer in man or animals cannot legally be put into the food or drink of man or animals.” 
Other studies have linked fluoride toxicity to a wide variety of health problems, including:
• Increased lead absorption
• Disrupts synthesis of collagen
• Hyperactivity and/or lethargy
• Muscle disorders
• Thyroid disease
• Bone fractures
• Lowered thyroid function
• Bone cancer (osteosarcoma)
• Inactivates 62 enzymes and inhibits more than 100
• Inhibited formation of antibodies
• Genetic damage and cell death
• Increased tumor and cancer rate
• Disrupted immune system
• Damaged sperm and increased infertility 
Astonishingly, the most common types of fluoride in drinking water are actually hazardous wastesproduced by the fertilizer industry.
The evidence continues to grow.. and water fluoridation continues to be legal. How much longer?
In Addition To Being Harmful, It’s Actually Rather Pointless
Many modern toothpastes contain fluoride that and are applied directly to the surface of the tooth. On the other hand, fluoride in water makes minimal contact with the teeth and then is swallowed, meaning that the benefits of fluoride in the water supply are negligible and quite possibly completely unnecessary.
What You Can Do
A few steps you can take…
1) First of all, ascertain the fluoridation level in your local area. A Google search should enable you to find out whether your tap water is fluoridated.
2) Fluoride can be removed from drinking water by reverse osmosis or distillation, however these processes also remove other minerals that may be valuable.
3) The Berkey company what some people consider to be the “Rolls Royce” of home water filters… The “Big Berkey” water filter (Amazon link) removes pathogenic bacteria, cysts and parasites entirely and extracts harmful chemicals such as herbicides, pesticides, VOCs, organic solvents, radon 222 and trihalomethanes. It also reduces nitrates, nitrites and unhealthy minerals such as lead and mercury. This system is so powerful it can even remove food coloring from water without removing the beneficial minerals your body needs. Their special fluoride filter attachment also removes pre-oxidized Arsenic III and Arsenic, MTBE and other heavy metal ions. Check it out here (Amazon link)
 Developmental Fluoride Neurotoxicity: A Systematic Review and Meta-Analysis. Environ Health Perspect. (2012) http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3491930/
 Harvard Study Confirms Fluoride Reduces Children’s IQ. Huffington Post.http://www.huffingtonpost.com/dr-mercola/fluoride_b_2479833.html
 Dr. Dean Burk – Fluoride causes cancer (interview) https://www.youtube.com/watch?feature=player_embedded&v=ClqK7XvfLg0