WEHN STATEMENT ON WATER FLUORIDATION - NOVEMBER 2025
Community water fluoridation has recently become a controversial issue. The debate has been characterized by strong opinions and biased examination and interpretation of the data. The information presented below is not meant to be a comprehensive review of the literature but an attempt by the Wisconsin Environmental Health Network to present the issues in light of new research identifying fluoride as a developmental neurotoxicant.
What is fluoride? Fluoride is a naturally occurring mineral. Fluoride has no known essential function in human growth and development and no signs of fluoride deficiency have been identified in humans. Fluoride is found in drinking water, food, beverages and dental products1.
What are the health benefits of fluoride? Fluoride inhibits tooth decay by inhibiting demineralization, promoting remineralization and inhibiting plaque bacteria. Fluoride is effective when it is administered topically. Sources of topical exposure to fluoride include fluoridated water, toothpaste, varnishes and rinses. The predominant benefit of fluoride is topical exposure to post-erupted teeth. There is minimal benefit of exposure to fluoride to the developing fetus or young infant prior to the eruption of teeth2.
What is community water fluoridation (CWF)? Water fluoridation is the addition of fluoride to community water supplies. In the US, fluoride is added to municipal water sources to achieve a level of 0.7 mg/L. This can vary by community1.
Other sources of fluoride: Community fluoridated water makes up about 60% of fluoride intake. The remainder is made up from fluoride from other sources such as food, dental products, industrial emissions and pharmaceuticals. Foods such as black tea, coffee, sodas may contribute to fluoride levels1.
Is there fluoride in breast milk? Breast milk contains extremely low concentrations of fluoride as there is poor transfer from the mother’s blood to the breastmilk.
Formula-fed infants have approximately a 70-fold higher fluoride intake than exclusively breast-fed infants. The vast majority of formula fed infants are fed formula that is powdered and reconstituted with tap water. There is limited research on this. One study found that infants fed formula made with fluoridated tap water had decreased non-verbal IQ3.
How effective is fluoride? Early studies estimated that the proportion of children without dental caries (cavities) increased 5 to 22% in communities with water fluoridation. Most of these studies were performed prior to 1975, before the availability of fluoridated toothpaste, rinses, gels and other topical applications.
Data since 1975 has been recently reviewed by the Cochrane Library (a highly respected independent source of systematic reviews of medical evidence). Cochrane concludes that “adding fluoride to water may slightly increase the number of children who have no tooth decay in either their baby teeth or permanent teeth. However, these results also included the possibility of little or no difference in tooth decay. This equates to a difference in decayed, missing or filled teeth (DMFT) of approximately one-quarter of a tooth in favour of CWF.” 4
It should be noted that not all Western countries add fluoride to the water supply. Countries that do not add fluoride such as France, Switzerland, Germany, Finland, Japan and the Netherlands have shown the same decrease in decayed, missing or filled teeth as countries with fluoridated community water supplies.5
What are the risks of water fluoridation? The primary risk of water fluoridation is neurodevelopmental. There is considerable evidence that fluoride in water at levels above the recommended 0.7 mg/liter is associated with diminished cognitive function in children. This is documented with both in utero exposure and in infants exposed postnatally.6,7,8
In 2025, the National Toxicology Program of the National Institute of Health published a meta-analysis of research on fluoride exposure and children’s IQ scores. They found that children’s IQ scores decreased as the level of fluoride in the water increased. When the higher quality studies were analyzed, fluoride in water at less than 1.5 mg /liter was also associated with lower IQ scores.9
A rigorous study published in Journal of the American Medical Association-Pediatrics showed a decrease in IQ of 1.5 in boys exposed prenatally to the recommended level of fluoride versus boys whose mother did not drink fluoridated water. This decrease has significant implication on a population level.10
Other risks include skeletal and dental fluorosis, bone fractures, and effects on thyroid hormone levels.
Understanding how the EPA determines a safe level.
When determining a recommended “safe” level of exposure, the EPA risk assessment protocol recognizes that in the human population there is a 10 fold variability in individual sensitivity and exposure to toxic chemicals. Hence, the estimated “safe” level is generally 10 times lower than the toxic level. Since there is clear evidence of fluoride toxicity at 2.0 mg/L, the safe level would be expected to be no higher than 0.20 mg/L. The current level of 0.7 mg/L is 3.5X higher than this identified hazard level. 9
In a recent citizens’ case against the EPA, the presiding judge ruled that “plaintiffs have proven, by a preponderance of the evidence, that water fluoridation at the level of 0.7 mg/L – the prescribed optimal level of fluoridation in the United States –presents an unreasonable risk of injury to health.”11
What are ways to decrease dental caries in the absence of water fluoridation? Use of fluoridated toothpaste, rinses and gels with fluoride. Because diet is a major factor in dental decay, reducing sugar consumption is effective at decreasing caries. 5,6
Is this a social justice issue? The issue has been raised that fluoridation of drinking water is a social justice issue because lower socioeconomic communities have increased cavities. The increase in cavities has many causes including lack of access to healthy food, increased sugar intake and lack of access to dental care.
Because low-income communities are exposed to a variety of neurotoxicants (ie, lead in older homes, industrial and air pollutants), it is not clear if the benefits of fluoride outweigh the added risk of another neurotoxicant.
Providing better access to healthy food and dental interventions such as topical application of fluoride by health care providers may be a more equitable alternative.
Conclusion: Community water fluoridation is highly complex. We interpret the data to conclude that the current benefits of community water fluoridation are limited and that there is potential harm to the brains of the fetus and young children.
Most importantly, we believe that debate on this issue should be evidence based, informed and respectful. A community may reasonably decide to stop or continue community water fluoridation. We do not believe that dismissive statements advance civic dialogue or scientifically-based decision making.
There are clearly major gaps in our knowledge and we are hopeful that as further research on the risks and benefits of community fluoridation and its alternative becomes available, it will stimulate meaningful and open discussion.