Is Fluoride in Water Actually Dangerous?

Although the addition of fluoride to drinking water has been credited for protecting the dental health of millions of Americans, it has also been a topic of controversy for decades, and the debate has recently been reignited.

United States Secretary of Health and Human Services Robert F. Kennedy Jr. has clearly expressed his opposition to water fluoridation. Recently, Utah became the first state to ban fluoride in drinking water, and late last year, Florida Surgeon General Joseph Ladapo issued public guidance advising communities against fluoridating their water. 

While some celebrate it as a public health triumph, others question the safety and necessity of adding fluoride to drinking water. Let's explore what fluoride is, its history in water fluoridation, and what current research reveals about its implications for our health.

What is fluoride?

Fluoride is a naturally occurring mineral found in soil, water, and certain foods. It is best known for its ability to strengthen teeth and prevent cavities. When fluoride is applied to teeth, it helps rebuild enamel and may reverse early signs of tooth decay. 

According to the CDC, “Almost all water contains some naturally occurring fluoride, but usually at levels too low to prevent cavities.” Due to its potential benefits for dental health, fluoride has been widely added to dental products such as toothpaste and mouthwash, as well as to public water supplies.

Why is fluoride added to water in the United States?

The practice of adding fluoride to drinking water began in 1945 in Grand Rapids, Michigan, when researchers embarked on a project to determine if water fluoridation would effectively reduce the rate of tooth decay among local children. The results were clear: Kids born after fluoride was introduced to the water supply experienced a 60% reduction in their rate of tooth decay. (Today, it's estimated that water fluoridation lessens your risk of cavities by about 25%.)

These findings made the research a remarkable success, and fluoridation became widespread across the United States in the following decades.

The CDC has previously recognized community water fluoridation as "one of the 10 greatest public health achievements of the 20th century." By increasing the accessibility of fluoride, public health officials have observed significant improvements in dental health, particularly in communities with limited access to professional dental care.

However, water fluoridation has its opponents. Criticism of the practice has existed since its inception, and the debate over whether consuming fluoride is safe, as well as whether communities should have access to water without it, continues into 2025.

How does fluoride improve your dental health?

Fluoride strengthens your tooth enamel and ultimately helps prevent cavities. According to the CDC, “Studies continue to show that widespread community water fluoridation prevents cavities and saves money, both for families and the health care system. Drinking fluoridated water keeps teeth strong and reduces cavities by about 25% in children and adults.”

Dr. Lauren Becker, DDS, PC, owner and general dentist of her namesake dentistry practice in New York City, explains further, telling Food & Wine that “Fluoride acts as a dental barrier between teeth and helps keep the teeth strong during everyday use like chewing, drinking, and eating.” She adds, “Fluoride creates a shield so that the tooth is protected from potential bacteria, plaque, and overall buildup from occurring.”

Is fluoride in water safe?

Opponents of water fluoridation, including RFK Jr., have raised concerns that the mineral is linked to various health and developmental issues, such as cancer, weakened bones, and declines in IQ. But is there any merit to their claims?

A little background information is helpful here. To maximize the benefits of this mineral in water systems, the U.S. Public Health Service (PHS) recommends a fluoride concentration of 0.7 milligrams per liter (mg/L) in drinking water, which is considered optimal for preventing tooth decay while minimizing potential side effects.

In 2024 the National Toxicology Program (NTP) published a systematic review of research surrounding the connection between fluoride and cognitive development. This study did discover that higher levels of fluoride, such as those found in drinking water with more than 1.5 mg/L of fluoride, “are associated with lower IQ in children.” 

A level of fluoride greater than 1.5 mg/L would exceed the guidelines for drinking water set by the World Health Organization and could lead to issues such as dental fluorosis — a cosmetic issue that causes discoloration of tooth enamel — or, more concerningly, skeletal fluorosis — a bone disorder.

The NTP notes that “There were insufficient data to determine if the low fluoride level of 0.7 mg/L currently recommended for U.S. community water supplies has a negative effect on children’s IQ,” and it “found no evidence that fluoride exposure had adverse effects on adult cognition.”

These findings suggest that further research is necessary to gain a clearer understanding of the connection between lower levels of fluoride (like those found in water supplies) and IQ.

Per Becker, beyond cognitive development, “There are speculations that fluoride in our drinking water may cause alternative health issues like thyroid problems or impact bone health. However, this is not scientifically backed.” The dental professional explains, “It's true that overexposure to fluoride has the potential to create other issues, but this is unlikely to occur from the safe amounts in drinking water.”

Finally, a majority of health resources, including the American Cancer Society and City of Hope — a nonprofit clinical research center for cancer — note that there is no clear or conclusive link between fluoride and cancer.

How much fluoride is in my water?

Want to ensure your drinking water has an appropriate level of fluoridation? To check the fluoride levels in your community's water supply, the CDC offers a helpful tool called My Water's Fluoride. This online resource allows users to verify if their local water is fluoridated and at what concentration.

Can removing fluoride from water cause harm?

Calgary, Canada, presents a relatively recent example of what can happen if a community decides to remove fluoride from its water. 

After eliminating the mineral from its water supply in 2011, the city observed a significant increase in tooth decay and related issues — particularly among children — when compared to another major city in its province that had continued water fluoridation. 

As a result, Calgary voted to reinstate water fluoridation in 2021 in response to the increase in tooth decay, although the mineral has not yet been successfully reintroduced. 

What are the long term impacts of fluoride?

Supporting the strength of your teeth isn’t just about achieving a picture-perfect smile. Dental health can impact overall health, quality of life, and financial well-being.

If left untreated, tooth decay can lead to pain, infections, and even tooth loss, potentially affecting daily activities such as eating or speaking. Furthermore, the economic burden associated with dental issues can be substantial, as fillings, root canals, and extractions often incur high costs for individuals and healthcare systems.

Per the CDC, “Communities of 1,000 or more people see an average estimated return on investment (ROI) of $20 for every $1 spent on water fluoridation. The ROI for community water fluoridation increases as the community size increases, but even small communities save money.” Adults and children are also likely to miss fewer days of work or school for dental appointments.

Although more research is welcome and needed, as the facts stand, dental experts and scientists have made it clear that water fluoridation benefits both your teeth and the community, as long as it is maintained within recommended levels.