Fluoride in drinking water: What we know about its safety and risks

Fluoride – a natural constituent of teeth and bones – is added to public drinking water supplies throughout the U.S. for its purported dental health benefits. But this process, known as fluoridation, has its critics, who warn that the chemical may cause harm to the body.

Health and Human Services Secretary Robert F. Kennedy Jr. is adding fresh fuel to this perennial debate. Kennedy has vowed to end HHS’ longstanding recommendation to add fluoride to drinking water supplies. He’s called fluoride “an industrial waste associated with arthritis, bone fractures, bone cancer, IQ loss, neurodevelopmental disorders, and thyroid disease.”

Fluoride in tap water at levels two or more times higher than what is typically added in the U.S. is associated with decreased IQ and higher amounts of fluoride also damage teeth. 

But epidemiological studies have found that fluoride at certain levels in drinking water can reduce dental cavities in children and adults. The Centers for Disease Control and Prevention considers water fluoridation to be one of the top public health victories of the 20th century. Water supply fluoridation is recommended by federal and state health agencies, the American Academy of Pediatrics and dental health organizations.

Many public health officials have expressed concerns about any move by the HHS to deter fluoridation, and the negative implications for dental health.

Who’s right? 

The answer isn’t straightforward.

Determining the optimal concentration of fluoride in water to minimize potential harm while maximizing dental health benefits has been one of the most hotly debated subjects in public health over the past half-century. 

At EWG, we challenge the status quo by revisiting the science and assumptions behind public policy decisions. Too often, these choices about chemical additives or contaminants in food, water or consumer products prioritize corporate interests over public health.

EWG has questioned the assumptions behind the fluoride levels added to drinking water systems since 2005. Since 1962, the U.S. government recommendation has been to add up to 1.2 micrograms per cubic liter, or mg/L, a position that was officially changed in 2015.

In 2011, in response to a lawsuit filed by the Fluoride Action Network, EWG and Beyond Pesticides, the HHS lowered its recommended fluoride level to 0.7 mg/L. This was an important win, and at the time EWG questioned whether the level should be reduced even further.

The Environmental Protection Agency’s current Safe Drinking Water Act limit for fluoride in drinking water is 4 mg/L. The agency is now considering lowering it to 1.5 mg/L, following recommendations by the National Toxicology Program, or NTP, an HHS division.

Even at 1.5 mg/L, the level of fluoride allowed in drinking water may be still too high for the underserved populations. EWG’s recently updated Tap Water Database shows that 2 million people in more than 1,260 community water systems across the U.S. have average fluoride concentrations in their drinking water above 1.5 mg/L. 

Ongoing health concerns

Recent studies and reports have continued to identify health concerns with fluoride. The NTP in an August 2024 report found levels of fluoride in water above 1.5 mg/L – twice the level typically added to drinking water – are associated with lower IQ, with higher fluoride levels causing greater harm. 

But the report also said there is insufficient data to determine whether the fluoride levels added to water at 0.7 mg/L had any negative impact on children’s IQ. This report included a comprehensive 2023 meta analysis, or review of numerous papers, fluoride’s effects on IQ.

Another scientific review by government scientists published in January 2025 found that higher levels of fluoride, exceeding 1.5 mg/L, were associated with IQ loss. 

Additionally, a Cochrane review published in 2024 found that fluoride added to water was less effective in preventing cavities compared to studies done before 1975, due to the widespread use of toothpaste with fluoride. Many uncertainties remain, and two studies that did not meet the review’s criteria for inclusion found significant increases in cavity rates after water fluoridation ended in Calgary, Canada, in 2011 and in Juneau, Alaska, in 2007. 

A 2024 health bulletin from Alaska noted that while dental health improved across the state, childhood cavity rates doubled in Juneau. Calgary is planning to resume water fluoridation.

Reframing the debate: A health care issue

Beyond the scientific debate, some experts say the fluoride debate should refocus on the broader failings of the health care system rather than just fluoride levels in drinking water. Community water fluoridation as a public health measure is entangled with systemic failures in the U.S. health care system, particularly for dental care access, that can and should be addressed.

A 2021 National Institutes of Health report, “Oral Health in America,” highlights that access to dental health care is a more pressing issue than the back-and-forth over whether adding fluoride to drinking water is safe.

EWG has historically questioned the scientific basis for policies in favor of fluoridation of public water supplies. Published research clearly shows that high concentrations of fluoride are toxic to human health. 

The best way to achieve dental health benefits is by providing comprehensive, accessible dental health care practices for all communities. Persistent disparities along economic and demographic lines have left many Americans without access to both preventative and therapeutic dental care. 

A more effective approach to improving dental health outcomes should include:

1. Advocating for federal policies that ensure comprehensive dental care for all Americans, prioritizing vulnerable populations that currently experience poor dental health. Communities that opt not to fluoridate their water should receive additional federal support for dental health care.
2. Opposing any measures that reduce access to dental health care, such as proposed Medicaid cuts that would widen existing disparities.
3. Recognizing that the scientific evidence shows that dental products with fluoride are an effective means of topical fluoride delivery. Fluoridation of water exists as a “public health victory” within the context of a failing health care system that does not ensure healthy dental self-care or adequate access to treatment.
4. Supporting efforts to improve preventive health care policies, including coverage for dental care under Medicare Parts A and B, which currently do not cover these services.

How we’re exposed

Exposure to fluoride comes from more than just water. Fluoride is a naturally occurring mineral, and exposure can also occur from other foods and beverages, with tea often containing levels much higher than those found in fluoridated water.

Brushing teeth is important and using fluoride toothpaste may be critical. A review of studies on oral hygiene found that brushing alone had no impact on cavity rates unless accompanied by the use of toothpaste with added fluoride. 

The American Academy of Pediatrics, or AAP, supports water fluoridation, highlighting the environmental justice aspects of water fluoridation and dental care. It found historically underserved communities had the highest rates of untreated dental cavities in children and adults. Additionally, the AAP mentions both fluoride dental products and fluoride supplements among the options that pediatricians may recommend.

Fluoridating water is an imprecise way of delivering benefits for tooth health, but it leads to reduced cavity rates. That’s important for those who cannot afford dental care or insurance. At a personal level, the most effective way to reap the benefits of fluoride is by using fluoridated toothpaste. 

At the community level, any effort to alter, add or remove fluoride from drinking water systems must be based on careful consideration of the latest science on health harms. 

It should also take into account the potential benefits through the lens of environmental justice, particularly the opportunity to reduce cavity rates for everyone, including those in underserved communities. 

What can you do?

If you’re concerned about fluoride in drinking water, here are some tips from EWG:

• For infants, use formula made with water that does not contain fluoride. (Levels of fluoride in breast milk are typically low and not affected by drinking water fluoridation.)
• If fluoride is removed from your drinking water, you can use toothpaste or other oral hygiene products with fluoride.
• If you are concerned about either added or naturally occurring fluoride in your water, reverse osmosis filters can remove it.
• If your drinking water system has high naturally occurring levels of fluoride, consider getting a home water filter to remove it.