Drinking water safety is defined and determined by federal, state, and
local regulations. The main federal law that ensures the quality of
Americans' drinking water is the Safe Drinking Water Act (SDWA). Under
SDWA, the U.S. Environmental Protection Agency (EPA) sets standards for
drinking water quality and oversees the states, localities, and water
suppliers that implement those standards.
CDC promotes effective public health practices, such as community water
fluoridation. It is not CDC’s task to determine what levels of fluoride
in water are safe, yet our understanding about the safety of
fluoridation is guided by federal regulations, comprehensive reviews by
expert panels, and individual studies.
- Scientific Reviews about
Discovery of the decay-preventing effects of naturally occurring
fluoride in water led to the start of community water fluoridation in
1945. For more than 65 years, water fluoridation has undergone extensive
scientific studies and reviews to assess its public health benefits and
For many years, panels of experts from different health and
scientific fields have provided strong evidence that water fluoridation
is safe and effective. See Scientific
Reviews: Assessing the Weight of the Evidence for more details.
National Academy of Sciences on Fluoride in Drinking Water
The National Academy of Sciences, including its National Research
Council (NRC), has considered the health effects of fluoride in
drinking water on several occasions. Additional information on the
NRC and its reports can be found on National Academy of Sciences (NAS) on Fluoride in Drinking Water.
Additional information on the NRC report including a
Report in Brief *
and how to order
copies of the full report is available at
The proper amount of fluoride helps prevent and control tooth decay.
Fluoride ingested during tooth development can also result in a range of
changes in tooth enamel. Because dental fluorosis is a condition that
occurs when teeth are forming, only children aged 8 years old or younger
are at risk. Children older than 8 years, adolescents, and adults are
not susceptible to dental fluorosis.
Dental fluorosis occurs among some people in all communities, even in
communities that do not fluoridate or have a low natural concentration
of fluoride in their drinking water. Everyone is encouraged to know what
steps can be taken to reduce the occurrence of dental fluorosis.
The proper amount of fluoride at all stages of life
helps prevent and control tooth decay. Recent studies have raised the
possibility that mixing infant formula with fluoridated water,
particularly for infants exclusively on a formula diet during the first
year of life, may play a more important role in dental fluorosis
development than was previously understood.
The safety of fluoride in drinking water at levels
recommended for preventing tooth decay has been affirmed by numerous
scientific and professional groups. Scientists have found a lack of evidence
to show an association between water fluoridation and a negative impact on
people, plants, or animals.
Three additives—sodium fluoride, sodium fluorosilicate, and
fluorosilicic acid—may be used to adjust the natural fluoride levels in
water to concentrations that prevent or control tooth decay.
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* Links to non-Federal organizations are
provided solely as a service to our users. Links do not constitute an
endorsement of any organization by CDC or the Federal Government, and none
should be inferred. The CDC is not responsible for the content of the individual
organization Web pages found at this link.
Date last reviewed: December 16, 2011
Date last modified: December 16, 2011
Division of Oral Health,
National Center for Chronic Disease Prevention and