Frequently Asked Questions
Tooth Decay and Fluoride
What is community water fluoridation?
Community water fluoridation is the adjustment of the fluoride
concentration in the community water supply to a level beneficial to
reduce tooth decay and promote good oral health. The mineral fluoride is
essential for strong healthy teeth that resist decay. Almost all waters
contain some quantity of naturally occurring fluoride, but usually at
levels insufficient to prevent decay. The optimum concentration of
fluoride in water has been determined to be between 0.7 to 1.2
milligrams per liter (mg/L) depending on the air temperature in a given
region. Given the dramatic decline in tooth decay during the past 60
years, the Centers for Disease Control and Prevention (CDC) named water
fluoridation one of Ten Great Public Health Interventions of the 20th
Century. Community water fluoridation has been recommended by the past
five United States Surgeon General’s. More information can be found on
our Benefits page.
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How does fluoride work?
Tooth decay is caused by bacteria in the mouth. When a person eats
sugar, or other refined carbohydrates, these bacteria produce acid that
removes minerals from the surface of the tooth, a process known as
demineralization. If demineralization goes on long enough, a cavity is
formed. Fluoride can promote the remineralization of enamel, thereby
preventing the cavity from continuing to form. In addition, fluoride
reduces the ability of the oral bacteria to produce acid. More
information can be found in a fact sheet on
Background Information.
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Is tooth decay still a serious problem?
Yes. More than two-thirds of U.S. children and adolescents aged 19
years or younger, 91% of U.S. adults, and 93% of Americans aged 60 years
and older have experienced tooth decay.
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Will community water fluoridation benefit my family?
Fluoride’s action in preventing tooth decay benefits both children
and adults throughout their lives. The health benefits of fluoridation
are
- Fewer cavities and less severe cavities.
- Less need for fillings and tooth extractions.
- Less pain and suffering associated with tooth decay.
- Better self-esteem from teeth that work well and look good.
See the The Benefits of Fluoride statement from the Office of
the Surgeon General
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Have Americans had less tooth decay since water fluoridation began?
Yes. Independent studies initiated in 1945 and 1946 followed four
communities and assessed the value of water fluoridation. By 1960, tooth
decay rates in these communities declined, on average, 56% more than in
demographically similar communities whose water supplies were not
fluoridated. Now that there are additional ways of obtaining fluoride
benefits such as in toothpaste, rinses, and professional treatments, as
well as in many foods and beverages produced in fluoridated areas; more
recent studies show that water fluoridation reduces tooth decay in
permanent teeth by approximately 18%—40%. Although this reduction in
decay is not as dramatic as it was in the 1950s and 1960s, it continues
to be significant when compared with tooth decay in many nonfluoridated
communities.
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Is community water fluoridation a cost-effective method for disease
prevention?
Yes. In 2004, an estimated $78 billion was spent on dental services,
representing about 5% of all expenditures for personal health care in the
United States. A CDC study estimated that every $1 invested in community
water fluoridation saved $38 in avoided costs for dental treatment. The
national average cost to fill one cavity with dental amalgam is
approximately $65—the approximate cost of providing fluoridation to an
individual for a lifetime.
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Safety and Fluoridation
Is community water fluoridation safe?
Yes. Extensive research conducted over the past 60 years has shown
that fluoridation of public water supplies is a safe and effective for
all community residents. More recent reviews of the safety of water
fluoridation include a comprehensive review of the scientific literature
by the U.S. Public Health Service in 1991 and by the University of York
in 2000. Additional information on safety
can be viewed.
The overall value and safety of community water fluoridation has been
endorsed by
- CDC.
- U.S. Surgeon Generals (Oral Health in America and other reports).
- U.S. Task Force on Community Preventive Services.
- American Dental Association.
- American Medical Association.
- American Association of Public Health.
- U.S. Public Health Service.
- World Health Organization.
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Can I use fluoridated water for preparing infant formula?
Yes. You can use fluoridated water for preparing infant formula.
However, if your child is exclusively consuming infant formula
reconstituted with fluoridated water, there is the increased potential
for mild dental fluorosis, which is a white spotting on teeth.
Additional information can be found in a fact sheet on
Infant Formula.
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Fluoride in Drinking Water
How can I find out the fluoride concentration of my drinking water?
All public water systems are required by the U.S. Environmental
Protection Agency (EPA) to publish an annual Consumer Confidence Report
with information about their drinking water, including the fluoride
level.
- If you are on a public water system, you can call the water utility
company and request a copy of the utility’s most recent Consumer
Confidence Report.
- If you live in a state that participates in CDC’s
My Water's Fluoride you can go online and find information on your water system’s
fluoridation status.
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My home gets it water from a private well. What do I need to know about
fluoride and groundwater from a well?
Although most U.S. households are connected to a public water system,
the U.S. Geological Survey estimates that approximately 15% of U.S.
residents rely on private wells that are not regulated by the EPA Safe
Drinking Water Act. Fluoride is present in virtually all waters at some
level, and it is important to know the fluoride content of your water
since too little may not protect against tooth decay and too much may be
a health concern. It is recommended that you have a sample of your well
water analyzed by a laboratory. If you have water fluoride levels under
0.6 ppm, your child's dentist or pediatrician should evaluate whether
your child can benefit from daily fluoride supplements. Their
recommendation will depend on your child's risk of developing tooth
decay and as well as exposure to other sources of fluoride (e.g.,
drinking water at school or daycare, toothpaste). If the natural
fluoride level of your well or community drinking water is greater than
2 ppm, you should consider an alternate source of drinking water for any
child 8 years and younger. Their teeth are still developing and will be
at risk for enamel fluorosis. If you have an infant
which is predominately consuming infant formula reconstituted with water
with fluoride greater than 0.7 mg/L, you may wish to review the fact
sheet on Infant Formula and the Risk for Enamel Fluorosis. If
you have additional questions on your well and fluoride levels, please
see the Fact Sheet on Private Well Water
and Fluoride FAQs.
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How much does it cost the community to fluoridate the water?
The per person cost of fluoridation varies by the size of the
community population. The average cost of providing fluoridated water to
communities with more than 20,000 residents is about 50 cents per year.
For communities of 10,000–20,000 residents, the cost is about $1, and
for those living in communities of less than 5,000, the cost is about $3
per year.
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Will using a home water filtration system take the fluoride out of my
home’s water?
Removal of fluoride from water is difficult. Most home treatment systems
are installed at single faucets and use activated carbon filtration, which
does not remove fluoride.
If your fluoride level is above 2 ppm and you are trying to reduce the
amount of fluoride in your water a home device must meet National Sanitation
Foundation (NSF) Standard 58 criteria for fluoride removal. The Standard 58
requirements are for a device to achieve a 1.5 milligrams per liter (mg/L)
concentration in the product water if the original concentration was 8.0
mg/L, or approximately an 80 percent removal. This percentage removal may
not be consistent at lower concentrations of fluoride. Check with the
manufacturer of the individual product for specific product information. If
you are concerned about the fluoride level in your home water (above the
level of 2 mg/L), you may consider using water from a commercial bottler
whose water has the level of fluoride you desire as an alternative to
removing the fluoride.
Fluoride is not released from water when it is boiled or frozen. One
exception would be a water distillation system. These systems heat water to
the boiling point and then collect water vapor as it evaporates. Water
distillation systems are typically used in laboratories. For home use, these
systems can be expensive and may present safety and maintenance concerns.
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Does bottled water have fluoride?
Some bottled waters contain fluoride but most do not. The U.S. Food and Drug
Administration (FDA) does not require bottlers to list the fluoride content
of water, and only requires that if fluoride is added, the additive used be
listed. Most bottlers will use National Sanitation Foundation certified
additives for quality control. If you are interested in the fluoride content
of a specific water brand, you should ask the bottler. In 2006, the FDA
announced that bottled water with greater than 0.6 and up to 1.0 mg/L could
be labeled with the statement “Drinking fluoridated water may reduce the
risk of tooth decay.” Additional information is available in our
Fact Sheet
on Bottled Water and Fluoride.
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Does water fluoridation result in pipe corrosion or increased lead in
drinking water?
Water fluoridation does not increase
corrosion of pipes or cause lead
to leach (dissolve) from pipes and household plumbing fixtures. Although
lead in public drinking water is typically found to be very low or is below
laboratory detection, there are locations where old lead pipes, solder, or
plumbing fixtures in old homes may leach lead into water. This is
principally a problem in some older homes because newer homes have been
constructed in accordance with new plumbing standards that prohibit the use
of lead in plumbing pipes and fixtures.
Ask your local water utility system if there have been problems with higher
lead levels in water from older homes in your community. Claims that
fluoride might result in increased lead leaching from pipes and fixtures
have not been substantiated in the peer-reviewed literature.
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Regulations, Standards
What standards does the U.S. Environmental Protection Agency (EPA) set for
levels of fluoride in water?
The EPA establishes criteria for safe drinking water under the Safe Drinking
Water Act and its amendments (1974, 1986, and 1996). These standards include
the maximum contaminant level goal (MCLG), the maximum contaminant level (MCL),
and the secondary maximum contaminant level (SMCL).
The MCLG is a health goal set at a concentration to minimize adverse health
effects. This goal is not enforceable and serves as an advisory to the
states. The MCL is an enforceable regulatory standard that is set as close
to the MCLG as practical, taking into consideration factors such as
treatment technology and costs. The SMCL is a nonenforceable secondary
standard that, in the case of fluoride, provides guidance on cosmetic or
aesthetic considerations related to tooth enamel fluorosis.
In 1986, the EPA established an MCLG and MCL for fluoride at a concentration
of 4 milligrams per liter (mg/L) and an SMCL of 2 mg/L. The Safe Drinking
Water Act requires periodic reassessment of regulations for drinking water
contaminants.
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Does the U.S. Food and Drug Administration (FDA) or U.S. Environmental
Protection Agency (EPA) regulate fluoride added to drinking water?
The EPA and FDA established in a 1979 Memorandum of Agreement that the EPA
would regulate drinking water for public water systems and the FDA would
regulate consumer beverages, including commercial bottled water. The EPA has
issued maximum drinking water contaminant standard for fluoride of 4 mg/L,
based on health considerations, and has entered into an agreement with
National Sanitation Foundation (NSF) International to formulate program
standards for drinking water additives. Those standards are known as
NSF/ANSI (American National Standards Institute) Standard 60. The FDA
requires bottlers to list the chemical used to adjust the fluoride
concentration, and permits manufacturers to claim the benefits for improved
oral health when fluoride is adjusted to a range of 0.6 to 1.0 mg/L.
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How does the release of the 2006 National Research Council (NRC) report
affect the standards set by the EPA?
On March 22, 2006, the NRC issued the committee's report, Fluoride in
Drinking Water: A Scientific Review of EPA’s Standards. The report addresses
the safety of high levels of fluoride in water that occur naturally at
levels of 2 mg/L and higher, and does not question the use of lower levels
of fluoride to prevent tooth decay. The findings are consistent with CDC’s
assessment that water fluoridation at optimal levels (0.7 mg/L–1.2 mg/L) is
beneficial for good oral health. For more information on this report, see
the CDC Statement on the 2006
NRC Report.
The recommendations from CDC remain the same—that community water
fluoridation is safe and effective for preventing tooth decay. CDC continues
to recommend steps to prevent moderate and severe enamel fluorosis; these
recommendations were made in the August 17, 2001, MMWR report,
“Recommendations for Using Fluoride to Prevent and Control Dental Caries in
the United States” . These steps include using an alternate water
source for children aged 8 years and younger if the primary drinking water
source has naturally occurring fluoride above 2 mg/L, and supervising the
use of toothpaste by children younger than 6 years to prevent swallowing
excess toothpaste. Fluorosis can only occur when the teeth are developing
(ages 0 to approximately 8) Other steps to prevent fluorosis include:
Parents should place only a pea-sized amount of toothpaste on the child’s
brush. Children under age 6 should not use fluoride rinses as they are prone
to swallow them. Check with your child’s medical doctor or dentist about the
use of dietary fluoride supplements if you live in an area with low levels
of fluoride in your water.
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Fluoride Additives for Water
What additives are used to fluoridate water?
Fluorosilicic acid is the most commonly used additive for water
fluoridation, followed by two dry additives—sodium fluorosilicate and sodium
fluoride. Fluorosilicic acid is derived from production of phosphate
fertilizers. Phosphate rock which is comprised of calcium phosphate, calcium
fluoride, apatite ore, and limestone, is mixed and heated with sulfuric acid
to form a phosphoric acid-gypsum slurry, the starting point to make
pelletized phosphate fertilizers. The hydrogen fluoride and silicon
tetrafluoride that would otherwise be left in the gypsum slurry is
deliberately recovered from the slurry by evaporators and condensed to a
high purity fluorosilicic acid that can be used for water fluoridation. Both
sodium fluorosilicate and sodium fluoride are created by neutralizing
fluorosilicic acid with either sodium chloride (table salt) or caustic soda.
See Water Fluoridation Additives for a more detailed
explanation.
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Do these additives have to meet standards for quality and purity?
The American Water Works Association (AWWA) prepares standards for the
manufacturing, quality, and verification of the fluoride additives. NSF/ANSI
(National Sanitation Foundation/American National Standards Institute)
prepares standards that cover impurities of drinking water treatment
additives from their production and distribution to user, and documents the
purity of additives. Verification testing by independent certification
entities including NSF and Underwriters Laboratories documents that the
actual purity exceeds the
NSF Standard 60 requirements.*
A key concept is that an additive should not add more than 10% of the
EPA-established MCL (Maximum Contaminant Level) of any regulated drinking
water substance in order to ensure the protection of the public. The
NSF/ANSI standard 60 was developed by a consortium of associations,
including NSF International, AWWA, ANSI, the Association of State Drinking
Water Administrators, and the Conference of State Health and Environmental
Managers.
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Is fluorosilicic acid the residue of the production of pesticides,
rodenticides, or the nuclear industry?
No. It is a valuable coproduct derived from the production of fertilizer. It
is not derived from pesticide, rodenticide, or nuclear power production.
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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:
April 25, 2008
Date last updated: April 25, 2008
Content source:
Division of Oral Health, National Center for Chronic Disease Prevention and
Health Promotion |
