CDC Statement on the 2006 National Research Council (NRC) Report on Fluoride
in Drinking Water
CDC recommends community water fluoridation as a safe, effective, and
inexpensive way to prevent tooth decay (dental caries) among populations
living in areas with adequate community water supply systems. Similar to
many vitamins and minerals we consume for our health, fluoride should be
taken in the proper amount. Past comprehensive reviews of the safety and
effectiveness of fluoride in water have concluded that water
fluoridation is safe and effective. Fluoride is present naturally in
most water at a very low level, and more than 180 million people on
public water systems in the United States enjoy the benefits of having
their water adjusted to the optimal level (0.7–1.2 mg/L, or 0.7–1.2
parts per million [ppm]) for preventing tooth decay.
Some water has naturally occurring fluoride at levels much higher than the
optimal. A recent report, Fluoride in Drinking Water: A Scientific Review of
EPA’s Standards from the National Research Council (NRC), released on March
22, 2006, addresses safe maximum fluoride levels. The report addresses the
safety of high levels of fluoride in water that occur naturally, and does not
question the use of lower levels of fluoride to prevent tooth decay.
This new report was prompted as part of a routine, periodic review by the
Environmental Protection Agency (EPA), the federal agency that is responsible
for all regulated contaminants in drinking water, including fluoride. As part
of its congressionally authorized mission, to protect the health of the
public, the EPA sets standards for safe drinking water. Drinking water can
contain many minerals, compounds, and organisms, some of which are considered
“contaminants” under EPA’s regulations. There currently are 96 contaminants
that are regulated under the Safe Drinking Water Act; fluoride is included as
a naturally occurring mineral.
The purpose of the review of fluoride was to determine the adequacy of
current guidelines set by the EPA on the maximum allowable concentration of
fluoride in drinking water to protect children and others from adverse health
effects. The National Research Council (NRC) Committee found that the current
EPA maximum contaminant level goal (MCLG) of 4 milligrams of fluoride per
Liter (mg/L) of drinking water should be lowered to better protect people
from health risks associated with high natural fluoride levels. The report
recommended that the EPA update its risk assessment in order to determine the
appropriate level for the MCLG.
The NRC Committee evaluated many health effects that have the potential to
be associated with fluoride in drinking water. The NRC concluded that only
three adverse health effects warranted consideration in developing regulatory
standards for high levels of fluoride in drinking water—severe enamel
fluorosis from exposure to these high levels between birth to 8 years of age,
and the potential risk for bone fractures and the more severe forms of
skeletal fluorosis after lifetime exposure. Severe skeletal fluorosis is a
rare condition in the United States.
This report is important for people living in areas with high
concentrations of natural fluoride greater than 2 mg/L or 2 ppm. This
represents approximately one half of one percent of the U.S. population. The
EPA estimates that approximately 220,000 Americans receive water from public
water systems with fluoride levels that are equal to or exceed 4 mg/L. The
Committee concluded that people who consume water with this high fluoride
content over a lifetime, when compared to people consuming water with 1 mg/L,
are likely to be at increased risk for bone fractures. Another 1.4 million
people in the United States drink water from community water supplies that
have a natural fluoride level ranging from 2.0 mg/L to 3.9 mg/L. The
Committee found that water at 2 mg/L or greater may put children 8 years old
and younger at increased risk for severe enamel fluorosis, a condition that
causes staining and pitting of the enamel surface of teeth. In communities
with fluoride levels greater than 2 mg/L, CDC recommends that parents and
caregivers of children 8 years and younger should provide children with
drinking water from an alternative water source. At levels less than 2 mg/L
(equivalent to 2 ppm), the committee found that the prevalence of severe
enamel fluorosis was very low (near zero).
The findings of the NRC report are consistent with CDC’s assessment that
water is safe and healthy at the levels used for water fluoridation (0.7–1.2
mg/L). CDC reviews the latest scientific literature on an ongoing basis and
maintains an active national community water fluoridation quality assurance
program. CDC promotes research on the topic of fluoride and its effect on the
public’s health. CDC’s recommendation remains the same—that community water
fluoridation is safe and effective for preventing tooth decay. Water
fluoridation should be continued in communities currently fluoridating and
extended to those without fluoridation.
CDC has previously recommended 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 and can be found at
http://www.cdc.gov/OralHealth/waterfluoridation/guidelines/index.htm.
In addition to using an alternate water source for children 8 years and
younger if the primary drinking water source has naturally occurring fluoride
above 2 mg/L, these recommendations include: seeking professional advice on
use of fluoride toothpaste for children younger than 2 years; using a
pea-sized amount of fluoride toothpaste and supervising toothbrushing for
children younger than age 6; prescribing fluoride supplements judiciously;
and using fluoride mouth rinses appropriately.
Consumers wishing to know the fluoride concentration in their water can
contact their local water utility, or local, county or state health
department. Currently, 39 states provide information on water
systems that is available to the public through the
My Water’s Fluoride
section of the CDC Web site.
Date last reviewed: September 24, 2008
Date last updated: September 24, 2008
Content source:
Division of Oral Health, National Center for Chronic Disease Prevention and
Health Promotion |