Fact Sheet on Fluoride in
Private Drinking Water Wells
What is fluoride?
Fluoride is a common element found in minerals, rock and
soil. It naturally occurs in the earth’s soil.
How does fluoride get into drinking water?
As groundwater passes through minerals, rocks and soil it
picks up fluoride and becomes dissolved in the groundwater.
What is the best level of fluoride in drinking water?
To protect teeth from decay, the best level of fluoride in
drinking water is between 0.7 mg/L to 1.2 mg/L (“mg/L” is
a measurement used to determine how many milligrams are
in each liter of water). This range is based on the temperature
of an area. In areas where it is hot, people tend to drink
more water and, therefore, less fluoride is added to the
water. In areas where it is cooler, people tend to drink
less water and therefore more fluoride is added to the
There are different recommended levels for fluoride all
over the United States. In our Northwest region, the US Public
Health Service recommends a fluoride level of 1.1 mg/L.
Stop the use of fluoride supplements (usually in the form
of drops or tablets) if you have fluoride in your drinking
water. Then talk to your dentist about the proper levels
of fluoride for your family.
In what ways does fluoride protect teeth?
Your body uses fluoride to help strengthen the surfaces of
the teeth and the whole tooth.
Fluoride acts on teeth in two ways. When you use fluoridated
toothpaste or mouthwash, fluoride is washed over your teeth
protecting the teeth from decay. When you ingest fluoride
through water, your body incorporates the fluoride into developing
teeth making them stronger and protecting them from decay.
The right amount of fluoride is needed to protect teeth.
Too much fluoride can be harmful to teeth and bones and too
little fluoride will not protect teeth.
How do you find out if you have fluoride in your drinking
If you have your own well, you can have your drinking water
tested at a state certified laboratory. See the attached
list for laboratories in Whatcom County that can test your
drinking water for fluoride.
What is a dangerous level of fluoride?
A fluoride level above 4.0 mg/L is not safe to drink. With
long-term use, fluoride levels above 4.0 mg/L can cause
skeletal fluorosis which is a serious bone disorder.
A fluoride level above 2.0 mg/L can cause dental fluorosis
in children. Dental fluorosis causes the staining and pitting
of teeth. This is a cosmetic problem and not a health risk.
What if there is too much fluoride in your drinking water?
There are treatment systems available that remove fluoride
from your drinking water. The most common types of treatment
systems that remove fluoride are reverse osmosis and distillation.
To contact people who sell treatment systems look in the
telephone book under “water treatment” or “water
purify”. You need to test your water after installing
the treatment system to make sure it is working properly.
What if there isn’t enough fluoride in your
A fluoride level below 0.7 mg/L does not protect teeth against
decay. Your child’s physician or dentist can prescribe
fluoride drops or tablets to help prevent tooth decay. The
amount of fluoride prescribed depends on the fluoride level
in the water.
Quick Reference for Fluoride Levels in Drinking Water
If your fluoride level is:
Less than 0.7 mg/L
- This level of fluoride is low and does not protect teeth
- Action: Talk to your dentist about fluoride
supplements for children.
Between 0.7 mg/L
to 1.2 mg/L
- This level of fluoride protects teeth from decay.
- The best level of fluoride for
our Northwest region is
- Action: No fluoride supplements
should be taken if you have fluoride in your water.
Stop the use of fluoride supplements
until you talk to your dentist about the proper levels
of fluoride supplements for your family.
Between 1.2 and 4.0 mg/L
This level of fluoride may cause dental fluorosis (brown
staining and pitting of teeth) in children with long term
- The Environmental Protection Agency (EPA) considers
this condition to be a cosmetic problem and not a health
- Action: Stop the use of fluoride supplements. You need
to test your well to see what the level of fluoride is
drinking water. See information on this sheet under “How
do you find out if you have fluoride in your drinking water”.
Greater than 4.0 mg/L
- This level of fluoride is a dangerous level for children
and adults to drink.
- Children and adults are at risk for skeletal fluorosis (a
serious bone disorder) with long-term use.
- Action: You will
need to find another drinking water source or install a
treatment system to remove fluoride from your
drinking water. See information on this sheet under “What
if there is too much fluoride in your drinking water?”
If you have additional questions please call our office
at 360-676-6724 or contact your dentist.
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