The United States has one of the safest water supplies in the
world. However, national statistics don’t tell you specifically
about the quality and safety of the water coming out of your
tap. That’s because drinking water quality varies from place to
place, depending on the condition of the source water from which
it is drawn and the treatment it receives. Now you have a new
way to find information about your drinking water, if it comes
from a public water supplier (EPA doesn't regulate private
wells, but recommends that well owners have their water tested
annually). Starting in 1999, every community water supplier must
provide an annual report (sometimes called a consumer confidence
report) to its customers. The report provides information on
your local drinking water quality, including the waters source,
the contaminants found in the water, and how consumers can get
involved in protecting drinking water. You may want more
information, or have more questions. One place you can go is to
your water supplier, who is best equipped to answer questions
about your specific water supply.
What contaminants may be found in drinking water?
There is no such thing as naturally pure water. In nature, all
water contains some impurities. As water flows in streams, sits
in lakes, and filters through layers of soil and rock in the
ground, it dissolves or absorbs the substances that it touches.
Some of these substances are harmless. In fact, some people
prefer mineral water precisely because minerals give it an
appealing taste. However, at certain levels, minerals, just like
man-made chemicals, are considered contaminants that can make
water unpalatable or even unsafe. Some contaminants come from
erosion of natural rock formations. Other contaminants are
substances discharged from factories, applied to farmlands, or
used by consumers in their homes and yards. Sources of
contaminants might be in your neighborhood or might be many
miles away. Your local water quality report tells which
contaminants are in your drinking water, the levels at which
they were found, and the actual or likely source of each
contaminant. Some ground water systems have established wellhead
protection programs to prevent substances from contaminating
their wells. Similarly, some surface water systems protect the
watershed around their reservoir to prevent contamination. Right
now, states and water suppliers are working systematically to
assess every source of drinking water and to identify potential
sources of contaminants. This process will help communities to
protect their drinking water supplies from contamination.
Where does drinking water come from?
A clean, constant supply of drinking water is essential to every
community. People in large cities frequently drink water that
comes from surface water sources, such as lakes, rivers, and
reservoirs. Sometimes these sources are close to the community.
Other times, drinking water suppliers get their water from
sources many miles away. In either case, when you think about
where your drinking water comes from, its important to consider
not just the part of the river or lake that you can see, but the
entire watershed. The watershed is the land area over which
water flows into the river, lake, or reservoir. In rural areas,
people are more likely to drink ground water that was pumped
from a well. These wells tap into aquifers, the natural
reservoirs under the earths surface, that may be only a few
miles wide, or may span the borders of many states. As with
surface water, it is important to remember that activities many
miles away from you may affect the quality of ground water. Your
annual drinking water quality report will tell you where your
water supplier gets your water.
How is drinking water treated?
When a water supplier takes untreated water from a river or
reservoir, the water often contains dirt and tiny pieces of
leaves and other organic matter, as well as trace amounts of
certain contaminants. When it gets to the treatment plant, water
suppliers often add chemicals called coagulants to the water.
These act on the water as it flows very slowly through tanks so
that the dirt and other contaminants form clumps that settle to
the bottom. Usually, this water then flows through a filter for
removal of the smallest contaminants like viruses and Giardia.
Most ground water is naturally filtered as it passes through
layers of the earth into underground reservoirs known as
aquifers. Water that suppliers pump from wells generally
contains less organic material than surface water and may not
need to go through any or all of the treatments described in the
previous paragraph. The quality of the water will depend on
local conditions. The most common drinking water treatment,
considered by many to be one of the most important scientific
advances of the 20th century, is disinfection. Most water
suppliers add chlorine or another disinfectant to kill bacteria
and other germs. Water suppliers use other treatments as needed,
according to the quality of their source water. For example,
systems whose water is contaminated with organic chemicals can
treat their water with activated carbon, which adsorbs or
attracts the chemicals dissolved in the water.
What if I have special health needs?
People who have HIV/AIDS, are undergoing chemotherapy, take
steroids, or for another reason have a weakened immune system
may be more susceptible to microbial contaminants, including
Cryptosporidium, in drinking water. If you or someone you know
fall into one of these categories, talk to your health care
provider to find out if you need to take special precautions,
such as boiling your water. Young children are particularly
susceptible to the effects of high levels of certain
contaminants, including nitrate and lead. To avoid exposure to
lead, use water from the cold tap for making baby formula,
drinking, and cooking, and let the water run for a minute or
more if the water hasn’t been turned on for six or more hours.
If your water supplier alerts you that your water does not meet
EPAs standard for nitrates and you have children less than six
months old, consult your health care provider. You may want to
find an alternate source of water that contains lower levels of
nitrates for your child.
What are the health effects of contaminants in drinking
EPA has set standards for more than 80 contaminants that may
occur in drinking water and pose a risk to human health. EPA
sets these standards to protect the health of everybody,
including vulnerable groups like children. The contaminants fall
into two groups according to the health effects that they cause.
Your local water supplier will alert you through the local
media, direct mail, or other means if there is a potential acute
or chronic health effect from compounds in the drinking water.
You may want to contact them for additional information specific
to your area. Acute effects occur within hours or days of the
time that a person consumes a contaminant. People can suffer
acute health effects from almost any contaminant if they are
exposed to extraordinarily high levels (as in the case of a
spill). In drinking water, microbes, such as bacteria and
viruses, are the contaminants with the greatest chance of
reaching levels high enough to cause acute health effects. Most
peoples bodies can fight off these microbial contaminants the
way they fight off germs, and these acute contaminants typically
don’t have permanent effects. Nonetheless, when high enough
levels occur, they can make people ill, and can be dangerous or
deadly for a person whose immune system is already weak due to
HIV/AIDS, chemotherapy, steroid use, or another reason. Chronic
effects occur after people consume a contaminant at levels over
EPAs safety standards for many years. The drinking water
contaminants that can have chronic effects are chemicals (such
as disinfection by-products, solvents, and pesticides),
radionuclide’s (such as radium), and minerals (such as arsenic).
Examples of these chronic effects include cancer, liver or
kidney problems, or reproductive difficulties.
Who is responsible for drinking water quality?
The Safe Drinking Water Act gives the Environmental Protection
Agency (EPA) the responsibility for setting national drinking
water standards that protect the health of the 250 million
people who get their water from public water systems. Other
people get their water from private wells which are not subject
to federal regulations. Since 1974, EPA has set national
standards for over 80 contaminants that may occur in drinking
water. While EPA and state governments set and enforce
standards, local governments and private water suppliers have
direct responsibility for the quality of the water that flows to
your tap. Water systems test and treat their water, maintain the
distribution systems that deliver water to consumers, and report
on their water quality to the state. States and EPA provide
technical assistance to water suppliers and can take legal
action against systems that fail to provide water that meets
state and EPA standards.
What is a violation of a drinking water standard?
Drinking water suppliers are required to monitor and test their
water many times, for many things, before sending it to
consumers. These tests determine whether and how the water needs
to be treated, as well as the effectiveness of the treatment
process. If a water system consistently sends to consumer’s
water that contains a contaminant at a level higher than EPA or
state health standards or if the system fails to monitor for a
contaminant, the system is violating regulations, and is subject
to fines and other penalties. When a water system violates a
drinking water regulation, it must notify the people who drink
its water about the violation, what it means, and how they
should respond. In cases where the water presents an immediate
health threat, such as when people need to boil water before
drinking it, the system must use television, radio, and
newspapers to get the word out as quickly as possible. Other
notices may be sent by mail, or delivered with the water bill.
Each water suppliers annual water quality report must include a
summary of all the violations that occurred during the previous
year. For more information call the Safe Drinking Water Hotline
How can I help protect drinking water?
Using the new information that is now available about drinking
water, citizens can both be aware of the challenges of keeping
drinking water safe and take an active role in protecting
drinking water. There are lots of ways that individuals can get
involved. Some people will help clean up the watershed that is
the source of their community’s water. Other people might get
involved in wellhead protection activities to prevent the
contamination of the ground water source that provides water to
their community. These people will be able to make use of the
information that states and water systems are gathering as they
assess their sources of water. Other people will want to attend
public meetings to ensure that the communities need for safe
drinking water is considered in making decisions about land use.
You may wish to participate as your state and water system make
funding decisions. And all consumers can do their part to
conserve water and to dispose properly of household chemicals.