Water Quality
The United
States has one of the safest water supplies in the world.
However, national statistics dont tell you specifically about
the quality and safety of the water coming out of your tap.
Thats 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 doesnt 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 hav 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 hasnt 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 water?
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 dont 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), radionuclides (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 consumers 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 at 1-800-426-4791.
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 communitys 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 communitys 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.
