Drinking Water

and Health

What You Need

to Know!

What contaminants may be found in drinking water? . . .

Where does drinking water come from? . . . How is

drinking water treated? . . . What if I have special health

needs? . . . What are the health effects of contaminants

in drinking water? . . . Who is responsible for drinking

water quality? . . . What is a violation of a drinking water

standard? . . . How can I help protect drinking water?

United States Office of Water EPA 816-K-99-001

Environmental Protection (4606) October 1999

Agency Washington, DC 20460
Introduction

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 water’s source, the contaminants

found in the water, and how consumers can get involved in protecting

drinking water. If you have been looking for specific information about

your drinking water, this annual report will provide you with the

information you need to begin your investigation.

These annual reports will by necessity be short documents. 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. This booklet will help you find other

sources of information.

At the end of this booklet there is a postcard with a listing of free

publications available from the Environmental Protection Agency

about drinking water. To order a publication, please check off the

items you would like to receive, and mail the card. For other

assistance, please visit http://www.epa.gov/safewater/ or contact the

Safe Drinking Water Hotline at 1-800-426-4791.

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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, and a summary of the results will be in future

water quality reports.

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

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suppliers get their water from sources many miles away. In either case,

when you think about where your drinking water comes from, it’s

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 earth’s 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.

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4

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 EPA’s 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.

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6

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 people’s 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 EPA’s 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
7

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, visit

http://www.epa.gov/safewater/

or call the Safe Drinking Water Hotline at

1-800-426-4791

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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

community’s 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.
To order a printed copy of any of the following documents:

o call the Safe Drinking Water Hotline at 800-426-4791 OR

o fill in, cut out, fold, staple, and mail the card below

These are only some of our free publications. To learn about others,

order our publications catalog, visit our web site, or call our Hotline.

Name

Street address Apt.

City State Zip

#

o Office of Ground Water and Drinking Water Publications (810-B-99-001)

o Water on Tap: A Consumer’s Guide to the Nation’s Drinking Water

(815-K-97-002)

o It’s YOUR Drinking Water: Get to Know it and Protect it!: How the rightto-know provisions of the Safe Drinking Water Act can help you learn about

and protect your drinking water. (810-K-99-002)

o EPA/CDC Guidance for People with Severely Weakened Immune Systems

 (816-F-99-005)

o Lead in Your Drinking Water: Actions You Can Take to Reduce Lead in Your

Drinking Water (810-F-93-001)

o America’s Drinking Water in 1997 (816-F-99-001)

o Safe Drinking Water is in Our Hands: poster (815-F-98-008) and booklet

(815-F-98-007) that list the contaminants that EPA regulates

o Getting Involved in Protecting Your Community’s Source of Drinking Water

(816-F-97-009)

o Citizen’s Guide to Groundwater Protection (440-6-90-004)

o Citizen Monitoring: Recommendations to Public Water System Users

(570-9-90-005)

o What You Can Do to Keep Your Drinking Water Safe (570-9-90-500)

o Underground Injection Wells and Your Drinking Water (813-F-94-001)

Drinking water contaminant fact sheets:

o Inorganic Chemicals [metals & minerals] (811-F-95-002-C)

o Synthetic Organic Chemicals [pesticides] (811-F-95-003-C)

o Volatile Organic Chemicals [industrial chemicals & solvents] (811-F-95-004-C)

fold

in half
PLACE

STAMP

HERE

US Environmental Protection Agency

Water Resource Center (RC-4100)

401 M St. SW

Washington, DC 20460