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UNDER THE
SAFE DRINKING
WATER ACT
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Prepared By:
Association of State Drinking Water Administrators
1911 North Fort Myer Drive
Arlington, Virginia 22209
Under Grant # X-814294-01 From:
Environmental Protection Agency
Office of Drinking Water
401 M Street, SW
Washington, DC 20460
Copyright © 1990
by
Association of State Drinking Water Administrators
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Historical Perspective
The transmission of certain infectious diseases
through drinking water has been a recognized
public health problem since before the turn of
the century. An influx of workers to the cities during
the Industrial Revolution coupled with unsanitary
practices (i.e., disposing of animal and human
wastes in streets, etc.) led to contamination of
drinking water supplies by microbiological
organisms. The presence of these organisms in
water led to the frequent transmission of diseases,
including such serious illnesses as cholera and
typhoid fever.
Chlorine
Chlorine was introduced as a disinfectant of
water supplies in the United States in 1908. The
subsequent widespread use of this disinfectant has
resulted in dramatic decreases in the number of
reported waterborne disease outbreaks and individual
cases of illness. The number of deaths attributed to
typhoid fever and cholera dropped to virtually zero in
the U.S. by the mid-20th century.
The potential adverse health effects of chemical
agents in drinking water have also been recognized
throughout this century. U.S. Public Health Service
standards, first established in 1914, were initiated to
maintain biological integrity of drinking water and
were associated with certain diseases. In the ensuing
decades, however, the recognition of hazards from
other microbiological organisms and from natural and
man-made chemical contaminants in drinking water
grew and led to a number of revisions to the public
health standards. Earlier standards focused on the
presence of inorganic metals and minerals such as
lead and arsenic. These substances were recognized
at that time primarily for their short-term (acute)
toxic and lethal effects.
Today, public water supplies are regulated
under the Safe Drinking Water Act (SDWA) which
was passed by Congress in 1974 and amended in
1986.
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Sources of Drinking Water
Well
Drinking water originates as either groundwater
or surface water. Surface waters include rivers,
streams, lakes, and reservoirs, while
groundwater generally comes from aquifers and
springs. Aquifers are underground, water bearing
formations of sand, gravel, limestone or other porous
material. Typically, wells are drilled to tap
underground aquifers. Aquifers are generally
recharged by the percolation of rainwater and
snow through soils and may recharge surface
water sources.
Treatment of drinking water varies
depending on the source of the supply. Since
surface waters are open to the atmosphere
and can be easily contaminated through
human and animal use, they require more
complicated treatment before being provided for
human consumption. In contrast, groundwater
provides a relatively clean source of water in relation
to bacterial contamination, but may require
treatment to remove inorganic or organic chemical
contaminants.
Types of Contaminants, Sources, and Health Effects
Over the past two decades, several advances have
been made in the ability to detect and measure
contaminants present at low levels in air, soil,
and water. This, together with advances in the
understanding of chemical toxicology, has led to an
increased awareness of the health consequences of
short-term (acute) and long-term (chronic) exposure
to drinking water contaminants. Cancer-causing
substances in particular have received a high
degree of attention because of the assumption that
there is no threshold limit below which a cancer-
causing substance does not pose some risk,
however small.
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The agents responsible for the contamination of
drinking water in the United States include both
microbiological organisms and chemical substances.
A description of these agents and their potential
health effects is provided below. ,
Microbiological
Organisms
Giardia
Microbiological contamination of
drinking water was an important concern in
the early part of this century. Although a
number of diseases no longer present a serious health
hazard, concern has recently focused on two diseases,
giardiasis and cryptosporidiosis, which are caused by
small parasitic organisms. Due to the small size of
these organisms and their resistence to disinfection,
they are able to survive conventional water treatment
practices. Due to these concerns, the EPA is
requiring water utilities to install more stringent
treatment methods which will remove these
disease causing agents.
Microbiological organisms that can cause
and spread disease through water include
bacteria, viruses, and parasites. These microor-
ganisms are principally "enteric" (i.e. associated
with the intestine) and are transmitted by human
and animal fecal material which contaminate the
source water or, in some cases, enter the distribution
system through faulty piping. At present, the most
common illnesses due to microbiological
contamination of drinking water are acute (short-
term) disorders resulting in cramps and diarrhea that
range from mild to very severe. Other diseases
associated with these microorganisms include
dysentery, hepatitis, typhoid fever, and cholera
although drinking water is rarely a carrier for these
diseases today. Giardiasis and cryptosporidiosis
have, however, been recently associated with several
waterborne disease outbreaks.
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Chemical
Substances
«
v
TCE
4 jfaas
Radon
IBMs
The chemicals that have been found in
drinking water cover a wide spectrum of both
naturally occurring and man-made substances.
Naturally occurring contaminants are primarily
metals and minerals which are present in water of
certain geologic formations. Some of the naturally
occurring contaminants, such as radon gas, are
radioactive elements. Man-made chemicals that have
been found in drinking water include both organic
(containing carbon) and inorganic substances used as
industrial, commercial, and agricultural products.
Contamination of groundwater by certain solvents
and degreasing agents was well-documented in the
1970s and 1980s. More recently, research has
revealed the presence of a number of pesticides and
herbicides in certain water supplies as well.
Some chemical contaminants in drinking water
have been found to be a product of the water
treatment and delivery process itself. In the early
1970s it was discovered that chlorine, used to disinfect
water, combines with materials produced from
decaying vegetation to form the potentially cancer-
causing compounds known as trihalomethanes.
Recently, increased attention has been given to the
significance of the leaching of lead from pipes and
solder in home plumbing and in water distribution
systems.
Inorganic chemicals are metals, salts, and other
chemical compounds that do not contain carbon.
Many inorganic chemicals such as arsenic, fluoride,
and nitrate are naturally present in water in certain
geographic areas. Other chemicals such as lead may
enter the water as a result of leaching from lead pipe
and lead-based solder pipe joints found in the water
distribution system or more commonly, home
plumbing. Still other inorganic chemicals
contaminate drinking water supplies through
industrial waste and pesticide and fertilizer use.
Among the principal health effects associated with
these chemicals are liver, kidney, and nervous system
disorders and the condition known as
methemoglobinemia ("Blue-baby syndrome") which is
specifically associated with high nitrate levels.
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Organic chemicals include natural or synthetic
compounds and disinfection by-products that contain
carbon. These chemicals fall into four main
categories: synthetic organic chemicals (SOCs),
volatile organic chemicals (VOCs), polychlorinated
biphenyls (PCBs), and disinfection
by-products. SOCs are mainly used
in the manufacture of pesticides and
a wide variety of agricultural and
industrial products while VOCs are
•• ¦ used as degreasing agents,
varnishes, paint thinners, pesticides,
and in petroleum products. As their name implies,
VOCs generally evaporate at normal temperatures.
In general, health effects associated with SOCs
include liver, kidney, and nervous system disorders
while VOCs and SOCs may be carcinogenic.
Trihalomethanes (e.g., chloroform) are a special class
of organic chemicals which are produced as by-
products of disinfection. These contaminants may
also be carcinogenic. PCBs are generally found in
electrical transformers and capacitors and have been
found to be carcinogenic.
Radiological contaminants, also termed
radionuclides, can enter water naturally from some
soils, from the leaching of radioactive wastes, or from
the mining of phosphorus or uranium. Radionuclides
\ in drinking water may include such elements as
RADIOACnv^ radon, radium, and uranium. Drinking water may
A also become contaminated with radionuclides from
man-made sources. These latter sources are typically
associated with the improper disposal of nuclear
waste. Radionuclides, which continuously
breakdown, releasing energy, have the power to
damage living cells or tissue. The major health
effects associated with inhalation and ingestion of
radionuclides is cancer.
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How Drinking Water Supplies are Regulated
Congress enacted the Safe Drinking Water Act
(SDWA) in 1974 with the goal to provide safe
drinking water to all persons served by public
water supplies (water systems serving 25 or more
persons on a regular basis or a system with 15 or
more service connections). This Act gave the U.S.
Environmental Protection Agency (EPA) authority to
develop a uniform national drinking water protection
program and establish national standards (acceptable
or "safe" levels) for known or suspected drinking
water contaminants. Between 1974 and 1986, EPA
developed approximately 20 standards. Partly in
response to the growing awareness of further
potential threats to drinking water, Congress
amended the SDWA in 1986 and called for EPA to
establish standards for 83 contaminants by 1989. In
addition, 25 more contaminants must be regulated at
three year intervals, beginning in 1991. It is the
responsibility of the states to ensure that public
water supplies test for these contaminants on a
regular basis and that the levels meet the required
standards.
Public
Water System
Public water supplies fall under three major
categories: community water supplies which serve
the same population on a year round basis (e.g.,
cities, villages, mobile home parks), non-transient
non-community systems which supply water to the
same individuals at least six months of the year (e.g.,
day care centers, schools, factories), and non-
community systems which serve transient
populations (e.g., campgrounds, highway rest
areas). Private water supplies are regulated
under separate state or local public health
programs.
Community
Water System
Community
Water System
Non-Transient
Non-Community
Water System
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To establish standards, the EPA determines both
a maximum contaminant level goal (MCLG) based on
health data and an enforceable maximum
contaminant level (MCL). In some cases, the EPA
: establishes a treatment technique for a particular
contaminant if an MCL is not feasible. Public water
supplies are required to test for these drinking water
contaminants on a regular basis based on the public
water supply classification (e.g., community) and the
source of drinking water (Le., surface water or
groundwater) and must meet MCL or treatment
technique requirements.
Public water supplies are required by law to
notify the public whenever they fail to test for a
required contaminant or when a drinking water
standard has been exceeded. This notification may be
made by: newspaper, radio or TV, hand-delivery to all
residents, mailing in monthly or quarterly utility bills,
or by posting in specified locations. The method
of public notification is dependent on the type
and severity of the violation and type of public
water supply.
The federal government and the states are also
authorized to initiate enforcement action against
public water supplies which violate requirements of
the SDWA. The primary goal of enforcement is to
bring systems into compliance with the SDWA and to
ensure future compliance.
Although, in general, consumers can now drink
water from a public water supply tap with little fear
of acute chemical poisoning or the serious infectious
diseases common a century ago, there are still
important health challenges that must be met with
respect to our nation's drinking water.
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Facts the Consumer Should Know
None of the contaminants found in drinking water
supplies are pervasive. Whether they are in your
water depends on geographic location, the source of
water, the treatment it receives, the effectiveness
of the treatment, and, in the case of lead, may
depend on the type of plumbing materials in your
home, the components of your water utility
distribution system, and the nature of the water being
delivered.
Health risks are dependent on a number of factors
including the nature of the contaminant, the level of
the contaminant in drinking water, the
susceptibility of the person consuming the water,
and the period (i.e., days, months, years) over
which a person drinks water from the same supply.
In general, EPA regulates drinking water
contaminants which may cause cancer based on a
risk of 1 in 10,000 to 1 in 1,000,000. A risk of 1 in
1,000,000 for a lifetime indicates that one person in
every 1,000,000 people exposed to the causative
contaminant can be expected to contract a specified
disease.
All consumers of water provided by public water
supplies should be aware of the source, quality,
monitoring requirements, and violations associated
with their water supply. Consumers should contact
their state public health or environmental office, or
their local water utility for this information.
In general, persons served by public water supplies
do not require point-of-use (single tap) or point-of-
entry (whole house) treatment devices such as
carbon or reverse osmosis units in their homes
since the water has already been treated at the
water plant. Generally speaking, no single home
treatment unit is effective against all possible
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contaminants. Moreover, the treatment unit itself
must be properly maintained to remain effective. If
consumers are interested in home treatment units
they should first find out about the quality of their
water to determine if such units are necessary, then
research the units thoroughly. Information regarding
water treatment units is provided by the National
Sanitation Foundation (Ann Arbor, MI) and the Water
Quality Association (Lisle, IL).
Consumers should also be aware that bottled water is
not necessarily better than water provided by public
water supplies. Some bottled waters are disinfected
spring water, while others may simply be water
collected from a public water supply and treated
with ozone to remove chlorine taste and odor. While
bottled water may be necessary in some
circumstances, it is important for the consumer to
research the source and quality of the bottled water to
determine if it is better than the water already being
provided by the public water supply.
A number of useful pamphlets and documents have
been prepared by the EPA and several consumer
action groups. Please see the end of this pamphlet
for pertinent telephone numbers.
Summary
Even though the vast majority of drinking water
systems provide a safe supply of drinking water,
EPA and states have taken great strides in
passing laws and regulations designed to protect
consumers from potential drinking water
contaminants. Today, laws exist to regulate organic,
inorganic, and radionuclide contaminants as well as
microbiological and parasitic organisms. Surface
water systems are required to filter and disinfect
their water and soon groundwater systems will be
required to disinfect. All these laws are designed to
protect the consumer.
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Public health officials should not, however, be
complacent in their regulation of drinking water. It
must be recognized by all parties, that water is a
precious commodity and that its protection requires
diligence, commitment, and a willingness by
consumers to pay the full costs of a safe, potable
water supply.
For More Information
American Water Works Association
(Water utility information) (303) 794-7711
Association of State Drinking Water
Administrators (State drinking
water information, consumer education
guides) (703) 524-2428
EPA Safe Drinking Water Hotline
(Publications on lead, pesticides,
radon, etc.) (800) 426-4791
International Bottled Water
Association
(Bottled water information) (703) 683-5213
Local Water Utilities
(Water quality information) Local Directory
National Rural Water
Association
(Small water utility information) (405) 252-0629
National Sanitation Foundation
(Water Treatment units, bottled water
information) (313) 769-8010
State Drinking Water Programs
(Water quality information) Local Directory
State or Local Health Departments
(Water quality information) Local Directory
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Water Quality Association
(Water treatment units)
10
(708) 505-0160
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