Water: From Its Source to
Our Taps
Water is a vital element in each of our lives.
Not only is it essential to our health, but we also use it for numerous
household tasks. Every day we use water for cooking, bathing, and cleaning,
and drinking; but how often do we think about its source?
Where does our water come from? How is it
treated? How do we know it is safe to drink?
To answer these questions, it's important
to go back to the basics. There are two main sources of water: surface
water and groundwater. Surface Water is found in lakes, rivers,
and reservoirs. Groundwater lies under the surface of the land,
where it travels through and fills openings in the rocks. The rocks that
store and transmit groundwater are called aquifers. Groundwater must be
pumped from an aquifer to the earth's surface for use.
Consumers receive their water from one of
two sources: a private well, or a community water system. A household well
pumps groundwater for household use. The source of a community water system
may be either surface water or groundwater.
Private Household Wells
Approximately 15 percent of the U.S. population
relies on individually owned and operated sources of drinking water, such
as wells, cisterns, and springs. The majority of household wells are found
in rural areas.
Those who receive their water from a private
well are solely responsible for the safety of the water. Private wells
are not subject to federal regulations, and are generally regulated on
a very limited basis by states. Local health departments may assist well
owners with periodic testing for bacteria or nitrates, but the bulk of
the responsibility for caring for the well falls on the well owner.
Since the well owner is primarily responsible
for the water, it is important to know what poses a threat to the well
and the groundwater which is its source. A variety of sources can cause
well water to become contaminated.
Several contaminants occur in nature that
may present a health risk if they are found in drinking water. They include
bacteria, viruses, uranium, radium, arsenic, and fluoride. Many of these
contaminants are naturally present in rock formations, and consequently
end up in the water supply.
Other sources of contamination are a result
of human activity such as manufacturing or agriculture, or individual misuse.
The following activities may cause harmful chemicals to enter the well
water owner's water supply.
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Leakage from waste disposal, treatment, or storage
sites.
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Discharges from factories, industrial sites,
or sewage treatment facilities.
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Leaching from aerial or land application of pesticides
and fertilizers on yards or fields.
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Accidental chemical spills.
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Leakage from underground storage tanks.
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Improper disposal of household wastes such as
cleaning fluids, paint, and motor oil.
Well owners generally disinfect or otherwise
treat the water from their wells to remove the contaminants that are caused
by such activities.
Community Water Systems
Approximately 85 percent of the U.S. population
receives its water from community water systems. Community water systems
are required to meet the standards set by the U.S. Environmental Protection
Agency (EPA) under the authority of the Safe Drinking Water Act (SDWA).
The SDWA was passed by Congress in 1974 to
establish nationally consistent drinking water standards. A standard is
the maximum level of a substance that the EPA has deemed acceptable in
drinking water.
In 1986 the SDWA was amended to require the
EPA to publish standards for 83 specific contaminants, and additional standards
thereafter. To date, the EPA has issued or proposed limits for 87 substances.
Community water systems are currently revising their drinking water programs
to meet the more stringent requirements of the amendments.
Community water systems must ensure that the
drinking water they supply does not have contaminant levels higher than
the standards of the SDWA, the SDWA amendments, or state regulations.
In order to set a standard for a drinking
water contaminant, the EPA first reviews the data concerning the health
effects the substance may cause. The EPA then proposes nonmandatory Maximum
Contaminant Level Goals (MCLG's). MCLG's are set at zero for contaminants
that are known or probable human carcinogens. For noncarcinogens, MCLG's
are set at a level where no adverse health effects would occur with a margin
of safety.
At the same time, the EPA also proposes a
Maximum Contaminant Level (MCL), the enforceable drinking water
standard, which is set as close to the MCLG as possible, taking into account
technological and economic considerations.
After a time for public comment and review
of the MCL and MCLG, the EPA enacts a final regulation. States are expected
to adopt the standard within 18 months of enactment.
The SDWA requires utilities to conduct routine
monitoring and testing of public water supplies. Two types of sampling
are required. Routine Sampling takes place on a regular basis and
ensures that a treatment plant is running properly for delivering a consistent
quality of drinking water. It also determines whether water quality meets
the MCL's.
When a routine sample analysis indicates elevated
levels of a particular contaminant that may exceed EPA or state standards,
states may require systems to take a check sample. Check samples
are used to confirm the results of a problem discovered during routine
sampling.
The EPA generally delegates to the states
the authority to enforce all federal drinking water standards, but can
intercede when necessary. Sates must set standards that are no less stringent
than the EPA's.
Point of Use Technologies
Whether consumers receive their water from a
household well or a community water system, they may wish to treat it at
its point-of-use (POU). Even water supplied by a community water system,
which meets EPA standards, can generally benefit from POU treatment. Consumers
have the option to choose the higher quality of water that POU technologies
can provide.
POU technologies treat water at single or
multiple taps or for the whole house, and improve water quality in a variety
of ways. Unusual taste, color, and odor or water may be corrected by POU
technologies, and some POU devices also reduce harmful contaminants.
One of the most popular POU technologies is
water softening. An important characteristic of water is hardness, which
is measured in grains per gallon (gpg). The more grains per gallon, the
harder the water. The U.S. Geologic Survey reports that hard water is found
in more than 85 percent of the United States. Hard water has many disadvantages.
It can clog pipes and appliances, reduce clothing longevity by 15 percent,
leave a soapy film on bathtubs and shower tiles, and increase water heating
costs by nearly 30 percent while shortening the life of the heater. A water
softener reduces the hardness of water, eliminating these problems and
resulting in substantial savings.
Besides softening, a variety of POU equipment
is available for improving drinking water and other special purposes. Each
technology is designed to solve one or several different water quality
problems. In order to choose the right equipment, it is important to confirm
the nature and extent of the problem.
The first step in correcting a water quality
problem is often to have the water tested. When the safety of the water
is in question, it should always be tested by a state-certified or other
reputable laboratory. Testing for aesthetic concerns such as taste, odor,
color, and hardness may be performed in the home by a professional water
treatment dealer.
Testing the water will help determine the
proper treatment necessary. Before purchasing a product, become an educated
consumer. Determine which contaminants the product reduces, and to what
level. Also check the product's performance capabilities, maintenance provisions,
and warranty.
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