What Constitutes Safe Drinking Water?

Safe Drinking WaterFor years, Americans have taken the availability of safe drinking water for granted. Recently, however, an increasingly health-conscious public  has responded to reports of harmful contaminants in public and private  water supplies by turning to bottled water or home water treatment  units. While some consumers purchase home water treatment units because they are dissatisfied with the aesthetic quality of their drinking water,others buy such units because of real or perceived health concerns.Industry officials estimate that there are approximately 600 manufacturers  and assemblers of HWTUS and 4,000 to 5,000 dealers and retail  vendors.

Consumers who wish to make informed decisions about which units best suit their needs must possess some knowledge about the quality of their  drinking water and about home water treatment options before purchasing a unit. Specifically, consumers need to know :

(1) what constitutes safe drinking water
(2) how to learn about the condition of their drinking water, and
(3) which units are appropriate to address their drinking water concerns.

What Constitutes Safe drinking Water is considered safe to drink if it meets the Environmental Protection Agency’s (EPA) and states’ maximum contaminant level requirements.

Drinking Water?

In response to the Safe Drinking Water Act, as amended, EPA has set maximum contaminant levels for a wide range of potentially harmful contaminants, including volatile organic chemicals, pesticides, metals, radionuclides, and microbiological contaminants. EPA has also developed  secondary drinking water standards for contaminants that do not affect  health but do affect the taste, odor, color, and other aesthetic characteristics of drinking water.

The Safe Drinking Water Act calls for EPA to  continually review and expand its regulation of drinking water contaminants. The maximum contaminant levels set by EPA under the Safe Drinking  Water Act apply only to public water systems that serve 25 or more individuals or provide water to 15 or more service connections. Approximately 85 percent of the U.S. population receives its drinking water from these public water systems, while most others are served by private wells.

Although private wells are not subject to federal drinking water regulations and are generally regulated on a very limited basis by
the states, EPA also recommends using the maximum contaminant levels for public water systems as a guide for determining whether well water is safe.

For many consumers, the decision to purchase a HWTU is based upon a desire to improve the aesthetic quality of their drinking water. However, before consumers purchase a unit out of concern about the healthfulness of their drinking water, they need to obtain objective information about the quality of their drinking water supply.

Consumers get their drinking water primarily from two sources: public water supplies and private wells. The process for learning about
drinking water quality differs depending upon which of these two sources provides water to the consumer.

Consumers who receive their drinking water from a public system may check their water quality by contacting their local water utility office or their state or local health departments. All public water systems are  required to regularly test the water they provide to ensure that it meets  drinking water standards set by EPA and the states.

The results from these tests are available to the public. For consumers using a public  drinking water supply that meets national and state drinking water  standards, home treatment would seldom be needed for health protection.

In contrast, private well owners are responsible for the quality of their  drinking water. EPA recommends that those who draw drinking water  from private wells should have their water tested periodically by a state or independent laboratory to determine if it meets health standards.  Well owners may contact their local health department for assistance  with well water problems.

Description of Commonly Used home water treatment units

Type

Description

Contaminants Treated

Notes

Water Softener A Resin saturated with sodium exchanges sodium for hardness(i.e., calcium
and magnesium ions).
Improves aesthetic quality of water by
removing hardness. iron, and
manganese. May also remove radium.
Can, for example, eliminate the
nuisance of stained clothes and build-
up on pipes. However, may make
water more corrosive, which can
increase leaching of lead from pipes
into drinking water.
Activated Carbon Filter Porous carbon absorbs and retains chemicals from the water Removes disagreeable tastes, odors,
and colors from drinking  water. Can
also remove many organic
contaminants, like chlorine.
Does not remove microorganisms from
drinking water and is not usually
considered an effective technology for
removing most inorganic
contaminants (like salts and metals}.
Certain specially prepared units can
remove lead.
Reverse Osmosis Unit Water separated from contaminants through pressure in a membrane removes most inorganic
contaminants, such as salts, metals
{including lead), asbestos, minerals,
and nitrate. Also removes some
organic contaminants.
Can also remove most bacteria, cysts,
and viruses, but not recommended for
use on microbiologically unsafe water
because some organisms might leak
through broken membranes.typically
produces only 1 gallon of drinking
water for every 4 gallons entering the
unit.
Physical Filter Filter acts like a sieve to filter particles Removes
from water.
Removes large particles like grit,
sediment, or rust from water; some
remove small particles like asbestos.
Some filters can remove some
microorganisms but are inadequate to
treat microbiologically unsafe water.
Ultraviolet
microbiological
treatment unit
Germicidal lamb inactivates
remove small particles as they pass by light.
Destroys bacteria and inactivate
viruses in drinking water.
Most commercially available units
provide insufficient intensity to meet
requirements for use on
microbiologically unsafe water.
Distillation unit Water boiled in chamber; steam  condensed; impurities left behind. Removes most salts, metals, minerals,
particles, and some organic
chemicals.
Some organic chemicals are vaporized
and condensed, which may cause an
increase in their concentration.
Although the heat used to vaporize
the water kills microorganisms, in
some cases bacteria may pass
through to the product water.

In addition to deciding which type of unit is most appropriate for their  needs, consumers must also determine whether they need to treat all of the water entering the home or only water passing though one tap. While some contaminants only pose a threat when ingested, others are as hazardous when inhaled or absorbed through the skin. Home units used to treat water at a single tap are called “point-of-use” units, while those designed to treat all water entering the home are referred to as
“point-of-entry” units.

Consumers must also be aware that most HWTUS are not designed to be used on microbiologically contaminated water, or water of unknown source or quality. Complete microbiological purification is not easily achieved by IIWTIJS. Very few units are considered water purifiers because they cannot make microbiologically contaminated water safe for human consumption.

Finally, proper maintenance of home water treatment units  is essential to ensuring that an appropriately selected unit continues to remove the contaminants it was purchased to remove. Consumers should familiarize themselves with the maintenance requirements of any treatment unit they own or buy. In addition, some dealers and manufacturers offer maintenance contracts, which provide for periodic filter replacement or other necessary upkeep to help ensure safe drinking water.

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