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Table of Contents
Home water treatment facts pg.2
Advice for people with severely compromised
immune systems (Sidebar) pg.2
Local water quality pg.3
Cost and maintenance pg.4
At-home solutions to water
quality problems (Sidebar) pg.4
Performance pg.4
Point of use devices pg.5
Point of entry devices pg.6
How filters work (Sidebar) pg.6
Certification pg.7
Contact information ...
EPA registration of
water filters (Sidebar)
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Advice for people with
severely compromised
immune systems
Some people may wish to take
special precautions with the water
they drink In particular; people
with immune systems that are
weakened by AIDS, chemothera-
py or transplant medications are
more vulnerable to microbial con-
taminants in drinking water such
as Cryptosporidium.
Cryptosporidium is a microscopic
parasite that lives in the intestine of
infected animals and humans. It
passes in the stool in its dormant
oocyst form.The oocyst is protect-
ed by an outer shell that allows it
to survive outside the body for
long periods of time and makes it
very resistant to chlorine-based
disinfectants. It occurs mainly in
surface water sources, such as
lakes, streams and rivers. In healthy
adults, Cryptosporidium can cause ill-
ness, but for people with weakened
immune systems, it can cause
severe illness and even death.
Those who wish to take extra
measures to avoid waterbome
cryptosporidiosis can bring their
drinking water to a boil for a full
minute. Boiling water is the
most effective way of faffing
Cryptasporidium.As an alterna-
tive to boiling water, people may
take the following measures:
Use a pointrof-use filter
Consider using point-of-use (per-
Home Water Treatment Facts
Americans spend billions of dollars each year on home
water treatment units.According to the Water Quality
Association, more than four out of 10 Americans use a
home water treatment unit These units range from
simple pitchers costing less than $20 to sophisticated
reverse osmosis units costing hundreds of dollars.
Some people use a home water treatment unit to
improve the taste of their tap water. Others treat their
water because of health concerns. While EPA does not
endorse specific units, the Agency does set and
enforce national standards for the tap water provided
by public water systems.
Drinking water can reasonably be expected to contain
at least small amounts of some contaminants. As long
as those contaminants are at levels no higher than
EPA standards, the water is considered safe to drink
for healthy people. People with severely weakened
immune systems or other specific health conditions, or
those concerned about specific contaminants present
in local drinking water, may wish to further treat their
water at home or purchase high quality bottfed water.
Before purchasing a home water treatment unit, con-
sider local water quality, cost and maintenance of the
unit, product performance, and certifications to make
sure that the unit will meet your needs.
Local water quality
Begin by learning as much as possible about your tap
water. If you haven't already received it, contact your
local water supplier and ask for the annual water
quality report (sometimes called a consumer confi-
dence report). This report lists the levels of contami-
nants that have been detected in the water and
sonal use, end-of-tap, under sink)
filters that remove particles one
micrometer or less in diameter
Filters that use reverse osmosis,
those labeled as "absolute one
micron filters," or those labeled as
certified by an American National
Standards Institute (ANSI) -
accredited organization to
ANSI/NSF Standard 53 for "Cyst
Removal" provide the greatest
assurance of removing
Cryptosporidium. As with all filters,
follow the manufacturers instruc-
tions for filter use and replace-
ment
Use bottled water
Check the label or call the bottler
to find out how bottled water is
treated. The following bottled
water treatments protect against
Cryptosporidium: reverse osmosis,
distillation, ultraviolet light, or filtra-
tion with an absolute one micron
filter. Bottled waters derived from
protected well and spring water
sources are less likely to be con-
taminated by Cryptosporidium than
those containing untreated munic-
ipal drinking water from less pro-
tected sources such as rivers and
lakes.
Those who choose to take these
precautions should remember
that they can be exposed to
waterbome pathogens through
water used for brushing teeth,
making ice cubes, and washing
fruits and vegetables - not just
through water they drink
shows how these levels compare with EPA's drinking
water standards.
Some contaminant levels remain constant throughout
the year, while others vary according to season,
weather, or from house to house. For example, lead
typically occurs when it leaches from the lead pipes
and solder that are in some homes. If you are con-
cerned about a contaminant whose level may vary,
consider getting your water tested (use a certified labo-
ratory for the most reliable results). Use this informa-
tion to help decide on a home water treatment unit
If your water comes from a household well, EPA
recommends annual water testing for nitrates and co\-
iform bacteria. In addition, check with your heo/th depart-
ment or local water systems that use ground water for
information on contaminants of concern in your area.
Armed wifh this specific information, you can deter-
mine your purpose in buying a home water treatment
unit to remove specific contaminants; to take extra
precautions because a household member has a
compromised immune system; to improve the taste of
the water, or some combination of these concerns.
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At-home solutions to
water quality problems
Improve taste
If you object to the chlorine
taste of your tap water, try
placing the water in an
uncovered pitcher in the
refrigerator overnight. This
will reduce the chlorine taste.
Most tap water is treated
with chlorine to kill disease-
causing microbes. Water sys-
tems use chlorine because it
is an effective disinfectant for
viruses and bacteria, and
because it continues to disin-
fect water as it travels
through pipes.
Reduce lead
If you have tested your water
and know that it has high lev-
els of lead, or if your home
has lead pipes, flush the cold
water tap by running it until it
becomes cold if the water
hasn't been used for several
hours. Lead accumulates after
extended contact with lead
pipes. You may use this
flushed water to water plants
and do other household
chores.
Cost and Maintenance
Prices vary depending on type (pitcher, faucet filter,
etc.), where and how the unit is installed, and what
contaminants it removes. Prices can range from $20
for a simple pitcher to hundreds of dollars for a
reverse osmosis unit
All units require some maintenance, and it is impor-
tant to follow #7e manufacturer's recommendations
for replacements. For example, activated carbon filters
are designed to filter a certain amount of water; after
that, the filers become clogged and ineffective. Check
the schedule and cost for replacement filers.
Performance
The following information briefly describes how differ-
ent types of home water treatment units work For
details, read information that accompanies
the product and look for independent
certification of manufacturers' claims.
Different units remove different contaminants or classes
of contaminants from the water. Sophisticated units
may use multiple technologies to remove several types
of contaminants and to provide backup protection in
case one treatment fails.
A water treatment device can either be free-standing
attached to a tap, plumbed in with a dedicated faucet
(also called a point-of-use device) connected to a
refrigerator's water and ice dispensing system; or cen-
trally attached to treat all water entering a house (a
point-of-entry device).
For most contaminants, a point-of-use device is effec-
tive for treating only Jfte water that is consumed.
However, some contaminants, such as radon, disinfection
byproducts, and some organic chemicals, easily turn
At-home solutions to
water quality problems
Kill microbes
If you have a contaminated
private well, have special
health needs (see left side of
page 2), or in an emergency
situation such as a flood, boil
water for one minute to kill
microbes (or three minutes
at altitudes greater than one
mile) and place in a clean,
covered container.
into gases and may pose a risk when inhaled, such
as when showering. A point-of-entry device can
reduce concentrations of these contaminants and
others that cause aesthetic problems such as scal-
ing, staining, or odor.
Point-of-Use Devices:
Filter pitchers: Water filtration pitchers are an
affordable and commonly used free-standing home
water treatment device. Most water pitchers use gran-
ular-activated carbon and resins to bond with and
trap contaminants.These filters are effective at
improving the taste of water, and many will also
reduce lead and other contaminants.
Specific contaminants removed vary by model and
depend on Jfte pore size and other factors. An acti-
vated carbon filter, by itself, is not designed to remove
all disease-causing organisms. Carbon filers have a
specified shelf life and should be replaced regularly
according to the manufacturer's instructions.
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How filters work
A water filter is composed of
a screen with many micro-
scopic holes. The smaller the
holes, the more contaminants
the filter can remove. Filter
holes are measured in
microns. (The period at the
end of this sentence is 500
microns.) When considering
filter size, look for an
absolute (the largest hole),
not a nominal (the average
hole), rating. EPA and CDC
recommend an absolute one
micron filter (or one labeled
for cyst removal) to remove
Cryptosporidium.
Some contaminants and their
size in microns:
Giardia lamblia - 8 to 12
microns
Cryptosporidium parvum -
4 to 6 microns
Bacteria (such as E. coli and
salmonella) - 0.2 to 4 microns
Viruses - 0.004 to O.I
microns (Generally, only a
few filters, such as ultrafilters
and reverse osmosis, have
holes small enough to assure
removal of all viruses.
However, viruses can be
killed using a disinfectant).
Filters that attach to a faucet or are installed
under the sink for a drinking water third faucet
These fifeers generally use the same technologies as their
pour-through pitcher counterparts. Some filters use fabrics,
fiber, or ceramic screening to physically remove contami-
nants. The most common types use a molded block of
activated carbonJhese filers are effective at improving the
taste of tap water, and some wil also reduce lead, proto-
zoan cysts, and many other contaminants. Like filter pitchers,
shelf lives and specific contaminants removed vary so read
the label and instructions carefully.
Distillers: Distillers heat water to the boiling point,
and then collect the water vapor as it condenses, killing
disease-causing microbes and leaving most chemical
contaminants behind. Contaminants that easily turn
into gases, such as gasoline components or radon, may
remain in the water unless the system is specifically
designed to remove them. Distilled water may taste flat
to some people because the water's natural minerals
and dissolved oxygen often have been removed.
Reverse Osmosis Units: Reverse osmosis unte force
water through a semtpermeable membrane under pres-
sure, leaving contaminants behind. Reverse osmosis
units use approximately three tones as much water as
they treat, but they are effective in eliminating all disease-
causing organisms and most chemical contaminants.
Pofnt-of-Entry Devices:
Adsorptive media: Liquids, so/ids, dissolved or
suspended matter adhere to the surface of, or in the pores
of, a solid material. Carbon filers use this technology.
Aerators: Aerators force water to travel over air jets.
Contaminants that eas^ turn into gases, such as gasoline
components and radon, are removed. Other contamnants
are notThe water may be additionally filtered after it passes
through this system to remove additional contaminants.
Removing specific con-
taminants
Giardia and Cryptosporidium
- distillation, reverse osmosis,
absolute one micron filters,
ultraviolet light, and filters
certified for cyst removal.
Bacteria and viruses - distil-
lation, reverse osmosis, ultra-
violet light, and disinfection.
Arsenic - adsorptive media
Disinfection byproducts -
point-of-entry adsorptive media
systems distillation, aeration,
carbon filtration and reverse
osmosis.
Lead - distillation, reverse
osmosis and some carbon
filters.
Nitrates - distillation, reverse
osmosis or ion exchange.
Pesticides - some carbon
filters.
Radium - ion exchange, dis-
tillation or reverse osmosis.
Radon - activated carbon
filter and aeration.
Water Softeners: Water softeners use a cation
exchange resin, regenerated wtth sodium chloride or
potassium chloride, to reduce the amount of hardness
(calcium, magnesium) in the water.Trie hardness ions in
the water are replaced wifft sodium or potassium ions.
Ion exchange water softeners simultaneously remove
radium and barium while removing water hardness.
Certification
Make sure that the unit you intend to purchase can
address your concerns.There are three different certifi-
cations to look for on the labeLThese organizations
can also assist you in selecting a device that meets your
needs. If a home water treatment unit isn't certified by
one of these organizations, contact the manufacturer
directly and ask for proof of the manufacturer's claims.
Three organizations are accredited by the American
National standards Institute (ANSI), and they each certify
units using ANSI/NSF standards. EachANSI/NSF stan-
dard requires verification of contaminant reduction per-
formance claims, an evaluation of the unit, including its
materials and structural integrity, and a review of the
product labels and sales literature. Each certifies that home
water treatment units perform to meet or exceed
ANSI/NSF and EPA dmkhg water standa/ds. ANSI/NSF
standards are issued in two different sets, one for health
concerns (such as removal of specie contamhants) and
one for aesthetic concerns (such as improving taste or
appearance of water). Certification from these organizations
wif be tied to one or both of these specific standards.
NSF International: The NSFWater treatment Device
Certification Program requires extensive product testing
and unannounced audits of production faclitiesThe goal
of this program is to provide assurance to consumers that
the water treatment devices they are purcriashg meet the
design, materiai and performance requirements of national
standards.
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EPA registration of water
filters
Some units have an EPA regis-
tration number and an EPA
establishment number. EPA
registration (unlike that of
NSF, WQA, or UL) is not
intended to guide consumers
in selecting a water treat-
ment device, and is not an
endorsement of the product.
EPA registers any product
that contains an antimicrobial
(germ-killing) or bacteriostatic
(slowing or inhibiting growth
of germs) agent. EPA registers
these products because con-
sumers cannot independently
verify whether the germ-
related claims they make are
true.
For most units, an EPA regis-
tration number means that
the filter uses a bacteriostatic
agent to slow the growth of
microbes within the filter, the
unit does not pose a human
health threat, and EPA has
verified all bacteriostatic
claims on the label.
Registration is not an
endorsement of the filter or
its performance. The most
commonly used bacteriostatic
agent is silver.
Underwriters Laboratories: Underwriters
Laboratories, Inc., is an independent, accredited testing
and certification organization that certifies home
water treatment units which meet or exceed EPA and
ANSI/NSF drinking water standards of contaminant
reduction, aesthetic concerns, structural integrity, and
materials safety.
Water Quality Association: The Water Quality
Association is a trade organization that tests water
treatment equipment, and awards its Gold Seal to
systems that meet or exceed ANSI/NSF standards for
contaminant reduction performance, structural integrity,
and materials safety.
For more information about water
treatment units:
NSF International
P.O. Box 130140
Ann Arbor, Ml 48113-0140
877-8-NSF-HELP; (877) 867-3435
www.nsf.org
info@nsf.org
Underwriter's Laboratories, Inc.
333 Pfmgsten Road
Northbrook, IN 60062-2096
(877) 854-3577
www.ULcom/water
mail to: water@us.u/.com
Water Quality Association
4151 Naperville Road
Lisle, IL 60632-3696
(630)505-0160
www.wqa.org
Jnfo@maf7.wqa.org
EPA also registers a type of
water treatment device
known as a purifier.A purifier
must remove, kill, or inacti-
vate all types of disease-caus-
ing organisms from the water,
including viruses. Few water
treatment devices can meet
these criteria. These units
typically work using a disin-
fectant within the filter to kill
or inactivate microbes. Most
purifiers are used by hikers
or campers and are not gen-
erally needed in homes
served by public water sys-
tems unless there is a water
emergency.
EPA's Office of Pesticide
Programs' Antimicrobial
Division website provides
additional information on
EPA product registrations,
www.epa.govloppadOO I.
You may also contact the
Antimicrobial Hotline at 703-
308-0127 (phone); 703-308-
6467 (fax); or e-mail
info_antimicrobial@epa.gov.
For more information about tap water:
EPA's Safe DrinkingWater Hotline
I (800) 426-4791
www.epa.gov/sofewater - includes drinking water
standards, state certification officers for water testing
and information for household well owners.
<
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www.epa.gov
September 2005
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