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 ......................................... pg.8

EPA registration of

water filters (Sidebar) .................................... pg.8 
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 bottled water.

Before purchasing a home water treatment unit,consider 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 confidence report).This report lists the levels of contaminants that have been detected in the water and

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, chemotherapy or transplant medications are

more vulnerable to microbial contaminants 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 protected 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 illness,but for people with weakened

immune systems, it can cause

severe illness and even death.

Those who wish to take extra

measures to avoid waterborne

cryptosporidiosis can bring their

drinking water to a boil for a full

minute. Boiling water is the

most effective way of killing

Cryptosporidium.As an alternative to boiling water, people may

take the following measures:

Use a point-of-use filter 

Consider using point-of-use (per2

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 manufacturer’s instructions for filter use and replacement.

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 filtration with an absolute one micron

filter.Bottled waters derived from

protected well and spring water

sources are less likely to be contaminated by Cryptosporidium than

those containing untreated municipal drinking water from less protected sources such as rivers and

lakes.

Those who choose to take these

precautions should remember

that they can be exposed to

waterborne 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 concerned about a contaminant whose level may vary,

consider getting your water tested (use a certified laboratory for the most reliable results).Use this information 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 coliform bacteria.In addition,check with your health department or local water systems that use ground water for

information on contaminants of concern in your area.

Armed with this specific information,you can determine 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 diseasecausing microbes. Water systems use chlorine because it

is an effective disinfectant for

viruses and bacteria, and

because it continues to disinfect water as it travels

through pipes.

Reduce lead

If you have tested your water

and know that it has high levels 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.

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.

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 important to follow the manufacturer’s recommendations

for replacements.For example,activated carbon filters

are designed to filter a certain amount of water;after

that,the filters become clogged and ineffective.Check

the schedule and cost for replacement filters.

Performance

The following information briefly describes how different 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 centrally attached to treat all water entering a house (a

point-of-entry device).

For most contaminants,a point-of-use device is effective for treating only the water that is consumed.

However,some contaminants,such as radon,disinfection

byproducts,and some organic chemicals,easily turn

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 scaling, 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 granular-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 the pore size and other factors. An activated carbon filter,by itself,is not designed to remove

all disease-causing organisms.Carbon filters 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 microscopic 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 0.1

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).

Removing specific contaminants 

Giardia and Cryptosporidium

- distillation, reverse osmosis,

absolute one micron filters,

ultraviolet light, and filters

certified for cyst removal.

Bacteria and viruses - distillation, reverse osmosis, ultraviolet 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, distillation or reverse osmosis.

Radon - activated carbon

filter and aeration.

Filters that attach to a faucet or are installed

under the sink for a drinking water third faucet:

These filters generally use the same technologies as their

pour-through pitcher counterparts.Some filters use fabrics,

fiber,or ceramic screening to physically remove contaminants. The most common types use a molded block of

activated carbon.These filters are effective at improving the

taste of tap water,and some will also reduce lead,protozoan 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 units force

water through a semi-permeable membrane under pressure,leaving contaminants behind.Reverse osmosis

units use approximately three times as much water as

they treat,but they are effective in eliminating all diseasecausing organisms and most chemical contaminants.

Point-of-Entry Devices:

Adsorptive media: Liquids,solids,dissolved or

suspended matter adhere to the surface of,or in the pores

of,a solid material.Carbon filters use this technology.

Aerators: Aerators force water to travel over air jets.

Contaminants that easily turn into gases,such as gasoline

components and radon,are removed.Other contaminants

are not.The water may be additionally filtered after it passes

through this system to remove additional contaminants.

Water Softeners:Water softeners use a cation

exchange resin,regenerated with sodium chloride or

potassium chloride,to reduce the amount of hardness

(calcium,magnesium) in the water.The hardness ions in

the water are replaced with 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 certifications to look for on the label.These 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.Each ANSI/NSF standard requires verification of contaminant reduction performance 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 drinking water standards. ANSI/NSF

standards are issued in two different sets,one for health

concerns (such as removal of specific contaminants) and

one for aesthetic concerns (such as improving taste or

appearance of water).Certification from these organizations

will be tied to one or both of these specific standards.

NSF International:The NSF Water treatment Device

Certification Program requires extensive product testing

and unannounced audits of production facilities.The goal

of this program is to provide assurance to consumers that

the water treatment devices they are purchasing meet the

design,material,and performance requirements of national

standards.

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EPA registration of water

filters

Some units have an EPA registration 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 treatment 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 consumers cannot independently

verify whether the germrelated claims they make are

true.

For most units, an EPA registration 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.

EPA also registers a type of

water treatment device

known as a purifier.A purifier

must remove, kill, or inactivate all types of disease-causing organisms from the water,

including viruses. Few water

treatment devices can meet

these criteria. These units

typically work using a disinfectant within the filter to kill

or inactivate microbes. Most

purifiers are used by hikers

or campers and are not generally needed in homes

served by public water systems unless there is a water

emergency.

EPA’s Office of Pesticide

Programs’ Antimicrobial

Division website provides

additional information on

EPA product registrations,

www.epa.gov/oppad001.

You may also contact the

Antimicrobial Hotline at 703-

308-0127 (phone); 703-308-

6467 (fax); or e-mail

info_antimicrobial@epa.gov.

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,MI 48113-0140

877-8-NSF-HELP; (877) 867-3435

www.nsf.org

info@nsf.org

Underwriter’s Laboratories,Inc.

333 Pfingsten Road

Northbrook,IN 60062-2096

(877) 854-3577

www.UL.com/water

mail to:water@us.ul.com

Water Quality Association

4151 Naperville Road

Lisle,IL 60632-3696

(630) 505-0160

www.wqa.org

info@mail.wqa.org

For more information about tap water:

EPA’s Safe Drinking Water Hotline

1 (800) 426-4791

www.epa.gov/safewater - includes drinking water

standards,state certification officers for water testing,

and information for household well owners.

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