Water Health Series Filtration Facts (PDF)

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 waterquality 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 ofwater filters (Sidebar) .................................... pg.8

Home Water Treatment Facts

Americans spend billions of dollars each year on homewater treatment units.According to the Water QualityAssociation,more than four out of 10 Americans use ahome water treatment unit.These units range fromsimple pitchers costing less than $20 to sophisticatedreverse osmosis units costing hundreds of dollars.

Some people use a home water treatment unit toimprove the taste of their tap water.Others treat theirwater because of health concerns.While EPA does notendorse specific units, the Agency does set andenforce national standards for the tap water providedby public water systems.

Drinking water can reasonably be expected to containat least small amounts of some contaminants.As longas those contaminants are at levels no higher thanEPA standards, the water is considered safe to drinkfor healthy people. People with severely weakenedimmune systems or other specific health conditions, orthose concerned about specific contaminants presentin local drinking water,may wish to further treat theirwater at home or purchase high quality bottled water.

Before purchasing a home water treatment unit, con-sider local water quality, cost and maintenance of theunit, product performance, and certifications to makesure that the unit will meet your needs.

Local water quality

Begin by learning as much as possible about your tapwater. If you haven’t already received it, contact yourlocal water supplier and ask for the annual waterquality report (sometimes called a consumer confi-dence report).This report lists the levels of contami-nants that have been detected in the water and

Advice for people withseverely compromisedimmune systems

Some people may wish to takespecial precautions with the waterthey drink. In particular, peoplewith immune systems that areweakened by AIDS, chemothera-py or transplant medications aremore vulnerable to microbial con-taminants in drinking water suchas Cryptosporidium.

Cryptosporidium is a microscopicparasite that lives in the intestine ofinfected animals and humans. Itpasses in the stool in its dormantoocyst form.The oocyst is protect-ed by an outer shell that allows itto survive outside the body forlong periods of time and makes itvery resistant to chlorine-baseddisinfectants. It occurs mainly insurface water sources, such aslakes,streams and rivers. In healthyadults,Cryptosporidium can cause ill-ness,but for people with weakenedimmune systems, it can causesevere illness and even death.

Those who wish to take extrameasures to avoid waterbornecryptosporidiosis can bring theirdrinking water to a boil for a fullminute. Boiling water is themost effective way of killingCryptosporidium.As an alterna-tive to boiling water, people maytake the following measures:

Use a point-of-use filter

Consider using point-of-use (per-

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sonal use, end-of-tap, under sink)filters that remove particles onemicrometer or less in diameter.Filters that use reverse osmosis,those labeled as “absolute onemicron filters,” or those labeled ascertified by an American NationalStandards Institute (ANSI) -accredited organization toANSI/NSF Standard 53 for “CystRemoval” provide the greatestassurance of removingCryptosporidium.As with all filters,follow the manufacturer’s instruc-tions for filter use and replace-ment.

Use bottled water

Check the label or call the bottlerto find out how bottled water istreated. The following bottledwater treatments protect against Cryptosporidium: reverse osmosis,distillation,ultraviolet light,or filtra-tion with an absolute one micronfilter.Bottled waters derived fromprotected well and spring watersources are less likely to be con-taminated by Cryptosporidium thanthose containing untreated munic-ipal drinking water from less pro-tected sources such as rivers andlakes.

Those who choose to take theseprecautions should rememberthat they can be exposed towaterborne pathogens throughwater used for brushing teeth,making ice cubes, and washingfruits and vegetables – not justthrough water they drink.

shows how these levels compare with EPA’s drinkingwater standards.

Some contaminant levels remain constant throughoutthe year, while others vary according to season,weather, or from house to house. For example, leadtypically occurs when it leaches from the lead pipesand 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,EPArecommends annual water testing for nitrates and col-iform bacteria. In addition,check with your health depart-ment or local water systems that use ground water forinformation on contaminants of concern in your area.

Armed with this specific information, you can deter-mine your purpose in buying a home water treatmentunit: to remove specific contaminants; to take extraprecautions because a household member has acompromised immune system; to improve the taste ofthe water, or some combination of these concerns.

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At-home solutions towater quality problems

Improve taste

If you object to the chlorinetaste of your tap water, tryplacing the water in anuncovered pitcher in therefrigerator overnight. Thiswill reduce the chlorine taste.Most tap water is treatedwith chlorine to kill disease-causing microbes. Water sys-tems use chlorine because itis an effective disinfectant forviruses and bacteria, andbecause it continues to disin-fect water as it travelsthrough pipes.

Reduce lead

If you have tested your waterand know that it has high lev-els of lead, or if your homehas lead pipes, flush the coldwater tap by running it until itbecomes cold if the waterhasn’t been used for severalhours. Lead accumulates afterextended contact with leadpipes. You may use thisflushed water to water plantsand do other householdchores.

At-home solutions towater quality problems

Kill microbes

If you have a contaminatedprivate well, have specialhealth needs (see left side ofpage 2), or in an emergencysituation such as a flood, boilwater for one minute to killmicrobes (or three minutesat altitudes greater than onemile) 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 whatcontaminants it removes. Prices can range from $20for a simple pitcher to hundreds of dollars for areverse osmosis unit.

All units require some maintenance, and it is impor-tant to follow the manufacturer’s recommendationsfor replacements. For example, activated carbon filtersare designed to filter a certain amount of water; afterthat, the filters become clogged and ineffective. Checkthe schedule and cost for replacement filters.

Performance

The following information briefly describes how differ-ent types of home water treatment units work. Fordetails, read information that accompaniesthe product and look for independentcertification of manufacturers’claims.

Different units remove different contaminants or classesof contaminants from the water. Sophisticated unitsmay use multiple technologies to remove several typesof contaminants and to provide backup protection incase 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 arefrigerator’s water and ice dispensing system; or cen-trally attached to treat all water entering a house (apoint-of-entry device).

For most contaminants, a point-of-use device is effec-tive for treating only the water that is consumed.However, some contaminants, such as radon,disinfectionbyproducts, and some organic chemicals, easily turn

into gases and may pose a risk when inhaled, suchas when showering. A point-of-entry device canreduce concentrations of these contaminants andothers that cause aesthetic problems such as scal-ing, staining, or odor.

Point-of-Use Devices:

Filter pitchers:Water filtration pitchers are anaffordable and commonly used free-standing homewater treatment device.Most water pitchers use gran-ular-activated carbon and resins to bond with andtrap contaminants.These filters are effective atimproving the taste of water, and many will alsoreduce lead and other contaminants.

Specific contaminants removed vary by model anddepend on the pore size and other factors. An acti-vated carbon filter, by itself, is not designed to removeall disease-causing organisms. Carbon filters have aspecified shelf life and should be replaced regularlyaccording to the manufacturer’s instructions.

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How filters work

A water filter is composed ofa screen with many micro-scopic holes. The smaller theholes, the more contaminantsthe filter can remove. Filterholes are measured inmicrons. (The period at theend of this sentence is 500microns.) When consideringfilter size, look for anabsolute (the largest hole),not a nominal (the averagehole), rating. EPA and CDCrecommend an absolute onemicron filter (or one labeledfor cyst removal) to removeCryptosporidium.

Some contaminants and theirsize in microns:

Giardia lamblia - 8 to 12microns

Cryptosporidium parvum -4 to 6 microns

Bacteria (such as E. coli andsalmonella) - 0.2 to 4 microns

Viruses - 0.004 to 0.1microns (Generally, only afew filters, such as ultrafiltersand reverse osmosis, haveholes small enough to assureremoval of all viruses.However, viruses can bekilled using a disinfectant).

Removing specific con-taminants

Giardia and Cryptosporidium- distillation, reverse osmosis,absolute one micron filters,ultraviolet light, and filterscertified for cyst removal.

Bacteria and viruses - distil-lation, reverse osmosis, ultra-violet light, and disinfection.

Arsenic - adsorptive media

Disinfection byproducts -point-of-entry adsorptive mediasystems distillation, aeration,carbon filtration and reverseosmosis.

Lead - distillation, reverseosmosis and some carbonfilters.

Nitrates - distillation, reverseosmosis or ion exchange.

Pesticides - some carbonfilters.

Radium - ion exchange, dis-tillation or reverse osmosis.

Radon - activated carbonfilter and aeration.

Filters that attach to a faucet or are installedunder the sink for a drinking water third faucet:These filters generally use the same technologies as theirpour-through pitcher counterparts.Some filters use fabrics,fiber,or ceramic screening to physically remove contami-nants. The most common types use a molded block ofactivated carbon.These filters are effective at improving thetaste of tap water,and some will also reduce lead,proto-zoan cysts,and many other contaminants.Like filter pitchers,shelf lives and specific contaminants removed vary so readthe label and instructions carefully.

Distillers: Distillers heat water to the boiling point,and then collect the water vapor as it condenses, killingdisease-causing microbes and leaving most chemicalcontaminants behind.Contaminants that easily turninto gases, such as gasoline components or radon,mayremain in the water unless the system is specificallydesigned to remove them.Distilled water may taste flatto some people because the water’s natural mineralsand dissolved oxygen often have been removed.

Reverse Osmosis Units: Reverse osmosis units forcewater through a semi-permeable membrane under pres-sure, leaving contaminants behind.Reverse osmosisunits use approximately three times as much water asthey treat,but they are effective in eliminating all disease-causing organisms and most chemical contaminants.

Point-of-Entry Devices:

Adsorptive media: Liquids, solids, dissolved orsuspended matter adhere to the surface of,or in the poresof, 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 gasolinecomponents and radon,are removed.Other contaminantsare not.The water may be additionally filtered after it passesthrough this system to remove additional contaminants.

Water Softeners:Water softeners use a cationexchange resin, regenerated with sodium chloride orpotassium chloride, to reduce the amount of hardness(calcium,magnesium) in the water.The hardness ions inthe water are replaced with sodium or potassium ions.Ion exchange water softeners simultaneously removeradium and barium while removing water hardness.

Certification

Make sure that the unit you intend to purchase canaddress your concerns.There are three different certifi-cations to look for on the label.These organizationscan also assist you in selecting a device that meets yourneeds. If a home water treatment unit isn’t certified byone of these organizations, contact the manufacturerdirectly and ask for proof of the manufacturer’s claims.

Three organizations are accredited by the AmericanNational standards Institute (ANSI),and they each certifyunits using ANSI/NSF standards.Each ANSI/NSF stan-dard requires verification of contaminant reduction per-formance claims,an evaluation of the unit, including itsmaterials and structural integrity,and a review of theproduct labels and sales literature.Each certifies that homewater treatment units perform to meet or exceedANSI/NSF and EPA drinking water standards. ANSI/NSFstandards are issued in two different sets,one for healthconcerns (such as removal of specific contaminants) andone for aesthetic concerns (such as improving taste orappearance of water).Certification from these organizationswill be tied to one or both of these specific standards.

NSF International:The NSF Water treatment DeviceCertification Program requires extensive product testingand unannounced audits of production facilities.The goalof this program is to provide assurance to consumers thatthe water treatment devices they are purchasing meet thedesign,material,and performance requirements of nationalstandards.

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EPA registration of waterfilters

Some units have an EPA regis-tration number and an EPAestablishment number. EPAregistration (unlike that ofNSF, WQA, or UL) is notintended to guide consumersin selecting a water treat-ment device, and is not anendorsement of the product.EPA registers any productthat contains an antimicrobial(germ-killing) or bacteriostatic(slowing or inhibiting growthof germs) agent. EPA registersthese products because con-sumers cannot independentlyverify whether the germ-related claims they make aretrue.

For most units, an EPA regis-tration number means thatthe filter uses a bacteriostaticagent to slow the growth ofmicrobes within the filter, theunit does not pose a humanhealth threat, and EPA hasverified all bacteriostaticclaims on the label.Registration is not anendorsement of the filter orits performance. The mostcommonly used bacteriostaticagent is silver.

EPA also registers a type ofwater treatment deviceknown as a purifier.A purifiermust remove, kill, or inacti-vate all types of disease-caus-ing organisms from the water,including viruses. Few watertreatment devices can meetthese criteria. These unitstypically work using a disin-fectant within the filter to killor inactivate microbes. Mostpurifiers are used by hikersor campers and are not gen-erally needed in homesserved by public water sys-tems unless there is a wateremergency.

EPA’s Office of PesticidePrograms’ AntimicrobialDivision website providesadditional information onEPA product registrations,www.epa.gov/oppad001.You may also contact theAntimicrobial Hotline at 703-308-0127 (phone); 703-308-6467 (fax); or [email protected].

Underwriters Laboratories: UnderwritersLaboratories, Inc., is an independent, accredited testingand certification organization that certifies homewater treatment units which meet or exceed EPA andANSI/NSF drinking water standards of contaminantreduction, aesthetic concerns, structural integrity, andmaterials safety.

Water Quality Association:The Water QualityAssociation is a trade organization that tests watertreatment equipment, and awards its Gold Seal to systems that meet or exceed ANSI/NSF standards forcontaminant reduction performance, structural integrity,and materials safety.

For more information about watertreatment units:NSF InternationalP.O. Box 130140Ann Arbor,MI 48113-0140877-8-NSF-HELP; (877) [email protected]

Underwriter’s Laboratories, Inc.333 Pfingsten RoadNorthbrook, IN 60062-2096(877) 854-3577www.UL.com/watermail to:[email protected]

Water Quality Association4151 Naperville RoadLisle, IL 60632-3696(630) [email protected]

For more information about tap water:

EPA’s Safe Drinking Water Hotline1 (800) 426-4791

www.epa.gov/safewater - includes drinking waterstandards, state certification officers for water testing,and information for household well owners.

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