Point of Entry (Whole House) Water Treatment:
Filters, Softeners, and Conditioners

The Bottom Line:
Whole house water treatment systems are used mostly to reduce contaminants that affect aesthetic qualities of water rather than contaminants of health concern. This page will focus on the three main types on the market that are commonly used to treat municipal water:
1) Filtration Systems: sediment, activated carbon, kdf
2) Water Softeners: ion exchange - regenerate with salt
3) Non-Salt Water Conditioners - magnetic, special signals, catalysts
There are just a few whole house filters that are certified to reduce a limited number of contaminants.
If a whole house filter is certified to reduce a specific contaminant like chlorine for a specified number of gallons, there is no guarantee that other contaminants of concern will be reduced as effectively as the certified contaminant.
WQA and NSF are working with a Task Force to propose a revision to the WQA S-200 and NSF/ANSI 42 and 53 standards and determine if it is possible to create a testing procedure that protects consumers while helping to reduce the cost to manufacturers for certification.
Ion exchange water softeners, used to reduce water hardness, can be certified for effectiveness by both NSF and WQA.  They are certified under different standards than water filters.
There is currently no certification and also little scientific proof that magnetic, electronic, or catalytic water conditioners are effective.
Be very skeptical of claims made for non-traditional water treatment products like filters that contain special modules to “energize” the water in some way.  There are no processes recognized by science that can change the energy, chemical, or physical characteristics of pure water to make it more beneficial to health than 'regular' water. Examples include Vortex Revitalizerd Water, Energized Water, Structured Water, Wellness Filter Technology, Vitality Enhancing Technology ("VitaTech").
There are many types of Point of Entry (POE) or whole house filtration systems and conditioners on the market, yet there are few resources available to consumers that can help them evaluate contaminant reduction and filter life claims made by the manufacturers. 

This discussion will not address cation exchange water softening for which there is NSF/ANSI certification (standard 44)  or specialty water treatment products that are mostly used on private water sources like iron, manganese, nitrate, sulfur and neutralizing filters, chlorinators, etc.

Point of Use (POU) water treatment products that treat a relatively small amount of water (typically under 1,000 gallons a year) are covered elsewhere on this site.  Many POU systems are certified by NSF International and the Water Quality Association (WQA) to reduce specific contaminants to specific levels. 

Product certification is a valuable tool consumers can use to make informed choices about selecting POU water treatment systems.  There are a number of products on the market that make exaggerated or fraudulent  claims, and certification provides provide a third-party validation of performance claims. 

In contrast to cation exchange systems and POU treatments, Point of Entry Filtration Systems treat tens to hundreds of thousands of gallons of water per year, and very few POE water filtration systems are certified by NSF or WQA. 

As a rule, the number of contaminants POE filters are currently certified to reduce are also small – typically Chlorine, Taste and Odor Reduction.  Some systems are also certified to reduce mine, particulates, and turbidity.  WQA certifies specialized Point of Entry filtration systems for acid neutralization, and voc, iron, manganese, arsenic, and/or sulfur reduction - contaminants more likely to be encountered by people using well, spring or surface water rather than municipal water.  Several ultra filtration POE systems are certified to reduce cysts, bacteria, and viruses.

If a consumer is concerned about contaminants in the water entering a dwelling that affect health, certified POE and POU devices should be used in tandem to cover a broad range of aesthetic and health claims.

 Links to find certified POE systems:
NSF Certification - Select "Drinking Water/Water Filter" from the Product Category dropdown menu and click on "Search".  Then "Point-of-Entry" from the Product Type dropdown menu.
WQA Gold Seal Certified Product Listings
- Select Product Type = "Point of Entry" then click the "Search by Product Type" button.

I asked representatives of both WQA and NSF if they would answer some questions about certification for whole house water treatment systems, and they graciously provided the answers below:
  - Cheryl Luptowski, Consumer Affairs Officer, NSF International
  - Pauli Undesser, Director of Regulatory and Technical Affairs, Water Quality Association
  - Thomas P. Palkon Director of Product Certification, Water Quality Associationn
  - Joseph F. Harrison, Water Quality Consulting Services

Q: Why aren't there more whole house filtration systems certified to reduce more impurities?
A:  NSF Response -
There are many factors that affect product performance, including product design and construction, service cycle length, as well as the contact time between the water and the filter media. NSF/ANSI standards for water filters require that systems not only reduce a contaminant by a minimum amount, but they must maintain that reduction for the service cycle promised by the manufacturer. While there are several manufacturers of POE systems that have earned NSF certification, depending upon the contaminant of concern, there may be no whole-house systems certified for the purpose, only point-of-use systems. (Cheryl)

A: WQA Response - It is much more common for companies to certify POU devices but the industry standards do allow for POE devices to be tested and certified.  WQA has certified some POE devices for chlorine, iron, manganese, sulfide, VOC, and TTHM reduction in accordance to the NSF/ANSI 42, 53 and WQA S-200 standards. 

All impurities (contaminants) that a company intends to certify must be tested individually by the certification body.  Because the cost of testing is considerably high for POE systems that have high capacity claims it becomes cost prohibitive for companies to have each of their claims verified by a third party such as WQA or NSF. 

I feel that the main reason companies do not certify POE devices is due to the cost of testing and certification compared to the number of units that will need to be sold to recoup the costs.   Testing and certification to the WQA S-200 or NSF/ANSI 42 and 53 standards are very complex and expensive.  Part of the reason for the high costs is due to the fact that these standards require contaminant reduction testing that verifies the POU or POE systems capacity.  In order for WQA or NSF to verify of POE system's capacity of a 1 million gallon claim we actually have to spike water with the contaminant, send the water through the treatment system to the claimed capacity, and verify that the unit reduces the contaminant for the rated life of the filter. 

Also, for many claims we actually have to test the system to 200% of the rated capacity.  POU systems typically have capacities ranging from 40 gallons to a few thousand gallons requiring tests to last a few weeks but POE systems will have to be tested for several months or years before their rated capacity is reached.  For example, to test a POU filter for one contaminant (Lead in this example) that has a flow rate of 0.5 gpm and a capacity of 1000 gallons the costs will total around $30,000 to complete all the required tests.  A POE system claiming a 100,000 gallon capacity could cost over $200,000 to test and verify one performance claim such as lead.  (Tom)  

Q:  Have any whole house filtration systems been evaluated to determine if exaggerated performance claims are made?  Whole House Filtration systems of similar size and description from different manufactures can be found that have rated treatment volumes that differ by a factor of 10 (i.e. 100,000 vs. 1 million gallons)?  In the absence of certification, how can a consumer determine which marketing claims are true?  Are there any regulatory requirements that water filter claims must be truthful?
A: NSF Response -
With the exception of a handful of states, certification through an independent third party such as NSF is generally voluntary and not required in order for a company to be able to sell a water treatment system. In some cases, proof of performance may be required if a manufacturer makes a claim that their product reduces a health-related contaminant. Because so few regulatory agencies require product certification in this area, consumer demand for proof of performance before purchasing a product will be key in helping to address these gaps. (Cheryl)

A: WQA Response - WQA has never evaluated exaggerated performance claims for whole house filters.  Unless the company is actually certifying the product with the water quality association we do not have any mechanism to evaluate performance claims.  You are correct that activated carbon is capable of adsorbing contaminants for a certain amount of time and is not regenerated in people’s homes.  Typically, the media in whole house carbon filters is replaced after a certain time period or after the media has been exhausted.  The capacity of the activated carbon media varies depending on the make of the consumer water.  It is also common for whole house activated carbon filters to effectively remove chlorine in drinking water for capacities up to or exceeding 1 million gallons.  WQA has certified systems for chlorine removal for these this type of claim.  If this same system is being used to reduce high levels of disinfection by products it will probably only be effective for 100,000 gallons.  (Tom)

In the absence of certification, it is up to the consumer to determine which marketing claims are true. This can be an easy task if the product manufacturers have conducted sound testing. However, if the testing is not sound, then this becomes a daunting task for a consumer.

In regards to regulations that mandate truthfulness in marketing claims for POU and/or POE products, the best example would be when regulations mandate third party certification. States such as California, Wisconsin, and Iowa have regulations that require third party certification for sale in those states. (Pauli)

Q: I searched for information about whole house filtration systems from reputable sites (mostly .edu domains) and was unable to find much of anything to help people select a whole house filter. Is there a reason there is little accurate, unbiased information published on whole house filtration systems - or am I somehow just missing sites that really exist?
A: NSF Response - - When it comes to water treatment, much of the focus during the past few years has been on drinking water rather than the water used for non-potable water purposes. With 70 – 80 percent of household water being used for non-drinking water applications (i.e. flushing toilets, washing clothing or dishes, or irrigation), there may not have been as much interest or focus in treating water not intended for consumption. (Cheryl)

A: WQA Response - I’m not sure why this information is not publicly available. The media used in POE systems are used in many small and large drinking water treatment systems around the world which are used to protect public health and safety on a daily basis. The systems that WQA has evaluated typically perform very well for the performance claims made by the manufacturer.  (Tom)

Q: Do you know of any resources where consumers might be able to obtain reliable information about the accuracy of water treatment claims for non-certified products?
A: NSF Response -
In the case of non-certified products, we encourage consumers to contact the manufacturers and sellers to ask why the product isn't certified to an ANSI-adopted standard. With regards to whole house filters such as carbon filters, standards actually exist to which many of these products can be tested (i.e. NSF/ANSI 42 and/or 53). However, it is important to note that these systems must be just as effective as their point-of-use counterparts when it comes to their ability to reduce contaminants, which can sometimes be a challenge with higher flow rates and longer service cycles.

Consumers would most certainly benefit from independent certification of POE systems as well as those intended for POU applications. There are also several companies with POE filter systems already certified to these standards, a list of which can be accessed online at: www.nsf.org/certified/consumer/listings_advanced.asp (select "Water Filter" then "Point-of-entry" from the product type dropdown menu"). (Cheryl)

A: WQA Response - No. In the absence of certification, it is up to the consumer to determine which marketing claims are true. This can be an easy task if the product manufacturers have conducted sound testing. However, if the testing is not sound, then this becomes a daunting task for a consumer. (Pauli)

Regarding the necessity to certify POE claims, health contaminant reduction performance claims should be substantiated via accredited third party testing and certification. But most consumers use certified POU products, not POE, for protection against health contaminants in drinking water. POE products are largely used for aesthetic enhancement of water supplies because the majority of the water is flushed down the drain rather than ingested. Here product testing and certification is not as critical because the consumer can see or sense for himself when the system is working or not working to remove the smell and taste of chlorine, the bath tub scum, dingy laundry, and ruined fixtures from hard water, or the unsightliness of iron stains.  (Joe)

Q: Since certification of POE filtration systems under NSF/ANSI Standards 42 and 53 may be impractical for most manufacturers, would it be possible to create separate standards for POE systems so more systems could be certified?
A: NSF Response -
To your point about the possibility of creating a separate standard for POE devices, consumers looking to purchase a POE system would most likely expect it to be just as effective at reducing a contaminant as a POU system. If separate standards were developed for POU and POE devices that had different requirements for design or performance, this could very likely lead to confusion as well as misunderstandings regarding potential product performance.

Because the cost for certification of POE systems can be significant given their larger service cycles, an NSF task force has been created to look into potential options. The task force has participation from a broad base of interested parties, who are working together to see if it is possible to create a testing procedure that protects consumers while helping to reduce the cost to manufacturers for certification. (Cheryl)

A: WQA Response -  WQA and NSF are working with a Task Force to propose a revision to the WQA S-200 and NSF/ANSI 42 and 53 standards which would incorporate an accelerated test procedure for POE systems. If validation work can verify this accelerated test is as accurate or equivalent to normal flow through testing this revision could make testing POE systems more affordable for companies which would increase the number of Certified POE systems. We do not want to make the testing criteria for POE systems less stringent because this could compromise consumer safety but we do recognize a need for a standard revision to make testing and certification of POE systems more affordable for manufacturers.  (Tom)

Q: Because there are few certified POE filtration systems (and few contaminants of health concern that systems are certified to reduce), what criteria should a consumer who is considering the purchase of a POE system use to evaluate the effectiveness of different systems and the accuracy of performance claims?
A: NSF Response - Regardless of whether you are purchasing a POE or POU device, it is important to take a moment to first identify what performance capabilities that you need in a system, i.e. what contaminants you want the system to reduce. Then you can ask the manufacturer for “proof of performance” to show if any testing has been done on their product to address that particular impurity. Ultimately, when purchasing a non-certified system, regular testing on the water being produced by the system may be necessary to determine performance.

A: WQA Response -  It is suggested to follow the same criteria that the national standards use. To properly evaluate the performance of a POE or POU system, at a minimum, testing must validate the following criteria:

  • Material safety
  • Structural Integrity
  • Performance – test data to support a rated capacity at a rated service flow using a relevant influent challenge and specified pass/fail criteria
  • Do marketing materials match test data?

Ion exchange (salt) water softener: The science behind traditional ion exchange water softeners is a proven and well understood technology - water passes through an ion exchange resin in which the positive calcium and magnesium ions "hardness minerals" in the water are replaced with sodium (or potassium) ions - levels of other minerals may also be reduced.  Sodium ions do not precipitate out of the water and form insoluble scale deposits like calcium and magnesium.  There is a large body of information on ion exchange water softeners: Neb Guide - Water Softening, Wikipedia - Water Softening

 Non-salt water conditioners:
Non-salt water conditioners, on the other hand, claim to use other treatment methods to reduce the tendency for calcium and magnesium to form scale deposits.  These processes are intriguing for a number of reasons.  If they could actually condition water as effectively as a traditional ion exchange softener, they would be significantly less expensive to operate and would not add brine to the waste water as traditional softeners do while regenerating.

Often these treatments involve permanent magnets or electromagnets that are affixed to the water pipes.  The magnets are alleged to alter the characteristics of the hardness minerals (mostly calcium and magnesium) so they do not create scale in pipes or on surfaces.  Promoters of other technologies may indicate their devices "uses electronic frequencies to physically change the shape and charge of the minerals in water, which prevents scale build-up. Promoters of other technologies may claim their product "acts as a catalyst reducing the degree of super saturation required to form solid calcium carbonate crystals".  Other companies use various combinations of processes "This extraordinary catalyst is then combined with multiple powerful magnets...", or process names without any theory are mentioned "Our revolutionary Beotron Water Treatment System conditions water without using salts, chemicals or magnets. Several companies do not even bother to describe the 'conditioning' methods used.  Most of the process descriptions I have read are scientifically naive and contain pictures of treated and untreated water that are completely meaningless - much like the water crystals photographed by Masaru Emoto that allegedly demonstrate different crystal structures that are based on thoughts or words taped to the water bottles.

The 'scientific' basis for the ability of these devices to “soften” water is disputed by many scientists and water treatment professionals and often considered to be “pseudoscience”.  It is difficult to prove that they actually work consistently under the same conditions as a traditional water softener since the chemical composition of the water is not changed. There is currently no independent testing standard to certify that “salt-free” systems actually soften or condition the water. Since these systems do not remove hardness minerals from water, it it inappropriate to call them water softeners -  in fact their treated water will have the same amount of hardness minerals (calcium and magnesium) as untreated water. 

Perhaps the main warning flag for these products is that there are no consistent, experiments performed by companies (or research groups) that do not have a stake in the product which demonstrate effectiveness at reducing scale or improving cleaning in a normal home environment.  One might expect that if these products were as effective as traditional water softeners there would be considerable scientific interest and a many research projects designed to clearly demonstrate and help understand the effects and expand their uses.  Hard Water and Water Softening

If you see certifications listed for these products they are currently only for material safety or reduction of contaminants for which there are certification standards like chlorine reduction, sediment reduction, etc. and NOT certification for product effectiveness at conditioning water - read the literature carefully.  "WQA Tested & Certified to NSF/ANSI-61 Quality Standards" for example " means "
covers indirect additives products and materials, including process media, protective materials, joining and sealing materials, pipes and related products, mechanical devices, and mechanical plumbing devices (including faucets). In essence, every material from the well or water intakes through to the faucet are covered."  Nothing about conditioning! Similarly, NSF/ANSI standard 41 is for the reduction of specific aesthetic or non-health-related contaminants (chlorine, taste and odor, and particulates). NSF/ANSI Standards

Because of the fact that there are many different techniques promoted as effective at conditioning water without salt, and there are no industry standards, no certification processes (for actual performance), and no high quality scientific evidence to support the multiple claims and treatment methods used in the various processes, the customer only has the word of the product manufacturer or sales representative that the product is effective. 

To protect your investment you might want to consider these steps if you are thinking about purchasing one of these products:

Find a company with a good money-back guarantee and an A+ Better Business Bureau rating.  Before the conditioner is installed, determine exactly what you wish the new conditioner to do and make a list of measurable goals.  For example if you regularly have scale buildup on dishes, sinks or shower heads note how long it takes and how hard the scale is.  If cloths don't come out clean with a measured amount of detergent, list the amount of detergent you use and the problems.  If you can open a pipe to measure scale buildup directly, note what it looks like before the conditioner is installed. 

In other words, carefully document what the problems are with your water that you wish the conditioner to fix and what you expect the conditioned water to do. 

Ask the company you plan to purchase the conditioner from how long it will take to solve the problems and exactly what should measurable changes should occur in your list of problems and how long the changes will take to occur.

At the end of the warranty period if the product has not performed according to product claims and your expectations return it.

Q: What is the position of NSF and WQA on non-salt water conditioners?
A: NSF Response - With regards to non-salt water conditioners consumers need to demand that the manufacturers and sellers of these products work with an ANSI-accredited standards developing organization to help them develop a universal American national standard to which their products can be tested to ensure they perform in accordance with the claims being made by the seller while also meeting minimum standards for structural integrity, material safety, electrical safety, etc. as needed.

A: WQA Response - http://www.wqa.org/pdf/Consumer_Alert_softening.pdf

Other Sources of information on non-salt water conditioners:

Larry Henke of the Robert B Hill Co, published an article in 1998 entitled "Do Magnetic and Electromagnetic Water Conditioners Work? in Water Conditioning & Purification Magazine.  The article reviewed over 100 papers on the subject.  He concluded, "There are few scientific studies referenced in accepted technical journals, and most don't support these claims.  Of the few that do, this article only wishes to call attention to certain limitations."  The article is reprinted here with permission of Water Conditioning & Purification Magazine, © 2010

I found a 2001 report from the WQA Magnetics Task Force on a Culligan website.  The task force reviewed available papers on a variety of magnetic and other physical water treatment processes.  The task force was not charged with evaluating the science behind the technologies, processes, or devices or determining whether the treatment processes work.  Nonetheless, the thirty four papers that met the task force's criteria for scientific validity "provided indications that physical water treatment does work, that it does not work, that it may work but only in certain circumstances, and that it may work in conjunction with or as a result of coincidental trace chemical or ionic leaching mechanisms or other combination technologies. ...These questions are not answered by this report."

Many types of non-salt home water conditioners are sold, as mentioned above.  In the absence of good scientific evidence that these products work the companies often provide documents that on the surface provide evidence of effectiveness but in truth are taken out of context.  A good example is the review, Non-Chemical Technologies for Scale and Hardness Controll, reposted on the GMX water conditioner site.  This study, released in 1998 and commissioned by the Department of Energy, seems to validate the technology.  I was curious, though, when I could not find copies of the document on sites of organizations that produced the report - so I wrote and asked... Below are the replies from Cyrus Nasseri and Steven Parker of the Battelle Company that demonstrate a clear misrepresentation of available evidence by a company {my emphasis}.

Steven: The New Technology Demonstration Program under the DOE, Office of Federal Energy Management Programs (FEMP), did issue a Federal Technology Alert (FTA), "Non-Chemical Technologies for Scale and Hardness Control" in 1998.

The report was directed toward commercial applications, such as cooling towers and boiler systems. The report was not meant to cover potable water applications.

Nether DOE nor PNNL did any testing of the technology. Federal Technology Alerts are summary reports describing the technology and its potential application.

The DOE retired the Federal Technology Alert in 2000, removed it from print and the FEMP web site, and it is no longer available. Neither FEMP nor PNNL have assessed the technology since the 1998 report.

At that time, there were some non-validated reports that the technology may work in certain applications and may not work in other applications. It was not possible to predict the results. Your e-mail referenced the old report. There are many "altered" versions being distributed by vendors via the internet. I cannot confirm their content for accuracy.

In a demonstration performed by the U.S. Army Construction Engineering Research Laboratories (USA CERL), they found the technology to have no impact in a boiler feedwater application. (A copy of the 2001 CERL report may be ordered from NTIS at www.ntis.gov, NTIS Order Number: ADA399455).

E-Source, a private membership organization, has reported on magnetic water treatment since the FEMP FTA was retired. See publications TAS-TN-9-08 and TAS-TN-6-04.  {also here}

The Sacramental Municipal Utility District (SMUD), Consumer Advanced Technology Program conducted an assessment of pulsed-power water treatment (Clearwater Dolphin) and issued a summary report in 2003. The report assess the water treatment aspect of the technology but did not measure or document the energy aspect. The report is located on their web site at http://www.smud.org/en/education-safety/cat/Documents/PulsePower.pdf  {Note this report is for commercial applications, not home treatment devices - RJ}

Cyrus: I know that ASHRAE has done some research on non-chemical water treatment for biological issues (the results were not positive) and I think that they have also done some research on non-chemical treatment for issues such as your web site – scale and hardness.

A June 2001 report on Magnetic Water Treatment by the U.S. Army Corps of Engineers concluded: "There is a long history of controversy regarding the effectiveness of magnetic water treatment for preventing scale in water systems. Magnetic “treatment” consists of passing potentially scaling water through a magnetic field. Promoters of magnetic devices claim that this simple operation provides a scale-control method, even for water having a high tendency for scaling. It is also often claimed that magnetic exposure can inhibit corrosion. The attached document provides an evaluation of current magnetic water treatment technology. Scientific literature is reviewed and summarized and several devices are tested for scale prevention. In summary the magnetic water treatment devices were not effective for scale control."

An experimental study, “Evaluation of Magnetic/Electrostatic Water Treatment Devices”, (described in the emails above) was conducted under the Operations and Maintenance, Army; Work Unit F88, for the U.S. Army Center for Public Works, and the results were released in a 105 page report September of 2001.  "The objective of this work is to conduct a field test of the performance of magnetic devices. The results will be used to evaluate whether or not the specific tested devices were effective in preventing mineral scale formation in this study. ...This study concludes that these results indicate no clear advantage for any of the three devices tested over a control for the inhibition of mineral scale formation or the corrosion of copper. The test protocol was designed to simulate the method of production of hot water used in many larger institutional type settings that employ a shell and tube heat exchanger for the production of hot water. These findings do not support the claims of the manufacturers regarding the ability of their respective devices to prevent mineral scale formation in hot potable water systems."

Magnetized water: Science or fraud - Another review of available evidence from the Journal of Chemical Education in 2008 concluded "Despite the wide use of water magnetizers and their endorsement in the scientific literature, there is no scientifically proven evidence of their effectiveness or mechanism of action. Although some studies suggest that magnetic fields can alter specific properties of aqueous solutions, the underlying mechanism remains obscure and the alleged effects must depend on a number of physicochemical variables including temperature, pH, ionic composition of the water, intensity of the magnetic field, flow rate of the water through the field, pipe material (copper, PVC) and various geometric parameters of the system which must be further investigated in depth before any solid conclusions can be established regarding the claimed effects of magnetic fields on water properties."

http://www.wcponline.com/NewsView.cfm?pkArticleID=1752 - Clamp-on water treatment: ...Since there is no U.S. standard (although an effort was made to enlist the financial support of the equipment manufacturers themselves for one a few years ago to very little effect), there's no way of proving the above claims. Even the German standard simply is a measure of scale prevention; it goes no further in detailing additional properties or under what variable conditions the equipment might be effective. As such, WC&P's position on this is neutral. Whether or not the adage "buyer beware" is appropriate here is anyone's guess. You buy at your own risk. (2002 article)