WQA POSITION: WQA supports a pass/fail criterion of 80% for IAPMO Z601, and cannot continue to support the standard if the criterion is lowered to 60% which equates to doubling the amount of scale build-up which would be seen by consumers.
SUMMARY: WQA has been a key proponent of the IAPMO Z601 standard from the beginning, which dates back to the WQA Magnetics Task Force Report, published in March 2001. That task force included representatives from the water treatment industry, academia, and NSF International. Its objective was to review scientific studies relating to physical water treatment for scale reduction and “broaden acceptance of the industry through consumer confidence and trust in water.”

After reviewing 106 papers on the topic of physical water treatment for the reduction of scale, the task force’s report called for the development of an ANSI standard for certification of scale-reduction devices. This eventually prompted IAPMO, in August 2007, to issue an ANSI PINS announcement in which consumers were identified as the primary stakeholder, and members of our industry (manufacturers) were identified as supporting the need. The following excerpt is taken from IAPMO’s ANSI PINS announcement:

The scope of standard shall include material safety, minimum performance requirements and structural integrity (if applicable) of scale prevention devices.
Stakeholders: Consumer
Project Need: Requested by Manufacturers for Testing and Certification

Since that time, WQA has been actively promoting this standard to water treatment dealers and manufacturers with the belief that it will finally allow consumers to differentiate between the wide array of products purported to reduce scale based on those which actually provide a discernable benefit. This in turn will promote fair competition in the marketplace. These goals to broaden acceptance, improve consumer confidence and promote fair competition are expressed in the following excerpt from the introduction to the standard:

0.1 Although several alternatives to ion‐exchange water treatment devices have the potential to offer solutions to consumers’ need for scale reduction, lack of an appropriate test protocol that can be used to certify their effectiveness has slowed their adoption.

0.2 This Standard is written to enable testing of devices that have the potential to reduce scale in water in a wide variety of residential and similar applications and associated plumbing. To encourage competition among manufacturers for the benefit of consumers, the definition of a “device” has been intentionally left open so that any appropriate means and methods with the effect of reducing scale can be tested for their effectiveness. This approach makes it possible to test a variety of devices including those based on permanent magnetic, electromagnetic, electric, electrolytic, capacitive, catalytic, media, chemical ion exchange technologies, and other emerging technologies. Physical and chemical scale-reduction devices are promoted for use in residences or commercial establishments as an alternative to ion-exchange resin-based water softeners. Studies by the Battelle Memorial Institute and Scientific Services S/D Inc. collectively identified the following benefits of ion exchange water softening:
 Decreased energy usage and increased longevity of hot water heaters;
 Prevention of clogging in low-flow faucets and shower heads;
 Improved stain removal and detergent savings in laundry applications;
 Energy saved through lowering the temperature of laundry cycles; and
 Detergent savings and prevention of spotting in dishwashing applications.

IAPMO standard Z601 focuses specifically on measuring scale-reduction in water heating applications. If physical devices certified under IAPMO Z601 are to be considered credible alternatives to ion-exchange water softeners, it is incumbent that they achieve similar energy savings in water heating applications, or some other discernible benefit to consumers.
The difference in scale production between 60% and 80% equates to doubling the amount of scaling. Ion exchange water softeners eliminate virtually all scale formation in water heaters, and research has shown that even a small amount of scale can significantly increase energy usage during water heating applications. A 2013 U.S. Department of Energy report indicates that even a 1/16th of an inch (0.06 inch) coating of lime scale can decrease the efficiency of heat exchange in a boiler by an average of 11%.

A study by the United Kingdom of Great Britain and Northern Ireland Ministry of Health found that a scale build-up of only 1/50th of an inch resulted in a 9.4% loss in heat transfer efficiency. A sugar industry study found that a scale build-up of only 1/32nd of an inch caused an efficiency loss of 7%. In short, it has been well established that even small amounts of scale can have a big impact on heat transfer efficiency. Therefore, it has always been WQA’s position that no amount of scale is good.
However, a precedent was set by the DVGW 512 standard (Deutsche Vereinigung des Gas- und Wasserfaches), developed in Germany, which sets the pass/fail criteria for scale reduction at 80%.
DVGW Cert GmbH is the largest water industry certification body in Europe, and the 80% pass/fail criteria in DVGW-512 has been in use since 1996. Like IAPMO Z601, the German standard applies to all types of scale-prevention devices, and is not designed to cover only water softeners. While we would like to see a tighter pass/fail criteria adopted in this standard, WQA has supported, and will continue to support, an 80% pass/fail criteria based on the German precedent.
After completing initial product testing prior to the publication of IAPMO Z601, NSF International has proposed that the 80% pass/fail criteria should be lowered to 60%. The primary reason justifying this change is given to be that “the pass/fail minimum criteria should be at a point that a benefit can be realized by the user of the product.”

Despite this assertion, NSF International has provided no scientific proof that there will be a discernable benefit to consumers at 60% scale reduction.
It has been the experience of our members that customers begin to complain their softener is not working when even a small amount of scale begins to build up on their shower doors, fixtures, shower heads, and dishes. Once IAPMO Z601 is published, consumers will begin to see products labeled as “certified scalereduction devices” and it is our strong desire that consumers be able to discern noticeable benefits from those devices, especially significant energy savings. A low performance threshold could undermine consumer confidence of the water treatment industry in general, and their trust in third-party certifications. This approach also undermines fair competition in the marketplace by promoting a pass/fail threshold that cannot be justified by precedent or reputable studies showing discernable consumer benefits.
Lowering the pass/fail criteria from 80% to 60% would result in twice the amount of scale build-up. NSF International has suggested this change without providing any studies showing that there would be discernable consumer benefits at this threshold. The current performance threshold of 80% is supported by data and precedent. WQA feels that lowering the performance threshold to 60% will undermine consumer confidence in the industry and product certification in general. We also feel that setting such a low threshold for performance will undermine fair competition in the marketplace by encouraging the promotion of products which have no discernable benefit for consumers.
1. D. D. Paul, V.V. Gadkari, D.P. Evers, M.E. Goshe, and D.A. Thornton, “Study on Benefits of Removal of Water Hardness (Calcium and Magnesium) from a Water Supply” Battelle Memorial Institute, 2010.
2. SH Widder and MC Baechler, “Impacts of Water Quality on Residential Water Heating Equipment” Pacific Northwest National Laboratory, prepared for the U.S. Department of Energy, November 2013.
3. “WQA Magnetics Task Force Report”, March 2001
4. Feighner, George C. “Evaluation of the Effects of Water Hardness on Performance of Automatic Dishwasher Detergents and Savings Possible by Softening Water” Scientific Services S/D, Inc., 2011.
5. Feighner, George C. “Evaluation of Relative Effects of Hardness, Detergent Dose and Temperature to Evaluate Stain Removal Efficacy” Scientific Services S/D, Inc., 2011.
6. Ministry of Health “Report of the Water Softening Sub-Committee of the Central Advisory Water Committee” Prepared for His Majesty’s Stationery Office, 1949
7. Cuddihy, Simoneaux, Falgout, and Rauh “Boiler Water Treatment and Related Costs of Boiler Operation: An Evaluation of Boilers in the Louisiana Sugar Industry” Midland Research Laboratories, Inc., 2005
8. Herman, Rob “Rationale for Minimum Performance Criteria of 60 Percent Scale Reduction in IAPMO Z601” NSF International, prepared for the IAPMO Z601 Technical Subcommittee, May 11, 2015