NSF/ANSI Set Standards for Drinking Water Treatment Units

Many water filter brands only apply for WQA certification & not NSF. One of the reason is because NSF is more stringent & difficult to comply.

But that's not all. If you read the article below, you'll find other interesting reasons.



Building & Plumbing Officials

NSF/ANSI Set Standards for Drinking Water Treatment Units
CLEAN, SAFE drinking water – something we once took for granted – now makes headlines on the evening news. As evidence of the public's growing concern, products ranging from hand-held filter pitchers and faucet filters to in-line water softeners and reverse osmosis systems are ringing up big sales at home improvement and home furnishing stores.

In response to public and regulatory demands, NSF has, through its American National Standards Institute (ANSI), developed procedures and standards to address performance issues related to the aesthetic and health effects of water filtration products. NSF standards are referenced in the National Plumbing Codes, International Plumbing Code, National Standard Plumbing Code, and Uniform Plumbing Code.

These standards and the NSF Mark give building officials and mechanical and plumbing inspectors the guidance they need to ensure that water filtration products are installed correctly and were designed for that application. For your reference, here's a summary of the NSF Drinking Water Treatment Unit Standards and their scope.

ANSI/NSF 42: Drinking Water Treatment Units – Aesthetic EffectsStandard 42 establishes minimum requirements for materials, design and construction, and performance of drinking water treatment systems that reduce specific aesthetic-related contaminants (nonhealth effects) in public or private water supplies.

ANSI/NSF 44: Residential Cation Exchange Water SoftenersStandard 44 establishes minimum requirements for materials, design and construction, and performance of residential cation exchange water softeners.

ANSI/NSF 53: Drinking Water Treatment Units – Health EffectsStandard 53 establishes minimum requirements for materials, design and construction, and performance of point-of-use and point-of-entry drinking water treatment systems that reduce specific health-related contaminants in public or private water supplies. The scope includes point-of-entry drinking water treatment systems used to treat all or part of the water at the inlet to a residential facility, or a bottled water production facility and the material and components in these systems.

ANSI/NSF 58: Reverse Osmosis Drinking Water Treatment SystemsStandard 58 establishes minimum requirements for materials, design and construction, and performance of reverse osmosis drinking water treatment systems.

All of the above standards specify the minimum product literature and labeling information that manufacturers must supply to authorized representatives and system owners, and the minimum service-related obligations manufacturers must extend to system owners. Recently, the Drinking Water Treatment Unit standards developed by the Water Quality Association (WQA) were proposed for recognition in plumbing codes at the national, state, and local levels.

There are major differences between the WQA and NSF standards, including the development process, water contact materials, and reduction of contaminants, as explained below.
WQA and NSF Standards: Industry v. Consensus DevelopmentNSF standards are developed through the ANSI consensus process and are granted the ANSI designation to indicate this. In fact, NSF is the first organization granted the "ANSI Audited Designator of Standards" classification for all of its ANSI standards development.

The ANSI process includes requirements to ensure that no one group dominates the process. NSF standards committees are comprised of an equal number of producers, users, and regulators.

In contrast, WQA standards are developed by industry and are not consensus-based. For this reason, the International Code Council's Plumbing Committee has routinely disapproved the inclusion of WQA standards in the International Plumbing Code.

Water Contact MaterialsA second major difference between the NSF and WQA standards relates to the materials in contact with water. NSF standards require disclosure of complete formulation information for all materials in contact with drinking water to determine which extractable contaminants may be present.

The entire device then undergoes an extraction test to make sure the materials in contact with drinking water do not impart levels of extractable contaminants exceeding health effect levels.

In contrast, WQA standards do not require complete formulation information by the manufacturer or mandate that the entire device undergo extraction testing. WQA standards also do not contain a procedure to determine the health effect levels for contaminants that do not have a Maximum Contaminant Level (MCL) established by the U.S. Environmental Protection Agency.

Contaminant ReductionA third major difference between NSF and WQA's standards is illustrated by the requirements for the contaminant reduction performance for Reverse Osmosis Systems. WQA S-300 does not include the following contaminants addressed in ANSI/NSF 58: barium, cadmium, chromium (hexavalent), chromium (trivalent), copper, fluoride, lead, mercury, nitrate plus nitrite, organic chemicals by surrogate (39 chemicals in all); radium; and selenium.

Over the past several years, NSF and WQA have been working to harmonize the differences between their standards. In fact, the harmonization of ANSI/NSF 58 and WQA S-300 was completed in March 1998. Joe Harrison, WQA's Technical Director, is active in development of the NSF standards on Drinking Water Treatment Units. Due to ANSI process guidelines, Harrison has been designated as "a nonvoting liaison."

In presentations, Harrison has affirmed WQA's willingness to discontinue its standards when NSF standards include requirements that address their members' concerns. NSF expects to complete the harmonization effort in the next few years.
If you have questions or want more information, please contact Shannon Murphy at 800-NSF-Mark.