Water isn’t literally everywhere, but it is overwhelmingly abundant, taking up 332,500,000 cubic miles of the earth’s surface. H2O also comprises 60% of our bodies’ mass—it even constitutes 64% of human skin. Unfortunately, less than 1% of all water is fresh and accessible. This places an importance on NSF/ANSI/CAN 61 (also known as NSF 61 or ANSI 61) and similar drinking water additives standards.
What is NSF 61?
This standard—NSF/ANSI/CAN 61-2021: Drinking Water System Components – Health Effects—sets minimum health effects requirements for the chemical contaminants and impurities imparted from products, components, and materials to drinking water systems. It does not establish performance, taste and odor, or microbial support requirements.
NSF 61-2021, in focusing on evaluating contaminants or impurities imparted indirectly to drinking water, covers a range of materials. This includes but is not limited to
- Process media (e.g. carbon, sand)
- Protective materials (e.g. coatings, linings, liners)
- Joining and sealing materials (e.g. solvent cements, welding materials, gaskets)
- Pipes and Related Products (e.g. pipes, tanks, fittings)
- Mechanical devices used in treatment/transmission/distribution systems (e.g. valves, chlorinators, separation membranes, point-of-entry drinking water treatment systems)
- Mechanical plumbing systems (e.g. faucets, endpoint control valves)
The materials chosen during the construction of these products play a key role in the impact that they can have on the water system during their lifetimes. Because of this, NSF/ANSI/CAN 61-2021 only calls for the selection of certain materials that are known to be more suitable for coming into contact with drinking water.
Determining Lead Content With NSF/ANSI 61
As of January 4, 2014, due to an amendment made to Section 1417 of the Safe Drinking Water Act (SDWA), drinking water products sold or installed for use in public water systems, as well as plumbing in facilities, need to meet a weighted average of not more than 0.25 percent lead.
In the US, drinking water components are tested to the NSF/ANSI/CAN 61 standard, and the leachate testing addressed in the document helps evaluate products for all contaminants of health effects concern, not just lead.
Previously, ANSI 61 also contained procedures specifically for determining the lead content of drinking water system components in Annex G, “Weighted average lead content evaluation procedure to a 0.25% lead requirement.” This information, however, was retired from NSF/ANSI 61 in October 2013. The previous contents of Annex G are now part of NSF/ANSI 372-2022: Drinking Water System Components – Lead Content.
In accordance with NSF 61, manufacturers should include information on testing and their products’ composition relevant to their exposure with water systems.
With this information, users of the NSF/ANSI/CAN 61-2021 standard are able to determine the contaminants that could emerge in the water that travels through the piping system over time, even when factoring in a variety of conditions. This can provide the means to protect those who depend on this water in their everyday lives.
Users should also note that water exposure could vary depending on the water age, which can be incredibly high in certain situations in which the water does not regularly flow through the piping. For example, this might occur in schools, where the buildings would be stagnant for months at a time, and thus, the water might not be regularly accessed.
EPA Additives Advisory Program for Drinking Water System Components
The ANSI 61 and ANSI 60 standards were first developed in the 1980s in response to a competitive request for proposals from the US Environmental Protection Agency (US EPA), a Consortium led by NSF International (NSF) to develop voluntary third-party consensus standards and a certification program for all direct and indirect drinking water additives.
Since this time, NSF/ANSI/CAN 61 and the subsequent product certification against it has replaced the US EPA Additives Advisory Program for drinking water system components. The EPA terminated its advisory role in April 1990. For more information with regard to US EPA’s actions, refer to the July 7, 1988 Federal Register (53FR25586).
Changes to NSF/ANSI/CAN 61-2021
NSF 61 revises the 2020 edition of the same American National Standard. To keep it current, it underwent the following changes:
- Removed Table N-1.3a, “Extraction water selection.”
- The pH 5 extraction water test was added to brass / bronze surfaces in Table N-1.3, “Extraction water selection” (this was Table N-1.3 b in the 2020 edition of the standard).
- The requirement of a use limitation statement on product literature and certification listings was added for products that fail for copper at pH 5.
- Units of in2/L were added to DSA-to-volume ratio numbers.
- Additional guidance was added to Table 4.2, “Single time point exposure schedule,” to be consistent with other
- exposure sequence tables in the standard.
- The reference to exposure protocol from Sections N-220.127.116.11 to N-18.104.22.168 for other mechanical devices was corrected.
- Clarification was added guidance for reverse osmosis systems in Table N-1.7, “Product exposure,” to indicate that typical exposure conditions occur within the product itself.
- Clarification was added to additional guidance on decanting and refilling of samples for in-line and other mechanical devices to be consistent with other exposure sequence tables in the standard.
Changes to NSF/ANSI 61-2020
Users might also be interested in revisions made to the previous iteration of this document, NSF 61-2020, so we have listed them below:
- Corrected an error found under the product / material evaluation procedures in Section N-22.214.171.124.
- The flux sample preparation method under Section N-126.96.36.199 was revised.
- An optional, more stringent requirement for lead release for Section 9 devices (Section 188.8.131.52) was added. It also added a definition for the term consumer-facing.
Changes to NSF 61-2019
The 2019 edition of this American National Standard was a substantial update to the document. In all, in revising the 2018 edition, NSF/ANSI 61-2019 contained the following changes:
- Clarified language regarding muffle furnace temperatures.
- In section 184.108.40.206, “Products other than fire sprinklers,” stainless steel was added to the evaluation assumptions for inserts in PVC, CPVC, and PP transition fittings.
- The reference to US EPA Method 521 was removed.
- Clarification to use the most rigorous conditions for evaluating products.
- Polystyrene was added to Table 3.1 for “Material-specific analyses.”
- Test water tolerances were added to the extraction water protocol in Annex N-1, “Product / material evaluation.”
- The use of UV treatment to reagent water to destroy trace organics became allowed.
- Radionuclides analysis was removed from the “required minimum test battery” for several process media products. Guidance on potassium-40 subtraction for gross beta particle emissions and a threshold for gross beta speciation is also now provided under Annex N-1.
- The evaluation of copper and copper alloy pipe, tubing, and fittings was added.
- The alternate exposure water selection for several materials was changed.
- All annexes were changed from alpha characters to numeric and updated to be preceded by “Normative” or “Informative.”
Standard for Health Effects Evaluation in Drinking Water (NSF 600)
NSF 61-2021 has a companion document: NSF 600-2021: Health Effects Evaluation and Criteria for Chemicals in Drinking Water. This information previously existed in NSF 61 under Annexes A and C (as well as Annexes A and D in NSF 60), but the need for accessibility of this content necessitated the publication of a new standard. NSF 600 became its own document among the changes to the 2018 edition of NSF 61. Anyone who acquires NSF 61-2021 from the ANSI Webstore receives a copy of NSF 600-2021.
NSF/ANSI/CAN 61-2021/NSF/ANSI/CAN 600-2021: Drinking Water System Components – Health Effects is available on the ANSI Webstore.