NSF/ANSI 60-2021: Drinking Water Chemicals Health Effects

Clear, healthy drinking water flowing into glass with no negative health effects thanks to NSF/ANSI 60-2021 for chemicals.

The health effects of water are of prime importance. Chemicals make water potable, letting it safely enter our bodies to keep our temperature regular, lubricate joints, protect our spinal cord, and expel waste. In doing this, they, of course, must not contribute to any adverse effects. NSF/ANSI/CAN 60-2021: Drinking Water Treatment Chemicals – Health Effects establishes minimum health effects requirements for chemicals, chemical contaminants, and impurities added directly to drinking water from treatment chemicals.

What is NSF/ANSI 60-2021?

NSF/ANSI/CAN 60-2021, also known as NSF/ANSI 60 or just ANSI 60, confronts a key issue with the treatment of water. While natural water is often not potable, the treatment performed to purify it must be conducted with care to prevent chemicals from residing within the treated public water source at harmful concentrations.

The treatment chemicals covered by the standard are intended to be present within the finished, potable water, but some others that will not be present are included as well. NSF/ANSI 60-2021 strongly emphasizes that treatment chemicals shall not exceed their single product allowable concentration (SPAC), or “maximum concentration of a contaminant in drinking water that a single product is allowed to contribute”.

Chemicals Covered by NSF/ANSI/CAN 60-2021

NSF/ANSI/CAN 60-2021 covers coagulation and flocculation, softening, precipitation, sequestering, pH adjustment, corrosion/scale, and disinfection and oxidation chemicals, as well as miscellaneous treatment and water supply chemicals.

To give some examples, chemicals mentioned in NSF/ANSI 60-2021 include:

Coagulation and flocculation: bentonite, aluminum chloride
Corrosion and scale control: phosphoric acid, monopotassium orthophosphate pH adjustment: magnesium hydroxide, magnesium oxide
Disinfection and oxidation: anhydrous ammonia, chlorine
Miscellaneous treatment: calcium fluoride (fluoridation), copper sulfate (algicide)

The standard is not applicable to products resulting in the intentional introduction of microorganisms to treat drinking water. NSF/ANSI/CAN 60-2021 also doesn’t cover contaminants produced as byproducts through reaction of treatment chemicals with a constituent.

Changes to NSF/ANSI/CAN 60-2021

In the 1980s, in response to a competitive request for proposals from the U.S. Environmental Protection Agency (EPA), a consortium led by ANSI-accredited standards developing organization NSF International agreed to develop voluntary third-party consensus standards and a certification program for all direct and indirect water additives. In 1988, these efforts culminated in the initial publication of NSF 60 and NSF 61.

Today, NSF/ANSI/CAN 60, as it is now designated, is revised periodically to remain current. NSF/ANSI/CAN 60-2021 revises the 2020 edition of the same American National Standard. When compared to the previous edition, it contains these two changes of note:

Consistencies were added to the normalization equations throughout the standard.
Sodium dichloroisocyanurate, trihloroisocyanuric acid, and sodium permanganate were added to Table 6.2, “Disinfection and oxidation products – Product identification, and evaluation.”

NSF/ANSI/CAN 60-2021: Drinking Water Treatment Chemicals – Health Effects is available on the ANSI Webstore. An addendum has also been released for this standard. NSF/ANSI/CAN 60-2021 ADDENDUM adds Informative Annex 6, “Sampling guidance for sodium hypochlorite for producers, diluters, and repackagers.”

Changes to NSF/ANSI 60-2020

The previous revision of this document was also substantial. For your reference, the changes made to NSF/ANSI/CAN 60-2020 included:

The tamper evidence requirements for packaged products were updated.
Language was added to clarify requirements for the application of tamper-evident seals.
3-chloro-1,2-propanediol was added to the minimum test battery for epichlorohydrin, a polyamine-based coagulant, under Table 4.1, “Coagulation and flocculation products – Product identification and evaluation.”
Labeling requirements were added for sodium hypochlorite products.
Chlorine dioxide and Bromochlorodimethylhydantoin (BCDMH) were added to the list of disinfection and oxidation products contained in Table 6.2.
Acetic acid was added as a miscellaneous treatment application.
New definition for “biological substrate.”
The appropriate use of citric acid was clarified, specifically for use with copper-based algicides, in well development / rehabilitation, and as an offline separation process cleaner.

Changes to ANSI 60-2019

For users of the standard who need an even deeper history of the changes, below are the updates made to the 2019 revision:

The typical use level (TUL) for sodium silicate was raised from 16 mg/L to 100 mg/L, and synonyms for sodium silicate were corrected.
The use and fate of chlorate & chlorite in drinking water was clarified.
New guidance was provided in Annex N-1 on conducting the potassium-40 correction method for radionucleotide analysis, and this language also standardized the threshold for conducting gross beta particle speciation.
Remineralization was added to the scope of the processes covered by drinking water treatment chemicals.
They typical use level (TUL) for fluoride products was lowered from 1.2 mg/L to 1.0 mg/L.
Annex names were changed from alpha characters to numeric and preceded by “Normative” or “Informative,” e.g. “Annex A” became “Informative Annex 1 (N-1).”

NSF/ANSI/CAN 61

We hold this liquid molecule in high esteem, and rightfully so—human beings require a gallon of water every day to perform basic functions, as well as some other sources here and there to cook and conduct various hygiene-related tasks. As such, there are numerous standards devoted to water.

While NSF/ANSI/CAN 60-2021 deals with the health effects of chemicals directly imparted to drinking water systems, NSF/ANSI/CAN 61-2022 establishes the health effects from drinking water system components.

This standard applies to products like process media, protective materials, joining and sealing materials, pipes, mechanical devices used in treatment systems, and mechanical plumbing systems.

You can learn more about this standard in our post NSF/ANSI 61-2022: Drinking Water System Components – Health Effects.

NSF/ANSI/CAN 600

Some drinking water standards even come with companion standards to sufficiently organize guidance pertinent to their compliance. The companion standard to NSF/ANSI 60 and NSF/ANSI 61, NSF/ANSI/CAN 600, focuses on the “Health Effects Evaluation and Criteria for Chemicals in Drinking Water.” This information is referenced in section 3.4 of NSF/ANSI/CAN 60, which details contaminant concentrations.

NSF/ANSI/CAN 61-2022: Drinking Water System Components – Health Effects and NSF/ANSI/CAN 60-2021: Drinking Water Treatment Chemicals – Health Effects come with a complementary copy of NSF/ANSI/CAN 600 on the ANSI Webstore.

You can learn more about NSF/ANSI/CAN 600 in our post Companion Standard to NSF/ANSI 61 & 60 for Drinking Water.