Water is, of course, the liquid molecule that we need to sustain life. Any kind of contaminant in water can be detrimental not only to granting this basic need, but it can wickedly and unnecessarily introduce new health problems and even deter individuals from consuming it. Therefore, it is crucial that public water supplies remain clean while supporting a system by which most people in modern society live.
Numerous standards published by NSF International, an ANSI-accredited standards developing organization, focus on guidelines for drinking water treatment and components, helping to assure the safe and reliable treatment and delivery of potable water. In fact, several of these American National Standards were revised in late 2017. These include:
This American National Standard establishes guidelines for the materials, design and construction, and performance of point-of-use (POU) and point-of-entry (POE) filtration systems designed to reduce specific aesthetic-related contaminants in public or private drinking water supplies. Aesthetic contaminants are those that are non-health-related, including chlorine, taste, odor, and particulates.
NSF/ANSI 42-2017 contains the following revisions from the 2016 version: the standard now addresses sample collection for systems containing multiple potable water outlets, an alternative use pattern has been added to the methods for point-of-entry devices, an optional iron influent challenge of 10 mg/L has been added, a method for exposure of fine media has been incorporated, the EPA Method 521 reference for analyzing nitrosamines in materials extraction testing has been included, and evaluation criteria columns have been moved to Annex D in NSF/ANSI 61-2017.
***Update: The current edition of this standard is NSF/ANSI 42-2019: Drinking Water Treatment Units – Aesthetic Effects.
This American National Standard sets minimum guidelines for point-of-use and point-of-entry drinking water systems designed to reduce specific health-related contaminants in public or private water supplies, covering their materials, design and construction, and performance. It is intended to help reduce microbiological, chemical, or particulate substances that may be present in public or private drinking water and are considered health hazards.
NSF/ANSI 53-2017 contains several important changes, so we’ve covered it in its own post: NSF/ANSI 53-2017: Drinking Water Treatment Units—Health Effects.
***Update: this standard has been revised. NSF/ANSI 53-2019: Drinking Water Treatment Units – Health Effects is available on the ANSI Webstore.
This American National Standard fulfills a unique need among the other documents in this list. While federal, state, and local objectives provide safe water supplies without user treatment, users can still be faced with contaminants of aesthetic and health concern in their water supplies. Therefore, this standard establishes guidelines for the reduction of microorganisms using ultraviolet radiation (UV) water treatment systems, covering Class A and Class B systems for inactivating or removing different bacteria. The success of microbiological flora reduction is dependent on the intensity of the UV treatment.
NSF/ANSI 55-2017 contains the following changes from the 2016 edition: normative references were updated, and evaluation criteria columns have been moved to Annex D in NSF/ANSI 61-2017.
***Update: This standard has been revised. NSF/ANSI 55-2019: Ultraviolet Microbiological Water Treatment Systems is available on the ANSI Webstore.
This American National Standard sets health effects criteria for numerous water treatment chemicals that are added directly to water and are intended to be present in the finished water. Water treatment chemicals covered include corrosion and scale inhibitors, coagulants, disinfection and oxidation chemicals, pH adjustment and softening chemicals, and well drilling aids. Most governmental agencies in North America require compliance with NSF/ANSI 60 for water treatment chemical products.
NSF/ANSI 60-2017 includes the following revisions from the 2016 edition: language permitting the use of high substituted carboxmethyl (>0.4) for drilling and remediation of water wells has been added, language for hypochlorite storage in Section 6 has been clarified, and updates have been included to several pass/fail values in Annex C on Drinking Water Criteria.
***Update: The current edition of this standard is NSF/ANSI/CAN 60-2019: Drinking Water Treatment Chemicals – Health Effects (Includes: NSF/ANSI/CAN 600-2019).
This American National Standard sets health effects criteria for water system components, specifically the materials or products that come into contact with drinking water, drinking water treatment chemical, or both and can potentially impart chemical contaminants and impurities. System components covered include protective barrier materials (cements, paints, coatings), joining and sealing materials (gaskets, adhesives, lubricants), mechanical devices (water meters, valves), pipes, plumbing devices, and process media. Most governmental agencies in North America require compliance with NSF/ANSI 61 for water treatment and distribution products.
NSF/ANSI 61-2017 contains the following revisions: exposure and normalization criteria specific to concrete aggregate have been added, a new informative Annex H: Water quality criteria considerations for piping materials in contact with drinking water has been added, language regarding tank covers has been incorporated, allowable volumes of test assemblies have been updated, updated terminology on control samples has been included, lead content requirements have been updated, and updates have been made to several pass/fail values in Annex D on Drinking Water Criteria.
***Update: This standard has been revised. NSF/ANSI/CAN 61-2019/NSF/ANSI/CAN 600-2019: Drinking Water System Components – Health Effects is available on the ANSI Webstore.
This American National Standard establishes the materials, design and construction, and performance guidelines for POU/POE drinking water distillation systems and the components that comprise these systems. Distillation systems heat water to a boiling point and then collect the water vapor as it condenses. This reduces specific chemical contaminants from potable drinking water supplies as they are left behind during the process, but other contaminants can turn into gases and carry over with the water vapor. Distillation systems can also reduce microbiological contaminants.
NSF/ANSI 62-2017 possesses the following changes: normative references have been updated, the component burst pressure test has been removed, and evaluation criteria columns have been moved to Annex D in NSF/ANSI 61-2017.
***Update: The current edition of this standard is NSF/ANSI 62-2019: Drinking Water Distillation Systems.