Jun 05, 2019

Be Prepared

Standard helps reduce risks during water supply contamination events

Standard helps reduce risks during water supply contamination events

For people with compromised immune systems, an unexpected microbial contamination of their drinking water supply can be especially dangerous. While local municipalities usually are quick to issue boil-water advisories, there always is the chance that someone might drink from the tap after a water supply contamination event occurs but before the advisory can be issued. Additionally, private water sources such as wells are not always regularly tested, so contamination of this kind can occur in both public and private water supplies.

Reducing Risks

In 2018, NSF Intl. published a new American National Standard for drinking water filters designed to reduce potentially harmful microorganisms from municipal drinking water systems during the critical period between a water supply contamination event and a boil-water advisory. NSF/ANSI 244: Supplemental Microbiological Water Treatment Systems-Filtration establishes minimum requirements for mechanical water filtration devices that reduce bacteria, viruses and protozoan cysts, including point-of-entry and point-of-use filters. 

Supplemental water filters can play an important role in protecting public health, especially for people with sensitive immune systems. Filtration devices certified to the standard can reduce the risks associated with disease-causing microbes in the hours or days before a boil-water advisory can be issued. 

Although the U.S. has one of the world’s safest drinking water supplies, threats to drinking water are increasing. Each year there are thousands of boil-water advisories issued, either as a precaution due to an accidental water main break or low-pressure event, or because of a confirmed microbial contamination. 

Devices covered under the standard are intended only for protection against accidental microbiological contamination of otherwise safe drinking water. In the case of a contamination event or boil-water advisory, consumers should follow their municipal water authority’s instructions and maintain their filtration device per the manufacturer’s instructions once the event is over.

NSF/ANSI 244 establishes the minimum requirements and performance characteristics for products that claim to reduce the type of potentially harmful microorganisms that can get into the water supply if there is some kind of unexpected microbiological contamination event. Consumers, especially those with compromised immune systems, can be confident that products certified to the standard will provide protection if there is some kind of event with the public water system.

Testing under this standard include:

  • Structural integrity;
  • Material safety; and
  • Reduction testing to show a 6-log reduction of bacteria and 4-log reduction of viruses.

All products certified must include an end of life indicator. Product types eligible for certification to NSF/ANSI 244 include:

  • Ultrafiltration;
  • Microfiltration;
  • Nanofiltration;
  • Reverse osmosis; and
  • Ceramic.

Thoroughly Vetted

NSF/ANSI 244 was developed according to the American National Standards Institute (ANSI) processes by a committee of 33 stakeholders representing consumers, the water industry, and state and federal health and environmental agencies in the U.S. and Canada. The ANSI standards development process is designed to ensure openness, balance, consensus and due process for all stakeholders. NSF Intl.’s standards development group facilitated the standards development process. 

As the final step in the standards development process, NSF/ANSI 244 was ratified by NSF Intl.’s Council of Public Health Consultants, which includes representatives from the U.S. EPA, the U.S. Centers for Disease Control and Prevention, and the U.S. Food and Drug Administration. 

About the author

Stefan Buck is program manager of water systems filtration products at NSF Intl. Buck can be reached at [email protected]

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