Breaking Down: Water Filtration Systems, Product Certification & Counterfeit Filters

March 4, 2022

This article originally appeared in the March 2022 issue of WQP as "Filtration Systems & Product Certification"

About the author:

Stefan Buck is general manager of Global Drinking Water Treatment Units for NSF International. Buck can be reached at [email protected].

Access to clean drinking water is a luxury that Americans often take for granted. Water scarcity is a growing problem, with more than 2 billion people living in countries with an inadequate water supply and 4 billion people experiencing severe water scarcity for at least one month each year. While the issue of water contamination due to droughts and extreme weather events is a much larger problem that needs to be addressed, filtration systems can serve as a short-term solution to help eliminate harmful contaminants from drinking water.

Water filters reduce contaminants in water that in large amounts can make it unsafe to drink. Contaminants like lead are often undetectable to the naked eye, but can have severe consequences if consumed at unsafe levels. Filters are designed to reduce specific contaminants, however it is important to know that one filter may not address all possible pollutants. Finding out what contaminants may be polluting your water through your local water quality report is an essential first step in determining which water treatment system is right for your home. For this, NSF International provides a helpful guide on which filters are effective for common contaminants.

Understanding Water Filtration Systems

Consumers are the primary target for residential filtration units, especially those who have concerns with their water quality, have compromised immune systems or live on private wells. According to the U.S. Centers for Disease Control and Prevention (CDC), private wells are fairly common, with more than 15 million U.S. households relying on them for water. Those who live on private wells often need to use a water softener or remove particles from their water with a pre-filter.

Additionally, contaminants in water can be more prevalent in certain parts of the country than others. Rural areas, for example, typically fail to meet water health standards more frequently than urban areas. Even if none of those situations apply, there are still non-health-related applications of water filtration systems as many people purchase filters in the interest of improving the taste of their water.

Filtration systems are categorized by two main types — point-of-use (POU) systems and whole-house/point-of-entry (POE) systems. POU systems treat the water where you drink or use it, such as your kitchen sink or your refrigerator. Examples of POU systems include personal water bottles (pitchers, dispensers or pour-through filters), faucet mount filters, under-the-sink or plumbed-in systems, under-the-sink systems piped to a separate faucet type, plumbed-in to separate faucet systems, and refrigerator filters.

Conversely, POE systems treat the water as it enters a residence. They are usually installed near the water meter (municipal) or pressurized storage tank (well water). Whole-house treatment systems include UV microbiological systems, water softeners, or whole-house filters for chlorine, taste, odor and particulates. For these systems, it is important to note that decisions about which filters to install will likely be made or influenced by those involved in the construction process.

The Value of Certification

To ensure your filtration system is doing its job effectively, it is important to be mindful of whether your filtration system is certified by a professional organization or third-party regulatory body.

NSF tests and certifies water treatment products for material safety, structural integrity and the product’s ability to remove contaminants. These certifications ensure the product works how it claims to, which puts both consumers and manufacturers at ease. According to an independent study conducted on behalf of NSF, 75% of consumers would purchase a product with a certification mark over one without.

NSF-certified products are given certain numbers — i.e., NSF/ANSI 53 — that correlate to the specific standard to which the product has been certified. For example, a carbon filter that obtains an NSF/ANSI 53 certification has been tested to reduce a contaminant correlated with a health effect. These NSF standards cover different types of filtration systems used, the contaminants that are reduced, and also how effective softeners are at reducing water hardness, among several other requirements. These systems are not designed to eliminate all possible contaminants, so it is essential to make sure the system you purchase is designed to address the contaminants polluting your water.

Changing Your Filters

Once your water filtration system is installed, you must familiarize yourself with the product’s lifecycle, otherwise filters can lose their efficacy. When mechanical filters need to be replaced, the pores of the filter become clogged with debris, making it difficult for water to pass through. It is typically easy to tell when these need to be replaced since the water flow is reduced dramatically. Some filters, however, work by contaminants adhering to the surface of the filter media. For these, it is significantly harder to spot when the filter has reached the end of its lifecycle.

Most filters need to be replaced on a regular basis, and the recommended change cycle varies from product to product. Some filters may only last a few months, while others can remain effective for upwards of a year. The service cycle may be for a specific number of gallons or an estimate of the number of months that a cartridge will last in the average home. Some filters also have indicator lights that let you know when they are ready to be replaced, whereas others need to be monitored manually.


Spotting Counterfeit Filters

Finding an NSF certification logo on your filtration products is typically a testimony to its efficacy, but it is important to stay vigilant about avoiding counterfeit filters. Fake filters are becoming increasingly more prevalent and difficult to spot. In 2019, U.S. Customs and Borders Protection seized more than 5,000 fake refrigerator filters in California that were found in a shipment from China. Counterfeit filters are almost indistinguishable from NSF-certified filters, but they have not been inspected by the organization. These filters may not work the way they are supposed to and can potentially expose consumers to dangerous contaminants found in unclean drinking water or, even worse, they may introduce harmful chemicals into already clean water.

Fake filters are usually branded with the logo of a certification organization, making them especially difficult to differentiate from authentic ones. To avoid the possibility of purchasing a counterfeit filter, search for your products in the NSF database and always make your purchases through the manufacturer’s website or another legitimate source.


Water filtration systems serve several beneficial purposes and are designed to remove contaminants that may compromise the safety of your drinking water. Certifications guarantee that your filters are working properly and are successful in reducing the contaminants they are intended to reduce. It is the consumer’s responsibility, however, to remain attentive to when filters need to be replaced and to make sure filters are authentic by purchasing from trustworthy sources only.

About the Author

Stefan Buck

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