Your refrigerator’s water filter might not be removing microbes and toxins from your ice or drinking water. If your refrigerator makes ice and/or dispenses water, it probably has a water filter that is supposed to be replaced regularly, likely every six months. The replacement filters sold by refrigerator manufacturers often cost $30 to $50 apiece, but refrigerator owners often seek lower-cost alternatives. Although some may be as good as the name brands, many will do little or nothing to make the water safer or more pleasant to drink and others may not even fit properly, leading to leaks and water damage to homes.

In some cases, these ineffective filters are simply poorly made, off-brand substitutes sold by third-party companies, but in others, they are outright counterfeits falsely marketed to be the same filter sold by fridge makers.

What to do: Buy refrigerator filters (and other water filters) only from reputable, well-established retailers such as well-known home centers, department stores, drugstores and appliance sellers as well as major online retailers. On reputable websites, before buying a water filter made by or recommended by anyone other than the fridge’s manufacturer, read the reviews and ratings left by other buyers. If a third-party filter that fits your refrigerator has been reviewed by hundreds of customers and received scores comparable to those of the manufacturer’s filter, it is likely to fit properly and improve taste and odor effectively.

To ensure that the filter also removes important contaminants, confirm that the filter is certified by the Water Quality Association, NSF International and/or The International Association of Plumbing and Mechanical Officials. This certification should be noted on the packaging and on the merchant’s website. Helpful: There are two separate NSF certifications worth knowing about when shopping for refrigerator water filters. NSF 53 certification means that the filter removes contaminants that pose health risks such as lead and asbestos. NSF 42 certification means that the filter removes contaminants that are not considered health risks but that could affect the smell, taste or appearance of drinking water.