Many households have air or water filtration systems installed. However, most people are unaware of how to maintain these systems or the importance of doing so.

Some salespeople, in an effort to make a sale, exaggerate the functions of filters, painting a rosy picture and touting the products as having numerous features, wide-ranging applications, and requiring no maintenance or upkeep—all to entice customers to buy. Many consumers take these claims at face value, only to end up not only losing money but also facing health risks.

Whether it’s an air or water filter, the more advanced or sophisticated the system, the more important regular maintenance becomes. For example, with water filters, the filter cartridges should be replaced at least once a year—or even as frequently as every 3 to 6 months—depending on water quality and usage. Small air filters also require attention; typically, the filter screens should be cleaned and the cartridges replaced every 3 to 6 months.

Most central water filtration systems have an automatic cleaning function, and the filter media can remain effective for several years; however, water quality should still be tested and monitored every 2 to 3 years, and maintenance or replacement of the filter media should be performed as needed. Since water softeners do not perform filtration functions, their media typically does not need to be replaced for many years; however, water quality should still be checked regularly, and disinfection and maintenance procedures should be carried out as needed.

By Michael Chiu, MWS, CI
Previously published in Ming Pao Daily News – Updated and Revised in 2026