All of the countertop water filters we test use carbon filtration to clean tap water. These filters are lined with black granular activated carbon, which, like a magnet to metal, pulls solid and gas contaminants from the water and air that flows through it. Activated carbon-block technology is good at filtering funky tastes and odors, chlorine, sediments, and sometimes even lead, solvents, and pesticides, according to the Centers for Disease Control and Prevention. Carbon-block filters are not effective at eliminating bacteria, however.
If you’re concerned about a particular contaminant in your tap water, get a Consumer Confidence Report from your water supplier, or, if you have a well, have your water tested. Then choose a filter that’s certified to remove whatever concerning substances those tests reveal. Don’t assume that all filters are the same or use the same technology. For example, according to the CDC, filters that remove chemicals don’t often effectively remove germs and vice versa.
