A broad category encompassing any device that physically or chemically removes suspended solids, impurities, and contaminants from water. This includes simple sediment filters, activated carbon blocks, and ceramic filters, and can be applied as pre-filters, post-filters, or standalone units. They operate by trapping particulates or chemically bonding with substances like chlorine. Water filters are essential for improving the taste, odor, and clarity of water, and are vital for protecting more sensitive and costly purification components, like RO membranes, from premature clogging and damage.