A water filter is a device that removes impurities from water by using a physical or chemical process. Water filters can be used for various purposes, such as improving the taste of drinking water, removing harmful contaminants, and providing safe water for household or industrial use. There are many types of water filters available, including activated carbon filters, reverse osmosis systems, and UV water purifiers. The type of water filter you choose will depend on the specific impurities you need to remove and the intended use of the filtered water.