It’s recommended that you give your countertop water filter a deep clean every 2 to 3 months. If your water has a high mineral content, and is depositing limescale on the inside of the holding tank, you should clean it more regularly. For hanging gravity water filters, wash everything and dry thoroughly according to the manufacturer’s instructions after using it on a trip. You can also rinse it out on your travels if you’re away from home for a long time.