The water filter reduces limescale deposits, improves coffee quality, and ensures a perfect coffee aroma as well as a long-lasting performance of the machine. It is suitable for all fully automatic coffee machines in the entire ECAM series, ETAM series, and PrimaDonna series, as well as the combination coffee machines BCO 410.1 and BCO 420.1, and the espresso machines EC 680, EC 820, and EC 850.