January 13, 2026, 5:01 am | Read time: 3 minutes
A freshly brewed coffee is a morning ritual in many households. Thanks to modern coffee machines, such as capsule systems, portafilter machines, or fully automatic machines, enjoying a cup often requires just the push of a button. These devices have water tanks that can hold several liters of water. This raises the question: How often should the water be changed? myHOMEBOOK provides answers in this article.
How often you should change the water in the coffee machine is, quite literally, a matter of taste. Manufacturers of such fully automatic coffee machines do not commit to a specific frequency. Some recommend changing the water in the tank after each use or daily. Others take a more relaxed approach, advising to change the water only if the machine hasn’t been used for an extended period. However, what constitutes an “extended period” is not clearly defined.
Germ Load Increases
In general, tap water in Germany is subject to strict testing and is therefore safe to drink in most regions. However, external factors can introduce germs into the water tank, such as through the air. Light, heat, and dirt in the tank promote the growth of germs.
Since the water in coffee machines is heated to temperatures between 80 and 90 degrees Celsius, existing germs are killed, though not completely. To make water germ-free, it should be boiled for about three minutes. However, even brief brewing is sufficient to eliminate health risks. From a health perspective, water that has been sitting in the tank for several days or weeks poses no problem.
Coffee Enjoyment with Fresh Water
However, if you associate your morning cup of coffee with enjoyment, you should not use stale water for brewing, but rather fresh water. When water sits unused in the tank for a while, an invisible film of deposits forms on the surface. This so-called biofilm alters the taste of the coffee. Additionally, such deposits can clog the pipes over time. This fact alone should be reason enough to regularly empty and clean the water tank before refilling it with fresh water.
Therefore, it is generally advisable to fill the tank according to your drinking habits. If you use your coffee machine several times a day, you can fill the water tank completely. People who only drink coffee occasionally should not fill the tank completely.
Regardless of how often someone drinks coffee, the water tank should be regularly cleaned and the remaining water replaced. It is also advisable to descale the coffee machine at certain intervals.
Related: How to Descale the Coffee Machine with Home Remedies
By the way: The remaining water from the tank can be used, for example, in the iron’s tank or as liquid nourishment for plants. This way, it is put to good use.