Water is the most controlled food in Germany. However, some people use special water filters to treat tap water. They are supposed to remove pollutants and bacteria, but do they actually do that? Are water filters unnecessary or a practical addition? Or can they even harm the quality of the water?
Tap water in Germany is subject to strict controls and is of good quality: the German drinking water regulations sometimes even have stricter requirements than European law. Manufacturers of so-called “table water filters” promise even better quality, specifically even softer, pollutant-free water. But this also comes with additional costs: By purchasing and regularly changing the filter cartridges, the price for a liter of tap water increases from an average of 0.2 cents to 15 cents. But what do you really get for it? So are water filters useful or not?
Should we filter tap water?
One reason some people turn to water filters is because they fear that the drinking water may contain drug residues. In fact, thanks to modern analysis methods, even tiny amounts of pollutants can now be detected in tap water. Due to the widespread use of medicines and pesticides, such residues can actually be found in some samples. However, these are minimal, are well below the legal limits and, according to current knowledge, are harmless even when consumed daily. So there is no need to filter them out.
Germs such as legionella are also very unlikely in tap water because its quality is well monitored. If legionella is present in the water, it is not due to the public water supply, but rather to a problem with the hot water preparation – these cannot be removed with a filter, but must be killed professionally using thermal or chemical disinfection. The same applies to the supposedly harmful lead it contains: houses built after 1973 do not have lead pipes. Older houses do, but drinking water filters are not suitable for filtering out lead. Table water filters do not have sufficient filter performance for this.
Mostly inadequate performance
Under certain circumstances, drinking water filters can even be harmful instead of useful. Because they can provide a breeding ground for germs if the filter cartridges are not replaced regularly. In addition, activated carbon filters, as used by most manufacturers, can release the substances they have filtered out in concentrated form if too many have accumulated. “In addition, some devices even emit additional, undesirable substances, including sodium, chloride and silver,” reports the Hamburg Consumer Center. “This also applies to special baby water filters.” This is problematic because baby food should be prepared with water that is as low in sodium as possible.
Drinking water filters basically remove calcium and magnesium – i.e. lime – from the water and thus make it softer. Some tea and coffee lovers swear by the improved taste of the water with less lime. However, lime is not unhealthy and can even provide us with important minerals. A study by Stiftung Warentest also shows that softening only works to a limited extent: The table water filters tested by the testers only achieved around a quarter of the advertised filter performance and the market leader’s two test winners only achieved a satisfactory quality rating.
Safe use of water filters
If you still don’t want to do without filtering, you should change the water in the containers every day and keep the jug in the refrigerator and wash it regularly so that no germs can form. It is also recommended to replace the cartridge after four weeks at the latest.