The water filter is unnecessary (if you descale at least every two to three months, because that is all this expensive filter does and according to the user manual of the device you should continue to do this despite the filter being installed. in the user manual that the filter also needs to be replaced if you do not use the device for some time.That is because there are a kind of stones in the filter. When you empty the water tank and go on holiday, those stones dry out and they can come loose the next time you use it and end up everywhere in your machine and cause major damage! Hardly anyone knows that. For this reason, the filter is even advised against, including by the Coffee discounter. For the taste, the filter is not necessary at all and devices from other brands, without a filter, also work fine and they live just as long.