The invention provides a domestic appliance (100) configured to provide descaled water (2) during operation, wherein the domestic appliance (100) comprises (i) a descaling unit (200) for the production of descaled water (2), wherein the descaling unit (200) comprises a descaling reactor (210), a descaling unit inlet (201) for introduction of water (1) into the descaling reactor (210) and a descaling unit outlet (202) for release of descaled water (2) from the descaling reactor (210), and (ii) a scale inhibitor dosing unit (300) configured to provide a scale inhibitor (310) to the descaling reactor (210), wherein the scale inhibitor (310) comprises a phosphonate; wherein the descaling unit (200) further comprises an outlet unit (220) comprising (i) said descaling unit outlet (202) and (ii) a scale inhibitor adsorbent (230) configured upstream of said descaling unit outlet (202), wherein the scale inhibitor adsorbent (230) is selective for said scale inhibitor (210).