This European Standard specifies requirements relating to the construction and mode of operation and relevant methods for testing automatic, salt-regenerated, anion exchange nitrate removal devices for drinking water installations inside buildings, which are permanently connected to the mains supply. NOTE Products intended for use in water supply systems are to comply, when existing, with national regulations and testing arrangements that ensure fitness for contact with drinking water. The Member State’s relevant regulators and the EC Commission agreed on the principle for a future unique European Acceptance Scheme (EAS) which would provide a common testing and approval arrangement at European level. If and when the EAS is adopted, European Standards on products will be amended by the addition of an Annex Z/EAS under Mandate M/136, which will contain formal references to the testing, certification and product marking requirements of the EAS. Until the EAS comes into force, the current national regulations remain applicable.