The European Standard DIN EN 14154 applies, regardless of the measuring principle, for cold and warm or hot water meters intended for residential, commercial, light industrial and industrial use. The scope includes water meters based on electric or electronic principles and water meters based on mechanical principles incorporating electronic devices. It can be used for verification of conformity with the essential requirements of the European Directive 2004/22/EC on measuring instruments and therewith as the basis for the CE marking. Part 1 specifies dimensions, general and metrological requirements and certification procedures for water meters and metrological requirements for electronic ancillary devices when they are subject to metrological control. The new edition of the European Standard, in which cartridge meters and meters with exchangeable metrological units and their connection interfaces are now taken into account as well, has been prepared by CEN/TC 92/WG 2 "Water meters - General requirements" (secretariat: NEN, Netherlands). For Germany Working Committee NA 119-04-08 AA "Wasserzähler" ("Water meters") at NAW has collaborated in the preparation of this standard.