Hardly anyone has not noticed that in the last decade significant changes to the sanitary market have taken place. In particular, the variety of designs called for by the end customer due to special needs and the increasing demand for quality of the trays represented a particular challenge for the manufacturer. In order for sanitary appliances to obtain broad market access, the demand for optimal connection possibilities to the waste water disposal and water supply systems, if necessary, in the different countries with many different traditions of building and installation techniques has existed since the beginning of European standardization at CEN. Particularly the standardization of connecting dimensions allows for the marketability for both baths and shower trays. The standards DIN EN 232 and DIN EN 251 specify requirements for the connecting dimensions for baths and shower trays, regardless of the material used for their manufacture. Only those dimensions specified are compulsory. The shape of the trays represented in each figure is for illustration only. The standards in no way prejudice the shape of the trays which is left to the initiative of the manufacturer. Both standards apply to baths and shower trays used for domestic purposes and complement the standards for baths and shower trays made from different materials as well as the existing standards on tap ware and waste fittings (DIN EN 200 and DIN EN 274-1) in terms of their dimensional requirements. With regard to the previous versions, corrections have been made and some elements have been rendered more precise. These standards have been prepared by CEN/TC 163/WG 4 "Baths (W/Pools) - Shower trays (Performance testing)" (secretariat: BSI, United Kingdom) under the leadership of the employees of Committee NA 119-05-18-10 UA "Bade- und Duscheinrichtungen" ("Bath and shower devices") at the Water Practice Standards Committee (NAW).