A tank is proposed for appliances which use water, in particular domestic appliances or appliances for preparation of foodstuffs and/or drinks, such as automatic drinks machines, in particular automatic coffee machines, drinking water dispensers, cooking and baking appliances, steam appliances, in particular steam irons, steam cleaners, high-pressure cleaners, air cleaners and conditioners or the like, with a connection being provided on the tank for supplying water from the tank to the appliance and with a filter connection being provided for connection of a filter cartridge in the interior and/or outside the tank, while providing assurance that only the permitted filter type can be used. A tank according to the invention is distinguished by mechanical coding structures on the filter connecting element, in order to preclude the use of a filter cartridge which does not correspond to the tank.