Abstract: In order to improve the lifespan of the semi-permeable membrane or the yield of the reverse osmosis system in the treatment of drinking water by means of reverse osmosis, the invention provides a device for treating drinking water with at least one reverse osmosis vessel which is divided into at least two chambers by at least one semi-permeable membrane, wherein a first chamber has an inlet for the water to be treated and an outlet for the concentrate, and the second chamber has an outlet for the treated water, wherein the device comprises at least one pressure vessel which is connected to the outlet for the treated water via a line, wherein the device is designed in such a way that, in an idle state, treated water flows out of the pressure vessel, through the semi-permeable membrane and into the first chamber.

Abstract: A connection head for a filter cartridge, which is easy and safe to handle. The connection head comprises a housing that has an inlet and an outlet, wherein said inlet and outlet have a port to which a detachable adapter piece for water conduit can be mounted. The adapter piece is attachable by a quick-release fastener. The quick-release fastener comprises a locking element, which locks the adapter piece by being rotated by about less than 90°.