A mixing assembly includes a water tap connection with at least one cold water feed which is provided with a second cold water feed that is connected to a CO2 supply. The CO2 supply is connected by a CO2 conduit to a metering station which is connected to the second cold water feed and is configured as a nozzle projecting in the second cold water feed and arranged radially to the second cold water feed. Provided between the metering station and the water tap connection is a mixer in the form of a static mixer. The second cold water feed is connected to the main water line, but can also be connected to the cold water feed by a branch pipe. Suitably, the second cold water feed is configured between the metering station and the water tap connection as a reaction conduit of e.g. helical shape.