A connecting unit for a sanitary fitting is proposed, said connecting unit having, on one side thereof, plug-in sockets for connection to plug-in nipples of the sanitary fitting. On the opposite side, the connecting unit contains connections for the domestic installation pipes. The sanitary fitting and the connecting unit are connected by plugging in a direction parallel to the wall surface.The connecting unit may contain a flushing pipe which is designed as a continuous bore. When the connecting unit is not yet connected to the sanitary fitting, said flushing pipe can be used to flush out the pipes. Said flushing pipe is stopped from functioning when the connection between the sanitary fitting and the connecting unit is produced.