System for transmitting liquids, e.g. clean water and wastewater, between a stationary core and a rotatable story of a building in which said rotatable story is arranged substantially circumferentially around said stationary core and is rotatable with respect to said stationary core about a vertical reference axis that is the longitudinal axis of a section of the core at which the story is arranged, the system comprising an annular buffer duct extending circumferentially around the reference axis of the stationary core and having an annular lower duct portion extending along the entire circumferential length of the buffer duct, and an upper duct portion arranged from above in liquid communication with the lower duct portion and slidingly engaging the lower duct portion in at least one interface extending along the entire circumferential length of the buffer duct, one of the lower duct portion and upper duct portion being fixed to the stationary core and the other one of the lower duct portion and upper duct portion being fixed to the rotatable story, so that upon rotation of the story with respect to the core about the reference axis, the upper and lower duct portions (8, 7) rotate relative to each other about the reference axis, the buffer duct internally defining at least one annular transmission chamber into which the liquid enters from above through one or more inlet ports formed by the upper duct portion, and from which the liquid exits through one or more outlet ports formed by the lower duct portion, the transmission chamber being at atmospheric pressure, characterized by comprising: - transmitted liquid level sensor means for detecting a transmitted liquid level of the liquid in the annular transmission chamber and - a control system connected to the transmitted liquid level sensor means and adapted to control one or more inlet valves of the inlet ports in dependency on signals from the transmitted liquid level sensor means. the system comprising an annular buffer duct extending circumferentially around the reference axis of the stationary core and having an annular lower duct portion extending along the entire circumferential length of the buffer duct, and an upper duct portion arranged from above in liquid communication with the lower duct portion and slidingly engaging the lower duct portion in at least one interface extending along the entire circumferential length of the buffer duct, one of the lower duct portion and upper duct portion being fixed to the stationary core and the other one of the lower duct portion and upper duct portion being fixed to the rotatable story, so that upon rotation of the story with respect to the core about the reference axis, the upper and lower duct portions (8, 7) rotate relative to each other about the reference axis, the buffer duct internally defining at least one annular transmission chamber into which the liquid enters from above through one or more inlet ports formed by the upper duct portion, and from which the liquid exits through one or more outlet ports formed by the lower duct portion, the transmission chamber being at atmospheric pressure, characterized by comprising: - transmitted liquid level sensor means for detecting a transmitted liquid level of the liquid in the annular transmission chamber and - a control system connected to the transmitted liquid level sensor means and adapted to control one or more inlet valves of the inlet ports in dependency on signals from the transmitted liquid level sensor means. - transmitted liquid level sensor means for detecting a transmitted liquid level of the liquid in the annular transmission chamber and - a control system connected to the transmitted liquid level sensor means and adapted to control one or more inlet valves of the inlet ports in dependency on signals from the transmitted liquid level sensor means.