Abstract: The throttle shaft for the controlled discharge of dammed-up water, especially for the controlled flow of sewage and waste water to sewage-processing units, comprises a housing formed with an inlet and an outlet for a float-controlled throttle flap at the inlet regulating the flow of water into the housing in response to the water level therein. According to the disclosure, the housing is provided with a throttle channel for the water which communicates with the outlet and is provided with an adjustable shutter shiftable between a fully closed and a fully open position to vary the flow cross section of this channel or passage.