An equalizing tank for a hydraulic motor vehicle brake system, with a housing including a housing upper part and a housing lower part, and with a device for monitoring the fluid level in the equalizing tank, the device including a switching unit which is fastened to the housing and has a plug-in connector and a contact carrier, a portion of which projects into a guide pipe which extends into an interior space of the tank, and a sensor element or switching element which is arranged on the contact carrier in the region of the guide pipe and which can be switched by a transmitter in a switching point at which the switching unit generates a signal for an electronic control unit.