The sanitary appliance (400) comprises a receptacle (410) and a tube (420) provided with a tube wall (401, 402) and configured to contain—in use—an aqueous solution (1000) and a sensor circuit (105) for sensing inflow of matter into the sanitary appliance (400), wherein the sensor circuit (105) comprises a primary circuit and a secondary circuit that are mutually inductively coupled, wherein the inductively coupled secondary circuit includes a capacitive sensor comprising a first and a second electrode (101, 102), each of which are configured to be in use at least partially (101, 192) in contact with the aqueous solution (1000), which constitutes a medium of the capacitive sensor.