Abstract: A device for detecting leakage of liquid through a ceiling comprising at least one liquid concentrating tray having peripheral flanges for support from ceiling panel support rails and surfaces between said flanges sloping toward narrow troughs, electric conductors for conducting electricity, sensor terminals for contacting the liquid, warning device for warning of a leak in the ceiling, and a current source for actuating the warning means when the liquid contacts the sensor terminals. The sensor terminals are connected in parallel by the electric conductors to the electric current source and the warning device in the electric circuit.