Abstract: A mercury activated float switch is selectively positioned within a slot formed along an axial length of a perforated pipe. The pipe is vertically mounted to a weighted base, and the switch may be slid along the slot to adjust its operable height. The float member is pivotally mounted within the pipe and closes the associated switch when a preselected water level is detected. The closed switch then activates at least one type of alarm, such as an alarm bell or light, and may also be utilized to activate a transmitter which sends a signal to remotely positioned receiver.