A liquid level sensing device for sensing liquid in a container. The liquid level sensor has a housing with a power source and an alarm. A first reference surface is positioned on the housing and cooperates with a top surface of a container when the liquid level sensor is initially positioned on the container. A sensor extends from the first reference surface. A positioning member is provided on the liquid level sensing device and cooperates with the container to provide a reference to allow the liquid level sensing device to be accurately moved from the initial position to other predetermined positions relative to the container to allow a user to fill the container with one or more liquids to the desired level. A reservoir portion may be provided on the liquid level sensing device for storing and dispensing a liquid.