Abstract: A safety device which is responsive to excessive wave motion of a body of water includes a housing having a pivotable telescoping arm connected thereto. A pair of spaced apart probes are mounted on the end of the arm. The probes are connected to a control circuit located in the housing. The control circuit measures the electrical resistance between the two probes, which is normally an open circuit. In use, the arm is manipulated so as to position the probes a desired distance above the normal water level when no one is in the pool. Thus, the space separating the two probes is normally not bridged by water from the pool. When a person enters the pool, however, larger waves are created. These larger waves splash across the probes, bridging the space therebetween. As a result, the electrical resistance between the probes decreases. The control circuit is responsive to this change for generating an alarm. The safety device may also include a pressure responsive switch secured to a step of a ladder in the pool.