Abstract: A magnetically activated float switch apparatus is disclosed for opening and closing an electrical circuit in response to a predetermined change in the level of a liquid. The apparatus includes a float element having an interior chamber. There is a capsule mounted within the chamber. A permanent magnet is mounted in the capsule and is slidable between first and second positions therein. A switch is mounted in the chamber adjacent to the capsule and is electrically connected to the electrical circuit. The switch is responsive to the permanent magnet in the first position for maintaining a first state and is responsive to a permanent magnet in the second position for maintaining an opposite second state. One of the states is open and the other is closed. The float element is suspended by a cable in an upright condition when the liquid is below a known level such that the magnet is in the first position and the switch is in the first state.