Swimming pools are a big attraction to children who should never be unsupervised around any body of water. Additionally, it's a good idea to invest in a pool alarm. There are several types [source: International Association of Certified Home Inspectors]:
• Alarm wristbands: A child wears an alarm, much like a watch, around his or her wrist. The alarm will activate when it becomes wet.
• Surface wave sensors: This alarm has an electrical circuit with two points of contact: a sensor that floats in the water and one that's attached to the pool deck just above the water surface. When a surface wave contacts the deck sensor, an alarm sounds.
• Sub-surface disturbance sensor: This sensor is mounted to the pool wall below the water surface and is activated by wave-induced pressure changes.
These sensors should never take the place of supervision and a locked gate or other restricted access around your pool.