There are several different types of pool alarms on the market today. Surface alarms float on top of the water in above ground and inground swimming pools. Subsurface alarms rest below the waterline and sound an alarm once an object falls in. A personal immersion alarm is a device that’s connected to a specific person or animal, and lastly, a pool perimeter is an alarm that detects movement around the outside of the pool.Regardless of the type of pool alarm you choose, they’re a necessary safety feature that should be included on your pool’s supplies list. Pool alarms play a huge role in swimming pool safety—even if you don’t have children or pets of your own. Neighborhood children or pets can wander into your backyard unsupervised, so you should always outfit your pool with an alarm.