Pool Alarms, Gate Alarms and Wearable Alarms: How They Help

Pool alarms help by making noise when a door or gate to the pool opens, or when something or someone enters the water. They are a backup layer: useful when supervision slips, but never a replacement for a four-sided fence and an adult watching the water.

There are four main kinds. Each covers a different gap, and each has limits worth knowing before you buy.

Alarms are a backup layer

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Gaps in supervision are when alarms earn their place. Pool Safely, the U.S. Consumer Product Safety Commission (CPSC) campaign, lists pool fences, pool covers, door alarms, pool alarms, and anti-entrapment drain covers (opens in a new tab) among the safety devices families can install.

But the American Academy of Pediatrics (AAP) is clear about where alarms rank: none are substitutes for a properly installed pool fence (opens in a new tab). The U.S. pool alarm standard says the same. ASTM F2208 is not intended to replace other standard safety requirements (opens in a new tab), which it lists as adult supervision, fences, gates and locks.

Think of it this way: a fence stops a child. An alarm tells you a child may already be on the way, or in the water.

Door and gate alarms

These sound before a child reaches the pool, which makes them the most useful type for families with toddlers.

• Door alarms go on every door from the house to the pool area. CPSC recommends them whenever an outside wall of the home serves as one side of the barrier (opens in a new tab).
• Gate alarms go on the pool fence gate and sound if it opens.
• Touchpads let adults pass without setting them off. The AAP notes that door and gate alarms can be equipped with touchpads to let adults pass through (opens in a new tab).

CPSC's guidelines say a pool door alarm should start within 7 seconds, sound for at least 30 seconds, reach at least 85 decibels at 10 feet, sound unlike the phone, doorbell or smoke alarm, and reset itself after an adult passes through. The full list is in door alarms and locks.

In-pool alarms

These sense movement in the water and sound when someone falls or jumps in. ASTM F2208 describes three kinds that are fixed to the pool:

• Surface alarms, which float on the water's surface (opens in a new tab) and sense waves.
• Subsurface alarms, which sit below the water surface (opens in a new tab).
• Perimeter alarms, which detect movement at the perimeter of or above the water surface (opens in a new tab), such as a beam around the pool edge.

Their main limit is that they react to entry, not approach. The AAP also warns that alarms that detect waves do not always work with children because they may not make enough waves (opens in a new tab). The standard's detection criteria are for a child one year of age and older (opens in a new tab).

Because swimmers would set them off, in-pool alarms are usually paused during swim time, so someone has to remember to turn them back on. Make that part of closing up the pool.

Wearable immersion alarms

ASTM F2208's fourth type is the personal immersion alarm, a device located on the person (opens in a new tab), such as a band worn by the child. It is designed to raise the alarm when the wearer goes into the water.

• It only protects the child who is wearing it, and only while they wear it.
• It warns you after the child is already in the water, so someone must be close enough to act at once.
• It can help for a child who wanders, alongside locks and a fence. See stopping toddlers from slipping outside.

Which alarm for which gap

Whatever you choose, it sits on top of the core layers in the home pool safety checklist, not in place of them. The National Drowning Prevention Alliance groups alarms with barriers as one layer and says each layer should be used together (opens in a new tab).

Testing and maintenance

An alarm that's switched off, muted or out of batteries gives false comfort.

• Test every alarm regularly during swim season, and after storms or power cuts.
• Replace batteries on a schedule. The AAP says to make sure alarms are in good shape with fresh batteries (opens in a new tab).
• Turn in-pool alarms back on as soon as swim time ends.
• Make sure the sound can be heard in every room, including bedrooms with doors shut.
• Follow the maker's instructions for installation, testing and winter storage.
• If you have a security system, keep the door chime on. The AAP suggests ensuring the door alert sound is turned on (opens in a new tab).

What you can do today

1. Find your gaps with the Pool barrier check. Start with the doors from the house to the pool.
2. Test the alarms you have. Can you hear them from the farthest bedroom?
3. Set a regular battery reminder on your phone.
4. Add "alarm on" to your end-of-swim routine, along with "gate latched."
5. Fix the fence first if it isn't four-sided. See pool fences and gates.