Nothing is fool proof when it comes to protecting against drownings, but a new pool alarm now hitting the market is receiving top marks in consumer tests.
Many pool alarms get a bad reputation for sometimes issuing false alarms. Many float on the water and react to surface disturbances.
But there are some alarms that are attached to the pool deck or on the pool's side at the waterline and use high tech to protect against drowning.
"The principle of operation is subsurface signal analysis, and that is a fancy way of saying we are looking at the shockwave under the water that is created when an object falls in and we are not paying attention to the surface noise," said Bill Whitehurst with MG International.
Many pool alarms sound when there's a little wind or a ball hits the water, but the ones 7 On Your Side tested do not -- and they do not.
7 On Your Side even tried to fake out the alarms. Good for false alarms, but do they work at all? An 18-pound toddler mannequin was just tipped off, and in five seconds the alarm sounded.
"The reality is you can't compress water. So when an object falls into the water there is an underwater wave that travels faster than the ripples on top of the water," said Whitehurst.
Anne Appleman owns this pool. She says the alarm is easy to use.
"It has a swim feature so when you are in the pool, it is disengaged, but if you are out of the pool for any amount of time it rearms itself," said Appleman.
"The question isn't just does it work, but do you trust it?" asked 7 On Your Side's Michael Finney.
"Yes, absolutely, absolutely," said Appleman.
Pool alarms cost between $500 and $700.
Related link: Pool alarms from Good Housekeeping
Note: There is no affiliation between National Drowning Prevention Alliance (NDPA) and Bill Whitehurst. The NDPA does not endorse any pool alarm products