Barrier or fences:

• Not very esthetic
• If door not closed or even in presence of the parents, a child can fall into the water without nobdy noticing !
• Installation usually mandatory by law in several countries to avoid children to approach the pool but does not guarantee children safety when they are inside the pool area even in presence of the parents

Roller covers and saftety covers

• While the cover is open, there is no security even in presence of the parents!
• Opening/closing time quite long.
• If doesn’t close correctly or if the straps are not properly tightened, your child can slide under the cover and you don’t see the child drowning.
• You will probably not close the roller cover when you have to go in the kitchen to take something and that’s where an accident can occurs  

 Traditional Alarm Systems

 

Wave detection (or variation of pressure):

• • To many false alarm due to
  • • wind
    • objects falling into the pool
    • filtration systems malfunction
  • These false alarms create too much disturbances for the neighbors

 Active sonar alarm systems

• These active sonar systems have actually never really been never completed or marketed
• Needed to be installed by professionals at construction of the pool
• Necessitates numerous transmitters and sensors with high power consumption for sonar power.

Infrared barriers

• Can be activated by your favorite pets and dogs even birds crossing the infrared rays and therefore generates many false alarms.
• Again too much disturbances for the neighbors 
• Only access surveillance. No fall detection!

Video surveillance

• Depending on the system especially for underwater surveillance, the time the system recognizes a motionless corps you already lost precious seconds if not minutes.
• Underwater systems don’t work in uncleared water !
• If used for access surveillance, there is no fall detection. 
• You might get many notifications with no real reason
• Remote notifications on your cell phone will make you fell to secure!
• In presence of parents, again no alarm when the child falls into the pool

Bracelets swimmvests or similar

 

The Califonia's health and safety code

• Swimming Pool Safety Act, Sections 115920-115929

states:

 

(6) A swimming protection alarm feature designed for individual use, including an alarm attached to a child that sounds when the child exceeds a certain distance or becomes submerged in water, is not a qualifying drowning prevention safety feature.