"No matter how well trained a lifeguard is, we are dealing with human vigilance," says Josh Brener, of Poseidon System, a computer-aided drowning detection system.
And, as CBS News Correspondent Sandra Hughes reports, in a busy pool, even a well-trained lifeguard isn't always enough.
In a demonstration, a man lying face down in the water is captured on camera within seconds. An alarm sounds, and a rescue is underway.
In the winter, most beaches in LA are unmanned, but now they are not unwatched. Last month, cameras started capturing the coastline 24 hours a day, sending images back to supervisors who can send out a lifeguard.
"Many times I would pull up and there would be school buses when there wouldn't be a lifeguard here," says Mike Frazer, of the Los Angeles County Fire Department. "This will enhance public safety."
It's an idea that's catching on and catching heat from some privacy experts, but most citizens say they don't mind cameras at the beach if it makes them safer.
In Ontario, Calif., crime is down 7 percent. And police give the credit to a wireless camera that helps identify crooks through fingerprints and photos.
The prints are sent back to headquarters and compared to a database of known criminals.
"If they know they are wanted in relation to a crime they will give us a false name," says Jim Renstrom. "We can be talking to a guy wanted for murder out here and not know that he is wanted."
In just seconds the computer will sort through hundreds of thousands of criminals. What used to take hours is completed in minutes.
The system, police say, is helping them catch and properly identify criminals.
Using the same cameras, Ontario is poised to start using facial recognition to track crooks.
If it all sounds like Big Brother, police say don't worry. If you're not a criminal they destroy your picture, and they say there is just no stopping the power of technology that helps fight crimes.
And in the case of a drowning 16-year-old, saves lives.