She wants children to take swimming courses with a water survival component; she is wary of puddle jumpers — popular life jackets that hold a child upright — which she believes can convince children they will float. Most of all, she says, she wants to see a cultural change around our attitude toward water safety, as has happened with the “Back to Sleep” education program and with car seat and seatbelt use.

“This can happen to anybody and it only takes a short period of time, and no one thinks this is going to happen to them,” said Dr. Sarah Denny, an associate clinical professor of pediatrics at Nationwide Children’s Hospital, who was the first author on the new American Academy of Pediatrics policy statement on drowning prevention. So there’s a good reason to bring this up every year, and review even what you think you already know.

[Read the full text of the Drowning Prevention statement. Review the A.A.P. Drowning Prevention Toolkit.]

“If you look at drowning deaths, there are two huge spikes,” said Dr. Benjamin Hoffman, who is the medical director of the Tom Sargent Safety Center at Doernbecher Children’s Hospital in Oregon, and was one of the authors of the statement. One is 1 to 4 years old, and the second is adolescents, especially boys, from 15 to 19. Many of them drown in open water, he said, sometimes “while boating, or jumping off a rock, or underestimating the power of mother nature.” Drowning is the second-leading preventable cause of death among 15- to 19-year-olds.

“We were lake people, we went to the lake every summer,” said Dana Gage, whose 15-year-old son, Connor, drowned in a Texas lake in 2012. “Connor was Coast Guard safety-certified,” she said. So when he got a last-minute invitation to a birthday party at the lake with friends, his parents agreed. It was the first time he had gone to the lake without them.

That evening, the boys at the party were playing follow the leader, and at 8:15 Connor jumped off the roof of the boathouse and did not resurface. At first, his friends thought he was joking, and then a frantic search began, and a dive team was called. “At 9 p.m. my son was pulled from the bottom of the lake, and of course, he could not be resuscitated,” Ms. Gage said.

An autopsy showed no other problems or injuries; he had not hit his head, Ms. Gage said.

“He was a heck of an athlete, an endurance runner, a swimmer. It’s inconceivable that he just jumped in the lake” and died.