"Most children drown because their parents turn their head for just a second or have no idea that their child is even near the pool," says Letter, who founded Water Watchers, a water-safety program run by Phoenix Children's Hospital, to honor her son and prevent similar tragedies. In nine out of 10 drownings, parents or caregivers say they'd been supervising the child at the time, according to research by Safe Kids Worldwide. But kids -- especially toddlers, who are at highest risk -- are impulsive and fast. They'll dart out a screen door, crawl through the doggy door, or wander into the pool area to get a toy.
"Almost all children who've drowned had been missing for less than five minutes," adds Tiffaney Isaacson, coordinator of Water Watchers. "However, four minutes under water can cause permanent neurological damage. If you have a pool and you don't know where your child is, always look in the pool first."
When a child drowns, it's nothing like what you might see on TV or in the movies. "Toddlers don't yell or splash, and they sink fast," warns Steven Kernie, MD, a pediatric critical-care physician at Children's Medical Center Dallas. Ironically, many drownings occur at parties with plenty of adults around. "Everybody assumes that someone else is watching the water," says Dr. Kernie. "That's why it's critical to designate one adult to keep an eye on the kids and the pool all the time."