While a father in Michigan was "distracted for three to five minutes" talking to someone--or "playing football," I'm not quite clear--his one-year-and-a-day-old daughter got out of the house, onto the porch, and into a 5-gallon bucket of water that'd been left out for the dog. That was it.
Unfortunately, it's the first bullet point on the American Academy of Pediatrics' Home Water Hazard for Young Children page [go read it. I'll wait.]: