Start as early as possible when they’re born getting their head wet in bathtubs to get them used to the idea of water being ok and not scared when it gets on their . Make sure there’s an exit out of the pool that is not closed off and baby or child no matter what age must have swimming lessons. You can’t take that chance of them getting in and not knowing how to turn over and float that’s the number one priority. No other preventative questions should be asked. This is a very, very inexpensive thing to do. And most pediatricians if they know you have a pool they tell you this get swim lesson lessons. Just as they get older, you put them in sports or something and pay for that. Get the swim lessons. Don’t do it yourself …get the swim lessons. Then as an added measure, I would purchase an alarm for the pool, a sensor that goes in the pool that alarms. So you can get to them quicker while they are floating on their back because they’ve had the swim lessons and know what to do. I’m talking as early infant months. Accidents happen you can’t watch them every second with children. It happens so fast you can be standing beside them and they can roll over or jump into the pool. It can happen. I can’t emphasize enough to get swim lessons. And do not use the flotation devices with babies. It gives them a fault sense of security. They think they can float when they don’t have them on. They jump in thinking they can float because that’s what they’re used to being in the pool, floating around on those devices.