About ten people drown every day in the United States in non-boating related incidents. Of those, about 300 will be toddlers under the age of 5. Water safety is highly important, not only for your family, but for your neighbours too. Most municipalities, if not all, specify that the pool must be able to be closed off when not in use. This is a safety measure in place to prevent accidental drownings. The easiest way to do this for an in-ground pool is to simply fence it off and have a latchable gate for access. Above-groud pools can easily have the deck fenced and gated as well. Most fences cost $5-$10 per foot. If your backyard is already fenced around the sides and the back, you should be able to gate across the side lawns inbetween you and your neighbours.
There are all sorts of fence types available to suit your price range and to match your style. Wooden fences can be built beautifully and provide an incredible amount of privacy, whereas a rod-iron fence might just look stunning in your backyard and be able to provide you with a view of the pool at all times so you can monitor your kids playing.