I need to do a project on a short-story I'm pretty sure is titled "The Lifeguard". I left the book at school, so I was going to google it to read it over again but I dont know who the author is...

The story's about how a teenager is a lifeguard at a pool and is constantly bothered by a little boy who makes a game out of floating upside down in the water. After the little boys parents die the main character visits the little boy and gets him to come back to the pool etc. etc.

If anyone's heard of this, can you pleasepleaseplease tell me the title & author ?