It's time to head for the pool again. There's nothing quite as nice as splashing around in cool water on a hot day. More than 6 million American families have pools in their own back yards. Then there are neighborhood pools, pools at clubs, school pools and pools at the Y.

As fun as they are, swimming pools can be dangerous places. Each year, between 600 and 700 people drown in swimming pools in this country. About half of the accidents happen in pools at people's homes. Many of these drownings could have been avoided by following a few basic safety rules.

If your family is lucky enough to have a pool, you probably already know a lot about how to avoid swimming-pool accidents. But safety experts say that it's a good idea to review the rules every summer as the swimming season begins:

Never, ever swim alone. Always swim with a buddy. Don't dive head first into water you haven't swum in before. Go in feet first to avoid hitting your head on a shallow bottom. Don't push others into the pool or jump on people who are in the pool already. Don't play rough games or run at poolside. Inflated tubes and air mattresses are fun to stretch out on in the water, but don't rely on them to keep you safe if you don't know how to swim. All children over age 3 should take swimming lessons from a qualified teacher.

The American Red Cross certifies swimming teachers. Ask if your teacher is certified. Swimming instructors say that kids should know at least these two basic water skills: They should be able to turn around in water and kick back toward the swimming-pool wall. And they should be able to float on their backs. Can you and other children in your family do these two things? Children under age 5 should be taught these skills again each summer when the pool opens.

When children are around water, they should be supervised all the time. There are no exceptions to this rule -- even if you just leave the pool "for a second." During the two minutes you're on the phone, in the bathroom or grabbing a towel out of a closet, a small child can fall in the pool and drown. Follow this rule whether or not children in the pool are using floats or air mattresses or wearing life jackets.

Be prepared for an emergency. Someone in your family should learn lifesaving methods, such as how to seize a struggling swimmer and assist him or her to the edge of the pool, and cardiopulmonary resuscitation -- the technique of pressing water from the lungs while puffing air into a person's mouth to help the swimmer expel swallowed water and resume breathing normally.

Post emergency numbers near the telephone so you can call for help quickly if an accident happens. When you and your friends swim, you probably stay in the water 'til you're shivering and your fingertips wrinkle up. When you get out, it's nice to stretch out in the sun to warm up again. As summer begins, it's a good idea to review a few rules about safety in the sun, too.

Sun damage to the skin builds up year after year and can eventually cause skin cancer. So it's important to start protecting your skin while you're still young. Luckily, it's easy to do: Use a waterproof sunscreen with a sun protection factor (SPF) of 15 or more and use it all the time. Put it on in the morning when you get up and again when you head out to the pool. When you use a sunscreen, apply it to every part of you that will be in the sun. Don't forget your ears, the tops of your feet and the part in your hair. After you swim, get someone to help you put on more sunscreen.

Wear a T-shirt. Pale colors reflect the sun's rays away from your body, so white or light colors are good summer fashion choices. Stay out of direct sunlight during the time when its rays are strongest: 10 a.m. to 2 p.m.

It may seem like there are a lot of rules to remember around a swimming pool. There are! But knowing the rules makes using your pool more fun: You can cool off, have fun, get good exercise and feel safe all at the same time.

Tips for Parents

Here's a pool checklist, adapted from materials from the American Red Cross and the National Safety Council: Never leave a child alone near a pool. Make sure your children take swimming lessons from a qualified instructor. Fence the pool on all sides with a non-climbable fence at least four feet high. Make sure the gate to the pool has a self-latching mechanism. Lock the gate when the pool isn't in use. Don't rely on flotation devices to protect young swimmers. Have a poolside phone to use in case of emergencies.

The National Safety Council urges pool owners to seek training in swimming, lifesaving, first aid and cardiopulmonary resuscitation (CPR). For a brochure "Shamu Says . . . Keep Your Swimming Pool Safe" write to National Safety Council, 444 Michigan Ave., Chicago, Ill. 60611.

Catherine O'Neill is a freelance children's writer.