It’s easy to bring home a small portable pool from a department store and set it up for the kids. Kid-proofing that pool to protect your children from drowning isn’t so simple. During the summer in the United States, a child dies every five days in a portable pool, according to the first national study on the subject. Most of these kids are under 5 years old.

Parents often purchase portable pools without much thought, even though they pose about the same drowning risk to young children as in-ground pools. “Often, there’s not a lot of premeditation,” says study author Gary Smith, M.D., director of the Center for Injury Research and Policy at Nationwide Children’s Hospital in Ohio. Smith’s recent study found 209 drownings and 35 near-drownings connected with portable pools from 2001 to 2009. While those don’t sound like huge numbers, Smith says drowning is different from other types of injury risk.

“If you fall from a piece of playground equipment, you usually get a second chance,” Smith says. But drowning is quick, silent and final. And there are few practical ways parents can make portable pools safer.

The most effective pool-safety measure, isolation fencing (completely enclosing the pool area in a non-climbable four-foot-high fence with self-closing, self-latching gates), isn’t an option for many parents using portable pools, because it would cost many times more than the pool itself. Emptying larger wading pools when not in use isn’t convenient or environmentally sound.

Since no one safety measure is a guarantee, Smith recommends that parents take as many precautions as they can to create “layers of protection” for their children:

• Take your pool seriously. Smith’s study of U.S. Consumer Product Safety Commission injury and fatality reports found that 39 percent of children who drowned or nearly drowned in portable pools were unsupervised, and 18 percent of the remaining cases occurred when the caregiver reported napping, socializing, doing chores, or answering the phone or the door while kids were in or near the pool. “Supervision is vital when children are in and around water,” says Smith.

• Fence if you can. Isolation fencing would have prevented at least 48 drownings in the cases Smith researched.

• Prevent easy access. Around 88 percent of children studied by Smith and colleagues entered the pool using the pool ladder or by climbing on a nearby object. Keep chairs or other objects out of the pool area. If you can, remove or block your pool ladder when the pool is not in use. If the pool is small enough, consider emptying it when you aren’t using it.

• Teach your kids to swim. Swimming lessons have been proven to help protect children against drowning. But they’re no substitute for supervision.

You should also follow the standard swim-safety rules. Children should only swim when supervised by a fully attentive adult. No chatting, phone calls, reading, etc. And keep CPR instructions, a telephone and emergency numbers, and life jackets or other lifesaving devices poolside.