By Jim Donovan

PHILADELPHIA (CBS) — They’re an inexpensive way to add some fun to your backyard.

But just in time for the long holiday weekend, the nation’s top consumer safety agency has a warning for parents before they buy a portable pool.

They seem pretty harmless. After all–what risk can a little pool filled with a foot or two of water do? But you’d be surprised.

The Consumer Product Safety Commission is urging parents to use caution when considering the purchase of a portable pool, ranging from blowup kiddie pools to larger models.

According to the head of the consumer product safety commission, Inez Tenenbaum, the small pools can pose risks.

“Portable pools have become more affordable, but they hold thousands of gallons of water. And so, parents need to know they need to take the same type of steps to save lives if they’re going to use a portable pool,” Tenenbaum said.

The CPSC advises owners to plan on emptying small kiddie pools after every use and to have a place to store them. Larger pools should have a cover, and the ladder should be stowed when not in use. And parents should learn CPR and other life-saving skills in case of an emergency.

Remember, children can drown in a very small amount of water. That’s why they should never be left unattended in a pool, no matter how small.

The CPSC also advises you to warn your neighbors if you’ll be using a temporary pool in your yard this summer. You never know when a small child will wander off, and a kiddie pool filled with water could be an invitation that could turn tragic.