With all outdoor pools, it is necessary to prevent young children from climbing up into an above ground pool. The steps or the ladder can be made to be secured, locked, or removed. Or, the steps or ladder can be surrounded by a barrier.
In the U.S., the Consumer Product Safety Commission (CPSC) has details on the federal requirements for swimming pool fencing on their website at http://www.cpsc.gov/cpscpub/pubs/Pool.pdf. The basics are that the top of the barrier should be 48 inches or more above the grade on the side of the barrier facing away from the swimming pool. If the top of the pool is above grade, as with an above ground pool, the barrier can be at ground level or mounted on top of the pool structure. When the barrier is on top of the pool structure, the vertical clearance between the top of the pool structure and the bottom of the barrier should be no more than 4 inches.
The openings in the barrier should not allow passage of a sphere (ball) with a 4-inch diameter. When the above ground pool fence is made of horizontal and vertical pieces, and the distance between the tops of the horizontal pieces is less than 45 inches, the horizontal pieces should be located on the swimming pool side of the fence. The vertical pieces should not be wider than 1-3/4 inches.
Likewise, when the distance between the tops of the horizontal pieces is at least 45 inches, the spacing between vertical pieces should not be greater than 4 inches.
For chain link fence, the maximum mesh size should not be more than 1-3/4 inches square unless the fence has slats fastened top and bottom that reduce the openings to less than 1-3/4 inches. For lattice fences, the maximum opening formed diagonally should be no more than 1-3/4 inches.
Any access gates to the pool should be equipped with a locking device, and pedestrian gates should open outward, away from the pool. They should also be self-latching, generally with the latch release on the pool side of the gate, 3 inches or more below the top of the gate.
