A positive drain (sometimes called a weep pipe) is required on any pool installation where more than 10” of digging is required to level the site. The drain provides a channel for ground water around the base of the pool to drain away safely, preventing sand washouts and other problems. The positive drain system consists of 4” diameter black corrugated landscaping pipe and a sock to cover it. The pipe should be the kind that has slits in it. The sock is white or black and comes in rolls about the size of a toilet paper roll and is sold next to the pipe at stores like Home Depot or Lowe’s. Often the pipe can be purchased with the sock already on it. The purpose of the sock is to keep dirt and mud from clogging up the holes in the pipe to keep good water flow.
The pipe should be laid so that the pipe ends are on either end of the pool on the low side like a horseshoe, or they can come to a T at the lowest end of the dig, allowing the water to exit from one area instead of two. Double check the pipe to make sure it is a little bit higher on the side of the pool opposite of where the ends will be daylighting the water. If it is not, you can use some dirt to raise it up temporarily. Once the pipe is covered with backfill, the dirt will fill in under the pipe and secure its elevation.
Now, all that is left to do is gently backfill over the pipe around the pool. Be careful not to push large rocks that may be in your dirt up against the pool wall, as this may damage the wall. Also, try not to push too much dirt too fast so as to not push the pipe out of position or the wall out of track.
