Swimming pools do not leak in random places. One of the most frequent sources of leaks is that the fittings across the pool skimmer, and it is also among the quicker and simpler problems to fix. You will have to either replace the gasket or employ a widely available pool patching compound — or even both. The procedure for repairing the leak is quite comparable for above-ground pools and in-ground pools, but you may need to resort to various patching materials.
Switch off the pump.
Lower the water level to at least two inches below the bottom of the skimmer faceplate.
Loosen and remove the screws that hold the faceplate to the skimmer using the right screwdriver. Set the screws and faceplate aside for reuse later.
Peel the gasket away in the skimmer wall.
Line up the holes of this replacing gasket with the holes in the skimmer wall. Put the faceplate over the gasket. Insert the screws, then one by one, to the holes and then gently tighten them into place with your hands.
Tighten the screws with the screwdriver. Use your hands to feel around the outside of the faceplate to make sure that there are not any gaps or surface irregularities where it meets the pool wall.
Fill the gaps — if you find any — with the proper patching material. For in-ground pools, combine the components of a two-part pool putty in your hand, then firmly press it around the edges of the faceplate. For above-ground pools, use a marine-grade silicon stove and press on the stuff tightly to the gaps. When using patching compound, read the manufacturer’s instructions for the proper cure time before refilling the pool.