How to Check a Leak at the Skimmer of an In-Ground Pool

Fill the pool up to the top of the skimmer. This is not usually recommended; but if you are injecting the dye to troubleshoot a leak, covering the entire skimmer in water will give you more accurate results.

Turn off the filter and allow the water to settle and become calm. In the meantime fill up a glass of water then add red food coloring until the solution becomes a dark red.

Step into the pool carefully with a turkey baster and the glass of red dye. Try not to disrupt the water and create ripples; this way it's easier to see where the food coloring goes.

Squeeze the top of the turkey baster and insert it into the glass of water. Release the bulb to fill up the baster with food coloring.

Inject the food coloring into the water around the skimmer where you suspect a leak. Repeat until you see the food coloring disappear. If you have a leak, the food coloring will seep into the leak and disappear. The skimmer is most likely not leaking if the food coloring floats elsewhere in the pool.