Air in the return jets is the tell.

A leaking pool skimmer almost always shows up as air bubbles streaming out of your return jets. You might also notice water loss that seems too fast for evaporation, or a soft, wet spot in the ground near the skimmer. If the pump struggles to prime or keeps losing prime, that’s another sign.

The skimmer body can crack from ground movement or freeze damage, or the gasket where the pipe connects can fail. Older pools sometimes develop hairline cracks that only leak when the pump is running and the skimmer is under suction.

If you see any of these, don’t wait. A small leak will get bigger, and you’ll waste water and electricity while the pump works harder. Patch kits exist, but a cracked skimmer usually needs replacement—call a pool guy.