My Pool is Leaking

[jp828]

Thanks for the info. The problem is that neither hole had a plug. How do I determine which one is the relief and which one is the main?

[PoolDoc]

If neither has a hole, the main drain may be plugged.

If the main drain is working, there will be suction flow, somewhere in the main drain when the pump is operating. Be CAREFUL, if you swim down: do NOT get your hand stuck on the hole, by valving 100% suction flow to the main drain!!