I suspect that my overflow water seeps between the concrete "deck" around the pool, and where the pool tile meets it. At the top of the tile is there is a plastic strip of some sort running around the pool. It's fairly concealed and I suspect it is a bond breaker to separate the tile adhesive from the deck.
I have not found anything visible that looks like an over flow drain.
I don't have problems, I'm just curious. When we have heavy rain, the pool level goes down in a few days.