Level dropping, but no obvious leak!

[Sotex]

Friends, over the past few months I've noticed that once I get my water level to my ideal depth, the level drops dramatically for about an inch. Once there's the initial drop in level, then it stabilizes. I've had the pool builder, a pool maintenance guy, my wife, and I have all looked high and low and we can't find any other evidence of a leak.

Hoping someone here can give me an idea of where to look that won't be so obvious. One friend said to check the grout for possible cracks, but would that cause a 1" drop in about a day?!?!

 

[Texas Splash]

I was going to mention the incredible wind we've had recently which most certainly contributes to water evaporation and loss. But you say this has been happening for months huh? Is the dropped (new) waterline near anything that would seem suspicious (i..e bottom of skimmer, grout line, etc)? No additional plumbing lines that might allow water out?

 

[woodyp]

Notice any wet spots around anywhere....downhill? Spa losing water too when at or above that pool level? Losing any water when it's not?

 

[JohnT]

Seems like it would have to be in a skimmer or the pool surface in that 1" of wall space. Steps?

I had leak problems this past year in my vinyl liner and was amazed how hard it can be to spot a leak. The tiniest crack can drain a lot of water when it runs 24/7. I ended up having to physically touch the entire pool surface in the area in which I'd isolated the leak (4" in my case) and closely inspect everything that felt remotely unusual. It helped to have a cold drink and to be resigned to spending all the time I needed!