Do you suspect that your pool may be leaking? Here's how to be sure.
Water Level Test
An accurate water level test is a great way to detect if you have a leak. Make a mark at the water level in the skimmer with a pen or grease pencil. Wait one day and check the mark. A pool should not lose more than .25 inches per day. If the water level goes down by more, you probably have a leak.
You can check for water leaks by walking the perimeter of the pool, and walking the path between the pool and the pool equipment. Do you hit a sloshy, wet area? That may indicate a leak. Obviously, don't bother doing this visual test right after a rain. Also, you'll want to do this test after the pool filter has been running for at least an hour. Some leaks only occur when the plumbing lines are pressurized (when the filter is running).
Visually inspect the pool for loose tiles or cracks in the pool deck as well as check the bond beam (the "shell" of the pool).
If you detect a leak, you'll need to call a pro. Don't assume the worst, many leaks are easy fixes.