Spa and pool leaks are normally indicated with the level of the water dropping. However loss of water can be attributed to evaporation, particularly in pools more exposed to the wind and the sun.
1. A Bucket Test is advisable first, if your pool water level is dropping.
2. If the pump sounds like it is sucking air, it is most likely you have a leak.
3. Spa pools lose more water than ordinary pools, due to evaporation.