Fill the level of your pool to normal operataing level (mid-tile or mid-skimmer)

Fill a bucket with pool water to about one inch from top

Place bucket on first or second step of pool

Mark water level on inside of bucket

Shut off pump and mark pool level on outside of bucket

Resume normal pump operation

After 24 hours, compare the two levels. If the pool water (outside mark) goes down more than the inside water level, there is probably a leak.