To find a leak in a swimming pool, fill a small bottle with water and a few drops of food coloring or dye. Add several drops to the pool water, concentrating on areas where you suspect a leak, and watch the dye closely. If the dye swirls around and disappears, inspect the area for cracks or holes around pool equipment, pool tiles or vinyl wall and floor liners.
To find a leak at the bottom of a swimming pool, add dye to the water. Watch the dye as it sinks to the bottom of the pool. A tear in the vinyl liner or a crack in the pool tiles will force the dye to move quickly toward the damaged area and disappear.
An evaporation test can also determine the presence of leaks in a swimming pool. To perform this test, turn off the swimming pool filtration system. Fill a bucket with water, and measure and mark the water level. Measure and mark the water level of the pool. Place the bucket near the pool.
After a few days, measure the water level in the bucket. Measure the water level of the pool. The water in the bucket and in the pool should evaporate at the same rate and remain at an equal level. A leak will cause lower water levels in the swimming pool.