If you suspect your pool is leaking, there are several reliable ways to check. Try one of these: Use a grease pencil to mark the water level of the pool at the skimmer. Check the mark 24 hours later. Your pool should lose no more than 1/4 inch per day. Otherwise, a leak is indicated. Try the bucket test: Place a bucket filled with pool water on a pool step (weight it with a rock or brick). Mark the water level on both the inside and the outside of the bucket. The starting point levels should be about the same. Check the mark 24 hours later. If there's a greater drop in the line on the outside of the bucket, a leak in the pool is indicated.
Be a sleuth. Here are clues to look for: Algae or other persistent water quality problems indicating imbalances in the chemistry can occur when a leak prevents the water level from staying constant. Loose tiles or cracks in the pool deck can indicate a leak. Cracks and gaps in the bond beam also can signify a leak. Water-saturated soils in the area around the pool, pool pumps or plumbing.
If you determine that your pool is losing water, turn off the filtration system and note where the water stops dropping. If the water stops at the skimmer, the leak is probably in the filtration system. The lines may crack at vulnerable elbows and fittings that are under stress from shifting soils. If the water stops at the light, the leak is probably there. If the water drops below the light, then there may be a leak in the drain at the bottom the pool.
If you suspect you have a leak in the filtration system these clues may help you pinpoint the location: If you see bubbles in the return water when the pool's pump is running, it's likely there's a leak in the suction side of the filtration system. If the pool is losing more water while running the pump, then water is being lost on the return side of the system.
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