Every pool loses water. A hot week with a dry wind can pull the level down faster than most owners expect, and that’s just evaporation. A leak is whatever’s left after you rule evaporation out.
The good news is that a leaking pool usually gives you a few clues before the water level tells the whole story. Here’s what to look for.
Six signs your pool may be leaking
- The level drops faster than it should. Faster than a bucket test says it should, or faster than a neighbor’s pool in the same weather.
- Wet or soggy ground. Near the pool or around the equipment pad, when nobody has been splashing or watering.
- New cracks. In the deck, the coping or the tile line.
- The auto-fill runs constantly. Or the water bill keeps climbing.
- Algae keeps coming back. Soon after you treat it, because fresh fill water keeps diluting your chemicals.
- The pump draws air. Bubbles at the returns, or a pump that keeps losing prime.
One sign is a clue. Two or three is a pattern.
Any one of these can have another cause. Two or three together usually means it’s time to test.
Rule out evaporation first
Before anything else, find out how much of the loss is evaporation. The simplest way is a bucket test: a bucket of pool water sitting on the step gets the same sun and wind as the pool. Both lose water to evaporation. Only the pool can lose it to a leak.
If the pool drops noticeably more than the bucket over the same period, the difference is leaving some other way. Our guide to pool leaks vs evaporation walks through the full test, step by step.
Where pool leaks usually start
A pool leaks in the structure that holds the water or in the pipes that move it. The usual places:
- The skimmer throat, where the plastic skimmer body meets the concrete shell.
- Return fittings, where the seal can crack or pull away from the plaster.
- The main drain, at the deepest point.
- The light niche, where the conduit can give water a path out along the cord.
- The tile line, where grout loosens as the deck moves against the shell.
- Suction and return lines under the deck, where buried PVC can crack from soil movement or old glued joints let go.
- The equipment pad, where pump, filter, valve and heater joints drip. Hard water leaves a white crust that often gives a slow leak away.
Dry summers, settling soil and the occasional earthquake all work on decks and the lines underneath them.
When to call
If the bucket test points to a leak, or you’re seeing more than one of the signs above, it’s worth having the pool tested. The aim is a marked spot and a plain explanation of what failed, and if everything tests clean and the loss turns out to be evaporation, you should hear that too.
See how pool leak detection works across Los Angeles and Orange County, or tell us what you’re seeing.
