If your pool loses more water when the pump runs than when it is off, the leak is most likely on the return side: the pipes that push filtered water back into the pool. Return lines are under pressure while the pump runs, so a crack leaks fastest then. Call (951) 299-3473 any time.
A return line leak sits underground, under the deck or the yard, so you rarely see it. Our pool leak detection in Murrieta visit pressure-tests each line and uses listening gear to pinpoint the break before any concrete is cut.
Why does a pool lose more water with the pump on?
When the pump runs, the return lines carry water under pressure from the filter back to the pool. A crack in one of those lines pushes water out into the ground. When the pump stops, the pressure drops and the leak slows or stops. So a pool that drops faster with the pump on points to the return, or pressure, side of the plumbing.
The opposite pattern tells you something too. If the pool loses more with the pump off, the leak is often on the suction side, like a skimmer line or main drain, or in the shell itself.
| What you notice | Where the leak usually is |
|---|---|
| Loses more with the pump on | Return (pressure) lines or equipment after the pump |
| Loses more with the pump off | Suction lines, skimmer, main drain |
| Loses the same either way | Pool shell, light niche, fittings in the wall |
| Stops at the skimmer opening | Skimmer body or skimmer line |
| Stops at the light | Light niche or conduit |
