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Swimming Pool Leak Detection in Los Angeles
Every pool loses water. In the San Fernando Valley, 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.
That’s where pool leak detection in Los Angeles starts for us. We separate the two first, then test the shell, the fittings and the buried plumbing until we can narrow down where the water is going. The aim is a marked spot, and the pool stays full the whole time.
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Leak or evaporation?
- Evaporation ruled out first
- Shell and fittings tested
- Buried plumbing under the deck
- The pool stays full the whole time
Signs worth checking
Signs your pool may be leaking
Faster than the bucket
The level drops faster than the bucket test says it should, or faster than a neighbor’s pool in the same weather.
Soggy ground
Wet or soggy ground near the pool or around the equipment pad.
New cracks
New cracks in the deck, the coping or the tile line.
Auto-fill always running
The auto-fill runs constantly, or the water bill keeps climbing.
Algae keeps coming back
Algae comes back soon after you treat it, because fresh fill water keeps diluting your chemicals.
The pump draws air
The pump draws air: bubbles at the returns, or a pump that keeps losing prime.
Two or three together usually means it’s time to test.
Try this first
Start with the 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 and the bucket dropped about the same, it’s evaporation. If the pool dropped noticeably more, the difference is leaving some other way. Rain spoils the result, so start over if it rains.
- Turn off the auto-fill and don’t add water during the test.
- Set a bucket on the first or second step.
- Fill it until the water inside matches the pool level outside.
- Mark the water line inside the bucket.
- Mark the pool level on the outside of the bucket.
- Run the pump on its normal schedule for 24 hours, with nobody swimming.
- Measure how far each level dropped.
- Reset the marks and repeat for 24 hours with the pump off.
Evaporation changes with heat, wind, shade and humidity, so a shaded pool in Encino and a pool in full sun a few miles west can lose very different amounts in the same week.
Reading the result
Is it the shell or the plumbing?
A pool leaks in the structure that holds the water or in the pipes that move it. They’re tested and repaired differently.
Your two bucket tests give the first clue.
More loss with the pump running
Losing more with the pump running often points to the return lines, which are under pressure while the pump runs.
More loss with the pump off
Losing more with the pump off tends to point to the suction side.
About the same both ways
If the loss is about the same both ways, the shell, the tile line or a fitting in the wall is the likelier suspect.
Water that drops and then holds at the skimmer or the light is often leaking at that height.
Where to look
Where pool leaks usually start
Dry summers, settling soil and the occasional earthquake all work on decks and the lines underneath them.

Spa leak detection
Spa leak detection and pool-spa combos
A spa built into a pool shares much of its plumbing, so the two get checked together. The spillover edge can crack or lose its tile seal. Each spa jet has its own fitting and line, and the valves that switch water between pool and spa can let it slip through.
One pattern isn’t a leak at all. A raised spa that drops while the pool rises is usually water passing back through a leaking valve or a damaged spillover. It’s worth fixing, but the water hasn’t left your yard.

After the leak is found
After the leak is found
You get a marked location and a plain explanation of what failed and what fixing it usually involves. If everything tests clean and the loss turns out to be evaporation, we’ll tell you that too.
We can talk you through repair options on site, and our leak repair page explains how repairs on buried lines usually go.
If the wet ground is out in the yard rather than beside the pool, a buried water line may be the real culprit. See underground and main line leak detection.
FAQ
FAQs about pool leaks
How much water should a pool lose a day?
There’s no single number. Evaporation depends on heat, wind, shade and humidity, so the same pool loses very different amounts in July and January. The bucket test gives you a real answer for your pool. If the pool drops more than the bucket, something besides evaporation is taking water.
How long does pool leak detection take?
It depends on the pool. A pool with an attached spa, several returns and long runs back to the equipment has more lines to test than a simple rectangle. Tell us about your layout when you book and we’ll give you a better idea.
Keep reading
Related services
Pool leaks across the Valley and Orange County
Our Chatsworth office covers backyard pools across the San Fernando Valley, including Porter Ranch, Northridge, Woodland Hills and Encino. Valley summers are long and hot, and plenty of homes have a plaster pool out back. See leak detection in the San Fernando Valley, or our page on pool leak detection in Woodland Hills.
Our Irvine office handles pool leak detection in Orange County, from private backyard pools to community pools in Irvine, Tustin and Newport Beach.
