Every pool owner has noticed their water level drop at some point. The immediate assumption is usually evaporation — and in the Los Angeles heat, that's a reasonable first thought. But evaporation only accounts for about ¼ to ½ inch of water loss per day. If your pool is dropping more than that, you may have a leak.
The challenge is that pool leaks can be subtle. They often go unnoticed for months, quietly wasting thousands of gallons and inflating your water bill. Knowing the warning signs can help you catch a leak early — before it becomes a major structural or landscaping problem.
Here are the seven most reliable signs that your pool has a leak, not just evaporation.
Sign #1: You're Adding Water More Than Once a Week
What to watch for
If you're topping off your pool more than once a week during mild weather, you're likely losing more water than evaporation can explain. A good benchmark: losing more than 2 inches per week warrants a professional inspection.
In Southern California, evaporation rates are higher in summer (especially during heat waves), but even then, a well-maintained pool shouldn't need constant topping off. If you're filling the pool every few days, that's a red flag.
Sign #2: Your Water Bill Has Spiked Unexpectedly
What to watch for
A sudden or gradual increase in your water bill — especially if you haven't changed your habits — is often one of the first clues of an undetected pool leak. Even a slow leak can waste tens of thousands of gallons per year.
Compare your current bill to the same month last year. If it's significantly higher and you haven't installed new irrigation or had any plumbing work done, your pool should be the prime suspect.
Sign #3: Wet or Soggy Areas Around the Pool
What to watch for
Wet patches in your lawn, soft or muddy soil near the pool deck, or puddles that appear without rain are clear indicators of underground water loss — often from a cracked underground pipe or return line.
This is particularly common in older pools where the underground plumbing has had time to corrode or crack. If your decking also feels soft underfoot or shows signs of sinking, a subsurface leak may have been going on for some time.
Sign #4: Cracks in the Pool Shell or Deck
What to watch for
Visible cracks in your pool plaster, tiles, or surrounding concrete can allow water to escape. Even hairline cracks in the shell can leak significantly over time, especially under pressure.
Check the waterline tiles carefully — these are a common failure point. Also inspect expansion joints where the pool deck meets the pool shell, as these can separate with ground movement.
Sign #5: Your Pool Equipment Is Working Overtime
What to watch for
A leaking pool can cause your pump to draw in air, which makes it work harder and run less efficiently. You might notice the pump gurgling, losing prime, or struggling to maintain pressure.
Air in the system is a common symptom of a suction-side leak — where water is escaping through the return lines when the pump is off, or air is being drawn in through a crack while the pump is running.
Sign #6: You Notice More Algae Than Usual
What to watch for
Constantly battling algae despite regular chemical treatment? A leak can throw off your pool's chemical balance. As water escapes and is replaced with fresh tap water, the dilution affects your pH, chlorine, and other chemical levels.
If your pool requires unusually high chemical usage to stay balanced, or if algae keeps coming back faster than expected, don't just blame the sun — consider having a leak inspection done.
Sign #7: The Bucket Test Confirms It
What to watch for
The bucket test is the best DIY method to distinguish between a leak and evaporation. If your pool is losing significantly more water than the bucket control, you have a leak.
To perform the test: fill a bucket with pool water, place it on a pool step, mark both water levels, and compare after 24–48 hours with the pump running. See our full bucket test guide here.
What To Do If You Spot These Signs
If you've noticed one or more of these signs, the next step is a professional leak inspection. DIY methods like the bucket test can confirm that a leak exists, but they can't tell you where the leak is — which is exactly what our technicians specialise in.
We use a combination of:
- Pressure line testing — to isolate which section of plumbing is leaking
- Dye testing — to pinpoint exact failure points around fittings, lights, and the shell
- Acoustic listening equipment — to detect leaks underground without excavation
- Underwater inspection — to examine the pool shell and main drain
Most inspections take 1–3 hours, and the majority of leaks we find can be repaired the same day.
Spotted Any of These Signs?
Don't wait — a small leak can cause major damage. Book your professional inspection today. If we can't find your leak, it's FREE.
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