Do I Really Have a Pool Leak? 7 Checks Before You Call a Leak Company

1. Get a Feel for What “Normal” Might Be

Before you go into full leak-panic mode, take a second to look at what’s happening around your pool.

• Hot, sunny, windy days = more evaporation.
• Cool, still, humid days = less evaporation.
• Kids, dogs, cannonballs, water volleyball = extra splash-out.
• No one using the pool and no features running = lower water loss.

If you only see a tiny drop during rough conditions, that might be normal. If the water is falling fast in
calm weather with very little use, that’s more suspicious and worth checking further.

2. Use a Bucket Test as Your First Measurement

Instead of guessing, you can compare your pool to a small body of water sitting in the same conditions.
That’s what the bucket test is for.

In short, you set a bucket of pool water next to (or partly in) the pool, mark the water level in the bucket
and on the pool, wait about 24 hours, and then compare how much each one dropped. If the
pool drops significantly more than the bucket, that extra loss points toward a leak. If they
drop about the same, weather and normal use may be doing most of the work.

For a step-by-step version with pictures, see our full guide here:
How to Do the Pool Leak Bucket Test.
(It opens in a new tab so you don’t lose your place on this page.)

3. Watch When the Pool Loses Water (Pump On, Pump Off, Night Only)

The pattern of water loss can tell you a lot about where the problem might be hiding.

• Loses more with the pump ON: this leans toward plumbing under pressure—return lines,
  cleaner lines, or leaks at or near the equipment pad.
• Loses more with the pump OFF: this leans toward suction-side issues or a static leak in
  the shell around the normal waterline, skimmer, tile, or steps.
• Mostly drops at night with everything off: cool, dry nights can increase evaporation, but a
  steady night-only drop can also point to a shell or tile-line leak.

If you can safely do it, try a simple experiment: one day with the pump on a normal schedule, and one day
with the pump off as much as your system allows. Mark the waterline each morning and compare how much the
level falls in each case. A clear difference between “pump on” and “pump off” is a big clue.

➜ For a deeper dive on this pattern, see:

Pool Losing Water Only at Night? What It Really Means
.

4. Pay Attention to Autofill Behavior

An autofill is great at keeping your waterline looking perfect—and that’s exactly why it can
hide a leak. The autofill doesn’t cause leaks; it just quietly replaces the water you’re
losing, so you may not see the level drop at all.

Ask yourself:

• Does the autofill seem to run much more than it used to?
• Do you notice it trickling almost every time you walk by?
• Has your water bill crept up without a clear reason?

If you can safely do it, try turning the autofill off for a day or two, mark the waterline, and watch how
quickly the level falls when nothing is topping it off. A strong drop without the autofill helping is
powerful evidence of a leak.

➜ Learn more:

Autofill Never Shuts Off? How to Tell If It’s Hiding a Leak
.

5. Look for Physical and Equipment Clues

Some leaks leave physical clues if you know where to look. A quick inspection around the pool and equipment
can save you a lot of guesswork.

At the equipment pad

• Damp concrete or soggy soil that never fully dries out
• Drips from pump lids, unions, filter tanks, heaters, or valves
• A backwash or waste line that’s always a little wet in “filter” mode

Around the pool shell and deck

• Soft spots or localized wet soil along one side of the pool
• Settling, cracking, or wash-out near the beam or deck edge
• Rust stains or water marks near skimmers, returns, or light niches

Inside the pool

• Cracks around skimmers, steps, benches, and tile lines
• Loose or broken plastic at returns, vac ports, and main drains

One damp spot doesn’t automatically mean a major leak, but ongoing moisture in the same place
is something you don’t want to ignore.

➜ See also:

Wet Equipment Pad? Leak Signs Around Your Pool Equipment
.

6. Use Chemical Clues as Backup Evidence

Your chemistry can quietly confirm that water is leaving faster than it should. These clues don’t stand alone,
but they’re powerful when combined with what you’re seeing at the waterline.

Salt pools: salt level keeps dropping

Salt doesn’t evaporate—water does. If your salt level keeps crashing and you’re not doing any big drains or
long backwash cycles, that means salt water is leaving the system somewhere.

➜ More on this:

Salt Level Keeps Dropping in Your Salt Pool? Leak or Something Else?
.

Non-salt pools: stabilizer (CYA) always low

Stabilizer (cyanuric acid) usually falls when you remove water from the pool—draining, backwashing to waste,
or overflowing a lot of rain. If your stabilizer is dialed in and then drops hard with no big water removals,
that can be a sign that treated water is leaving through a leak.

➜ Learn more:

Stabilizer Always Low? When It Points to a Pool Leak
.

Chlorine use that doesn’t make sense

If you’re burning through chlorine much faster than usual, and you’re not dealing with heavy swimmers, big
storms, or extreme sun, combine that with what you see at the waterline. In many cases, you’re constantly
treating water that’s leaking out of the system.

Before you do big stabilizer or chlorine adjustments, it’s smart to:

• Get a decent chlorine reading (not zero).
• Clear up any active algae bloom first.

Dialing in stabilizer and fine-tuning chemistry works best once the water is reasonably clean and under
control.

7. Pull It All Together: Is This Leak Worth Paying For?

After you’ve gone through these checks, step back and look at the full picture. You’re trying to decide whether
you’re seeing normal loss plus a little noise or a real leak worth paying to find.

You’re more likely dealing with a leak that deserves professional attention if:

• The pool dropped clearly more than the bucket in your test.
• You see a noticeable level drop day after day in reasonable weather.
• The autofill runs a lot just to keep up.
• There are persistent wet areas, drips, or suspicious spots around the pool or equipment.
• Salt, stabilizer, or other chemicals are crashing without a clear reason.

On the other hand, if:

• The bucket test was close,
• Loss is small and slow,
• Autofill usage is moderate,
• Chemistry is relatively stable,
• And you don’t see obvious physical clues,

you might be better off documenting what you see and monitoring it a bit longer instead of
jumping straight into a full leak workup.

As PoolLeakFix grows, we’ll walk you through what to ask a leak company, how to understand the tests they
perform, and how to avoid overspending on something minor. For now, this checklist alone will put you far ahead
of most pool owners and give you a much clearer sense of whether you really have a leak that deserves
professional attention.