Leak detection 101

How Professional Pool Leak Detection Works

Wondering what actually happens when you hire a pool leak specialist? Here’s a plain-English breakdown—so you know
what to try yourself, what the pro will do, and roughly what it can cost.

Do the Bucket Test First
Connect with a Leak Pro
Ask a leak question

DIY checks you can do today

What pros test (step by step)

Typical cost ranges & visit time

Big picture: leak detection in 3 phases

Every honest leak specialist is trying to answer two questions:
“Is it really a leak?” and “Exactly where is it?”
Here’s how they usually get there:

Phase one

Confirm it’s not just evaporation

They’ll ask about how fast the water is dropping and usually recreate a
Bucket Test (or review your results) so everyone’s sure it’s not just weather.

Phase two

Narrow down the “zone”

By watching when it loses water (pump on/off), checking equipment, and using dye tests, they separate plumbing
issues from shell, skimmer, light, or equipment problems.

Phase three

Pinpoint & mark the leak

With pressure tests, listening gear, and more targeted dye work, they zero in on the exact fitting, crack,
or line section that’s leaking, then mark it for repair.

Good to know: most pros charge a flat fee for detection (often a few hundred dollars),
then quote repairs separately. The point of detection is to stop guessing and know exactly what you’re fixing.

Step 1: DIY checks before you spend money

Before you call anyone, you can do a few quick checks that many pros will ask about anyway:

Turn off autofill so it’s not hiding the water loss.
Run a proper Bucket Test — mark water on the tile and in a bucket on the first step,
compare 24 hours later (full guide here).
Watch the pump: is there air in the pump basket? Does the pump lose prime? That points to
suction-side leaks.
Look at the equipment pad: wet soil, dripping unions, or a weepy backwash/multiport valve can
lose a lot of water over time.
Check around the light and skimmer: water behind a light, or cracks at the skimmer throat, are
classic leak spots.

If your pool water is consistently dropping faster than the bucket, it’s time to talk to a pro—especially if there’s
air in the system, obvious wet spots, or the water stops at the same level every time.

Step 2: What a leak pro does on site

Here’s what a typical visit can look like. Not every pool needs every test, but this is the common toolkit:

Visual & basic checks

Confirm your bucket results and how fast the pool is dropping.
Look for obvious cracks in shell, tile line, and around fittings.
Inspect skimmers, returns, main drain covers, and light niches.
Check equipment pad, filter, heater, and valves for slow leaks.

Dye tests & listening

Use leak dye around suspected areas (skimmer throat, cracks, fittings).
Use listening gear on pressurized lines to hear where water is escaping.
Look for where the pool “stops” losing water—often a clue to the leak height.

Pressure testing the plumbing

Isolate suction lines (skimmers, main drains) and returns one by one.
Cap lines and pressurize with air and/or water while watching gauges.
Walk the deck and yard listening for hissing or bubbling underground.

Pinpointing & marking the leak

Once a line fails a pressure test, narrow it to a specific section.
Mark the deck or area where the leak is strongest before any digging.
For structural leaks, mark the crack or fitting that’s pulling dye.

Do they have to drain the pool?

Not usually. In many cases, detection can be done with the pool full or only slightly lowered.
A full drain is usually reserved for:

Major structural repairs (large cracks, resurfacing, etc.).
Situations where the shell itself needs significant work.

If anyone’s first suggestion is “drain it and see what happens” with no testing, that’s a red flag.
Good leak pros try to measure first, drain only when necessary.

Typical cost & visit time

Every market is different, but here are ballpark ranges so you’re not flying blind:

Basic leak detection visit: often in the ~$250–$450 range for a standard residential pool.
Complex systems: large, multi-pool, or spillover spas may cost more.
Repairs: minor patches might be included; bigger fixes are usually quoted separately.

Always confirm pricing up front: is it a flat fee for detection only, or does it include simple repairs (like patching
a small crack or skimmer throat)?

Pro tip: when you call or text a leak specialist, have your bucket test results, pump run schedule,
and any “only leaks when…” patterns ready. It saves time and can lower the total visit cost.

What to do next

If your bucket test and symptoms still scream “leak”, here’s your next move:

Run (or re-run) the Bucket Test
Request a leak specialist
Send us your leak question

FAQ — leak detection basics

How much does pool leak detection usually cost?

It varies by area, but many residential pools fall somewhere in the ~$250–$450 range for a full detection visit.
That typically covers confirming it’s a leak, testing the plumbing, and pinpointing the source. Repairs—especially
underground or structural work—are often quoted separately.

How long does a leak detection visit take?

Simple cases can be under an hour. More involved jobs—multiple skimmers, attached spas, long runs of plumbing—can
take a few hours. The goal isn’t speed; it’s leaving with a clear answer on where the leak is and
what it will take to fix it.

Should I try to fix a leak myself?

Small things—like a visible crack you can clearly see dye pulling into—might be patchable as a short-term fix.
But plumbing leaks, underground issues, and anything involving structural movement are usually better left to a
pro. A bad DIY repair can hide the leak temporarily and make the real fix more expensive later.

What information should I have ready before I call?

Have this handy:

Your bucket test results (how much the pool vs. bucket dropped).
How long it’s been leaking and roughly how many inches per day.
Any patterns (only leaks when pump is on/off, stops at a certain level, etc.).
Photos of any wet areas, cracks, or suspicious spots.

Sharing this up front helps the specialist decide which tests to run first and can save you both time and money.