If you suspect your swimming pool is leaking, you’re not alone. Pool leaks are one of the most common—and frustrating—issues pool owners face. Water loss can drive up utility bills, damage your pool’s structure, and even undermine surrounding decks or landscaping. While some leaks are easy to spot, many are hidden and require professional tools and expertise to find.
In this article, we’ll explore the top five tools professionals use to detect swimming pool leaks in residential in-ground pools. Each tool plays a unique role in identifying leaks quickly and accurately, with minimal guesswork or unnecessary damage.
1. Dye Testing Tools
What They Are
Dye testing is one of the most straightforward and widely used techniques in professional leak detection. The tool used is often a dye pen—a syringe-like applicator filled with a non-toxic, brightly colored dye. Professionals use this to introduce a small amount of dye near suspected leak areas while the pool system is turned off.
How They Work
The water in a swimming pool is naturally under pressure due to gravity. If there’s a leak in the structure—such as a crack in the plaster, a separation around a fitting, or a tear in a vinyl liner—water will be pulled through that opening. When dye is applied near the leak, it gets drawn in, creating a visible trail.
Professionals watch how the dye moves. A steady stream moving into a crack or fitting confirms the presence and location of the leak. It’s a simple yet highly effective diagnostic method.
When They’re Used
Dye testing is most effective when:
There’s a suspected leak in the pool shell, skimmer, main drain, or around light niches
The pool system is turned off, allowing the water to be still
Visibility in the water is good
Professionals will often perform a thorough dye test early in the leak detection process to check common failure points before moving on to more advanced tools.
Best For
Cracks in plaster or concrete
Tears in vinyl liners (above the waterline)
Leaks around pool lights, main drains, return fittings, or skimmers
Pros
Fast and non-invasive
Inexpensive and accurate for locating shell leaks
Easy to use in clear water conditions
Limitations
Requires still water for accuracy
Some small or intermittent leaks may not pull in dye clearly
2. Hydrophones and Deck Plates
What They Are
A hydrophone is an underwater microphone used to detect the sound of water escaping from a leak. These high-sensitivity devices are explicitly designed to pick up subtle noises—like hissing, gurgling, or bubbling—that are otherwise undetectable to the human ear.
Deck plates are companion tools used to listen through concrete pool decks or soil above buried plumbing lines. Combined with the hydrophone, they allow technicians to pinpoint leak sounds without digging or cutting.
How They Work
In structural leaks, a hydrophone is lowered into the water and moved along the pool walls, floor, lights, and fittings. If a leak is present, the escaping water produces a distinct sound that becomes louder as the hydrophone gets closer.
In plumbing leaks, professionals will often introduce air or a water-air mixture into a line. The escaping air makes a loud boiling noise at the leak site. By placing a deck plate on the surface above the plumbing, the technician listens for that noise from aboveground, narrowing in on the location of the problem.
When They’re Used
After dye testing or pressure testing suggests a leak exists, but hasn’t been visually located
When leaks are suspected around light niches, jets, or skimmers
To locate leaks in buried plumbing before excavation
Best For
Detecting leaks in the pool shell
Identifying leaks in plumbing near the pool’s edge
Locating underground leaks before digging
Pros
Highly accurate and non-invasive
Works underwater and through solid surfaces
Ideal for confirming leak locations
Limitations
Requires complete silence—no running pumps or loud background noise
Can be less effective in very deep or noisy environments
Doesn’t provide visual confirmation—only sound
3. Pressure Testing Equipment
What It Is
Pressure testing is a technique that checks the integrity of a pool’s plumbing system. It requires specialized tools, including inflatable or mechanical plugs to isolate each line and a pressure gauge or pump to monitor pressure levels.
How It Works
Each plumbing line—returns, skimmers, main drain, cleaner lines—is isolated and sealed. Water or air is pumped into the line to a known pressure, and then the system is monitored. If the pressure holds steady, the line is tight. If it drops, a leak is present.
This method doesn’t pinpoint the leak location, but it tells professionals which line is leaking so they can focus their efforts more efficiently.
When It’s Used
When water loss is significant and not found through surface-level testing
To determine whether the leak is in the structure or plumbing
As a routine part of any full leak inspection
Best For
Locating leaks in underground plumbing
Eliminating lines of suspicion
Creating a clear action plan for further diagnostics
Pros
Very accurate for identifying which line is leaking
Helps eliminate guesswork
Can test multiple lines independently
Limitations
Doesn’t reveal the exact leak location
Requires time and proper technique
Needs the correct plugs and fittings for each pool setup
4. Visual Examination Gear
What It Is
Professional leak detectors rely on their eyes—backed by the right equipment. This includes masks, snorkels, weight belts, underwater flashlights, and mirrors on telescoping poles. The goal is to visually inspect every part of the pool’s interior for signs of damage or separation.
In some cases, pool divers with SCUBA gear are used when deeper or extended inspection is needed.
How It Works
The technician enters the pool and systematically inspects:
Tile lines and grout
Plaster surface for cracks or discoloration
Liner for tears or wrinkles
Areas around return jets, drains, and lights
They use mirrors to look underneath fittings and behind difficult-to-see areas. Light is critical in identifying subtle cracks, pinholes, or material degradation.
When It’s Used
Early in the inspection, to identify obvious issues
After acoustic or dye testing to visually confirm a leak
To prepare for immediate repair
Best For
Cracks in plaster or gunite
Tears in vinyl liners
Loose fittings or visibly deteriorated components
Pros
Simple and direct
Can confirm or rule out leak suspects quickly
Allows for underwater repairs when applicable
Limitations
Only works when the leak is visible
It can be time-consuming in large or complex pools
Water clarity must be high
5. Underwater Cameras and Video Scopes
What They Are
Underwater video inspection tools come in two main varieties:
Waterproof handheld cameras for inspecting large pool areas visually
Pipe inspection cameras, which are flexible cable-mounted cameras designed to snake through plumbing lines
These tools often feature onboard lighting and transmit real-time video to a monitor. Some models include a sonde—a transmitter that can be located from above using a receiver—to pinpoint the camera’s location underground.
How They Work
When a plumbing line is suspected of leaking, a technician may insert a camera into the pipe via a clean-out or fitting. The video feed reveals internal damage, separation, or intrusions such as tree roots.
If a surface-level leak is suspected, a handheld waterproof camera can be used to inspect the pool floor, walls, steps, or spa areas in fine detail.
When They’re Used
After pressure testing narrows down the suspect line
To verify conditions before excavation or repair
When visual confirmation is required
Best For
Diagnosing leaks inside pipes
Confirming hard-to-reach shell leaks
Documenting damage before and after repairs
Pros
Provides a clear visual of the issue
Non-invasive and precise
Helps technicians plan repairs with confidence
Limitations
May not reach full pipe lengths
Debris or obstructions can block the camera’s progress
Requires specialized equipment and operator skill
Why These Tools Matter
Leak detection isn’t guesswork. It’s a disciplined, technical process that uses multiple tools in sequence. Professionals don’t rely on just one method—they combine dye testing, pressure testing, acoustic listening, visual inspection, and camera work to accurately locate and confirm leaks before proposing repairs.
For a homeowner, this means:
Less digging and disruption
Faster resolution
Confidence that the leak has been correctly identified
No unnecessary repairs or part replacements
Every tool has its strengths. When used together by a trained professional, they form a complete strategy for pinpointing even the most minor and most stubborn swimming pool leaks.
Trust the Experts at Precision Leak Detection
If your pool is losing water and you’re tired of guessing where it’s going, let the experts handle it. At Precision Leak Detection, we use all five of these tools—along with years of hands-on experience—to find even the trickiest pool leaks quickly and accurately.
Whether it’s a hairline crack in the plaster, a buried plumbing break, or a leak in your spa return, we’ve seen it all—and fixed it all. Our team specializes in non-invasive, high-accuracy leak detection that protects your pool investment and saves you time, money, and hassle.
We proudly service all of Palm Beach County, including towns like Palm Beach, Lake Worth Beach, Wellington, Palm Springs, and surrounding communities. If you’re a local pool owner looking for honest answers and expert solutions, you won’t find a more precise or professional team to trust.
Don’t let a hidden leak drain your peace of mind. Contact Precision Leak Detection today and get back to enjoying your pool with confidence.
