Over the past decade, leak detection technology has advanced significantly, making traditional methods like bucket tests, diving suits, and pressure tests increasingly obsolete. Modern equipment now includes ultra-sensitive listening devices that, when placed directly into the pool, can identify even the smallest leaks — whether it’s a pipe crack or a tiny tear in a vinyl liner.

Beyond being more precise, today’s hydrophones offer expanded capabilities for leak detection. With enhanced sensitivity and advanced filtering technology, technicians can detect cracks, leaks, and separations in both the pool shell and plumbing lines without ever getting wet.

Historically, high-tech leak detection tools were designed for plumbers and later adapted for the pool industry. These earlier tools, which often included only a listening deck plate and probe, were limited in their scope and couldn’t effectively identify leaks in areas like light niches, conduits, or jets.

Now, however, purpose-built equipment for pools has redefined the process, emphasizing simplicity and efficiency. When a pool leaks, the weight of the water escaping through a crack generates a distinct sound that hydrophones — specialized microphones designed to operate in water — can easily detect. As the technician moves closer to the leak, the sound grows louder. These noninvasive methods allow technicians to pinpoint leaks in a still, or “static,” pool with minimal effort.

Preparing the Pool for Leak Detection

Proper preparation is essential for successful leak detection using advanced equipment. Customers must ensure their pool is clean, filled to the appropriate level, and static — meaning all equipment is turned off — before the technician arrives. Visibility of the main drain is critical, as it permits a thorough inspection. Once on-site, the technician uses a hydrophone directly in the pool to listen carefully to areas such as the shell, return lines, jets, floor drains, suction lines, and lights. Interestingly, 95 percent of leaks are typically found within a three-foot radius of the pool, often identified solely through hydrophone use.

Smaller hydrophones, often referred to as pipe mics, have been developed to inspect plumbing lines, such as returns, skimmers, and spa jets. These devices are inserted into the line under investigation, and the sound of the leak becomes more pronounced as the mic approaches the source.

For leaks within plumbing systems that don’t naturally produce a detectable sound, technicians may need to create one using pressure. Unlike leaks in the pool shell, plumbing leaks farther from the pool may require a pressure rig to inject a mix of air and water into the line. This creates a boiling noise at the leak’s location.

Equipped with a sensitive microphone, a deck plate enables technicians to detect this noise through hard surfaces like concrete. Additionally, long soil probes allow one to identify leaks beneath landscaping materials such as grass or gravel.

Sonde Technology

Sonde-location technology has become an essential tool for pinpointing leaks underground or underwater. This advanced system (“sonde” is French for “probe”) involves a specialized probe that transmits information about its surroundings. In the past, locating a hydrophone beneath the ground after detecting a leak was a challenging process. Today’s hydrophones, equipped with sonde technology, make it much simpler.

These devices are inserted and pushed or pulled through plumbing lines, enabling the technician to listen for the leak. When the sound of the leak reaches its loudest point, the technician halts the hydrophone and connects it to a driver, allowing the mic to emit a signal, typically at 512 Hz. Using a receiver, the technician can then scan for this signal, accurately identifying the exact location of the leak beneath the ground.

This technology extends beyond listening devices. Cameras equipped with sonde-location capabilities offer additional benefits. While not designed as a primary method for detecting leaks, these cameras provide visual confirmation of what the technician hears. After identifying a leak acoustically, the technician can insert a video scope into the line for a closer look. Many cameras include dye injectors, enabling technicians to perform dye tests in previously inaccessible areas.

Once the visual inspection confirms the leak’s location, the camera’s sonde transmitter allows the technician to use a receiver to pinpoint its exact position underground. This combination of tools not only verifies findings but also creates documentation of the leak and guides repairs. In addition, it aids in bypassing existing lines during complex repair work, streamlining the process and enhancing accuracy.

Efficient Leak Detection in Vinyl-Lined Pools

Detecting leaks in vinyl-lined pools presents unique challenges due to their size and design, often requiring more time and effort than other pool types. However, specialized technology tailored for vinyl liners simplifies the process by combining traditional listening methods with tools specifically designed to scan the liner itself.

One effective approach involves introducing a small electrical current into the pool using a float with a metal plate. This creates an even electrical field across the pool. Vinyl, acting as an insulator, contrasts with a tear or hole, which serves as a ground. The electrical current naturally flows toward the ground, making it possible to locate leaks.

Technicians then use probes to scan the pool’s walls and floor, operating similarly to a voltmeter. At the precise location of the leak, the equipment emits a distinct beeping sound, signaling the breach in the liner.

To avoid false positives — an occasional drawback of this method — technicians can take preventive measures. For instance, they can first use a hydrophone to ensure no metal objects are present in the pool that might interfere with the voltage test. This combination of technologies allows for a more accurate and efficient leak detection process, minimizing unnecessary effort while ensuring precision.

Identifying and Addressing Leaks in Concrete Pools

Structural cracks in the walls or floor of concrete and gunite pools can pose serious risks to the pool’s integrity. As concrete shifts and moves, cracks may form, with the extent of the damage determined by the severity of the movement. Shifting can result from earth movement, settling, or substandard construction practices.

Over time, water seeping through these cracks erodes the surrounding soil, exacerbating the problem and causing further movement. If left unaddressed, the cracks can expand, creating voids in the concrete that lead to costly repairs. Regardless of the leak’s size, it is imperative to repair structural cracks promptly to prevent escalating damage.

Traditionally, spotting a crack meant that technicians had to dive into the pool wearing wetsuits to painstakingly dye test the entire length of the fracture. Today, modern electronic leak detection equipment has revolutionized this process, significantly reducing the time and effort required. Hydrophone technology, for example, enables technicians to locate leaks in structural cracks with greater precision and efficiency.

When water forces its way through the cracks, it produces a distinct ‘whooshing’ sound. A hydrophone, the same tool used for detecting leaks in vinyl-lined pools, allows technicians to listen for these sounds. By methodically dragging the hydrophone along the crack’s midline, technicians can pinpoint leak locations by identifying the loudest sound points.

Once the leaks are found, dye testing can confirm the hydrophone’s findings. After all leaks have been identified and verified, the pool can be drained for repairs.

The advancements in leak detection technology are prompting more pool service companies to offer these services. What once was a time-consuming and laborintensive task is now faster and more accessible, thanks to industry-specific innovations.

With a wide array of training and educational resources available, even technicians new to leak detection can quickly master the tools and techniques, making this service a valuable addition to any pool business.