One of the most common complaints we hear from homeowners is, “My pool keeps losing water, but I can’t figure out why.”
That was exactly the situation during a recent swimming pool leak detection appointment in Palm Beach Gardens. The homeowner had recently purchased the property and quickly noticed something wasn’t right. According to them, the pool was losing approximately three inches of water every week. Even after refilling the pool, the water level would consistently drop to just below the skimmer opening within a matter of days.
Because the previous owner had installed an automatic fill system, the leak may have been hidden for quite some time. Automatic fillers can mask water loss by continuously replenishing it, allowing homeowners to miss the problem until the system is disabled or closely monitored.
In this article, we’ll walk through the complete leak detection process, explain why water clarity and proper water level are critical before testing begins, and show how a combination of hydrophone listening, dye testing, pressure testing, and visual inspection enabled us to identify the leak’s source.
Why Pool Conditions Matter Before Leak Detection Begins
Before any professional leak detection can start, two conditions must be met:
- The water must be clear.
- The pool must be filled to its normal operating level.
These requirements may sound simple, but they are essential for accurate testing.
Clear water is important for both safety and visibility. If a pool is cloudy, filled with algae, or heavily contaminated, it becomes difficult and sometimes impossible to visually inspect drains, returns, lights, fittings, and structural components. Even experienced leak detection divers can lose visibility in murky water, especially in deeper sections of the pool where disturbed sediment quickly clouds the water.
The second requirement is maintaining the proper water level. A partially drained pool can yield misleading results. Structural leaks that would normally be submerged may become exposed, preventing accurate dye testing. Additionally, some plumbing leaks are more difficult to identify when the pool is operating below its normal water level, as the hydrostatic pressure created by the water’s weight has been reduced.
For this Palm Beach Gardens pool, the water level was close to the normal operating level, making it an excellent candidate for a comprehensive leak-detection evaluation.
Beginning the Investigation with a Hydrophone
The first piece of equipment used during most professional leak detections is a hydrophone.
A hydrophone is an underwater listening device designed to amplify sounds occurring beneath the water’s surface. It allows leak detection specialists to hear plumbing leaks, structural failures, water movement, and other abnormalities that would otherwise go unnoticed.
Many people assume a hydrophone instantly identifies leaks. In reality, the equipment is only as effective as the technician using it.
One of the most important skills a leak detection professional develops is recognizing the different sounds of leaks. Plumbing breaks, structural cracks, leaking light conduits, damaged fittings, and skimmer leaks often produce different acoustic signatures. Over time, experienced technicians build a mental library of these sounds, allowing them to recognize abnormal conditions quickly.
Equally important is learning what a healthy pool sounds like.
Wind, nearby equipment, pumps, traffic, landscaping, and environmental noise can all interfere with hydrophone readings. Knowing the difference between normal background noise and an actual leak signal is what separates accurate diagnosis from guesswork.
As we listened around the pool, the main drain area produced no concerning sounds. Return fittings also appeared normal. However, everything changed once we approached one specific skimmer.
The closer the hydrophone moved toward the skimmer opening, the more pronounced the sound became.
Inside the skimmer throat and skimmer housing, we could clearly hear what sounded like water moving across plastic surfaces. The sound was distinct and localized, immediately indicating that further investigation was needed in that area.
At this point, the skimmer became our primary suspect.
Dye Testing Confirms the Problem
Once the hydrophone suggested a possible leak around the skimmer, the next step was dye testing.
Dye testing remains one of the most effective methods for confirming structural leaks in swimming pools. The process involves introducing a small amount of dye near a suspected leak location while the water remains completely still.
The goal is not to flood the area with dye.
In fact, one of the biggest mistakes inexperienced pool owners make is releasing too much dye at once. Excessive dye creates turbulence, making it difficult to determine whether water is actively pulling the dye into a leak.
Instead, small amounts of dye are carefully released near joints, fittings, cracks, and penetrations. If a leak exists, the dye will be visibly drawn toward the opening.
After closely examining the skimmer area, the source of the water loss quickly became apparent.
The dye was being pulled directly into a separation located within the skimmer throat.
What Is a Skimmer Throat Leak?
Skimmer throat leaks are among the most common structural leaks found in concrete swimming pools.
To understand why they occur, it helps to understand how a skimmer is installed.
When a concrete pool is constructed, the pool shell and the plastic skimmer housing are two separate materials. Where these two components meet, a joint is created. This joint is commonly called the skimmer throat cold joint.
During construction, hydraulic cement is used to seal this connection and prevent water from escaping between the pool shell and the skimmer housing.
Over time, however, this material can deteriorate.
Years of expansion, contraction, settling, temperature changes, and chemical exposure gradually weaken the joint. Eventually, small separations develop, allowing water to escape through the gap.
When this happens, water from the pool begins leaking between the concrete structure and the plastic skimmer body.
Because the leak often occurs just beneath the coping and tile line, homeowners rarely see visible signs of the damage. Instead, they notice unexplained water loss.
In this Palm Beach Gardens pool, the skimmer throat leak perfectly explained why the water level consistently dropped below the skimmer opening.
Completing the Full Leak Detection Process
Even though the skimmer throat leak had already been identified, the inspection was far from over.
A professional leak detection should never stop after finding the first problem.
Many pools have multiple leaks, especially older or renovated pools. To ensure there were no additional issues, we continued with the complete inspection process.
This included:
- Dye testing the remaining pool and spa structure
- Pressure testing plumbing lines
- Inspecting return fittings
- Examining drains
- Evaluating the spa
- Performing a visual structural inspection
Completing the entire process ensures the homeowner receives a complete understanding of the pool’s condition rather than a partial diagnosis.
Pressure Testing the Pool and Spa Plumbing
Because this property included a pool and spa combination, the spa was drained into the pool to make testing easier.
Lowering the spa water level provides easier access to drains, returns, and plumbing fittings, while eliminating the challenges of working underwater.
Once the spa was emptied, inflatable pressure testing plugs were installed throughout the plumbing system.
Pressure testing works by isolating individual plumbing lines and introducing air pressure. If the pressure remains stable, the line is considered sound. If pressure drops, it indicates a plumbing leak somewhere within the line.
During this inspection, we successfully pressure tested nearly every plumbing line associated with the pool and spa.
However, one exception existed.
The One Plumbing Line We Could Not Test
While preparing to pressure test the spa drain line, we encountered an unusual situation.
The spa contained two drain covers connected to a common plumbing system. One drain allowed normal access and was successfully plugged for testing.
The second drain, however, was completely obstructed.
Upon removing the cover, we discovered that the pipe was packed with rocks, dirt, debris, and other material. The obstruction was so severe that there was no practical way to insert a pressure testing plug into the line.
Even attempts to clear portions of the debris were unsuccessful.
Because proper isolation of the line was not possible, the single spa drain line could not be pressure tested.
The homeowner was informed of the limitation, and it was documented in the findings.
Every other plumbing line on the pool and spa system tested successfully and showed no signs of leakage.
Repair Recommendations
Because the homeowner plans to renovate and resurface the pool in the near future, they elected not to perform a permanent repair at this time.
Instead, they requested that pool putty be applied as a temporary measure.
Pool putty can sometimes reduce water loss and slow down leakage, but it should not be considered a permanent solution. In most cases, a professional skimmer throat repair is recommended to address the underlying separation properly.
Once the pool renovation begins, the skimmer throat should be permanently repaired as part of the resurfacing project.
Frequently Asked Questions
How much water loss is normal in a swimming pool?
Most pools lose approximately 1/4 to 1/2 inch of water per day through evaporation, depending on weather conditions. Losses significantly exceeding that amount may indicate a leak.
What is a skimmer throat leak?
A skimmer throat leak occurs when the joint between the pool shell and the plastic skimmer housing separates, allowing water to escape around the skimmer opening.
Can pool putty permanently fix a skimmer leak?
No. Pool putty is generally considered a temporary repair. Permanent repairs usually involve rebuilding and resealing the skimmer throat joint.
Why does my pool stop losing water at a certain level?
When a pool consistently stops at the same water level, it often indicates that the leak is located at or near that elevation.
What does a hydrophone do during leak detection?
A hydrophone is an underwater listening device used to detect sounds associated with plumbing leaks, structural leaks, and other abnormalities.
Why does the pool need to be full before testing?
Proper water level creates the pressure necessary for accurate leak detection and ensures all potential leak locations remain submerged.
Can a skimmer leak damage the surrounding deck?
Yes. Long-term water loss can wash away supporting soil beneath decking and coping, potentially leading to settlement and structural damage.
Are skimmer throat leaks common?
Yes. They are one of the most frequently encountered structural leaks in concrete swimming pools.
How long does a professional leak detection usually take?
Most residential leak detections require several hours, depending on pool size, plumbing complexity, and the number of tests required.
Should I repair a skimmer throat leak immediately?
In most cases, yes. Delaying repairs can increase water loss and potentially cause additional damage in the skimmer area.
Need Professional Pool Leak Detection in South Florida?
If your pool is losing water and you’re not sure why, Precision Leak Detection specializes in identifying hidden swimming pool leaks using professional equipment and proven testing methods. Every inspection includes hydrophone listening, dye testing, pressure testing, structural evaluation, and a detailed explanation of our findings.
We proudly serve homeowners, pool companies, real estate agents, and property managers throughout:
- Palm Beach County
- Martin County
- St. Lucie County
- Northern Broward County
Whether you’re dealing with a suspected skimmer leak, plumbing leak, structural crack, or need a pre-purchase pool inspection before closing on a home, our goal is to provide accurate answers so you can make informed repair decisions.
Contact Precision Leak Detection today to schedule a professional swimming pool leak detection appointment.
Join the Discussion
Have you ever dealt with a skimmer throat leak or a pool that seemed to lose water for no obvious reason?
Leave a comment below and tell us about your experience. If you have questions about pool leak detection, dye testing, hydrophones, pressure testing, or swimming pool maintenance, post them in the comments, and we’ll do our best to help.
