How to Tell if Your Pool Leak Is Underground — Not in the Liner
One of the biggest questions New Jersey pool owners ask is simple: “Is my pool leak in the liner, or is it underground in the pipes?” Many divers will focus only on the liner because that is all they can see. But in communities across Monmouth, Ocean, Middlesex, and Mercer County, a large percentage of leaks actually occur in the underground plumbing.
Knowing the difference can save you from unnecessary liner replacements, wasted money, and ongoing water loss.
Signs Your Leak Might Be Underground
Underground leaks often show up as patterns rather than obvious visual damage. For example, you might notice wet spots in the yard along pipe runs, soft soil near the pool deck, or air bubbles constantly blowing from the returns when the pump is running. In towns like Freehold, Brick, Old Bridge, and Hamilton, older pools with long pipe runs are especially prone to underground leaks.
If the water stops dropping once it reaches the bottom of the skimmer or a particular return line, that is a strong clue that the leak is related to plumbing or fittings attached to that level. These are situations where relying on a diver to “look around” is not enough.
When the Liner Is Not the Problem
Liner leaks tend to show up as visible tears, small holes, or worn areas, especially around steps, corners, and high-traffic zones. A diver may be able to find and patch these. But if your liner looks clean and the pool still loses water at a steady rate, you should start thinking about what is happening outside the shell.
Many homeowners in Monmouth, Ocean, Middlesex, and Mercer County have been told by divers that “the liner is fine” or “we patched a couple of spots,” only to discover later that the real leak was in the suction or return lines. By the time the underground problem is finally found, a lot of water and money have already been lost.
Why Pressure Testing Is the Only Real Answer
The only way to confidently distinguish between a liner leak and an underground leak is through pressure testing and line isolation. With this method, each individual line is plugged, pressurized, and monitored. If it cannot hold pressure, there is a leak in that line. If every line passes and water is still dropping, attention turns back to the pool structure and fittings.
Real leak detection companies across Central New Jersey rely on this process precisely because it removes the guesswork. You are no longer guessing based on what someone thinks they saw underwater; you are working from test results.
Stop Guessing and Get Real Answers
If your pool is located in Monmouth, Ocean, Middlesex, or Mercer County and you suspect an underground leak, be cautious about hiring a diver-only service. Ask the company directly if they perform full plumbing pressure tests and underground locating. If the answer is no, keep looking.
Your liner may not be the villain at all. By insisting on real leak detection instead of diver-only opinions, you protect your pool, your yard, and your wallet — which is exactly what Ditch The Diver is here to help you do.
