We get asked a lot how exactly we can know which pool pipe is leaking and how do we pinpoint the location of the pipe break. Leak detection is a niche in pool business and information on how and what tools to use to pinpoint leak on a pool pipe is not widely available. People often think we use technologies that are not very useful in pool pipe break locating like cameras, ground penetrating radars, sonars, or even moisture readers and thermal cameras. While all these technologies can be helpful in certain situations, we mostly rely on good old pressure testing to find out which of the pool pipes has a break in it and then on an ultrasonic listener to help us locate the break. Remember your pool has at least four different pool pipes and some pools can have ten or even twenty different pipes. From our experience, we usually find a single break on one of the pipes when we pressure test a pool. It does happen sometimes that a pool has more than one broken pipe. Pools that have been neglected, or left leaking for a while can get another break on a different pipe or sometimes even two leaks on one pipe. The way pool pressure test works is similar how they pressure test a car AC system in a car shop. We have a pressure test gauge with a specialty plug that is used to seal up the open end of the pipe and then we build up some pressure through our pressure gauge. Of course, we need to plug off all open ends of that pipe using either hard rubber plugs, thread on plugs or pneumatic rubber plugs. Either way all ends of the pipe need to sealed off or then we build up pressure using air or water. Some people are worried that this pressure can damage the pipes, but that is not possible since pool pipes are tested at lower pressures, around 20psi, while PVC pool plumbing is rated at 160psi. Some may ask why the testing pressure is so low and one reason for that is that 20-30psi is usually a working pressure for most open-end pool pipes and also since pool pipes are larger in diameter (1.5in and larger) when they leak they tend to leak a lot, so that shows immediately on our pressure gauge. When we run into a broken pool pipe, sometimes it is even hard to build up any pressure on it at all. In other instances, the pressure drops within few seconds of reaching 20psi.
In a way, pressure test is a no brainer. First option, pipe loses pressure, that means that there is a break on the pipe. Second option, pipe doesn’t lose pressure that means this pipe doesn’t leak. Once we find a pipe that loses pressure we move on to ultrasonic listening. People confuse ultrasonic listening with ultrasonic imaging, which is something that is performed at hospitals for checking pregnancies. We can only wish that one day we will have ultrasonic imaging for pools- that would make jobs of pool leak detectors a lot easier. What we use is an ultrasonic listener, which is designed to pick up sound frequencies that are outside of human ear spectrum (e.g. water leak 4 feet underground) and convert it into something we can actually hear. We let the pipe leak, so it makes a noise and we walk around the length of the pipe with our devices that give a strength reading of that noise. Wherever the signal is the strongest is the spot of our pipe break.
Ultrasonic listeners have evolved quite a bit in last twenty years, but the basic technology remains the same. What newer ultrasonic listeners have over the old ones are more sensitive microphones and better hardware and software that interprets and displays the sound reading to end user. What hasn’t changed is the fact that using any ultrasonic listener requires a lot of practice and
experience to get good results and pinpoint pool pipe break accurately.