A dripping tap is usually easy to spot. At some point, when the house is quiet, there will be the recurring sound of water falling drop by leaky drop. Yet, how do plumbing professionals such as The Gentlemen Plumbers identify leaky pipes buried in concrete and/or earth which ooze invisibly? There isn't always the proverbial “wet patch” to identify the location.
Fortunately, pipe leak detection techniques used by The Gentlemen Plumbers and other experts have moved beyond dowsing. Most important is to make things as quiet as possible. Working in the middle of the night is one option. There are also mechanical devices which filter out most of the noises not connected to the leak. These leak locator's can “listen” for the tell-tale sounds of a leaky pipe and give you a graphic display that helps with location.
“Plumbing&Mechanical” magazine says that everyone can learn to hear these invisible leaks. It's a good idea, too, as undetected leaks cost money in both water usage and damage repair. “P&M” describes three different types of pipe leak sounds. The first is whooshing or hissing caused by pressurized water “escaping” through a crack. This pipe vibration makes the loudest sound of the three and is, thus, the easiest to hear. The second is gurgling, similar to the sound of a small stream, as the water flows through spaces in the soil. The third is a hammering or knocking when the water hits rock or gravel.
Many factors affect the type and quality of these leaky noises. One is the pipe material. Sounds transmitted in metal pipes will be much higher than those transmitted in PVC – 500 Hz to 1,500 Hz vs. 70 Hz to 850 Hz respectively. Another factor is the depth of the pipe. In pipes deeper than 8 feet (2.44 meters), the water pressure is often increased to magnify the sound of the leak because the surrounding soil very effectively muffles the sound.
Home and office dwellers will usually have an invisible leak brought to their attention by a spike in their water bills. The next step is a water leak survey. This basically means listening for the leak and trying to follow its path. The most efficient way to identify a leak is to use responsible companies such as The Gentlemen Plumbers whose ears and equipment are well-tuned to these hard-to-hear leak noises. If you suspect that you have a leak, it is suggested that you call in someone reliable to check it out, even before your water bill confirms your suspicions.