There are two common scenarios when facing a leaking water main. The first would be a visual inspection, if the water main was leaking at a pipe on the inside of your home it would be easy to see the leak and conclude that the pipe is leaking.
In other scenarios you may become aware of a leaking water main after receiving a violation notice from the city, or if your plumber has advised you that the pipe is leaking in a location that you cannot see, like behind a wall or below ground. You may have water leaking in front of your house under the sidewalk and are quick to assume that it is your leak due to the location of the leak. Or in other cases you may have water leaking in the roadway directly in front of your home and your opinion is that there is no way the water leak in the roadway is from your pipe!
In all of the cases noted above there is a simple test to assist in identifying a water leak which includes the use of a sonoscope. The sonoscope is a listening device that is used the same way a doctor would use a stethoscope. We simply place the listening device on the water main from the inside of the house, make sure that there is no active running water in the house and listen! In theory, if all of the plumbing fixtures inside the house are off, the pipe should be completely silent with no activity. If you are using the sonoscope and have detected a noise that sounds like running water, there is a good chance that the pipe is leaking and must be repaired.
It is very important to make sure that the test is performed by a licensed master plumber who has experience listening with a sonoscope as the noise we are seeking may not be apparent to the average homeowner. Ultimately there is only one way to guarantee that the pipe is leaking which includes exposing the actual leak. This may include excavating on the outside of your house or opening the walls of your home for a final confirmation. With that said, a noise test is a good indicator and should be taken into consideration when trying to identify the source of a leak.
