If you have been called into a household or property to lend your professional plumber's expertise to detect a leak, then you may want a refresher on how to go about pipe leak detection. You should remember to check the water meter, check for signs of leaks such as mold, erosion, and shifting household elements, and consider using professional sound equipment.
Check The Meter
One of the first parts of checking for a pipe leak is to check the water meter that tracks their water usage. If they've called you for a general plumbing check-up, such as with businesses needing to stay on top of building codes, then this step is an important part of determining if the measured water usage is out of sync with what the property owners should have been using. For homeowners, this can help you determine how large any leak is if they already know that there must be one. You can access the water meter by opening the residential box lid with screwdrivers.
Mold, Erosion, And Shifting
Once you have checked the measured water usage and cross-referenced it to the amount of water that *should* have been used, you can focus on more traditional signs of leaks. There are many different ways to find pipe leaks through these signs, but they can be organized into three main categories - mold (or musty smell) due to excess water, erosion from drips, and shifts (or warping) in the wall or flooring material (be that wood or wallpaper). If you see any of these elements in the cupboards, under sinks, around pipes, in or on the walls, the rafters, or anywhere else you can check, that's a sign (although not a guarantee) that there is a pipe leak somewhere in the pipework.
Finally, if you still aren't sure but still suspect there's a leak, then there are various tools that you can use to detect an invisible leak. For example, there is sound equipment that allows you to listen inside the walls for leaks. Thermal scans can show irregular hot or cold spots due to a hot water leak inside of the foundation, and you can even use video cameras that run inside of a pipe to see where water is going. This equipment is not necessarily used often, but it can still be of great help.
Detecting pipe leaks are one of the most common jobs a plumber is asked to do. When detecting pipe leaks, always check the meter and for obvious signs of leaks, and if need be, use professional equipment.