Finding an Underground Water Line Leak

The sounds leaking water makes in a water line are the key to finding an underground leak. Learn the different sounds water pipes make so you can find the source of your water line leak.

Acoustic Water Leak Detection

Water traveling through pipes makes distinct noises. Splashing indicates that water is flowing around the outside of the pipe. A steady, repetitive thump means water is spraying into the soil around the pipe. But the sound to listen for closely is hissing or whooshing. It can sound like static on your car radio. This hiss is the loudest noise made by leaking pipes that have a 30 psi or higher water pressure.

Finding the Leak

Leaking metal pipes hiss more loudly and at a higher pitch than concrete or PVC pipes. The smaller the pipe diameter, the higher the sound will be, too. Grass and loose soil around and above the pipe will muffle the leak's hiss, while compact soil and asphalt at the surface will magnify the sound.

Where to Listen

Listen at hydrants, valves and water meters for the hiss of a water leak. The closer you get to the leaking spot, the louder the hiss will become. Test with a ground microphone to pinpoint the leak's source.