Underground water pipe inspection sensor

Hi,

I'm trying to implement a water pipe inspection system using arduino but I don't know exactly how to use sensors to detect the leak. Most projects consider the valve is turn on, hence there will be a pressure or acoustic change on it, but for my project the valve is turn off so I'm thinking these methods can't be applied and a camera isn't the best option for now. Does anyone has any idea of how this inspection could work or how normally it's realized in water distribution network?

As you are already aware that the simplest method of leak detection of a pressurised system is by acoustics, it should be no surprise that the detection of leaks in a non-pressurised system can only be achieved by NDT (non-destructive testing) of the pipe carrying the water.

There are no NDT methods that can be implemented with an Arduino without considerable cost. If you've got loads of money to throw at this project, an Arduino wouldn't be the best starting point.

Look for a wet patch.

The traditional way , still used is for a bloke with a metal rod putting an ear to the pipe.

http://www.subsurfaceleak.com/find_leaks.html

Those meters can be quite simple , basically a microphone and amp.

Possiblly you could use arduino for DSP to discriminate the different sounds.

cflavs:
Hi,
, but for my project the valve is turn off so I’m thinking these methods can’t be applied

Unfortunately to detect a leak there has to be a leak.
No pressure = no leak.