Plumbers refuse to locate underground irrigation system pipe leaks?

[AntDude]

Hello.

Why do many plumbers refuse to locate underground irrigation system pipe leaks in an almost 2 acres hilly rural land? Others and I can't find the underwater leak(s) even though we know it's on the irrigation system's side after shutting down its main major pipe since water meter slow down big time. We can't find any wet spots by looking, feeling, listening to the pipes (not sure if we found all), poking the grounds, etc. There are many plants and trees in. We don't have any maps of the pipe system of this rural early 1980s home area. These days, we have to turn off the underground irrigation system to avoid the leaks and high water bills.

Thank you for reading and hopefully answering.

 

[snowhead]

You don't need a plumber, you need someone who specialises in leak locating on underground pipes.

Also I would say that these are some of the reasons,

in an almost 2 acres hilly rural land
We can't find any wet spots by looking, feeling, listening to the pipes
We don't have any maps of the pipe system
of this rural early 1980s home area.

Or just replace the complete system with new piping, it will probably work out cheaper.

To locate the leak, or leaks if more than one, it would need the pipework location tracing from where it first goes into the ground, then breaking up into sections and each section pressure testing to prove no leaks.
And replace leaking sections where found.