Distributed Underground Hot Water piping

[Joe_Joe]

In an apartment complex with 20 buildings served domestic hot water from a central boiler in a recirculating system, is there a way to check periodically for underground leaks?

Thank you!

 

[IFIXH20]

Do each building have one water service with a working service entrance valve?
Does the recirculating system have working shut-off valves ?

 

[camaroderrick73]

Infix hit it.. Only way is to isolate each and test separately