How to identify outlet pipe lekage from tank ..where there is no clue?

[Rajatmes]

The problem what I ve faced is unusal draw down water level of over head tank with out any visible lekage from outlet pipe / tap or flush tank..if it is from concealed pipe ..how to identify the actual point.

 

[V R Suresh Simha]

Monitor the water level in the tank is one way to identify the leakage in outlet pipe.