The Pollard Sonoscope Hand-Held Leak Detector is so good and so inexpensive it should be carried by every meter reader and all your field personnel.
The Pollard Sonoscope Hand-Held Leak Detector readily detects the sound of escaping water in valves, hydrants, meters, etc.
The Sonoscope/Water Phone is recommended by the AWWA Standards Committee in its inspection and maintenance procedures for hydrants.
Its regular use promotes leak awareness and identifies costly leaks.