"Sam" wrote in message
...
Hi,

This morning we saw a man from the water company walking down the
street; at first we thought he was reading meters. Actually he lifted
the "manhole"[*] cover at the end of each drive and put a metal rod
down onto the pipe and listened to the other end of the rod. I am sure
I have heard something about water companies listening to pipes but I
can't remember where I heard this (tv or usenet?) and I can't remember
what the point of it was. We were too shy to ask him

Why would he be listening to pipes? Is he listening for leaks?

Yes, it's a very well established technique, also works for detecing worn
bearings etc. Try it yourself, any old rod or stick will do. I fold the
little flap in front of the earhole over the hole and put one end of the
stick on that and the other on whatever metal you are listening to. You'll
hear a water leak all over the pipe system in the locale, they will have
been looking for where it sounded loudest, giving them a smaller area to
dig.


--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)