Question: Listening For Water Leaks?

[SantaUK]

We just had two guys going round our cul-de-sac lifting all the incoming water mains covers and sticking a pole down the hole, and listening into a big sucker on the other end. What are they listening for?

[Bob Minchin]

Yes, quite likely. You can hear quite low water flow in pipes. Bob

[Andrew Gabriel]

Leaks generate white(ish) noise, which tends to be identifiable. You can attach two microphones to two different points on a pipe, detect the phase shift between them, and work out exactly how far the leak is on the pipe from the microphones. Saves digging up a whole pipe just to find it.

[pete]

The gushing (from a big leak) or hissing (from a small one) sound that water escaping under pressure makes.

[john]

It's a characteristic 'hissing' noise and the very traditional device is known as a 'listening stick'. The old hands can find leaks more reliably than the modern electronic 'cross correlators'.

[The Medway Handyman]

Did some jobs last year for a lady who worked for the local water companys leak detection unit. They used sticks, electronic detectors & believe it or not - dowsing rods. She swore blind they worked a treat. I have my doubts.

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "The Medway Handyman" saying something like:

[The Medway Handyman]

'D' then 'Dowsing'.

[Mark]

illegal emigrants

[john]

Know a couple of water guys who carry dowsing rods (as standard kit) in the van. They say the rods are not infallible but can be useful when all else has failed. Given an on-the-spot demo where an obscure water main was pinpointed. Dowsing's a puzzler and I'm keeping my options open ;)

[Andy Dingley]

One of our neighbours does this. Quick stuff is the electronic gadget, harder stuff is a stick in the ear.

Then if it desn't work, you get out the dowsing rods. This gives you time to think, and it also makes the awed audience shut up for a bit, so you can actually hear the water.

[Neil]

Sure! - a couple of bent welding rods works a treat.

[Andy Dingley]

If anyone claims to be able to dowse with welding rods, I find the best response to be to fix them with a Hard Stare in your best crazy wiccan manner (I live near Bristol, we get lots of practice) and denounce them as a charlatan, for Cold Iron rods cannot possibly work for anything as fey as dowsing and the fast folk would never help you with them. Then produce a set of bronze (brazing) rods and use those. Silver or mithril would be even better.

[The Natural Philosopher]

The odd thing is that Randi makes the point that a dowsing system is actually something held at a point of extreme instability..the slightest vibration can cause the rods to twitch.. I wonder if its nothing more than a vibration detector.

[Neil]

Well I know nothing of dowsing but I've seen this work countless times - in fact we used to spend hours messing about (playing) while on night shift. Have you tried it? :)

[PeterC]

A lot of vibrations from water would be less than those from roads, unless the leak is close and a a reasonable rate.

There's a place NE of Doncaster that found and aquifer with v. good water in it and now sells the water. Given that this is flat land and used to have a lot of leaking septic tanks, this is remarkable. Some water was found about 10 - 15ft. down; drilling a bit further found nothing. A dowser was called in and he found the shallow source immediately. He then moved around and found more places - enough to get some sort of line. He reckoned that it was about 80ft. down and so it proved. What surprised me was that there was good water and any flow at that depth, as the area is about 5m above sea level.

[dennis]

They do that sort of stuff around 02:00 here. It was about then that they were poking sticks down stopcock holes last time I saw them.

If I saw a lunatic dowsing at that time of night I would phone for an ambulance to collect them.

[dennis]

I bet you could have drilled anywhere for miles and found water, that's the way aquifers are. If they aren't you are going to suck them dry almost immediately.

I bet experienced people with a geological map can study them and find the water without even having to go there and dowse.

[PeterC]

Yes, this one must wander around a bit. It apparentl goes to at least York and, given the lack of any hills, must just spread in the porous strata.

[SantaUK]

Thanks for the answers - even the one about illegal immigrants!