finding leak in underground poly pipe

[Logman]

Some time back there was a chat about finding leaks in poly pipes. I have the same problem now and wonder if a solution was found.
I know from experience that looking for where the grass is green , is ok for starters but remember water runs down hill and the leak can be miles away from where the grass is green....as I found out !! All poly should have a tracer wire in the same trench so it can be picked up with a metal detector. Or, as someone suggested, place 100 x100 squares of aluminium closer to the surface and spaced every 10-20 metres and at every change of direction. This is of course no help to anyone who has the same problem as me.

[steve-37]

Hi,

The simplest way would be to put a video camera down the pipe.

You could make your own DIY sewer drain snake inspection Video camera, like this one.
DIY sewer drain snake inspection VIDEO camera - a set on Flickr

Regards Steve.

[Logman]

Thanks Steve. Sounds like a good idea.

Hi,

The simplest way would be to put a video camera down the pipe.

You could make your own DIY sewer drain snake inspection Video camera, like this one.
DIY sewer drain snake inspection VIDEO camera - a set on Flickr

Regards Steve.

[BobL]

If the leak is via a junction seam or a fine crack a camera may not pick this up.

How deep/long is the pipe?

[Logman]

Thanks Bobl.
it's about 600 deep and 400 meters long.

If the leak is via a junction seam or a fine crack a camera may not pick this up.

How deep/long is the pipe?

[Fuzzie]

The leak spotters fill the pipe with compressed air and use a listener to locate the compressed air leaking out of the split.

[Logman]

Thank for that info Fuzzie.

The leak spotters fill the pipe with compressed air and use a listener to locate the compressed air leaking out of the split.

[Farmer Geoff]

If you know where the pipe is, try digging a hole every 50 metres and as long as the leak is big enough and the soil is not too sandy then the first hole on the downhill side of the leak may be wettest or fill with water. Pay particular attention near any known joints or branches. If the hole is small and not at a joint and pipe is inch and a quarter or bigger then you may be able to use a saddle with a plug in it to cover hole - much cheaper and less digging. If you have a pressure pump feeding this line and suspect a leak due to pump coming on when no taps are open then double check non return valve on inlet side of pump before digging. If finding pipe is a problem, try scalping a shovel width at right angles above suspected pipe location and look for different colour or texture of soil which will indicate a trench. Alternatively, feed a high tensile fence wire (with end bent back so it won't snag on way in or out) into pipe and use detector. Good luck.

[Logman]

Thanks Farmer Geoff. Very practical info. Sounds like a result of experience !!
The wire down the pipe is excellent . Do you reckon the wire could be left in the pipe for future location purposes ?

If you know where the pipe is, try digging a hole every 50 metres and as long as the leak is big enough and the soil is not too sandy then the first hole on the downhill side of the leak may be wettest or fill with water. Pay particular attention near any known joints or branches. If the hole is small and not at a joint and pipe is inch and a quarter or bigger then you may be able to use a saddle with a plug in it to cover hole - much cheaper and less digging. If you have a pressure pump feeding this line and suspect a leak due to pump coming on when no taps are open then double check non return valve on inlet side of pump before digging. If finding pipe is a problem, try scalping a shovel width at right angles above suspected pipe location and look for different colour or texture of soil which will indicate a trench. Alternatively, feed a high tensile fence wire (with end bent back so it won't snag on way in or out) into pipe and use detector. Good luck.

[Vernonv]

Do you reckon the wire could be left in the pipe for future location purposes ?

It will rust and may cause some issues long term (rust flakes, etc entering the water stream).

[Farmer Geoff]

Yes don't leave the wire in the pipe. If it is high tensile stuff you might be able to bend a crank shape on the outer end and turn and jiggle it enough so that a helper with a length of pipe as a stethoscope may be able to hear the rattle if the pipe is empty. If other end of pipe is open, pipe can be emptied by connecting uphill end to exhaust. Once you know where the pipe is, tie markers onto any fence that crosses it and/or bury a paver or brick flush with surface every 50 metres along the line. My father used to say 'no matter what nice things people may say at your funeral, they will curse you if you don't leave a map of your farm plumbing system attached to your will!'