Water supply pipe tracing

[PeterK]

I'm trying to find an alkathene supply pipe that crosses my property laid

30+ years ago - need to dig two trenches or one big trench to hold electric and gas supplies and they will cross somewhere in a 25m stretch. I don't want to dig the trench (40m) by hand so I've started a trial trench to attempt to locate the pipe.

If at around 400 - 500mm depth I hit a clay subsoil is it reasonable to assume that the pipe cannot be lower than that unless I see a colour/texture change i.e. can the original backfill revert back to looking like the subsoil?

PeterK

[Harry Bloomfield]

PeterK brought next idea :

Highly unlikely - disturbed soil will always show evidence of being disturbed, a fact made good use of by archaeologists.

[Phil L]

Water is almost always over 26 - 30 inches down (for frost penetration), gas and electricity don't have to go so far down, so why not just dig the trench

24in deep?

FWIW a mini digger won't do any harm to a water main providing someone is on hand to keep an eye open.

[dcbwhaley]

Contact your neighbourhood dowser. Every villagre has one.

[PeterK]

"The number of holes I've dug in the wrong place because of dowsers - that's why I moved to metering" Yorkshire Water employee last week

If the water pipe is anywhere close to the expected depth it will be a miracle with this house. Mini diggers are at my liability - the pipe is at least 1" and the pressure > 9bar - by the time I'd got a clamp on the pipe I'd have a full trench of water and the stop c*ck / service valve is somewhere in a field boudary 150m away ( " or it could be somewhere in the field")

PeterK

[Phil L]

I've just dug out 40m3 of soil with a mini digger and came across plastic gas and water pipes, neither of them was harmed

[hzatph]

In my limited experience it is easy to cut a water pipe and the presence of clay is no guarantee of safety. Water pipe are often not as deep as stated too. You could try listening for the pipe wiht a rod into the ground - but this will require rapidly flowing water to generate the noise.