Location of lead water main

[sparer]

Hi,
I've got an underground leak and we're losing about 4m3 of water a day. We've had a plumber, a leak detector guy and a groundworks guy out to detect the leak. They all failed except that the groundworks guy used a CAT and genny to locate the pipe run. The pipe is lead and runs under the building and along a (concreted) yard at the rear. It seems to enter the building at the rear but we can see no sign of it internally. In fact we can see any floor to ceiling pipe runs anywhere. The stop cock is in an out-building before disappearing underground under the main house.

We're going to replace the main with a new MDPE main but I need to locate the incomer so that it can be capped off.

The walls have all been studded out with plasterboard and I know that the internal incomer will be behind the plasterboard somewhere. Is there a reliable way of working out where because the pros seem to lose interest as soon as it becomes difficult.

Many thanks

 

[Harry Bloomfield]

The walls have all been studded out with plasterboard and I know that the internal incomer will be behind the plasterboard somewhere.

Metal detector?

Signal generator and detector?

 

[sparer]

Metal detector?

Signal generator and detector?

I'm guessing one of thise stud finders would probably do it but why didn't the pros try that? Also, is there a non groundworks version of a CAT and genny that I could use? Connect to any cold water pipe and use it like a stud finder?

 

[Harry Bloomfield]

I'm guessing one of thise stud finders would probably do it but why didn't the pros try that?

Maybe, it depends on the depth - a proper metal detector will 'probe deeper' into the wall.

 

[CountryFan]

Off the stopcock to inside, is it copper?

 

[sparer]

Off the stopcock to inside, is it copper?

No, it's lead and it disappears underground and I can't find where it reappears.

 

[CountryFan]

No, it's lead and it disappears underground and I can't find where it reappears.

I’d be looking in the kitchen or any downstairs bathroom/toilet area.

 

[accelerator]

If you want to try another professional, then based on his YouTube videos, this guy seems pretty good:

Original Leak Detective

My name is matt and i create videos on locating hidden water leaks and make it as enjoyable as i can! If you have leak! LETS GET IT!!! If You Enjoy My Content Like & Subscribe!ððµââï¸ www.originalleakdetective.co.uk

www.youtube.com

 

[ree]

OP,
All the lead water service pipe should be abandoned. There's no need to "cap it off".
Locate the external stop-valve. And, after checking for a water meter, connect a new MDPE service pipe to the external stop tap.
Determine where you want the new supply to enter the house, & dig a trench at 750mm depth to that position.

 

[sparer]

So, to conclude this. I found the incomer. Someone had removed the stoptap off the 22mm copper incomer and used a speedfit to connect it to PEX 15mm so it looked like a CH pipe. The leak was located on the 22mm copper to lead buried about 150mm underground, a pinhole in the joint to the lead main. This has been temporarily fixed and I need to negotiate a leak allowance with the water company to reclaim the £2000+ bill and a new MDPE main. Then the bill from the CAT and genny scan and groundworks to locate the fault. Bill incoming!

Expensive hassle for something so innocuous.

 

[Diver Fred]

I feel your pain!

Came back from Hol's in September to hear the sound of running water. Wife coulden't hear it initially but could after the plumber chap had been out. We proved the leak was outside but under the passageway between the two houses. I now think having changed the pipe it had been leaking for nearly 40 years - original pipe was galvanished steel installed in 1958.

Took the water company 10 days to get their act together, me and the plumber 3 days to dig out and prep. for them to do the job.