Cap off lead pipe but cannot turn water off

15 Feb 2008
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United Kingdom
I have had a new MDPE water supply put in and now need to cap off the old lead pipe. I've dug up outside and found where my branch pipe comes off the main supply pipe, under my back yard. I need to cut this off and permanently seal it. I think I can use a Leadloc fitting to copper and then a short piece of 15mm copper to a stop end. BUT... I can't turn off the water supply a) because I don't know where it can be turned off and b) even if I did, it would presumably turn off the water to the whole row of houses. Is it possible/safe/wise to just cut the branch pipe and try to get the leadloc on quickly, or do you have any other suggestions.
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Forget cutting it live!

This is only done on an emergency basis. You will need to find the stopcock, there must be one somewhere. Wait till Monday and phone up your water provider. Where is the new MDPE pipe connected to?

The MDPE pipe comes from a water main in the road at the front of the house. The old lead supply comes in at the back, I've dug it up to a tee off a bigger pipe about 4 feet out into the back yard. I think this runs along the back of all the houses supplying all of them at one time. Some (like me) have had new supplies put in from the front, now complete with its own stop tap in the road. Both new MDPE and old lead supplies are now active. I don't have any internal plumbing yet - they both just end in stop taps as they enter the house.
If you now have a new supply, the water supplier should disconnect the old one as you will now have a dead leg which is a definate no no.

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Can you just close the stop cock on the lead pipe and disconnect it?
Then work with the new supply?

Can you just close the stop cock on the lead pipe and disconnect it?
Then work with the new supply?


That would be classed as a dead leg and they wont allow them any more.

Until Monday when you can confirm with your water provider the next step to have it removed.

At least this way he can connect the new supply over the weekend.

Thanks to all of you for your advice. I will call United Utilities on Monday. Part of the deal with getting the new supply in MDPE was that we cut off the old one (without leaving a deadleg). The inspector who came to check that the trench and pipe were done correctly gave me the impression he wouldn't be coming back to check that the old lead supply was cut off properly - but that's no reason for me not doing it properly. I dont want the old lead pipe still coming into the house as it will be a future leak risk. - Its stop tap (inside the house) doesn't turn completely off so I've already had to put a second temporary one in series with it.
By th way, what counts as a deadleg - if the tee off to my house is cut and stopped off there will still be at least a few inches from the main pipe to the dead end. How long can this be before it counts as a deadleg ?
Anyway thanks to all who replied - I'' let you know what the outcome is after contacting UU on Monday.

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