Mystery Black Undergound Pipe Leak Repair Advice

[OneTwo]

Hi All

After having pooling water on my drive, I dug down around to find:

Black pipe poly/plastic dug 450mm deep spraying water at mains pressure from small hole/crack
The outside of pipe (measured with veneer caliper) at 23.5mm
Pipe Runs under drive, along side of property and looks to go under the garden, (possibly supplying a field for horses drinking water that used to belong to the house-speculation).
Turning off stopcock at road turns off water supply to house and mystery black pipe
Ive put a tempory repair on the pipe
Skill level: DIY

My Questions:

Could anyone advise on the type and bore size of the pipe - I assume its non-drinking water poly pipe. No markings on the bit I dug around.

When I repair it, I would like to block it off as I assume its not my main supply as it goes past the house under the garden. I summise it may be a branch off the main supply.

Just in case it shuts off the whole supply I was thinking of putting a stopcock there, so I can shut it off easily, and if it shuts off the whole supply, simply turn it on again and restore the supply and fix the hole in the pipe at the same time.

1. Can I put a stopcock underground/ good practice? Does it need something around it underground to stop dirt ingress.
2. Should I not do the above. Block it off, and if that shuts off my whole supply just join the pipe.
3. Non of this do something else

 

[fowlerboi]

Looks like black alkathene. It's joinable but if its really old you sometimes end up chasing repairs in it, best replaced with a new length of MDPE.

If its not possible to do then just repair it with a coupler, my go to is philmac. The hardest part with Alkathene is finding the right size stiffner to go inside the pipe before joining it. It wants to go in snug without having to hammer it home too much and be long enough for the fitting being used. My advice would be buy a variety from a plumbers merchant

Don't put a stopcock in the ground unless you're going to put a service tunnel in for it. Personally I would just scrap that idea

Not sure what you've currently used to repair it but it looks a bit micky mouse

 

[OneTwo]

Looks like black alkathene. It's joinable but if its really old you sometimes end up chasing repairs in it, best replaced with a new length of MDPE.

If its not possible to do then just repair it with a coupler, my go to is philmac. The hardest part with Alkathene is finding the right size stiffner to go inside the pipe before joining it. It wants to go in snug without having to hammer it home too much and be long enough for the fitting being used. My advice would be buy a variety from a plumbers merchant

Don't put a stopcock in the ground unless you're going to put a service tunnel in for it. Personally I would just scrap that idea

Not sure what you've currently used to repair it but it looks a bit micky mouse

Thanks for the advice moist grateful

That repair is just temporary to stop the water leaking, something from Tootstation 5.55pm on a Saturday night!

 

[Chuck]

There were two 'classes' of alkathene black pipe used in the 60s & 70s. You can't infer the ID from the OD but there may be identification printed on the pipe itself, e.g.

Black Alkathene Pipe Size Information

We don't stock the old black Alkathene plastic water mains pipe or fittings any more, though we do have some size information

www.stevensonplumbing.co.uk

IIRC, it was supposed to be buried 3ft deep (750mm) and surrounded with sand to protect from damage by stones.