Minimum depth of water pipe

[MrsP]

I’ve got a question about pipe depth. My old incoming water pipe is leaking but is below the neighbour’s subsequent big drainage pipe running across it and is hard to access, on a narrow pedestrian lane in a conservation area. (The experienced plumbers I got in dug down so far then backed away and said it would require machinery.) I'm wondering if a solution might be to lay modern piping above the drainage pipe at less than the specified depth with some sort of insulation against frost - is this ever done, does anyone know? Thanks!

 

[Last Plumber]

It needs to be 2'6" deep.

 

[MrsP]

Thanks - but various water boards online say “If you can’t do this, contact us” so it seems it’s not always possible. I’m trying to find out if there’s another way of sorting it. Thanks for any ideas - the alternative seems to be I let the water keep running (outside my water meter thank goodness) or if it gets really bad, turn the water off at the pavement stoptap (it only supplies me) and don't have water.

 

[king of pipes]

As above 30" is the norm .kop

 

[Riley]

I was always taught 750mm min -1350mm max need to be wary of the weight of passing traffic above

 

[MrsP]

Thanks Riley - it's a footpath, too narrow for a vehicle except a bike so that wouldn't be such a worry.

 

[Riley]

Well traffic isn’t always cars etc. It can be livestock, a small tractor with a hedge trimmer on that sort of thing

 

[Riley]

You also have to think about freezing if it’s not deep enough

 

[MrsP]

Yes, I thought about freezing and I wondered if there some special insulation they used in those cases (it's only a short stretch before it can go deep underground again, just enough to get over the waste pipe). I've never seen anything heavier than a bike go down the lane and it wouldn't be used for livestock any more. I take your point I wouldn't want it breaking though and there's always a first time.

 

[Riley]

It’s more a case of potential issues you could experience or even fines should your mains burst and cause water wastage or contamination back to the main supply

 

[Riley]

If I were you I would phone your local water board and get their opinion on it

 

[Riley]

If you approach it pragmatically and don’t tell them how to do their job then they are usually pretty flexible in terms of working through a problem with customers

 

[Last Plumber]

Yes, I thought about freezing and I wondered if there some special insulation they used in those cases (it's only a short stretch before it can go deep underground again, just enough to get over the waste pipe). I've never seen anything heavier than a bike go down the lane and it wouldn't be used for livestock any more. I take your point I wouldn't want it breaking though and there's always a first time.

Insulation will not prevent freezing. In some circumstances it can delay it but I wouldn't rely on that. Why can it not be run beneath the drain? Is it purely because the people digging it gave up? There are a lot of weak willed, not very determined types about these days you know!! Maybe you need some one with a bit more 'go'?

 

[MrsP]

The water board sent someone out who said it wasn’t their problem - I might have to try them again. Meanwhile I’m asking around locally for someone who doesn’t mind digging very deep holes manually if that’s going to be the only option! I was hoping there might be an easier solution. Thanks for the advice.

 

[Riley]

It’s not their problem but they should be able to advise you in terms of water regs how you might navigate the problem as they have eyes on it

 

[MrsP]

Thanks, yes, will contact them again and explain the difficulty.

 

[Last Plumber]

Thanks, yes, will contact them again and explain the difficulty.

From my experience, they will only repeat their-selves. Find a person who is not frightened of hard work and you will end up with the right job and never suffer from a lack of water in winter.

 

[Ric2013]

Also, the depth is to avoid the risk of the pipe warming to unhygienic temperatures in summer, and risk of contamination through the plastic pipe walls (which is the advantage of copper: it pretty much won't let ANYTHING through).

The water board will probably insist on 750mm minimum and you can sometimes mole a pipe without having to do too much digging, so really you have no reason to make the pipe shallower. The model water bylaws of 1950 wanted 2'6", so this sort of depth has been required for a long time.

 

[MrsP]

Thanks for all the comments - it doesn’t sound as if it’s a goer then!

 

[townfanjon]

I was always taught 750mm min -1350mm max need to be wary of the weight of passing traffic above

The favourite city and guilds exam question, the only one I remember lol