Manhole V Inspection chamber

[RichS]

I will be building my house in what is currently my garden.

The drainage is a combined system which I know needs an attenuation tank etc.

My SE who designed the drainage has shown a number of inspection chambers which discharge into a manhole within the new properties boundary which then discharges into the existing manhole of my current dwelling.

As the drainage to the new dwelling is only serving one property it is not classed as a sewer according to BR. So do I actually need to build a manhole (i.e. brick or large (expensive) plastic) as opposed to simply fitting a 450mm inspection chamber on the new plot which then discharges into the existing manhole.

My SE drawing says I do but I suspect there is a lot of "cut and paste" gone into it.

[jamiehamy]

Hmm. Our drainage system was similar,  way ott - 600mm plastic inspection chambers,  highway grade manhole covers etc.. 

 

My ground works Contractor suggested things to change to reduce cost,  the big one being to substitute plastic 600mm chambers and backdrops to the large round concrete affairs. Saved thousands with that. I asked him to speak to BC to get agreement which they did approve. So there is scope - I never spoke to the SE about it,  I went with the contractor and BC. 

[Oz07]

Cant see why it's been specced up. Does se usually design residential drainage strategy? Depends on drain depth I suppose but good groundworks contractor will put you right

[RichS]

Thanks for the replies, the only problem is that I am the ground works contractor, as I am also everything else that goes along with this self build malarky

So we don't think there is actually a definitive answer??

I can't find anything in the BR (England) that answers my own question. Suppose I'll have to wait 'till I appoint my BC inspector and run it past them.

[PeterW]

BRegs are more concerned about depth and size rather than what goes into each chamber. 

 

@RichS If I've read this correctly you are adding a new property to an existing system and then removing the existing property ..?? Or are you saying that you will have house A with a foul drain connection to a main sewer, and then you are adding house B and routing into the existing foul connection ..??

 

if it is the latter then the existing drain may need upgrading as you are creating a lateral drain - BRegs is not relevant here, the relevant standard from your sewage provider comes into play. Pipework and connections will need to meet those standards, not a small task as they need to be adopted by the provider. The law changed on this a while back and all laterals (those that serve 2 or more properties) are being adopted over time. 

 

It is sometimes cheaper to basically dig a parallel trench and have no sharing as you will be running your own connection. 

 

Probably not what you wanted to hear ..!! 

[RichS]

Hmmm thanks, your right, not what I wanted to hear

 

I will do as said above and wait 'till I have my BC Inspector sorted and see what we come up with.

[PeterW]

You'll need permission from the sewage provider to connect to a lateral anyway - most publish their developer guidelines online so easy to find out.