Soil pipe under new concrete floor

[Artrax]

Can I run a soil pipe under a new concrete floor with a few 30 degree bends, without needing an inspection chamber?

I want to build a 6m rear extension, but the main/public sewer is only 7m from the rear of my property (parallel to the rear wall). I know I need to notify my water provider if I am building within 3m of a public sewer, and I also read somewhere that if the sewer is between 1.1m and 2m deep, then there is a minimum distance of 600mm, or 1m if it's deeper.

My plan, before I realised how close the main sewer actually was, was to put a inspection chamber closer to the main sewer, outside he bounds of the extension, for my new pipework to connect to - but I'm not sure that I can do that with just 1m of space, if I was even allowed to.

I'll need to run new pipe from the side of the extension (see attached plan), and I'm hoping I can connect these to an inspection chamber, and the run new pipework to the existing pipe with some gradual bends.

I believe some existing properties may have soil pipes under the concrete floor - but I'm unsure if this would be conform to today's building regs. Estimated run would be 7.5m under the floor.

Thank you

 

[frutbunn]

As far as building Regs is concerned a private drain can run under an extension, an internal inspection is also allowed provided it has a sealed cover.
Personally I would not allow the arrangement with the bends as you propose. I will stress as no doubt others will your BCO may take a different view.
I would be asking for a direct line to a new sewer connectiion,

 

[Artrax]

Thanks frutbunn!

Reassuring to know that private drains under a concrete floor are allowed. I wasn't aware internal inspection chambers were allowed though so that's useful to know. I guess that gives me another option.

I know it all comes down to what my BCO will allow, but can I ask why you wouldn't allow it? What about 15 degree bends, rather than 30? I only chose 30 as it'd read this was the minimum without an inspection chamber - and 15 degrees would mean 4 bends instead of two.

A new connection to the main sewer is an option I did consider it, but a bit unsure on the cost. I plan to do this as a self build, but I wouldn't want to touch the main sewer myself. I know there is an application fee to the water company (Anglian Water in my case) but would I then arrange my own contractor to make the new connection, or is that something only the water company can do?