Connection to steep sloping lateral drain

[JackOrion]

We have a 100mm lateral drain that we will be connecting to. Runs right through our plot and is five metres or so from the edge of the house. This existing drain runs down a steep gradient (perhaps around 30 degrees), before it drops down to the mains below. We're in a valley hence the slope, and it's an old Victorian drain. We have been given the green light to connect by the water company for domestic foul water (with a soakaway for surface water).

 

Who governs the connection method and gradient of our connection? Building control or utility company?

 

Does anyone have any experience of connecting to a steep sloping lateral drain such as this, and is it likely to be a complex procedure? Have been reading quite a bit about maximum recommended gradients of 100mm drains being more like 14 degrees to avoid solids being left behind, and wondering whether the existing drain gradient makes our job trickier. We can control the gradient of our connection as we're on a plateau midway down the slope.

Edited Wednesday at 18:22 by JackOrion

[Temp]

Both.

 

Building Control normally want to see drainage plans and may want to inspect before trenches are back filled. The utility will also want to approve a connection to it.

 

Think I would get some drawings done and approved by the utility co. Think it's unlikely or less likely BC will object if the utility co is happy.

[Oz07]

If the gradient is existing then its not your problem. Make sure everything you do upto your connection point is ti the regs then all will be fine. Normally bco would inspect on this I've never had water board come out. 

[Mr Punter]

Plastic inspection chambers are not designed for steep gradients so you may need to build one to suit.  Talk to your groundworker and to BC.  What depth is the pipe?

[Nickfromwales]

36 minutes ago, Mr Punter said:

Plastic inspection chambers are not designed for steep gradients so you may need to build one to suit.  Talk to your groundworker and to BC.  What depth is the pipe?

Sounds like it needs (or would benefit from) a ‘backdrop’ chamber?

 

As above, get a (good) groundworker in and get a professional opinion. When they suggest a solution, then go to the BCO and ask if that satisfies their expectations. 

[Nickfromwales]