Connection from kitchen sink to mains sewer - advice on plan

[fathertobe]

We've moved the kitchen from the back of the house to the front and were planning to use the gulley drain outside the front window for foul water from two sinks, a washing machine and a dishwasher. (The second sink and washing machine are in an adjacent utility room).

We're on a combined system and so there would have been no issue with draining into gulley. However, at a late stage it occurred to me it might be a soakaway. And it seems it is. Fortunately there's a relatively easy solution - there's a manhole cover outside the external wall which we could link all wastes from the kitchen and utility room to.

I'm just trying to get the plan right. HEre's a picture (as seen from above) - obviously there's a fall from kitchen sink onwards.

Untitled

• fathertobe
• 27 May 2009
• 1

Here's what I'm proposing:
1) Running 1.5" (red in illustration) from sink and dishwasher through an internal wall into utility room. (The two 45 degree bends are in there to avoid some corner brickwork)
2) Running 2" from this point to utility sink and washing machine (blue in illustration)
3) Exiting the wall at the side of the house and dropping down into 4" pipe to run to existing manhole (about a 10ft run). PUtting a return on this run as it meets the man hole to ensure exiting water runs in same direction as current flow of waste.

Additional thoughts:
1) Should I be worried about 90 degree bends as it enters utility? How to best avoid this?
2) Inspection caps would probably be useful ... where do people think?
3) IS there any need for an admittance valve (durgo) somewhere in this to stop water being drawn out of the traps?

Really appreciate any comment. I'm not an expert so please be gentle...
[/img]

 

[fatplumber]

You don't need to run into 4". You can just splash down into the manhole from 2". I'd run as far as I can in 2". Saves bother later. Use swept bends for 90s.

 

[fathertobe]

thanks.

Would you consider fitting a durcon to avoid the traps getting emptied?

And inspection caps?

Was thinking about teeing in 1 of each in the blue 2" run that runs down the side of the internal wall in the utility room - it's not fantastically accessible but better than nothing.

Also was thinking about an inspection cap as we exit the external wall and go down.

 

[fatplumber]

An aav wouldn't hurt but the longer the run of 2" the less need for it.

 

[treerat]

Not to upset anyone but the green run of pipe should be in 110mm soil pipe as the water regs state that any service entering a man hole should have accsess for cleaning and alowing foul or gray water to splash down is also not permitted.
If this manhole excepts water from other propertys the onership of the pipe run is probibly under your water provider.

 

[fathertobe]

Don't worry. We did the green in 110mm.