Shower waste into WC waste branch

JWal · Oct 15, 2019

Hi Guys,

Can anyone advise if there are any regulations against running a shower waste into a WC waste branch before entering the soil stack?
I have checked BS 6700 and cannot find anything relating directly to this.

The client wants to put a shower cubicle in the cupboard located next to the WC.
They cannot drill through the external wall so wish to connect the shower waste to the nearby wc waste in the next room.
The connection will be located close by to the wc so may require non return valves etc.

appreciate any advice.

Thanks,

oz-plumber · Oct 15, 2019

Draw a picture or post a photo

Stigster · Oct 15, 2019

If you can get the correct fall on the shower waste pipe and come in to the top of the toilet waste pipe or even at a 45 degree angle into the top half of the toilet waste I don't see why not.

I do not believe there are any regulations against doing that. The size and fall on the pipe is what's important and that you don't set up a crossflow situation which you wouldn't be doing.

centralheatking · Oct 16, 2019

I would use a deep trap on the shower and be mindfull of the w.c. sucking the trap out
centralheatking

Stigster · Oct 16, 2019

Good point CHK. OP, how is the stack which the toilet waste connects too vented? If it is open to atmosphere that would be good.

JWal · Oct 22, 2019

Hi Guys,

thanks for the replies.
the wc branch runs outside externally to the open vented stack
I just wanted to confirm it isn’t against regulations to do this, due to the freeholder client cannot run shower waste externally to the stack.

With that said I’ll ensure there’s correct fall and no cross flow possibility.

Thanks