duztee

Not an intriguing topic I admit.
I have 3 sinks on the same wall, two on one side, one on the other.
I am planning a little remodel so needed to know the drain routes. One goes to a sump drain in the floor but the other two are discharging into the toilet waste pipe, I am not sure if this is actually correct or permitted.
I would hate for the authorities to tell me I have to rip up my new tiles and change the drains at anytime, so just thought I would ask if anyone knows if this is accepted practice or not.
Thanks.

Peter_in_Hungary

Given that you will have only one 110mm soil pipe leaving the property all the waste water ends up in this pipe anyway. The toilet waste pipe will be 110mm and the sump outlet will be 50mm and typically connected to the toilet 110mm pipe under the floor. The important thing to ensure is that there is a means for air to get into the 110mm pipe at the outboard end. In the UK that is usually done with a stack pipe to the outside. Here it is often ignored. when you connect the sink drain to the toilet waste pipe ensure that you have an air admittance valve on the system as close to the last item as possible. The air admittance valves are one way valves that allow air in to the soil pipe but stop air back-flow (so no smells) Its purpose is to stop the siphon effect of a large amount of water (loo flush) from sucking the water out of the sink traps.

Sachina

My Kitchen, bathroom and toilet were installed by an Hungarian plumber who one presumes knows what he's doing. My house is one storey and all the rooms lead off one another and the kitchen, bathroom and toilet are on the back wall of the house. Water from the kitchen sink and washing machine runs through a pipe which goes into the bathroom and is joined to the pipe which takes the water from the hand basin and shower. All the water plus the water from the hand basin in the toilet and the waste and water from the toilet itself, drain through a large pipe under my bedroom and across the driveway into a holding tank which needs emptying about every 6 months or so,

Hope that makes sense?

Forgot to add the plans for the holding tank in my front garden was approved by the local town planner.

Sachina

I have a stack pipe on the outside wall of my house and behind where the toilet is. I've also another one on the holding tank in the garden.

duztee

Thank you both for taking the time.
My confusion arose because all 3 sinks are on a common wall so why not simply have all of them use a common drain, instead of using 3 separate pipes with 3 holes cut into the 110mm soil pipe.
Also because the building was originally a garage before conversion to a doctors surgery, I wasn't sure if the floor sump might not have been designed to run to a different collection tank for contaminated liquid.

But you are correct and all of them end up in the toilet waste pipe.

Peter_in_Hungary

You can have all three sinks on a common drain pipe but to be safe an air admittance valve should be fitted at the upstream most sink. If you don't fit one and when using the down stream sinks if you hear bubbling at the upstream sink(s) then you need one.
To be correct an air admittance valve should be fitted at the upstream end of each leg connected to the 110 exiting soil pipe. My experience is that the valves last about 7-8 years befor the rubbers go hard and the possibility of smells coming back arises - then it is time to replace the valve.

duztee

I am removing 2 of the sinks as obsolete and obstructive to the new plan, with just the one then the 'u' bend should stop smells from the sink. Not so confident about the new shower drain which uses a couple of ping pong balls to seal the outlet when no water is flowing. I will leave the tiling until the drain system is fitted and fully tried and tested.
It is not only the 'orrible smells, there is a significant amount of very warm air coming up at the moment. Sooner I fit a new toilet the better. But as discussed many moons ago in another thread, the shelf type loo is not to my liking and had to go.

Peter_in_Hungary

Showers are usually connected to the drain in the floor which has its own water trap so in this event the ping pong balls are only a secondary trap. Of course if the shower goes straight to the 110 mm pipe then that is your only defence.

If it is going to be some time before loos and alike are fitted it might be worth getting a 110 mm drain plug. They are quite cheap and come in 2 types, one to go into a pipe end and the other to go in to a fitting socket. Alternatively stuffing an old towel in the end of the pipe works quite well.

+1 to that !!