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join sink to shower waste?

23178 Views 5 Replies 4 Participants Last post by  Vermonster
Hi -
I'm laying out a 2nd floor bathroom. Please look at the enclosed plan view. All shown runs are horizontal (except for slope in the drain pipes - and the vent pipe, which eventually rises to meet the main stack)
1. Can the sink drain pipe join the shower drain pipe as shown?
2. If so, can the shower and sink vent be the same as shown in this situation?
3. Can the vent pipes be Y'd off where the waste pipes go down to the basement or do the vent pipes have to come off closer to the drains or closet flange?

Thank you very much for any input.
P.s .. there is no room on the sink wall to run a vent pipe)


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wow ... not a single response. Must be me ...
this is an amature oppinion that i'm passing !!
in the first instance , it would depend on the size of the waste line , a shower needs a 2 inch ,a sink only 1 and a half .if you use the 2 inch it should be alright .
i find your diagram very dificult to follow ....
so no 2 , again depends on the pipe size , in this instance use a 1 and a half inch .
depending where you are ,your local inspectorate may alow wet venting of the sink .
number three ,i've no idea what you mean .
i repeat again this is only an amature oppinion really need to ask a licenced plumber or the local plumbing inspector.
I'm a carpenter, not a plumber, but I'll give it a try.

1. Yes, you can vent the sink drain into the shower drain.

2. Usually, they can share the same vent if the vent is within 5 feet of both fixtures.

3. The vent pipes usually would go straight up the wall (behind the fixture). I believe the rule states it has to go vertically for at least 6" above the highest 'rim' level before it can run in a horizontal direction.
The diagram shows the 2 fixtures side by side, when you contine the drain for the sink off the drain for the shower use a wye and bring it up so its just over the center line of the pipe. Continue this line across and up for the lavatory connection and continue up from there. After you have past the flood level rim of the lavatory plus 12" you will have to run this vent line back to the vent stack.
Lavatory drains can be make in 1-1/2" , as the waste size is only 1-1/4".

thank you very much!
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