Hello. I’m in the middle of installing a drain system for new bathroom.
I have a 2 inch pipe running straight up from the basement to the 2nd floor bathroom.
The vertical pipe can continue on up to vent through the roof.
I have a shower drain that runs under a sink then needs to connect to the vertical drain.
The shower is about 6 feet from the vertical pipe, and the sink is midway at 3 feet.
Two questions I hope you can help with:
1) Will I need a vacuum breaker trap at the sink because of the upstream shower?
2) Where the drain drops to the basement, should the horizontal to vertical connection be a 45 degree Y fitting or a 90 degree T, or does it matter?

Thanks!

Hi Condor,

1) Will I need a vacuum breaker trap at the sink because of the upstream shower?
No, the shower will enter the stack vent at a lower level then the lavatory and be wet vented. However you failed to mention where the toilet discharges to. I hope it ties in lower then the shower.

2) Where the drain drops to the basement, should the horizontal to vertical connection be a 45 degree Y fitting or a 90 degree T, or does it matter

As a rule we use a DWV drainage tee. However a combo's acceptable.
Good luck, Tom

Tom- thanks for your answer!
Now that you mention it, there is no toilet upstream from the shower, but I was planning on installing a bidet.
I want to have the bidet first with a 1 ½ inch drain,
Then 6 ft later the shower ties in with the 2 inch drain (the shower will be the step up type to allow height for the shower trap),
Then 3 ft on the sink drain comes in with a 45 degree fitting near the floor level,
Then another 3 ft on the 2 inch line drops via a drainage tee or combi to the 2inch vent/drain to the basement/roof vent. This last vent is only vent for the three fixtures planned.
Is this venting plan OK? If not, I’m wondering if the vacuum breaker trap at the sink will help.
Since the bidet would sit a bit higher than the step-up shower is that a problem?
Many thanks!

Condor,

I'm having a little difficulty visualizing your lay out. Would it be possible for you to draw up your lay out complete with mains,branches and vents and scan it into a post? If not I can give you my Email addy and you could send it there. Thanks Tom

Hi,

I found a drain diagram sort of like what I am planning, but the black line I added is the pipe to the bidet on the left. I hope this makes sense.

Main questions are:
How to avoid any problems with the bidet upstream of the shower.
Any issues with only having the one vent shown on the right.

Thanks!

Nice drawing but the bidet installation's confusing. You treat a bidet just like a lavatory. It has to be trapped and vented. The distences are too great, unless you can reconfigure your fixture lay out you're going to have to run a separate vent for the bidet. Regards, tom

OK,
Many Thanks!
I'll look for a way to add a vent.