Please note, this is NOT drawn to scale.

72" double bathroom vanity. If I want two P-traps that go into the wall, can I do it this way? (I have no idea if the one on the right can go directly into the drain/vent).

Someone suggested doing something similar to a kitchen sink offset, but not sure if 34" is too far apart for all that).

The only downside to that option is that I may have to cutout/adjust the back of the vanity (make sure the drawers don't hit, etc.) However, IF I do that, can i still tie in on the right-hand side (of drawing)?

The plus side to that option, though, is no drilling through the studs (2x6 studwall - load bearing--which supposedly I'm allowed 2" hole)





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Your better off stacking two 1-1/2” tees one for left drain one for right drain and back vent the left drain
Also you should get away with 2”VTR



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Ok, so something like this? (pardon my skills at drawing).
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I'm confused about the use of a "cross" (double sanitary tee). One says you can't use it, but another says you can if it's vertical vented? We follow UPC here. Although I know if you need to snake the line, it causes problems. Then you (if you can find one) possibly use a double fixture tee instead?

If you are only 34" from the drain/vent stack, and ties in with a sanitary tee, you do not need a revent for it as long as the slope is at 1/4" per foot and you are less then 6' away - now this is theoretical from math and not IPC or UPC so they may have a different max distance.

You can use a sanitary cross if the drain trap arms are coming from the left and the right with the stack in the middle, but yes snaking it could cause the snake to bounce from one branch across to the other instead of down. A double fixture fitting or sometimes called figure 5 fitting will be better. Some code do probibit sanitary crosses on back to back fixtures check with your AHJ. But your sketch does not show left right sinks with in between stack. The right sink ties right into the stack so I don't know a cross/double fixture will work there. It looks like a sanitary tee with side inlet may work for you.

Thank you!

I could put a little "stub" on the right-hand sink drain to make it in the middle if necessary (I think the P-trap arm can swing over enough to accommodate that).

Could also put a cleanout above the cross I think (I think UPC allows for that?)

Doesn't look like I can find a sanitary tee with side inlet that's under 3"

Looks like my initial measurements were a little off (a few inches does make a difference)

Can I do this? (and if so, do I need to tie into the vent and if so, can I just do it at the cross with a cleanout above the cross?)

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OK I am not a pro just a DIY that does quite a bit of plumbing of my own properties and learn new things here all the time. Wait for a pro to chime in to confirm.

Having said that pretty sure you need a vent if you run the two sinks towards each other because you have that vertical drop which means you are no longer venting them at the stack. So you need a revent in this case and ties back in at a higher point like the attic. The lower tie to the drain stack no longer need to be a sanitary tee, it can be a wye doesn't matter.



Do you need both sink's p-trap at the same height? Can one be moved a few inches lower and the other a few inches higher? If so you can run both towards the stack independently and tie in with two sanitary tees one on top of the other like this. You can even get the two sanitary tee closer by using a spigot (street) sanitary tee for the top one.

Awesome, thank you!

Yes, venting up that way (I thought it would be necessary but wasn't sure).

No, the drains do not need to be the same height. (they're in the cabinet so nobody really sees them)

Understood about the bottom portion. Probably a sweep 90 tee instead of a sanitary tee?



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If you do a branch vent for the two sinks and ties back to the main vent higher up, then the lower drain connection to the stack can use a sanitary tee, or a combo fitting or a wye with a 45 elbow. Doesn't matter which one I would probably use a combo (which is really a wye plus a 45 as one fitting instead of two).

If you run the trap arm for each sink at different elevations to the stack, than the are both stack vented and there is no need for a lower connection, each of the sink will be connected to the stack with a sanitary tee, the two sanitary tees will be one on top of another, the top one has a street connection to fit into the hub of the bottom sanitary tee to give the most compacted configuration. The main thing with this is to make sure the lower trap's U-bend can still clear the floor of the vanity sink cabinet.

There is another way to run both sinks to the stack at the same elevation using a special fitting like this. One trap arm in front one in the back. The problem is you need a larger wall cavity like a 2X6 and these fittings are probably not stocked at even plumbing supply stores and have to be special ordered and very expensive.





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we affectionately called those an "OWL" fitting.

Packy I once owned a condo and I need to redo a leaking kitchen drain (rusted out probably from years of tenant using Draino). I opened the wall and I saw two of these "owl" fittings one on top of the other. One faced left and one faced right.

The right facing one has my kitchen and my neighbor's kitchen running to it, and the left facing one is his lav drain and my lav drain running to it. Both cast iron fittings. I looked up online and the price of one blew me away LOL.

Frog eye tee