Code Compliance on Single-Floor Waste Stack/Wet Vent Solution

[MarkedForDIY]

My first post! I'm an avid DIYer in South Carolina (IPC 2021). I've studied codes and lots of websites/forums, but can't really settle my questions with similar enough situations to be totally sure.

Please review my diagram and let me know if (a) does an added powder room sink really need a dry vent when draining to a waste vent such as depicted, (b) does the new toilet location work wet vented to both a 2" sink drain and a 3" waste vent, and (c) any other issues you feel violate code?

The diagram also shows the existing (and working) configuration of the toilet, which is what seems like an incorrect wet-vented toilet location upstream of the existing sink, so the new plan addresses this and other issues. This is a single full bath into two half-baths conversion, and it's actually two conversion projects, with a tub-only conversion on one end of the house, and a shower-only conversion on the other. Both conversions otherwise need a near-identical solution, but I'm hoping you can help verify I'm on the right track with the wet vent/waste stack combination.

 

[Reach4]

Added sink needs a vent. You showed one way.

Elbow needs to be long sweep.

I think that works, but you don't need to roll the wye. I suspect you could.

See page 12 of https://wabo.memberclicks.net/assets/pdfs/Plumbing_Venting_Brochure_2018.pdf Your proposal does seem to be within the spirit to me. I am not a plumber.

 

[Sponsor]

 

[MarkedForDIY]

Yes, thanks, that was one of my sources Page 10 seems to support what I have done with the added sink. Thanks on the long sweep 90s. The toilet wet-vent combo with the stack has been a mystery. Page 12 supports what I have regarding the 2" existing sink drain/vent (without rolling), but the 3" stack being there as well has confused me. It sure seems to well exceed code regarding venting the toilet.

 

[MarkedForDIY]

For those interested, I updated my plan to what's below. Let me know if you spot an issue