Sanitary tee in horizontal position for vent to drain transition?

[Brandon Weiss]

Hey! So I know you never put a sanitary tee in a horizontal position to transition from a vertical drain to a horizontal drain. But what I’m unclear on is whether you can use one to go from a vertical vent to a horizontal drain.

Anecdotally, in diagrams I’ve seen both wyes and sanitary tees in a horizontal position. And I can find comments where people will say it’s not allowed in their jurisdiction, and others where they say it is allowed in their jurisdiction. So it seems like if it is allowed it might be jurisdiction-dependent, but I can’t seem to find the spot in the code book that tells you if it is or not.

Can someone point me in the right direction? Thanks!

 

[Mr tee]

It does depend on what code you are under. Baring local variations, knowing what state you are in may make an answer possible because it would indicate the applicable code.

 

[Sponsor]

 

[wwhitney]

UPC does not allow it, it requires a combo. And California uses the UPC.

Cheers, Wayne

 

[Kreemoweet]

Regardless of what the UPC says, it is allowed in some jurisdictions as a practical matter, because that UPC
rule is nonsense.

 

[Brandon Weiss]

Thanks! Yeah, I’m in California—I had a feeling it wasn’t allowed here, but I couldn’t figure out where it was stated.

 

[wwhitney]

Right here, note the last sentence of 905.3:

Chapter 9 Vents: Vents, California Plumbing Code 2019 | UpCodes

UpCodes offers a consolidated resource of construction and building code grouped by jurisdiction

up.codes

Cheers, Wayne