Minimum pipe size for a toilet vent?

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by lahabra, Dec 22, 2007.

  1. lahabra

    lahabra New Member

    Messages:
    50
    Location:
    California
    According to my hand book the minimum pipe size required to vent a toilet is:

    1.5â€

    Or

    2†as a wet vent for a sink.

    Am I understanding this correct?
  2. Herk

    Herk Plumber

    Messages:
    547
    Location:
    S.E. Idaho
    What code are you using? UPC requires 2" for a toilet vent.
  3. lahabra

    lahabra New Member

    Messages:
    50
    Location:
    California
    Wet vent

    Ok so I need at least a 2†vent for my toilet.

    Can I also drain my sink into the same 2†pipe?
  4. Herk

    Herk Plumber

    Messages:
    547
    Location:
    S.E. Idaho
    I still don't know what code you're using, or how you're going about it.
  5. It depends on your location

    It really depends on your local in the USA

    I get away with murder in INDIANA with our code....

    1 1/2 pvc is big enough for the whole house to be
    vented onhere....


    other parts of the country expect a full
    3 inch stack out hte roof..
  6. Terry

    Terry Administrator Staff Member

    Messages:
    14,891
    Location:
    Bothell, Washington
    With newer toilets that flush faster, you would want at least 2" on the vent.

    In some places you can wet vent a bathroom lav over a toilet, if that line is 2" or larger.
    A kitchen sink could not be wet vented.

    [​IMG]
  7. lahabra

    lahabra New Member

    Messages:
    50
    Location:
    California
    The book I am reading is a general construction book it covers everything from grading to roofing. The book dose not tell me specifically what size vent I will need for a toilet; however, it dose have tables soused from: "UBC Illustrated training manual (Walnut, calif: International association of plumbing and mechanical Officials 1985)."

    In one table I read that a private toilet counts for 4 fixture units. The next table shows 1.5" pipe being capable of venting 8 fixture units. Based on these two tables it appeared that 1.5" pipe could actually vent 2 toilets.

    In the houses I have worked on I always see 2" vent pipes for toilets, add to that your reaction and the fact that I don’t want to get into a challenge with my inspector, I am definitely not going to install a 1.5†vent on my toilet.
  8. lahabra

    lahabra New Member

    Messages:
    50
    Location:
    California
    acording to UPC 2006

    Thank you for the diagram Terry!

    So It is ok to use a 2" pipe as a wet vent for a toilet and a bathroom lav. Would this setup be in compliance with: "UPC 2006"?

    It has been my experience that most cities in the LA basin don't make up plumbing codes; instead they simply adopt "UPC". But I will need to confirm it in my particular city.
    Last edited by a moderator: Mar 7, 2011
  9. construct30

    construct30 New Member

    Messages:
    590
    Location:
    NorthWest PA
    I have the third edition of the code check plumbing for 2006, the little flip job books, it says the IRC does not require a vent on a water closet for residential. What's up with that?
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