Shower and Toilet Venting Question

Discussion in 'Remodel Forum & Blog' started by David1980, Jan 2, 2012.

  1. David1980

    David1980 New Member

    Jan 2, 2012
    I have spent probably 6-8 hours reading through this forum and other sites in an effort to figure out the correct way to run the waste lines for a bathroom remodel. Hopefully, someone here can tell me if I have it right or not!

    Basically, I need to drain a new shower into an existing toilet waste. The toilet waste is 3" and then changes to a 2" vent running up to the roof. My first thought was to simply run a 2" drain for the shower into the 2" toilet vent, which is located above the toilet connection. It seems though that the correct way to do it might be to connect the shower drain below the spot where the toilet connects. I have attached two rough drawings. They are not to scale and do not show the fittings...I'm just trying to get an idea of how to do the layout. I appreciate any help! bathroom drain1.jpg bathroom drain2.jpg
  2. Terry

    Terry Administrator Staff Member

    Aug 17, 2004
    Bothell, Washington
    The trap arm on the shower needs to be nearly level before the vent.
    You are allowed 1/4" per foot grade, up to five feet before it's vented with the Uniform Plumbing Code, which is used in Oregon.
    Therefor, it would be the top drawing.

    A wet vent needs to be a minimum of 2", which you have now as the toilet vent.

  3. Sponsor

    Sponsor Paid Advertisement

  4. hj

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona
    The shower connection ABOVE the toilet is correct. Putting it below the toilet connection would require that you install a vent on the shower drain line.
Similar Threads: Shower Toilet
Forum Title Date
Remodel Forum & Blog Help! My toilet is <15" from my shower Sep 18, 2013
Remodel Forum & Blog Swap Toilet and Shower Locations Mar 18, 2013
Remodel Forum & Blog Ensuite reno, adding shower, moving toilet Apr 24, 2010
Remodel Forum & Blog Combining shower, tub, and toilet drains... Aug 5, 2008
Remodel Forum & Blog Frameless shower walls and wall mounted toilet, any Help? Dec 18, 2005

Share This Page