(206) 949-5683, Top Rated Plumber, Seattle
Results 1 to 7 of 7

Thread: Clothes Washer drain size

  1. #1
    DIY Senior Member DavidTu's Avatar
    Join Date
    Dec 2009
    Location
    Seattle, WA
    Posts
    229

    Default Clothes Washer drain size

    I apparently mistakenly sized my clothes washer drain based on dfu's, unaware of the special requirement in UPC calling for a 3" drain. I've seen discussion elsewhere saying that enforcement and interpretation of this vary widely inspector to inspector, region to region. I'm in Seattle WA and wondering how I will likely fare with the inspector.

    Here is the setup: 2" trap & fixture arm going to 2" horzontal drain, which picks up a laundry sink and two lavs before going into a few feet of 3" pipe then 4" pipe on the horizontal and on down the stack.

    Thanks in advance.

  2. #2
    In the Trades Gary Swart's Avatar
    Join Date
    Sep 2004
    Location
    Yakima WA
    Posts
    7,246

    Default

    From your description, you are just fine. You need a 2" standpipe for new washers which you have and then it increases in size and that too is just fine.

  3. #3
    DIY Senior Member DavidTu's Avatar
    Join Date
    Dec 2009
    Location
    Seattle, WA
    Posts
    229

    Default

    Quote Originally Posted by Gary Swart View Post
    From your description, you are just fine.
    That's good to hear Gary... just to be clear, though, the horizontal 2" run (w/ 7 dfu) goes for about a total of 16' horizontal before going to 3" and 4" (horizontal for another 14' or so before vertical). Hope that doesn't change your reply.

  4. #4
    In the Trades Gary Swart's Avatar
    Join Date
    Sep 2004
    Location
    Yakima WA
    Posts
    7,246

    Default

    So long as you maintain the minimum slope of 1/4" per foot. That is required of every drain regardless of diameter of the pipe.

  5. #5
    Master Plumber-Gas Fitter shacko's Avatar
    Join Date
    Jan 2006
    Location
    Rosedale, Md
    Posts
    561

    Default

    I hope we have a vent somewhere on your hook-up?

  6. #6
    Journeyman/Inspector Inspektor Ludwig's Avatar
    Join Date
    May 2006
    Location
    In the good ol' UPC
    Posts
    168

    Default

    Are you wet venting this installation? Curious, what section of chapter 7 UPC are you referencing? I think I know which section you're talking about, the exceptions at the bottom of the DFU table. That language for 6 DFU is for laundrymats and multi-family laundry rooms where you would have a battery of clothes washers draining at the same time. It requires a 3" horizontal drain to address sudsing. Are there Inspectors that require a single family clothes washer to have a 3" drain on the horizontal? Must be Combo Inspectors because I've never heard of any Plumbing Inspector requiring that.
    Last edited by Inspektor Ludwig; 05-16-2010 at 11:21 AM.

  7. #7
    Forum Admin, Expert Plumber Terry's Avatar
    Join Date
    Aug 2004
    Location
    Bothell, Washington
    Posts
    14,201
    Blog Entries
    1

    Default

    I think the 3" is an IPC thing on the East Coast.
    I've always used 2" in Seattle.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •