Re-doing washer/sink plumbing, question(s)

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by funnyguyMI, Oct 7, 2013.

  1. funnyguyMI

    funnyguyMI New Member

    Messages:
    2
    Location:
    Michigan
    Hey all,

    Great forum you have here. I'm in the process of re-arranging my clothes washer, dryer and utility sink in my laundry room and could use a little help/advice. The washer was previously plumbed over the sink and I would like to plumb it through a standpipe instead.

    In my proposed plan in the image below, the W is the washer standpipe and the S is my utility sink. I am wondering if the red line of plumbing is necessary in my case? I've seen the included image of the black ABS plumbing many times. It looks like the vent extends beyond view in the image, and I'm wondering if it extends to other fixtures perhaps?

    And if the red line of plumbing is necessary, what purpose does it serve?

    And, does it matter if the sink or the washer is higher than the other in the drain going through the floor? In the image, I have the washer below the sink, but I'd like to know ahead of time, if I have the option of changing that..

    [​IMG]


    Thanks for any replies! :)
  2. Terry

    Terry Administrator Staff Member

    Messages:
    14,780
    Location:
    Bothell, Washington
    If serves to get the job passed off for the inspection.

    Wet venting is allowed on bathroom sets, but not for laundry trays or washers.
    If you are pulling a permit, and want to pass it the first time, you spend $3.00 more on pipe and get it done.
    Otherwise, expect to spend friendly time with the inspector arguing about who knows more about plumbing. The inspector, or the homeowner.

    I already know who wins that one :)

    It doesn't matter which one wyes or tees off first, as long as it's properly vented when you do that. There are maybe four correct ways, and a bunch of wrong ways.
    Venting breaks the siphon, which can pull the water seal from a p-trap.
    When a washer pumps it's load out, that's a ton of water all at once.
    When a laundry tray is suddenly drained, that's way more water than a lav drain.
    Last edited: Oct 7, 2013
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,270
    Location:
    Cave Creek, Arizona
    I have done it innumerable times, (in fact, I cannot remember any installation where I installed a separate vent for it when the sink and washer were next to each other), without the "red line" as long as the sink is above the washer connection.
  4. Terry

    Terry Administrator Staff Member

    Messages:
    14,780
    Location:
    Bothell, Washington
    Yes. We know the inspector in Cave Creek allows that hj.
    This guy is in Michigan, and his inspector may not be that friendly to a homeowner. I can't do it the hj way in Washington either.
    My inspector reads his code book. I guess your's doesn't, or chooses to ignore that part.
    Arizona and Washington both use the UPC code, but our inspectors in Washington follow the book.

    So if you are doing this in Cave Creek Arizona, you will be fine either way. hj does it that way.
    But really, if you don't live in hj's home town, you may be in for an argument. If the inspector argues with you, have him call hj at 480-473-8787
    Don't have him call me though.
    Last edited: Oct 8, 2013
  5. funnyguyMI

    funnyguyMI New Member

    Messages:
    2
    Location:
    Michigan
    Lol Terrry. Good stuff.

    Thanks for the replies guys.

    I'm not pulling permits as the plumbing will be on the outside of the wall and covered by a counter and the appliances themselves.

    I can appreciate getting it right the first time to pass inspections though.

    But, if I'm not worried about passing an inspection, it sounds like I'll probably be alright without the extra vent line.
  6. Terry

    Terry Administrator Staff Member

    Messages:
    14,780
    Location:
    Bothell, Washington
    As long as the sink is "above" the washer trap arm, and you use 2" up to the sink santee. That should be a 2.0x1.5x1.5
    The sink trap arm can be up to 42"
    The washer trap arm can be up to 60"
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