Adding Utlity Sink - Drain and venting

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by NewGuy, Jan 2, 2013.

  1. NewGuy

    NewGuy New Member

    Messages:
    11
    Location:
    Washington
    I am adding a utility sink next to a washer in a single story home. Is it okay to have a 1.5" branch connect to a vertical 1.5" sanitary T with a bushing on the bottom connecting to a 2" elbow. There is a 1.5" cleanout and dry vent on the top of the Sanitary T. There are no other drains attached (just the sink). I would use a 2x2x1.5" sanitary T to make the connection but it puts the drain line too low to provide a 1/4" per foot slope. the branch line is less than three feet to vent/San T.

    Basically, this would be a single branch draining in to a stack of the same size. However, the stack would immediately increase to 2" within 1" of the connection.

    I was not able to attach files in this forum for some reason. However, the sketches are attached in the following forum: http://www.diychatroom.com/f7/adding-laundry-sink-168000/

    I appreciate any help you can provide.

    Attached Files:

    Last edited by a moderator: Jan 2, 2013
  2. Terry

    Terry Administrator Staff Member

    Messages:
    14,890
    Location:
    Bothell, Washington
    What you have there will work.
    The 90 under the sink santee needs to be a long turn 90.
    You can also run it out horizontal and use a combo on it's back for the sink vent.

    The washer is 2" waste, 2" trap and standpipe, and 1.5" vent
    The sink is 2" waste, 1.5 trap, and 1.5" vent

    Pictures here need to be 800 pixels or less.
  3. NewGuy

    NewGuy New Member

    Messages:
    11
    Location:
    Washington
    long sweep

    Thanks for the reply and note on photos. Only a 2" San street elbow will fit under the San T. Is that not allowed with a cleanout directly above it? I could use a long sweep 1.5" elbow under the San T and then use a 1.5" to 2" reducer to switch to 2" at the bottom of the 1.5" elbow. Or, could I leave it 1.5" all the way to the 2" combo under the washer stack?

    Should I put a 2" cleanout above the washer San T as well?
    Last edited: Jan 2, 2013
  4. Terry

    Terry Administrator Staff Member

    Messages:
    14,890
    Location:
    Bothell, Washington
    Rule of thumb

    Venting on the vertical for a trap arm is with a santee
    Venting on the horizontal for a trap arm is with a wye fitting, or combo

    Vertical to horizontal is a long turn 90
    horizontal to vertical can be a medium 90

    The cleanout should be the full size of the pipe. If you put the cleanout on the upper vent, just run with 2" until that part.
  5. NewGuy

    NewGuy New Member

    Messages:
    11
    Location:
    Washington
    If I use the 1.5 combo on its back, can I use two 45 degree elbows to drop under the washer p trap? I added a sketch on the DIY forum with the new proposed layout. I am still unable to post pics here even with low resolution.
  6. Terry

    Terry Administrator Staff Member

    Messages:
    14,890
    Location:
    Bothell, Washington
    That's fine except that in Washington State the inspector wants to see 2" until you get to the trap arm.
    And the inspector would want a 2" x 2" x 1.5" combo on it's back, bushed down to 1.5" for the trap and trap arm.

    You only have a little ways to go with it.
  7. NewGuy

    NewGuy New Member

    Messages:
    11
    Location:
    Washington
    Sorry if this is a duplicate. I thought the branch line only required 1.5" for the sink and it terminated at the vertical transition. Can a vent be placed in the horizontal section if it has 1.5" pipe after the vent before transitioning to 2"? I can fit a 1.5 combo but not a 2". Is there any other options to make the drop?
    Thanks for the help and patience.
  8. Terry

    Terry Administrator Staff Member

    Messages:
    14,890
    Location:
    Bothell, Washington
    I only mention going to the last combo with 2" because I feel that giving advice that an inspector would turn down is kind of pointless.
    If you're not getting inspected, is that what you're asking?

    The other site doesn't have real plumbers answering questions.
    Certainly not ones that work in Washington State.
  9. NewGuy

    NewGuy New Member

    Messages:
    11
    Location:
    Washington
    It doesn't require an inspection but I would like it to pass one. I just can't figure out how to get below the ptrap with a 2" combo and still keep the correct slope. I rely on your advice to get it done right and use the other site for general ideas only. Thanks for all your help. This is great resource.
  10. Terry

    Terry Administrator Staff Member

    Messages:
    14,890
    Location:
    Bothell, Washington
    Can't you raise the p-trap a bit?
  11. NewGuy

    NewGuy New Member

    Messages:
    11
    Location:
    Washington
    I saw the code of 6 and 18 inches from the floor for the trap. I am not sure which part of the trap they are referring to but I am close to that now for the weir. The standpipe would also need to be above 36 to keep the min standpipe height. I will see if I can shift the trap up and over slightly to make it work. thanks
  12. NewGuy

    NewGuy New Member

    Messages:
    11
    Location:
    Washington
    Just wanted to say thanks. I ended up using the 2" combo on its back and using two 45 degree elbows to make the drop. It left just enough room (barely) to get the standpipe p trap in. Great forum.
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