Question about adding a new sink to my basement using existing line.

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by ddaniels, Aug 27, 2013.

  1. ddaniels

    ddaniels New Member

    Messages:
    1
    Location:
    Alberta
    Rookie question.

    I have a 1 1/2inch drain line that drains my kitchen sink on the main level of my house and runs through the basement into the ground. I need to know if I can add a bar sink to the exisitng drain. I have attached a photo to show my situation.
    Please let me know if this is possible or if you have any other suggestions.
    . Untitled.jpg .

    Thanks.

    Darren
  2. Ottawa97tj

    Ottawa97tj New Member

    Messages:
    12
    Location:
    Ontario Canada
    Hang in there a pro will confirm soon but from what I understand you can't do it the vent would have to be above the highest fixture in the line, if nothing is above the kitchen sink then the vent would have to tie in there
  3. Terry

    Terry Administrator Staff Member

    Messages:
    14,749
    Location:
    Bothell, Washington
    Not without a vent.
    When the upstairs drains, it will push air out of the trap below.
  4. Tom Sawyer

    Tom Sawyer In the Trades

    Messages:
    3,046
    Location:
    Maine
    To do it right you would have to increase the drain size to 2" to the point the bar sink connects and properly vent the bar sink. An AAV may be allowed in our jurisdiction.
  5. asktom

    asktom Member

    Messages:
    508
    Location:
    Victor, MT
    An AAV won't protect against positive pressure (that air being pushed down from the sink above).
  6. Tom Sawyer

    Tom Sawyer In the Trades

    Messages:
    3,046
    Location:
    Maine
    Hence the need to increase the drain to 2"
  7. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,227
    Location:
    Cave Creek, Arizona
    Connecting the vent back to the drain line WOULD work, but it would also be illegal. It has to tie in at a point above the sink on the upper level. Positive pressure is positive pressure whether the drain is 1 1/2", 2", OR 3".
  8. Terry

    Terry Administrator Staff Member

    Messages:
    14,749
    Location:
    Bothell, Washington
    If it were to be added to the waste stack, it would need to be done is such a way that no waste comes down the vent portion. It would need to be treated like an island fixture.
Similar Threads: Question adding
Forum Title Date
Plumbing Forum, Professional & DIY Advice, Tips & Adding a bathroom, and reconfiguring the existing bathroom - some general questions Apr 13, 2014
Plumbing Forum, Professional & DIY Advice, Tips & Question adding water line to sink No saddle valve Jan 29, 2014
Plumbing Forum, Professional & DIY Advice, Tips & Bathroom Remodel - Question on Adding New Drain for Additional Sink & BathTub Aug 29, 2013
Plumbing Forum, Professional & DIY Advice, Tips & adding shower to 1/2 bath - questions around drains Jan 29, 2012
Plumbing Forum, Professional & DIY Advice, Tips & Adding bathroom on second floor, questions Jan 20, 2012

Share This Page