Pam Kneebone
Pam Kneebone
  • Hometalker
  • Peru, IL
Asked on Apr 3, 2018

My kitchen sink was not draining- plumber said no air vent- help!

KellyWilliamMarcia Riley


The sink goes directly to gray line.Before we knew a drain pipe was broke,it ran fine after it was repaired I have had constant problems with draining.I could get it going after plunging but as soon as the water stopped it would do the same thing..Plumbers advise here to resolve problem.Thanks.

5 answers
  • Sharon
    on Apr 3, 2018

    Your plumber advised you to come here for a solution? I would get a new plumber!
  • William
    on Apr 3, 2018

    Something is creating a vacuum and preventing the draining. Plunging is releasing the vacuum so it works temporarily. Not knowing how the sink is hooked up to the gray line, but the storage for the gay water may be the problem. Venting the gray water storage could solve the problem. Could also be a back pressure effect from the gray line.
  • Marcia Riley
    on Apr 3, 2018

    My plumber was unable to locate the air vent when redoing my kitchen and he tried! Later learned it was in a different wall (previous owners had changed layout). I have the same problem with slow drainage. When this happens I just flip the disposal switch and it takes care of the problem. Less costly than opening another cupboard and wall.
  • William
    on Apr 3, 2018

    The plumber may be right. If there is no vent on the sink drain line that could be causing a vacuum and the sink is not draining properly or fast enough. Water draining has to displace the air in the drain line. If there is no where for the air to go the sink will drain sluggishly or gurgle as the air trying to be expelled. A vent line would allow the air to escape and the sink to drain.
  • Kelly
    on Apr 6, 2018

    Yep, "proper" new construction plumbing would have that sink hooked up to the vent stack to let air in to the line allowing the water to drain and air to fill the line behind it without the back gurgling that you are getting. You can get an undersink vent, "auto vent" or "sure vent" that installs in the PVC line under the sink, past the trap (on the sewer/tank side) that has a one way valve that allows air in behind the water but no sewer gas back into the house. If you can use PVC glue you can install it yourself. Fear not. Good luck and have fun with it. (not to be construed as plumbing code for our area :))
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