I have a drain pipe in my laundry room. It runs into a sewage drain that I imagine is in the slab. I had the local building inspector come check it out. I haven't investigated enough; but we both believe that this line does not include venting outside of the house.

The inspector told me I needed to add an Air Admittance Valve (AAV) before the two traps (sink + washer) on this drain.

I've never worked with this plastic. It may be PVC (it's white'ish -- could double-check).

Do I need to add some sort of a glue or bond when I attach the AAV (it's threaded)? If so, is there anything special I should use? Or just something compatible with the plastic?

Note: Since this valve depends on the air pressure, I assume it has to be air tight. That's what lead me to asking this question. The guy at Home Depot wasn't very helpful.

1 Answer 1


If the AAV is threaded, then you need to get a coupler that is threaded on one side and smooth on the other. You need to prime and glue the push-fit connector. The threaded connection does not get primed/glued.

  • +1, but use pipe dope on the threads.
    – Mazura
    Commented Oct 28, 2014 at 5:05
  • At least one manufacturer (Studor Mini-vent) instructs to use teflon tape and not pipe dope on the threads. Commented Mar 24, 2019 at 1:57

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