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.


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 Oct 28 '14 at 5:05
  • At least one manufacturer (Studor Mini-vent) instructs to use teflon tape and not pipe dope on the threads. – littleturtle Mar 24 '19 at 1:57

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