venting the kitchen sink

This kitchen sink vented into the cabinet under the sink. Is this something to report or is it okay?




I can’t tell for sure because none of the photos have a real clear shot at the device on top the white PVC. I “suspect” the black object is an “Air Admittance Valve” although I personally have never seen one made of ABS plastic. We see many these made of PVC especially if the sink is in an island or peninsula in the kitchen. We also see many in bathrooms. I have seen an increase in the use of these in new construction because that means one less hole cut thru the roof for DWV.

That is what I was thinking the black piece was too. I was concerned about the venting it into the cabinet. I guess since it is common there, then it is acceptable. This is the first one I have seen underneath a cabinet. Sorry about the pics, but those are the best I could get.


This appears to be or might be an Air Emittance valve.
I would recommend checking with the AHJ to make sure they are allowed.
Here in Maine they are illegal. Can no longer be used.

Marcel :slight_smile: :slight_smile:

Oatey sells an inline valve available at the HD

Try tis link

Well…there you go. The second black ABS plastic AAV in one day. In the words of Inspector Clouseau…“We have esol ved the case”

Here is some info about air emittance valves.

Here’s a section on air admittance valves that I uploaded to About Homes a couple of days ago and is in my [Interactive Report System]( for NACHI members.pdf).

[Air admittance valves]( 0663.pdf)

I’ve never heard of an AAV being referred to as a wet-vent Russel. The term “wet-vent” is defined by codes as - “A vent which also serves as a drain.”

Mechanical vents, such as these, are prohibited by most jurisdictions in CA. This application in CA, most likely, would have utilized an “island fixture vent.”


I have also not heard of them referred to as “wet vents”,but I have heard of the phrase “cheater Vents”.

They are used here all the time at the kitchen sink. This is because the current style is not to have the kitchen sink and against a wall where a conventional vent would easily be utilized.

One thing to check is that the vent must be 4 inches above the drain piping (it appears that it is in this photograph). I will often see them too low.

I hear it sometimes down here, and it was common usage in the areas where I lived/worked in Texas and Louisiana. I never ran across them in Detroit, Philadelphia, or Tampa.

That is why my exposé states "sometimes" called a wet vent.

They are quite common here in San Diego, especially in the newer subdivisions, and really especially in the newer, richer subdivisions because the obnoxiously wealthy don’t want all those ugly things sticking through the roofs.

I have heard “cheater vents” as well but don’t like the connotation associated with the word “cheater.” I also don’t use the term “cheater plugs” when dealing with electrical outlets.

I’ve heard them referred to as “cheaters,” but more commonly as “flutter vents.” Possibly due to the noise they make.

That’s the reason for the island-fixture-vent. It doesn’t go through the roof, it’s simply a “loop vent.” I’m sure you’ve seen them.

With “special permission,” you can do just about anything you want. This is how they are doing it in a newer tract just inside of Ventura County.

The entire pluming system shares one main vent, terminated in the attic. . .


Just wanted to thank you all - I think I have learned more about different methods of plumbing venting from this one thread than I thought possible.

Alwyas useful. RR - are those diagrams acceptable to be used by others, or are they copyrighted?

I’ve never heard them called “flutter vents.” I shall have to add “cheater vents” and “flutter vents” to my verbiage. Thanks.

The plumbers and AHJs don’t seem to like the loop vents.

I’ve never seen one in the attic. That’s a new one for me and I would probably call it out as a moisture concern since the dange things fail about as often as the GFCI outlets. Manufacturers recommend monthly testing for GFCI outlets. The same (inspection) should be true for AAVs.

I had a Client call me with two concerns a couple of weeks ago: (1) she didn’t know where to go to get the wonderful plants that I had emailed her about at her request; we set up a time this coming weekend to visit plant nurseries, and (2) she had a sewer smell in her house; I pointed her to the appropriate section in her report about the AAVs and told her to call a plumber immediately.

You may use them as long as you are a member of NACHI. When you quit NACHI, you must quit using them or I will have to have Joe Ferry send you a cease and desist order. :margarit:

Here’s an example of a wet vent and and a loop vent: