Should a brand new AAV be able to leak water?
I don't know much about AAVs (or venting in general). But I do know that disposals push a LOT of water (and everything else!) very hard &amp; very fast. If there is a clog in the line then stuff will come out elsewhere - e.g., in my case I have had output from a 2nd sink. So with a low-position AAV, I would not be at all surprised to see the disposal + clogged line overwhelm the AAV and end up with a mess.

Based on a little searching and my own experience (with disposals &amp; dishwashers, but not with AAVs) is that:


You do likely have a clog in the line, which will need to get snaked or otherwise cleared out, and until that is resolved the AAV is simply not going to stand up to the disposal.
The AAV, by design, just can't keep up with the disposal if the waste line is not running totally free. A regular vent would handle a clog better. However, the AAV should be fine when the line is reasonably clear.


You should also make sure your dishwasher has either an air gap or a high hose loop. Your diagram doesn't show either one. Without an air gap or high hose loop, the disposal discharge backup could go into your dishwasher as well as your AAV.