Want to move washing machine - vent question

[ajohnso5]

I want to move my washing machine to another wall of the same room. I want to know the guidelines on the vent for the waste line. Do I need to run a line to my roof? Can I just connect to the drain line if I am close enough to the main vent stack? Thanks for your help!!! - Allison

[hj]

You do need a vent, unless there are no other plumbing fixtures above the point where you make the connection. If you need a separate vent, then it either has to go through the roof, or connect to an existing one, such as the one at the original location.

[master plumber mark]

why cant this person just tie into the existing drain either in the crawl space or down the wall and install a trap and an auto air vent save lot
time and expence???

at least this flys ok in the midwest.

[Clayton]

Although air admittance valves are approved by most large code bodies they still are not allowed by every state or municipality. They are used too much as a short cut rather than a necessity. They are sometimes needed in todays complex building designs and unusual fixture layouts or locations, But one should not install something that can fail so easily and often just to save a dollar when there is a better and safer solution. I have already removed or replaced 5 AAVs during last month because they failed (stuck closed) and they all happened to be installed on washing machines. 2 of them I had to replace, but the others only required a couple ftgs, pipe and flashing and less than an 1 hr labor to vent them through the roof. One home owner was pretty upset to see it was that easy to vent properly, as now they have to replace 2 rooms of new pergo floating floor because of the water damage caused by an air locked drain.

[Mike Swearingen]

I've had the same air admittance valve on a downstairs lav sink since 1978, and it's still working fine. Maybe I'm just lucky. LOL
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Mike