I have a relatively new bungalow with an unfinished basement. The basement is roughed in for a bathroom (sink, toilet & shower/bathtub) however I do not see a vent line.

My question is can I use a common AVV off the sink drain line for all three or is one required for each. If one is required for each I will have break the cement for the toilet and the shower.

Hi Seadog

If there are no other pipes besides the pipe for the toilet, sink and tub or shower drain then yes, as long as AAVS are legal in your area you can use an AAV to vent the entire bathroom group.

Be sure to install the AAV under the sink so it can be changed if/when needed!

Mark

I agree with Mark. Your only other option would be to run a vent out the roof or tie back to a existing dry vent. Good luck. Tom

Thanks Mark and Speedball 1, that was the answer I was hoping to hear

Can you post some pics of your rough plumbing in the basement? Sure, if local code allows, you can use an AAV, but you would need the sink drain to be at least two inch, and the AAV, or more likely, studor vent, to be at least two inch. I would suggest finding a route for an actual vent to go up and out the roof, or tie into existing vent in the attic. If there is a closet or chase somewhere you can run the vent up through that. Mechanical vents are less than desirable in my opinion. I believe they were invented by a lazy person that had absolutely no plumbing background, lol.

AAVs are illegal in Massachusetts except under VERY special circumstances, so I understand what you are saying, Lee, but if allowed in his state, a 2" studor vent placed inside the sink cabinet will work just fine!

Frankly, I am not a big fan of these, but they are allowed in more states in the USA than they are not allowed, so I got to wonder sometimes (compared to the thousand or so dollars some of my customers spend getting the correct vents in place)??

;)

I would like to post some pics but unfortunately that area is packed ceiling as a temporary staging area for my wife's yard sale. Can not get at it for another month.

There is no way to tie into the main stack without creating a new route, something which I am not prepared to do. There is a 1 1/2" drain line about 30 ft away that I could tie into. This location is only about a foot from the stack. If I was come in from above this drain line do you believe this will give enough ventillation?

You would really need the vent to be a 2" vent to do this by code, but as some inspectors I know would say, an 1.5" vent is better than no vent (or a mechanical vent).

If you decide to go that route, then the vent from the bathroom group cannot connect into this drain pipe VENT unless it can connect into that drain/vent at a minimum of 45-46" off the finish floor (and vent must pitch back toward the bathroom group).

Back to you...

Mark