I bought the house a few years back. The homeowner put in a bedroom in the basement with full bathroom. I remember the inspector telling me the drain was slow due to an Air Gap problem. I've never fixed it, but we use it as a guest room. My wife wants me to fix the SLOWWWWWWWWW drain. Can someone help me? Im a complete novice at this stuff. There is no clog in it... its an air gap issue. Just not sure how to proceed.

 

I'm assuming the previous owner did not vent the drain. If you have access to the piping behind the sink, you can add an air vent to the drain pipe. There are units available at your big box store that will allow one way movement of venting air - allowing the water to drain, but keeping sewer gasses from escaping.

 

OK. being a dummy on this, when you say "access to piping behind the sink"... do you mean behind the entire vanity behind the wall??

Or... did you mean piping under the sink?? Which if course I can access.

Finally, is this easy to install?? Is there a name for what Im buying at Home Depot?

THanks!

 

He means access to the pipe behind the wall and is referring to an air admittance valve (AAV) which could be against code in your area.

Have you looked in the wall yet to see if the drain is vented? You can tell because the pipe coming up from the bottom (behind the wall) should go into a tee where your drain hooks in and continue up and to the roof/vent stack. If it just 90’s out to the drain then you could have a vent problem. The quick fix is to cut the 90 behind the wall out and replace it with a tee and put an AAV on top. The correct fix would be to forget the AAV and run a new vent going up and back to the main stack or into another vent somewhere.

Depending on how hard it would be to run the new vent you’ll probably get the AAV. If you do, try to figure out some way to keep access to it open. Like a removable panel in the back of the vanity.

How far does this sink's drain run before hitting the main stack and how big is the drain pipe?

 

Seems like its a 90 coming out of the wall behind the vanity and connecting to the drain pipe. The drain pipe is maybe 12-18 inches down, then I can access literally only a few inches of the 90 pipe coming in from the wall. I would have to rip a bunch of things up it looks like and/or try to pull the vanity out and see what I can do .

Im not a plumber, but I kind of get your drift on what needs to be done...

I appreciate your help

 

BANMAN87,
You do not have to install the Air Admittance Valve inside the wall. Install a tee (1-1/4") in the line going to the wall and install the AAV as high as possible. AAV's are normally used in island sinks where there is no pipe going upwards.