Double Bowl Kitchen Sink Drain Gurgle

[Matt M.]

Hi All,

I’ve lived in my current house for about 8 years, and we’ve always had some slow drainage/gurgling issues with our kitchen sink. When you first start running water, there are no gurgling/draining issues. Once you start washing some dishes is when the drainage issues kick in. It seems the combination of soapy water and a quick dump of a bowl full of water down the drain starts the issue, and it can’t catch up while the water continues to run. Pictures attached regarding the setup, but it’s a double bowl, with a garbage disposal. There is a dishwasher with a hose running to a sink mounted air gap, and the other air gap hose runs to the non-disposal drain. There is an AAV on top of the drain line that was there when I moved into the house. Going for the least invasive route, I just replaced that AAV in case it had failed, but that didn’t fix the issue. As a side note, when the sink when gurgling, I tried removing the new AAV, and the gurgling when away in the sink (obviously put the Air Admittance Valve back on after). I just replaced my kitchen sink and didn’t have to relocate any drains…but now that we have a new sink, the gurgle is driving my wife nuts to the point she is ready to call a plumber (mind you that the gurgle was acceptable for the prior 8 years). I’ve used various clog removers, build-up removers with enzymes, and even snaked it a bit when I was replacing the sink; all with little to no improvement.

I’m at a loss with what to do. I don’t know if the configuration under the sink is poor to begin with, or if there is some larger underlying issue. I recently read that it could be caused by an obstructed vent stack, which I will check when the snow is melted from my roof, but I would have thought the AAV would help to prevent that at the kitchen sink, and I have no drainage issues anywhere else in the house. Any help/ideas of what to check would be greatly appreciated.

Thanks,

Matt

 

[Plumber69]

If it was always a problem it won't be your vent stack.. is there anyway to see the plumbing below the sink. If so take a pic. You may have negative slope a partial plug... or even a double ptrap

A cleaner approach.

 

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[Michael Young]

remove THIS. If that solves the problem, go buy a new one

 

[Matt M.]

remove THIS. If that solves the problem, go buy a new one

View attachment 44728

Thanks for the reply. I mentioned initially that I did just replace it. The new one still gurgles. When I completely removed during the slow draining, the gurgle went away. I bought two different brands of AAV this weekend after replacing the studor to test if it improved, but unfortunately the other brands have a different thread size, and the height won’t fit under the sink with adapters without cutting the drain down.

 

[Matt M.]

If it was always a problem it won't be your vent stack.. is there anyway to see the plumbing below the sink. If so take a pic. You may have negative slope a partial plug... or even a double ptrap

I attached a picture from under the sink. Do you mean you want to see below the decking where the drain pipe goes below that, or is the picture attached sufficient?

 

[Jadnashua]

An AAV can't be the only vent in the system, and it probably isn't. If the lines below are not sloped properly, that could be the problem. You may need to snake the lines. A disposer can leave stuff in the line if you aren't selective about what you put down it.

 

[Matt M.]

An AAV can't be the only vent in the system, and it probably isn't. If the lines below are not sloped properly, that could be the problem. You may need to snake the lines. A disposer can leave stuff in the line if you aren't selective about what you put down it.

It’s not the only vent, but not sure how everything is tied coming to the stack out of the roof. This is the only drain in the house with issues. Guess I could remove the AAV and try snaking directly down.

 

[Plumber69]

I attached a picture from under the sink. Do you mean you want to see below the decking where the drain pipe goes below that, or is the picture attached sufficient?

Take a picture below the deck. I've seen under your sink already

 

[Matt M.]

Take a picture below the deck. I've seen under your sink already

Thanks for the reply. It’s glued to the cabinet framing, but I’ll see what I can do without tearing too much apart.

 

[Plumber69]

Thanks for the reply. It’s glued to the cabinet framing, but I’ll see what I can do without tearing too much apart.

Don't you have a room below the sink that you can see the plumbing

 

[Matt M.]

Don't you have a room below the sink that you can see the plumbing

The basement is finished, but the bathroom down there has a drop tile ceiling...it’s not directly under the sink, but I’ll remove some of the drop tiles after work and see what’s there.