Gurgling sound from air vent under sink

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BlueWRXPride

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Jan 12, 2022
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Location
Upstate NY
For quite some time now, I've noticed periodically a repeating gurgling sound coming from the air vent under the kitchen sink. Obviously, I'm on a septic system, which has a collection chamber and then a pump to get it up to the leach field. In my kitchen, it's a double sink with a garbage disposal on one side and an air vent under the sink coming off the combined drain pipe. When it happens, it loud enough to hear from beneath the sink with the cabinet doors closed, but not too loud. I took this recording with my phone right next to the air vent. The sound is very repetitive with it occurring every 6 seconds or so as you can hear in the recording, and overall will last for maybe a minute. All I could think of is it has something to do with when the pump is running in the collection tank? Anything to be concerned with?

Audio recording
 
If air is being pushed out ( pressurized ) then it’s bad.

If air is being sucked into the vent, that’s how it works.

Remove the vent and see which of the two above is happening by placing your hand over the opening when the sound is happening.

Is this the closest vent to the septic tank ?
 
Hard to say if it's the closest one. I can only think of 2 in the system, one on this sink and one on the sink in the garage. The bathroom sinks don't have vents. I think that the garage vent would be closer to the septic, from the perspective pipe distance. Are the vents usually just friction fit or would i have to cut PVC to get it off?
 
Ok, should be easy enough then. If it does end up being that it's being pushed out, what are potential causes/fixes of that?
 
Ok, should be easy enough then. If it does end up being that it's being pushed out, what are potential causes/fixes of that?

You could have a partial blockage some place restricting air, if it ever worked at all.

If it’s always done had this problem then you must install a vent to open air for a sure fix.
 
Yeah, it hasn't always been like this. But it definitely has for at least several months. I just never got around to investigating it... If it's relevant this is a house that is 7 years old
 
Last pumped 4 years ago. This summer our septic pump failed and it was replaced, and they said it didn't look like we needed to get it pumped yet.
 
Would it be valid to just remove the vent when it's making the sound and see if it stops?
You could but you’ll need to install some type of vent. You can’t cap it and you can’t leave an open pipe.

If you remove the toot vent and it stops, it might start back when you install the new toot vent.

You may have a partial pipe obstruction at some point. It’s hard to say sitting here in my chair. You can see how Im at a disadvantage.
 
Yes, you definitely are limited into how much you can see about my home's plumbing, but I appreciate your thoughts regardless!

Taking the thought exercise further, if the vent is fine, and the cause is a partial obstruction, how would I go about locating and removing it? Or does that go beyond the abilities of a fairly handy DIY person?
 
Most of the time it’s best to have a drain cleaner do the work. By the time you buy or rent the equipment and spend the time to learn how to safely use it, it’s just not worth it.

Drain cleaning can be dangerous, especially for the inexperienced. I had a helper cut a finger off, I took him to have it sewn back on. It can get serious...and the machine he was using was manual, not electric powered.
 
ok, point taken. I'm fine calling in a pro, I'd just ideally have some level of confidence that a partially clogged drain is the cause before I pay for the service. Feels like that is a more likely cause than a failed air vent
 
ok, point taken. I'm fine calling in a pro, I'd just ideally have some level of confidence that a partially clogged drain is the cause before I pay for the service. Feels like that is a more likely cause than a failed air vent

I understand. I can’t make any guarantees without being there and sometimes you still can’t make guarantees even being onsite.,

Sometimes investigative work can cost more than just trying the most likely solution first. This is where experience helps you and knowing the common problems in your service area.
 
It could be something to do with your pump. If this gurgling happens when the pump is on especially so !

You’ll have to start checking around when the gurgling starts .
 
I thought about if it could maybe have something to do with the pump, but that would be running continuously for some 30-60 second duration I'd guess, which doesn't really line up with the sound I'm hearing for 1 second every 6-7 seconds over a few minutes. But who knows.

No way for me to know when the pump is running, other than hooking the pump up to an outlet with a power meter so I can see when it's drawing power. So i'd have to run outside and check when I hear the sound. Difficult, but not impossible.
 
If I was your plumber I might could wire a light into the pump circuit to indicate when the pump was on.

Good luck, I wish I could give a more definite answer for you.
 
Just wanted to come back and provide an update here. A month ago or so I called my septic company and they thought the sound might be an indication that the tank needed to be pumped. They came by and did that, and I haven't had the sound since!
 

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