Plumbing question - sink gurgling

In the kitchen, I have 3 sinks. A double with a dishwasher hooked to it and an island with a sink by itself.

I’ve noticed over the last several months the island sink gurgles when we drain the water from the other sinks or the dishwasher drains. It’s not always done this and the plumbing is 6 years old. Installed by me.

These sinks share a vent with the washer and mud room sink. Thinking it wasn’t venting well enough, I added an AAV valve. It didn’t help. It’s actually pushing air when the other sinks/dishwasher drains.

I’ve ran water down the vent to see if it was clogged (mind you no issues with the washer) but that didn’t help.

Suggestions on what to check next?

 

You tried pissin in it?

Only thing I can think of is there's a blockage in the venting where the island ties-in.

Did you use a wye to tie it in? Location of traps also might create gurgling. This all comes down to venting bro. If the gurgling happens only when you drain the sink, there's probably a problem with the venting for that sink. The vent may not have been installed the correct distance from the trap, or its blocked. One of the two. For 1.5 in drain pipes, the vent should be installed within 3.5 feet of the bottom of the trap. If it's farther than that, it's likely a vacuum is developing and causing the gurgling.

 

I don't think this is the issue, but is the AAV you added high enough in relation to the island sink?

Pushing air tells me it's a venting issue further up the stack. Did you look down the main stack to make sure you don't have critters in it?

 

Yes. Made sure I ran quite a bit of water down the vent in the roof to make sure it wasn’t blocked.

I’m not having any other issues with what uses that vent other than the kitchen. Washer drains fine, mud room sink is fine...just the kitchen.

I’d like to try and push something through the lines (2” drains to a 3” header before hitting the 4” main septic line) to make sure they’re not clogged. We used to never have an issue so I’m not sure what changed.

I need to get under the house and make sure nothings out of place there.

It’s just more annoying than anything.

 

If you’ve never had gurgling before, I’d do as you’re thinking and run an eel through the pipes. I wouldn’t think you have a buildup problem, with a dishwasher (really hot and caustic drain water) running through those pipes, but, you never know. A couple bad habits, if someone in the household is doing either, are using a disposal for solid food items and pouring grease down the drain. Those two things will quickly wreck a drain system.

I started having bathroom sink drain issues, in 7yr-old pipes. When I disassembled the plumbing, it was ~3/4 built up with a goopy substance. I surmised there are not enough cleaning products flushed through the plumbing to clear the soap residue from frequent hand washing. Now, I routinely dump a gallon of bleach into that drain, split with the bathtub drain. It’s been more than ten years and those drains are still flowing as they should.

 

I like to see the trap setup under the trouble sink. And, don’t do the gallon of bleach thing down the drain if you have septic tank.

 

How old is the house?

I had a very similar problem. Almost identical really. I chased it for YEARS. It was just annoying enough to get me to work on it a little, but not annoying enough to really get after it. I finally rented a big auger and cleaned the lines in the yard. It turned out it was some small roots that had worked their way into the old clay pipes. Somehow that slight blockage and the way the vents worked only made one sink gurgle.

 

Metalhead is under your sink.

 

Gurgling sink? Feed it. It's hungry.

 

House is 6 years and 4 months old. Built by me, all piping is PVC, no trees near septic or lateral lines.

Trap setup is a p-trap (not s-trap), into a 90 and down under the house. I’ll snap a pic tonight of it.

When I installed the AAV last night I washed the trap out as well as looked into the vertical pipe for blockage and all seemed well.

We don’t have a garbage disposal so no solid foods down the drain and our dishwasher has a strainer in it to prevent that as well.

 

Or his desk. Hence the gurgling.

 

Do you have a strainer/drain stopper in one of the other sinks? We have one that makes noise if the stopper is in the adjacent sink.

 

When you say 'pushing air', you don't mean pushing it out of the AAV, do you?

 

No with the AAV in place it still gurgles. If I unscrew the AAV you can feel the air being pushed out the pipe as the other sink drains.

 

I had tree frogs get in the vent stack and do this. Water would not flush them out so I made a gig and removed them.

 

I'd try cleaning it out too, as you said nothing changed from its build date in construction. Just put a new faucet in our bathroom and the drain got replaced and torn apart, I couldn't believe how much shit was in the drain or how it never stunk.

 

My kids bathroom was that way. It was full of soap and hair gel. I pushed a solid turd of goop out of the trap with a towel. It was disgusting.

 

we do a preventative white vinegar / baking soda cleanse about every six months, seems to really help keep if flowing clean. Did the dishwasher once too, and the damn thing looked brand new inside when we were done

 

Ratio? I may do this tonight.

 

Drano Max works well on clogs.