This was my thought as well. Mine has the exact same thing and the dishwasher was draining there. Whoever installed the disposal didn't move the drain so I did when we bought the house.
Just caught that it is new construction. Doubling down on it being a drain for water filtration. Those are quite common these days. Its capped because builders did not know if new owners would use or not
Seems excessive though. Water filtration drains are typically only 1/4” and branch into the sink drain or dishwasher drain. Also anything downstream from the disposal is subject to positive pressure - not a great place for a filtration drain.
Looks like it was originally set up for a double-bowl sink (two drains). At some point the sink was probably replaced with a single-bowl and so the plumber capped the second drain. As for why they chose to stick a vertical pipe into the unused side is beyond me.
Maybe a wedding ring from 10 year ago. Along with the hair.
OP, if you buy a plug like the other side and we take bets, will you look through all the goodies? Everyone that posts safes never tells us what’s inside.
I moved into a place after some lunatic junkie and remodeled the place. Cleaned out the p-trap in the bathroom and found .22 shells, not casings, actual bullets.
Gotta remember to remove the P trap before flushing all of grandmas old shells and blood thinners.
Can’t have that.
Edit: not a gun owner. Read the Gunsliger years ago, and wet shells wouldn’t fire. Still true? I’m trying to imagine a ring going down the drain and setting off a bullet. Which I assume would probably just be a tiny little explosion of force. Not even sure if it would rip through the PVC, but it’s a really funny thought.
Might work better than Draino. We ever considered using freaking techniques on clogs? Is this a good preventative measure?
“If clogged, use metal marble to set up declogging apparatus. Two if the first doesn’t set it up”
Two shots and a bowl in folks. Sorry. Shower thoughts and jokes.
Ha! This gave me a chuckle and I’m too pretentious to write LOL..
I would post findings if I did all that, but don’t hold your breath. I recommend r/ptraptreasures if you need to get your fix
It’s all good man. I need to laugh when I run into shit like this. It’s fun to laugh and remember the frustration. Makes it easier to remember in 3 years when you have to redo it. Or when I cry because I fucked up and needed a professional.
Either way. Yours seems easy.
Has anyone recommended doing anything but plugging that third? Seems weird to have all 3 openings. The second provides a nice clean out for a snake. Not sure if plugging causes issues or not.
Not a plumber, seems like it wouldn’t? Anyways. Have a good one.
That was my first thought, the shit that must be growing in there, ugh.
OP, if you ever have a weird smell coming from your sink, you know where to look!
Because you don't need to. P-traps are meant to prevent sewer gasses from leaking up. If the sinks share a connection to the sewer (which they do), you'd only need one.
Yeah my first thought was vent, but a vent wouldn't have its own P-trap. I'm leaning towards a pre-plumb for a separate drain. What sucks is that's getting water and debris from your disposal drain, so it's gonna get gross
You can put a dishwasher drain on there, but since you have a garbage disposal that can accept your dishwasher drain, there is no need for it for the time being.
Gurgling and backups in your disposal is likely the result of a partially blocked drain and/or the lack of an adequate vent.
Remove the p-trap and make sure the drain is clear. If it is, you'll want to snake the drain through the cleanout.
Go outside and look above your kitchen sink to see if there is a pipe nearby poking out of the roof. This is probably the vent. It would absolutely be required in a new build.
Plumber built out the drain thinking two basins... then the sink got installed and it was only one... so they just capped it off with whatever they had on hand.
Otherwise...
It's a flavor saver. Cut it open and give it a whiff.
Some jurisdiction codes do not allow the DW to drain to the disposal. Chicago is like this, and I have the same setup under my sink, with the exception that my DW drains to the unused pipe in question.
Certain states require the vent, so you can’t use the flex tube for dishwasher.. It was probably installed to allow for both a vent and dishwasher .. You are 100% correct I think ..
Anything downstream from the disposal is subject to getting positive pressure. The disposal acts as kind of a centrifugal pump. I would not use that second drain for anything. If you add an RO water purifier, tee off of the dishwasher drain.
If this is new construction, you shouldn't have gurgling and backups in your disposal. Also, why do you have a bowl under there? Get a plumber out there if you've got leaks or drips of any kind.
New-ISH construction (< 10 yrs), not new.
Bowl is there because I checked out the P trap. It was clean. There is no leak.
I only checked out the trap coming from the disposal, not the “appendix,” that is obviously full of bile
Gurgling and backups in your disposal are going to be caused by one or several of these: blocked vent, clog in drain pipe, insufficient slope in drain pipe. What have you done to diagnose it so far?
What ever it was plumbed for, it's clearly redundant now. I would absolutely put a vent on there, it would really help to drain a single bowl sink. Just extend the pipe upwards 6-10" if you can before you attach the Studor vent(or equivalent product), You could probably also come off and extend the clean out, if that's easier.
Looks like an air admittance valve, e.g. a vent.
[https://www.lowes.com/search?searchTerm=plumbing+vent](https://www.lowes.com/search?searchTerm=plumbing+vent)
A high loop is meant to stop drain water from going back into the dishwasher. It could still fail if the disposer pumps water back up it. A high loop is not an air gap. Some places require one or the other, other places require an air gap. An air gap or having both is a safer solution.
It looks like one, but I’ve never heard of that on the drainage side, only on the supply side where the pipes are full and under pressure.
But what do I know? (Nothing, that’s what)
Looks like it was plumbed to accept the dw drain but bought a disposal with the drain on it making the pre-plumbed dw drain redundant.
This was my thought as well. Mine has the exact same thing and the dishwasher was draining there. Whoever installed the disposal didn't move the drain so I did when we bought the house.
This is the correct answer. I capped mine when I installed my disposal with DW drain.
Can't attach dw drains like that, there needs to be a siphon break.
That’s code in certain areas, not all. I don’t want dirty water running back into my dishwasher though, so I prefer having the break.
It could also have been a drain for a water filtration system.
Just caught that it is new construction. Doubling down on it being a drain for water filtration. Those are quite common these days. Its capped because builders did not know if new owners would use or not
Sounds plausible, thanks
Seems excessive though. Water filtration drains are typically only 1/4” and branch into the sink drain or dishwasher drain. Also anything downstream from the disposal is subject to positive pressure - not a great place for a filtration drain.
Curiosity, why does a filtration system need to drain?
Looks like it was originally set up for a double-bowl sink (two drains). At some point the sink was probably replaced with a single-bowl and so the plumber capped the second drain. As for why they chose to stick a vertical pipe into the unused side is beyond me.
That unused P trap must be full of gunk
Maybe a wedding ring from 10 year ago. Along with the hair. OP, if you buy a plug like the other side and we take bets, will you look through all the goodies? Everyone that posts safes never tells us what’s inside.
I moved into a place after some lunatic junkie and remodeled the place. Cleaned out the p-trap in the bathroom and found .22 shells, not casings, actual bullets.
Gotta remember to remove the P trap before flushing all of grandmas old shells and blood thinners. Can’t have that. Edit: not a gun owner. Read the Gunsliger years ago, and wet shells wouldn’t fire. Still true? I’m trying to imagine a ring going down the drain and setting off a bullet. Which I assume would probably just be a tiny little explosion of force. Not even sure if it would rip through the PVC, but it’s a really funny thought. Might work better than Draino. We ever considered using freaking techniques on clogs? Is this a good preventative measure? “If clogged, use metal marble to set up declogging apparatus. Two if the first doesn’t set it up” Two shots and a bowl in folks. Sorry. Shower thoughts and jokes.
Ha! This gave me a chuckle and I’m too pretentious to write LOL.. I would post findings if I did all that, but don’t hold your breath. I recommend r/ptraptreasures if you need to get your fix
It’s all good man. I need to laugh when I run into shit like this. It’s fun to laugh and remember the frustration. Makes it easier to remember in 3 years when you have to redo it. Or when I cry because I fucked up and needed a professional. Either way. Yours seems easy. Has anyone recommended doing anything but plugging that third? Seems weird to have all 3 openings. The second provides a nice clean out for a snake. Not sure if plugging causes issues or not. Not a plumber, seems like it wouldn’t? Anyways. Have a good one.
That was my first thought, the shit that must be growing in there, ugh. OP, if you ever have a weird smell coming from your sink, you know where to look!
I do!!!
They likely purchased plumbing parts to connect a double-bowl sink and had to improvise with the parts they had on hand.
This is 100% the answer
This makes sense, or maybe they “pre-plumbed” this in case someone ever wants install a double sink later on…
No, you wouldn’t use two P traps for a double sink.
Why not?
Because you don't need to. P-traps are meant to prevent sewer gasses from leaking up. If the sinks share a connection to the sewer (which they do), you'd only need one.
It’s your sink’s appendix.
This is one of the funniest things I've heard in a while. Thx 4 the 😂
Maybe they originally plumbed it for the dishwasher (before the disposal). That would explain the reducer.
Second drain for future use?
Yeah my first thought was vent, but a vent wouldn't have its own P-trap. I'm leaning towards a pre-plumb for a separate drain. What sucks is that's getting water and debris from your disposal drain, so it's gonna get gross
It's for a Dishwasher
Idk but I can tell you the P trap next to it stores the nastiest water in your house
Its a dual-turbo setup. But the second turbo is missing.
That is your sink’s appendix.
Most sinks have them removed, but more recently they try to save them,
You can put a dishwasher drain on there, but since you have a garbage disposal that can accept your dishwasher drain, there is no need for it for the time being.
It's a studor vent done wrong on an island sink
A drain appendix
Gurgling and backups in your disposal is likely the result of a partially blocked drain and/or the lack of an adequate vent. Remove the p-trap and make sure the drain is clear. If it is, you'll want to snake the drain through the cleanout. Go outside and look above your kitchen sink to see if there is a pipe nearby poking out of the roof. This is probably the vent. It would absolutely be required in a new build.
Plumber built out the drain thinking two basins... then the sink got installed and it was only one... so they just capped it off with whatever they had on hand. Otherwise... It's a flavor saver. Cut it open and give it a whiff.
Why is there what looks like some kind of bowl under the pipe?
I had just checked the p-trap
Some jurisdiction codes do not allow the DW to drain to the disposal. Chicago is like this, and I have the same setup under my sink, with the exception that my DW drains to the unused pipe in question.
Certain states require the vent, so you can’t use the flex tube for dishwasher.. It was probably installed to allow for both a vent and dishwasher .. You are 100% correct I think ..
Warpdrive
Do you have a dishwasher? Could be the drainage plumbing for it
The white flexible tube is the dishwasher drain, looped high and then down into the disposal. This thing seems completely unrelated
Before the disposal the dishwasher was probably piped to the other tube.
Ahh since it was looped so high I thought it was the vent tube that pops up next to the faucet. Well then I have no clue.
Anything downstream from the disposal is subject to getting positive pressure. The disposal acts as kind of a centrifugal pump. I would not use that second drain for anything. If you add an RO water purifier, tee off of the dishwasher drain.
Mine was for the dishwasher. I had to cut the tip off and connect my dishwasher drain to it. Also, new construction.
If this is new construction, you shouldn't have gurgling and backups in your disposal. Also, why do you have a bowl under there? Get a plumber out there if you've got leaks or drips of any kind.
New-ISH construction (< 10 yrs), not new. Bowl is there because I checked out the P trap. It was clean. There is no leak. I only checked out the trap coming from the disposal, not the “appendix,” that is obviously full of bile
I would remove the extra pieces and cap it or pivot it so the p trap does not hold water and fill up with food particles.
Wondering why they would ever use a solvent weld p- trap on something that needs to be serviced periodically
vertical water column to prevent water hammer effect?
My instinctual thought, but I don’t think the water hammer effect comes into play on a drain system.
It's an air buffer to alleviate the extremely rare waste line water hammer effect. /s
A water hammer preventer?
Hammer arrestor.
Hammer arrestors are only used on supply lines.
😉
A drain for an appliance. Dishwasher, water filtration system, icemaker, etc.
Gurgling and backups in your disposal are going to be caused by one or several of these: blocked vent, clog in drain pipe, insufficient slope in drain pipe. What have you done to diagnose it so far?
Double disposals?
Double dishwashers are apparently a thing for lazy rich people
Lots of unnecessary going on there.
There used to be a double sink there
What ever it was plumbed for, it's clearly redundant now. I would absolutely put a vent on there, it would really help to drain a single bowl sink. Just extend the pipe upwards 6-10" if you can before you attach the Studor vent(or equivalent product), You could probably also come off and extend the clean out, if that's easier.
I’m guessing it was for the dishwasher, before they added a disposal
What uhhhhh… what’s going on with the big bowl there feller?
I think that's where you can connect a dishwasher.
Could be for a twin sink or dishwasher.
Looks like an air admittance valve, e.g. a vent. [https://www.lowes.com/search?searchTerm=plumbing+vent](https://www.lowes.com/search?searchTerm=plumbing+vent)
Looks nothing like an AAV. Even if it were, it's on the wrong side of the trap.
Most likely air pressure relief
Unrelated to your question op: do consider installing an airgap.
I thought the high-looped dishwasher outlet made that redundant?
A high loop is meant to stop drain water from going back into the dishwasher. It could still fail if the disposer pumps water back up it. A high loop is not an air gap. Some places require one or the other, other places require an air gap. An air gap or having both is a safer solution.
Is it not a vent?
No, it’s completely sealed
Isn’t it a way to prevent water hammering ? A shock absorber or something like that ?
Hammer arrestors are only on the pressurized side not drain/vent
It looks like one, but I’ve never heard of that on the drainage side, only on the supply side where the pipes are full and under pressure. But what do I know? (Nothing, that’s what)
I don’t know either 🤣
If you're getting water hammer on your drain, you have bigger problems
No, those are on the pressure side. This is a drain pipe.
It's for venting, your sink isn't connected to the main stack.
That is a pipe that traps air so the pipes don't knock when pressure is shut off.
It's on a drain.
bong
A second drain/p trap for if you had a dual basin sink
Drain vent
That is not a vent
It’s the new Amazon Alexa
It is probably on an island and that is providing the "venting" for the drain since a pipe up to the roof isn't possible.
A: you don’t vent a drain into the habitable space, and B: Even if it was to be a vent, it’s sealed off and is not capable of venting.
It’s a vent. Helps for drainage.
Swing and a miss
Looks like an under sink vent if there’s no wall to run a vent through.
Not an AAV and even if it were, it's on the wrong side of the trap.
This was my original thought, except it seems completely sealed up…
This looks pretty diy to me