Under sink plumbing? - what is this?

[8Line]

Thanks in advance everyone, this is the sink in our new home; its a double tub with a disposal on one side. I'm installing a single tub sink (cant stand double tubs!) and will need to redo the plumbing slightly. The plumbing install isn't the problem, but i'm stuck on what this second pipe coming from the floor is for?

Primary drain flow path is in blue, what I'm removing is in black, what I don't understand is in red. Does anyone know what pipe is for?

 

[rlitman]

It's a vent.

 

[PCustoms]

Is this in an island?

Looks like your vent pipe to me.

 

[8Line]

It's a vent.

Ah ok ok , that makes sense. so definitely don't plumb the drain into the right side down pipe! haha

Is this in an island?

Looks like your vent pipe to me.

It is an island, didn't know that was a factor but makes complete sense now! learned Something today. thanks!

I'll have to figure out how to plumb the new piping. The drain in the new sink is almost where the current left-hand drain sits. But now with a disposal going there I may need to get creative.

Any tips or things to avoid when it comes to plumbing in the disposal? (don't do too many turns/bends?) Do I need to keep the drain height above the disposal drain? it looks tall in that picture for a reason....

 

[TurnipTruck]

 

[Norcal]

It's called a island vent.

 

[mike93lx]

Great opportunity to get rid of the disposal. They only cause problems as the best thing you can do is not send food waste down the drain.

Make sure you have a horizontal section between the trap and vertical section of drain down through the floor so you don't create an s trap

 

[Lassen Forge]

Depending where your final drain is on your new sink and how the current disposal is set up it almost looks like you can get rid of a lot of the blue line... go direct from disposal outlet to your drain connect. You might have to reroute your vent line (red line) a bit, but it shouldn't be too much of an issue. The biggie might be removing / relieving the bottom of your undersink cabinet to fit your disposal motor, as it's tall...

I hate to, but I kinda agree with Mike... we had nothing but issues with our disposal and the plumbing downslope of it, especially after we replaced the dishwasher with a more modern unit. Then again our plumbing was the original installed in the 1930's... Still, had clogging and sludging issues until we had a plumber run new drain lines.

 

[Jeff C]

Pick a single bowl sink with a drain on the right hand side or switch to a studor vent to clear out some space.

 

[mike93lx]

I hate to, but I kinda agree with Mike.

Hey now...

 

[rmmiller]

I don't believe my island is vented like that, going to have to look tonight. Is that a regional requirement or is it a new thing? Our house is just over a year old.

 

[nutjob]

I agree with the get rid of the disposal and since you are redoing the plumbing install this:

https://www.amazon.com/gp/product/B012Q5RTSW/?tag=atomicindus08-20



The small basket collects what would normally go down the drain.

Kevin

 

[billconner]

Not the only way to vent an island sink, but a good way IMHO. Regional preferences may affect this. Im somewhat guessing the island or loop vent is loosing popularity and air admittance valves (a Studor is one) gaining popularity, caused by greater code acceptance.

 

[The Cobbler]

as said, it's an island vent. any waste goes into the blue pipe and trap you marked

 

[billconner]

I find the anti-disposal comments. I think every place I've lived had a disposal and never had a problem. We don't use it heavily, just what's left after trying to put all scraps in waste bin.

 

[mike93lx]

I find the anti-disposal comments. I think every place I've lived had a disposal and never had a problem. We don't use it heavily, just what's left after trying to put all scraps in waste bin.

Part of my approach is from having septic systems. At my last place (in MA) removal was required to get a certification for sale by my local board of health because I was on septic.

I pulled it from the kitchen in my current house pretty quickly after moving in. Haven't used one in years and don't miss it at all. A basket catches all the scraps that don't get scraped, so only liquids go to the septic.

 

[billconner]

I have for quite some time been on city (or village) sewer system, so different.

 

[Norcal]

Part of my approach is from having septic systems. At my last place (in MA) removal was required to get a certification for sale by my local board of health because I was on septic.

I pulled it from the kitchen in my current house pretty quickly after moving in. Haven't used one in years and don't miss it at all. A basket catches all the scraps that don't get scraped, so only liquids go to the septic.

I ran the wiring for a disposal but because am on septic & the redwood tank and leech field is original from 1957, have been reluctant to install one.

 

[Zeke]

The vent loop needs to be above the sink drain as shown in the 5th post.

 

[CJ7VFR]

...Make sure you have a horizontal section between the trap and vertical section of drain down through the floor so you don't create an s trap

Is there a minimum length the horizontal section needs to be, in order to meet code?

Jim

 

[mike93lx]

Is there a minimum length the horizontal section needs to be, in order to meet code?

Jim

My understanding is 2x the pipe diameter

 

[CJ7VFR]

My understanding is 2x the pipe diameter

Thanks. My house has an "S" trap in the kitchen sink plumbing, which passed inspection when we bought the house back in 2010, but I am sure will not pass when we go to sell the place in the future. I was thinking of making it a "P" trap, but didn't know all that was needed was just a short section of horizontal pipe to fix it. I think there is room to rotate the drain pipes and the trap around a bit to get the short section in there. Jim

 

[mike93lx]

Thanks. My house has an "S" trap in the kitchen sink plumbing, which passed inspection when we bought the house back in 2010, but I am sure will not pass when we go to sell the place in the future. I was thinking of making it a "P" trap, but didn't know all that was needed was just a short section of horizontal pipe to fix it. I think there is room to rotate the drain pipes and the trap around a bit to get the short section in there. Jim

An air admittance valve can also help, but the best thing to do is make it a p trap.

 

[The Cobbler]

The vent loop needs to be above the sink drain as shown in the 5th post.

not for an island vent. . that's partly why the 2 clean outs

 

[bb29510]

i love my disposal, best thing i ever had

 

[no704]

 

[Zeke]

not for an island vent. . that's partly why the 2 clean outs

Nope. The loop vent needs to be above the sink outlet. Should be above the sink rim, but that's not likely unless there is a raised part of the cabinet for seating. Would you put an air admittance valve below the drain level?

 

[housewolf]

Not the only way to vent an island sink, but a good way IMHO. Regional preferences may affect this. Im somewhat guessing the island or loop vent is loosing popularity and air admittance valves (a Studor is one) gaining popularity, caused by greater code acceptance.

What OP has is exponentially better than a studor vent. A studor vent only allows admitting air into the system. When you add water into a system, the air (sewer gas) needs to be displaced ( vent through roof).

Post #5 shows a very good way to vent an island sink. Unfortunately all too often I see the vent line simply go back down and tie into the drain only. While this isn’t technically correct, I believe it’s better than a studor vent. If you look at it as a combination waste & vent system (it’s not really but would work similarly) it would be perfectly legal. I’ve never worked anywhere in my 45 years that a studor vent would pass an inspection. Maybe in a unique situation you might get an inspector to turn a blind eye.

Disclaimer; I haven’t much recent residential experience but I have seen some stuff allowed on fairly new residential codes that would have had an inspector demanding to see a plumbing license years ago.

 

[billconner]

Air admittance valves are acceptable by code. I'm not sure exactly how long but probably 5 to 10 years. I've never needed to use one but frankly, wouldn't hesitate.

 

[Glemon]

I haven't followed all of this,but as far as air admittance valves, I bought a cheap one at Menards for the garage sink I put in (I didn't want to worry about the trap freezing) It didn't seem to work very well, slow drain and occasional smells. Got a better one, Otey I think, and everything works fine now.

 

[mike93lx]

Air admittance valves are acceptable by code. I'm not sure exactly how long but probably 5 to 10 years. I've never needed to use one but frankly, wouldn't hesitate.

My kitchen has one as the sink is in a peninsula. Built in 2003. Seems to be working fine, but then again, I am anti disposal, so take it with a grain of salt

 

[Jim greengo]

Thanks in advance everyone, this is the sink in our new home; its a double tub with a disposal on one side. I'm installing a single tub sink (cant stand double tubs!) and will need to redo the plumbing slightly. The plumbing install isn't the problem, but i'm stuck on what this second pipe coming from the floor is for?

Primary drain flow path is in blue, what I'm removing is in black, what I don't understand is in red. Does anyone know what pipe is for?

Looks like a poorly installed island vent to me.

 

[mike93lx]

Looks like a poorly installed island vent to me.

The zip ties and several escutcheons scream homeowner hack, but the pvc belies that a bit. Odd setup for sure

 

[8Line]

Pick a single bowl sink with a drain on the right hand side or switch to a studor vent to clear out some space.

The cut out of the counter is limiting us HEAVILY on the replacement sinks. and we arent ready for a new counter top. Its a new build home so want to keep the builder warranty for the 2yrs. its active.

The vent loop needs to be above the sink drain as shown in the 5th post.

There isn't really any room behind, or to the side of the sink for this. I climbed in there and its really as high as it can go sadly.

The zip ties and several escutcheons scream homeowner hack, but the pvc belies that a bit. Odd setup for sure

This is the builders doing. is there something I can show them, code wise, that would require them to rework the piping and water lines?

 

[mike93lx]

This is the builders doing. is there something I can show them, code wise, that would require them to rework the piping and water lines?

Possibly the vent lopp height, but they will say it passed inspection and to pound sand. The rest is just poor workmanship.

If you have paid them, you are on your own at this point, IMO

 

[8Line]

Possibly the vent lopp height, but they will say it passed inspection and to pound sand. The rest is just poor workmanship.

If you have paid them, you are on your own at this point, IMO

that was my expectation however this builder has been extremely considerate after we paid/closed. a few things have already been corrected after that. (chipped floor tiles, paint errors, bathroom counters alignment....) I will say I am very happy with this builder.

Either way, we are installing this sink on our own, so they wont do it for us and we will be brining in our own plumber to run the piping.

I'm also having the sink powder coated to match the island dark grey cabinet color, the granite top is white with grey wisps. I'll snap some pics before/after.

 

[billconner]

Powdercoat the sink?

 

[8Line]

Powdercoat the sink?

yup. its stainless, and the powdercoat company does a few a year.

 

[mike93lx]

that was my expectation however this builder has been extremely considerate after we paid/closed. a few things have already been corrected after that. (chipped floor tiles, paint errors, bathroom counters alignment....) I will say I am very happy with this builder.

Either way, we are installing this sink on our own, so they wont do it for us and we will be brining in our own plumber to run the piping.

I'm also having the sink powder coated to match the island dark grey cabinet color, the granite top is white with grey wisps. I'll snap some pics before/after.

Glad to hear a positive experience for once

 

[kbuhagiar]

yup. its stainless, and the powdercoat company does a few a year.

With all due respect, you may want to do some research on this, as powder coating (as I know it) will not hold up to the daily abuse a kitchen sink will endure.