Adding washing machine drain to copper drain under kitchen sink

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Tooltalk

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Hey everyone,

I recently moved back into our family home that was built in the 1950s and I'm thinking about relocating the laundry room. The new location I am considering is in the basement under the kitchen and I thought it would be easy to tie the washing machine drain into the kitchen sink drain pipe. It is mostly 1.5" copper that runs from the cleanout in the basement floor up to the kitchen, but there is also a piece of cast iron pipe between the copper and the newer abs under the sink that was probably done by my late father.

My first thought was to cut a section out of the copper and splice in an ABS wye for the washing machine drain with some flexible fernco type adapters, but then I started wondering if I should just remove all the copper and that short piece of cast iron pipe. The copper is threaded into the cleanout in the basement floor, so if that threaded piece could be removed maybe there's a threaded abs adapter that would fit in there instead. Or maybe just leave a piece of copper at the cleanout and attach some ABS above that.

Does removing all the copper make any sense at all? I would like to keep the cost down on this, unless there's some real benefit to ripping things out and starting over. Which leads me to the next question.

The other problem I noticed is the kitchen sink does not appear to be vented. The only vent stack is at the back of the house where the bathroom and and the laundry are, but the kitchen is in the front of the house. There is also a window over the kitchen sink. I could perhaps add an AAV under the sink, but I think they're supposed to be above the sink, which isn't possible here. So not sure that's a good idea. We've lived in this house since the 60s and I'm not aware of there ever being any problems with the way this sink is plumbed.

Here's a few pics. Any advice on adding a laundry drain and ensuring everything is properly vented would be much appreciated.

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Tooltalk

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Was really hoping I might get some relies here, since this community generally seems very helpful and I've read lots of great advice to other people's questions.

I have asked in a couple other places, but not getting much help in those forums either. So I thought I'd try here again.

What I've learned so far is everything under the kitchen sink likely needs to be replaced to elimate the s-trap and provide proper venting. This may require relocation of the vertical drain to provide adequate horizontal length for the trap arm. Also an AAV may not be up to code in Ontario unless it can placed above the flood level of the sink and still remain accessible. This could require opening the walls and inserting a hatch of some sort.

If the kitchen sink can be properly vented then the 1.5" copper below that needs to be removed and upgraded to 2" ABS. This would likely involve removing the cast iron cleanout from the leaded joint in the cast hub embedded in the basement floor, then replacing it with ABS using a Fernco donut.

The new cleanout would provide a connection point for the new 2" ABS drain for the kitchen sink, washing machine, and perhaps a laundry tub, which would all need to be properly vented using an AAV.

Am I on the right track, or am I over complicating things?

I'd really appreciate any feedback.

Thanks.
 

Jeff H Young

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What I would do is leave kitchen alone or repipe as its substandard my opinion.
For washing machine remove clean out at basement run new line into the top . remove the lead and oakum and put a donut rubber and convert to ABS
 

Tooltalk

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Thanks very much for taking the time to reply. I picked up some parts last night to try and visualize how things might go together. Is this what you're thinking? Upgrade the cleanout, remove some of the copper, then insert 2" washing machine drain with an AAV?

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John Gayewski

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Yeah you definitely need a vent. An AAV might be ok for the washer. It'll be a lot of work to redo the kitchen sink. Keep on mind after your laundry is tied in you will be changing the dynamics inside of the plumbing there is a chance you could have to come back and redo the kitchen sink piping also. Maybe just start with adding the laundry, but keep the kitchen sink and washer tied in separately to the 4". Yes AAV for the washer
 
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Tooltalk

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Yeah you definitely need a vent. An AAV might be ok for the washer. It'll be a lot of work to redo the kitchen sink. Keep on mind after your laundry is tied in you will be changing the dynamics inside of the plumbing there is a chance you could have to come back and redo the kitchen sink piping also. Maybe just start with adding the laundry, but keep the kitchen sink and washer tied in separately to the 4". Yes AAV for the washer

Thanks very much. Looks like cleanout is due for replacement or at least a serious cleaning anyway. It's a 3 inch.

When you say "keep the kitchen sink and washer tied in separately" do you mean put a wye at the cleanout to split off the laundry, rather than tying into the copper between the kitchen sink and the cleanout?

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John Gayewski

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Thanks very much. Looks like cleanout is due for replacement or at least a serious cleaning anyway. It's a 3 inch.

When you say "keep the kitchen sink and washer tied in seperately" do you mean put a wye at the cleanout to split off the laundry, rather than tying into the copper between the kitchen sink and the cleanout?
Yes seperate wye for the washer and another for the kitchen sink. This will (hopefully) keep one drain from effecting the other.
 

Tooltalk

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Here's a sketch of what I've come up with so far that will fix the kitchen s-trap and add laundry drains in basement. Any obvious problems here?

Thanks very much.

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Terry

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That looks to be a big improvement. :)

The waste line to the kitchen upstairs should be 2", with 2' cleanout under the sink, with 1.5" trap and trap arm.
The washer standpipe is 2"
 

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Tooltalk

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That looks to be a big improvement. :)

The waste line to the kitchen upstairs should be 2", with 2' cleanout under the sink, with 1.5" trap and trap arm.
The washer standpipe is 2"
Thanks Terry! Took me awhile wrap my head around this. So glad I'm on right track. I was thinking 1.5" would be ok for kitchen drain, but makes sense to go with 2". Will also insert a wye with a cleanout cap.
 

Tooltalk

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Would there be any problem using a double sanitary tee inplace of the tee and wye circled in my attached drawing? That would make it easier to line up the drain for the laundry tub. Seems like it's better to use one piece instead of two as well. I would just add a 45 to the left side tee to go up to the kitchen.

Thanks again for all the advice.
 

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John Gayewski

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Would there be any problem using a double sanitary tee inplace of the tee and wye circled in my attached drawing? That would make it easier to line up the drain for the laundry tub. Seems like it's better to use one piece instead of two as well. I would just add a 45 to the left side tee to go up to the kitchen.

Thanks again for all the advice.
Yeah it's worse to use a double San tee. Your drawing is better. You could use a double fixture fitting, but it's not better just different.
 

Tooltalk

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Yeah it's worse to use a double San tee. Your drawing is better. You could use a double fixture fitting, but it's not better just different.
Thanks for the quick reply. What if the wye for the kitchen was on top of the tee for the laundry? I think that's worse too, maybe in terms of venting, but I'm not sure.

I was just trying to see if I could lower the trap arm a bit. Stacking the tee on top of the wye, which is on top of the cleanout, places the trap arm a bit high and the bottom of tub sits kind of low.

It will work the way I drew it originally, just trying some different options to connect everything.
 
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Terry

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You could use a santee first and head over to the washer. It will need to be vented with the AAV.
The upstairs kitchen can drop into the top of the santee as long as there is a vent on the trap arm.
 

Tooltalk

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You could use a santee first and head over to the washer. It will need to be vented with the AAV.
The upstairs kitchen can drop into the top of the santee as long as there is a vent on the trap arm.

Thanks Terry. Been doing some dry fitting and I need the trap arm to be about 12" to put the stand pipe where I want it. I've come up with the two options below. Option A is my original plan and Option B would be the setup you describe above. Option B would require all the fittings to be very tight together. Is there any problem with that? I know there needs to be 4" (2x pipe diameters) between trap and vent, but not sure how a 5" tee affects that calculation. I could probably make the arm a couple inches longer if it helps.

Option B would give me more flexibility to set the trap arm height and I could possibly move the tub tee to the stand pipe instead and connect the tub with no trap as seen in the attached image. Does that sound like a good option?

Thanks again for all the assistance. I think I've just about got this sorted. :)

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Jeff H Young

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looks good option b to me, for kitchen youll need another aav as that had no vent and the s trap was not good either
 

Tooltalk

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looks good option b to me, for kitchen youll need another aav as that had no vent and the s trap was not good either
Good to know option B will work. Thanks.

One thing that occurred to me this morning is that a sanitary tee may not be acceptable for a horizontal change in drain flow where the tub drain will connect to the laundry trap arm. So was thinking I should replace the tee for the laundry tub drain connection with a wye as shown in attached image. I'll add a 45 too, but don't have one handy.

Is that correct?

Or maybe a Sanitary Tee-Wye Reducer like in the attached pic is better if I can find one.
 

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