Wet venting 2 washrooms

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yourlocalhandsyman

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So our plumber decided he wanted to take some easy new construction subdivision jobs before winter instead of finishing ours (welcome to living in the middle of nowhere). I thought everything was roughed in but on looking in the crawlspace the drain pipes all just stick 2' down and aren't connected to anything, i.e no main line or p traps. Half the water lines do this as well....looks like anything that was difficult to get to he left that way and never came back.

Anyways, from my understanding this is the way my setup would need to be done in order to wet vent, correct? The kitchen sinks are actually fully plumbed and vented, so I'm assuming he was using these to went vent off of and also connect the other water lines too. Only issue is that these are actually the closest fixtures to the plumbing stack along with the toilets. Could I branch off one of these drain lines below the trap and run it to the end of the 4" for the wet vent? I'm assuming since the pipe wouldn't be carrying water (unless there was a plug below where it connected) that turn radius and total directional change are irrelevant?
 

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yourlocalhandsyman

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So our plumber decided he wanted to take some easy new construction subdivision jobs before winter instead of finishing ours (welcome to living in the middle of nowhere). I thought everything was roughed in but on looking in the crawlspace the drain pipes all just stick 2' down and aren't connected to anything, i.e no main line or p traps. Half the water lines do this as well....looks like anything that was difficult to get to he left that way and never came back.

Anyways, from my understanding this is the way my setup would need to be done in order to wet vent, correct? The kitchen sinks are actually fully plumbed and vented, so I'm assuming he was using these to went vent off of and also connect the other water lines too. Only issue is that these are actually the closest fixtures to the plumbing stack along with the toilets. Could I branch off one of these drain lines below the trap and run it to the end of the 4" for the wet vent? I'm assuming since the pipe wouldn't be carrying water (unless there was a plug below where it connected) that turn radius and total directional change are irrelevant?
Sorry, I'm just realizing there is a Canadian specific place I could of put this. Should I remake it or can it be moved Terry?

I made a new drawing that is more accurate. The kitchen sinks that are vented above the floor are what's already there, framed and covered in the wall. Everything below is proposed. Is this making sense?
 

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Jeff H Young

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Don't know about Canada but in the USA we must have a vent for lavs or at least an AAV .
 

yourlocalhandsyman

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Dont know about Canada but in the USA we must have a vent for lavs or at least an AAV .
I'm rereading the code and you cannot wet vent a bathroom through a kitchen sink. Also I opened up the wall because something seemed off - turns out the kitchen and bathroom sink share a vent but both run horizontal a short way then down through the floor like everything else to drain.

I seriously don't know what this guys big picture plan was. Going to sit and think on this and draw up something new. Seems 1 bathroom sink will need an AAV and I am going to have to open up the wall higher to put another dry vent in and run it down through the floor for the toilets and tubs. Also the kitchen sink plumbing has to go to 2" for a double kitchen sink. This whole situation is making my head hurt.
 

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I'm rereading the code and you cannot wet vent a bathroom through a kitchen sink. Also I opened up the wall because something seemed off - turns out the kitchen and bathroom sink share a vent but both run horizontal a short way then down through the floor like everything else to drain.

I seriously don't know what this guys big picture plan was. Going to sit and think on this and draw up something new. Seems 1 bathroom sink will need an AAV and I am going to have to open up the wall higher to put another dry vent in and run it down through the floor for the toilets and tubs. Also the kitchen sink plumbing has to go to 2" for a double kitchen sink. This whole situation is making my head hurt.
Its more that a kitchen sink can't drain through a bathroom horizontal wet vent system. It must tie in downstream.

Give us a detailed blueprint style drawing of where the fixtures are, where walls are and where the drain is that everthing needs to connect to.. Assuming you have a crawl space and the point of connection is low enough under the joists to get all the plumbing under the joists.
 

yourlocalhandsyman

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Its more that a kitchen sink can't drain through a bathroom horizontal wet vent system. It must tie in downstream.

Give us a detailed blueprint style drawing of where the fixtures are, where walls are and where the drain is that everthing needs to connect to.. Assuming you have a crawl space and the point of connection is low enough under the joists to get all the plumbing under the joists.
Here you go!

Correct me if I'm wrong, but can I run a vertical pipe up to the current venting (dry vent) and attach it to a 4" horizontal trunk that drains at the stack, connecting each below the floor parallel to the 4"? So the 1 1/2" vertical is dry but when it hits the 4 inch trunk horizontal connecting it all to the stack the 4" is wet? The 3" toilets connected to a double wye as the last fixture in the wet vent and then straight to stack?

Is the shared 1 1/2" dry vent enough for all those fixtures, or would I have to tear it out and replace it with a 2"?
 

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Tuttles Revenge

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OK... Scratch all that. I found the code for Ontario and its a lot simpler than I ever imagined horizontal wet venting to be.

Code Here
Similar post Here with helpful info.

seems the kitchen can drain through the bathroom horizontal wet vented system so long as it is vented separately..

I haven't really had a chance to process this much..
 

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I didn't run sizing on this. But appears that Ontario allows 2 bathroom groups on the same horizontal system. The kitchen could run through it too if vented separately. The most upstream bathroom sink is the vent for the entire horizontal system with the kitchen and other bathroom sink vented individually. My code allows only one wet vented fixture to tie in above the dry vent take off, so that is why I drew that tub above the bath sink, but that could switch if needed so the tub ties in downstream.

Again.. not totally familiar with this code.
 

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yourlocalhandsyman

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OK... Scratch all that. I found the code for Ontario and its a lot simpler than I ever imagined horizontal wet venting to be.

Code Here
Similar post Here with helpful info.

seems the kitchen can drain through the bathroom horizontal wet vented system so long as it is vented separately..

I haven't really had a chance to process this much..
I appreciate it. The table is why I was running a 4" wet vent, as the vent cannot decrease until it becomes a dry vent, and a 3" pipe with 2 toilets can only have 8 fixture units on it. I was assuming that the 2 kitchen sinks would count towards that # since they are draining into the pipe despite having their own vent. So 2 kitchen sinks is 3, plus 2 tubs 6, plus 2 bathroom sinks 9, plus 2 dishwashers is 11 fixture units.

Hmm, I will have a search and see about what can be upstream of the dry vent tie in in a wet vent. The examples I was looking at were American and was 1 fixture as you stated. Would be nice to have it closer to the middle.
 

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I didn't run sizing on this. But appears that Ontario allows 2 bathroom groups on the same horizontal system. The kitchen could run through it too if vented separately. The most upstream bathroom sink is the vent for the entire horizontal system with the kitchen and other bathroom sink vented individually. My code allows only one wet vented fixture to tie in above the dry vent take off, so that is why I drew that tub above the bath sink, but that could switch if needed so the tub ties in downstream.

Again.. not totally familiar with this code.
Yes, but when you do 2 bathroom groups the toilets have to be the last fixtures and on opposing arms of a double wye, as my dash sketch shows.

This is pretty complicated as far as plumbing I have done. When my parents die they are leaving me the house so I want to be sure and do everything properly and not just one of the local "git er done" redneck hack jobs. The last thing I did was a pex manifold because all their copper was full of lime and choking up. Repiped the whole house!
 

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Yes, but when you do 2 bathroom groups the toilets have to be the last fixtures and on opposing arms of a double wye, as my dash sketch shows.
That's not what Ontario Building Code 7.5.2.1(c) says: "when two water closets are installed, they are connected at the same level to a vertical part of the stack by means of a double fitting in accordance with Table 7.2.4.5."


But you can just separate the two WC into two separate wet vents. I marked up Tuttle's fine drawing to show this, didn't check anything else as far as Ontario Code, and I'm assuming the bit about the vented kitchen sink draining the wet vent is OK as previously commented. The two lavs and the kitchen sink will need dry vents.

Cheers, Wayne
 

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yourlocalhandsyman

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That's not what Ontario Building Code 7.5.2.1(c) says: "when two water closets are installed, they are connected at the same level to a vertical part of the stack by means of a double fitting in accordance with Table 7.2.4.5."


But you can just separate the two WC into two separate wet vents. I marked up Tuttle's fine drawing to show this, didn't check anything else as far as Ontario Code, and I'm assuming the bit about the vented kitchen sink draining the wet vent is OK as previously commented. The two lavs and the kitchen sink will need dry vents.

Cheers, Wayne
Hmm, I was watching a video by a licensed plumber, and it showed using a horizontal wye before the stack top connect 2 toilets with the wet vent running up the centre outlet for the rest of the fixtures to the dry vent at the end/2nd last. Perhaps I am remembering it wrong or it was not for Canadian plumbing. I stand corrected, it would be a double tee or wye at the stack where both toilets come in at the same level, which would be very difficult for this project.

Thank you!
 

yourlocalhandsyman

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That's not what Ontario Building Code 7.5.2.1(c) says: "when two water closets are installed, they are connected at the same level to a vertical part of the stack by means of a double fitting in accordance with Table 7.2.4.5."


But you can just separate the two WC into two separate wet vents. I marked up Tuttle's fine drawing to show this, didn't check anything else as far as Ontario Code, and I'm assuming the bit about the vented kitchen sink draining the wet vent is OK as previously commented. The two lavs and the kitchen sink will need dry vents.

Cheers, Wayne
I'm confused, you erased the line from the right hand toilet to the main pipe and attached it to the sink going to the main pipe. The sink only has a 1.5" drain, wouldn't it rather be the toilet connected directly to the main 4" before the stack, with the sink draining into the toilet pipe and being used as a wet vent? Which would then be against code because a 1.5" pipe cannot wet vent a water closet as in https://www.buildingcode.online/1100.html

So to get past the two water closet/toilet issue, would it rather be adding another connection to the kitchen sinks dry vent to go to the right side toilet and having the kitchen sink drain connected before the toilet? Or at least upgrading the pipe between the kitchen sink trap and the toilet that's acting as a wet vent to 2"?

I also added the required dry vent at the end of the wet vent with a cleanout, but no sure if that works. I can't find it in the code, but that many fixtures seems like too much for what ends up being a single shared 1.5"vent?
 

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yourlocalhandsyman

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That's not what Ontario Building Code 7.5.2.1(c) says: "when two water closets are installed, they are connected at the same level to a vertical part of the stack by means of a double fitting in accordance with Table 7.2.4.5."


But you can just separate the two WC into two separate wet vents. I marked up Tuttle's fine drawing to show this, didn't check anything else as far as Ontario Code, and I'm assuming the bit about the vented kitchen sink draining the wet vent is OK as previously commented. The two lavs and the kitchen sink will need dry vents.

Cheers, Wayne
Ah, the ontario code page has the old 2015 version of the national code. The current 2020 National code book reads as follows: c) where 2 water closets are installed, they are connected at the same level by means of a double sanitary T fitting if the vent pipe is vertical and by means of a double Y fitting if the vent pipe is horizontal

Anyways, after watching some apprentice videos based on the newest code and checking the charts, I think I have it now. The only work that has to be done above floor is adding the dry vent at the end and marking the AAV for the last lavatory. Thank you everyone for your time!
 

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Tuttles Revenge

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Wayne separated the WC from the HWV system in order to create 2 distinct HWV systems each with their own vent and tied in to the drain independent of each other. The UPC used to allow 2 bathroom groups to comingle their HWV systems the way I had drawn, and I interpreted the canadian code that way in my limited reading.

A Double WYE on the horizontal is considered to be Ungraded / Flat where the branches connect.. But some jurisdictions have recognized that if a street fitting is installed in the wye branches pitched to adjust for grade, then its OK to use. But the canadian code apparently says its OK just on its back with no adjustment. There is a slight pitch to the double wye if its being used as a drainage fitting, just fractionally and technically not as much as a wye by itself would be.

<redacted blurb about bribing officials>
 
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Jeff H Young

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There cant be slight pitch built into a double wye other wise it would be marked which side is up if running horizontal.
The double wye looks good on paper and looks kinda cool but can be a little harder to get right in practice especially or mainly when used horizontally. I basically block double wyes out of my mind except when vertical or up against some obstacle
I
 
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