Advice on wet venting my new basement bathroom

[david_c]

Hello, here is a picture of my basement bathroom layout (building permit approved, underground inspection to come). I'm in Ontario Canada.

Thought I'd replace my cast iron 4" waste drain while I'm at it, which was prone to clogging. Very friendly plumber at the hardware store told me I should tie in 5 feet from stack.

[Above: Top view of waste pipes]

Given my layout, could I wet vent the shower and the toilet through the sink? I would run 2" from the toilet pipe towards the sink, then 1.5" vent to atmosphere:

[Above: Side view of the sink showing wet vent]

Thanks for any thoughts, hope this makes sense. Basing it off a video where I believe plumber wet vents shower and toilet through sink:

 

[Stuff]

Tie the shower into the sink first. Otherwise flushing the toilet can empty the shower's trap.

 

[Sponsor]

 

[Reach4]

The sketch attached would let the lavatory wet vent the shower and toilet via 2 inch pipe. You might be able to use a 3-inch double wye to merge the lav, toilet, and shower. This may be controversial, or maybe everybody will agree that it is not good. Get an opinion of a plumber before doing that.

PVC shown in picture, but you would use ABS to match your other piping.

The lavavory and shower inputs would have 3x2 reducers.

 

[david_c]

Tie the shower into the sink first. Otherwise flushing the toilet can empty the shower's trap.

Thank you for the suggestion. Here is my modification to the plan:

 

[david_c]

This would let the lavatory wet vent the shower and toilet via 2 inch pipe.

Thanks Reach4, looks like you and Stuff were thinking a similar thing!
I'm trying to picture in my head how a suction or syphon gets created as the flushing toilet waste goes past the intersection where the shower is... But looks like others on this forum have had this exact problem so glad it got pointed out

 

[Reach4]

The tee for the lav and shower would be a combo, or you would use a wye and a 45.

Here is another idea. Not sure how it would be received. I wonder if it would get any support.

I'm trying to picture in my head how a suction or syphon gets created as the flushing toilet waste goes past the intersection where the shower is...

Read about venturi pumps maybe.

 

[david_c]

Here is another idea. Not sure how it would be received. I wonder if it would get any support.
View attachment 61076

I like this one the best. Also curious to see what others think

 

[david_c]

Here's another thread where a double wye is proposed - suggested that it's not legal in horizontal situations for most jurisdictions (can't find much re: ontario) https://terrylove.com/forums/index.php?threads/basement-4-double-wye-a-bad-idea.20145/

 

[Reach4]

Good find. I expect you can make the regular wyes work for you.

 

[hj]

The double Y has the same problem as your original design. The toilet flows past the shower and the shower does NOT have a vent. COncerning your video, I would NEVER let the carpenter tell me HOW to run my piping, the vents, or anything else. Just tell me what you want to do and get out of the way. They did NOT show anything regarding the shower, so I am not sure it was done correctly.

 

[Terry]

Anybody can post video, doesn't mean they know plumbing. I'm with hj on this.

The lav can run to the shower drain, and then that drain can go to the 3" line.
Don't run the toilet past the shower.

 

[david_c]

That "3/4 bath" diagram illustrates it perfectly, thanks Terry Love. Going to grab required fittings and go that route.

HJ, regarding the video - guess it goes to show you can't trust everything you see on youtube! Lots of education out there but got to sift through it.

 

[david_c]

Everything set in place now. Hopefully correct! Appreciate any feedback. (And yes - P trap of shower is snug up parallel to the main 4" pipe, only way I saw to get the shower drain in the center of shower - hopefully not a problem)