Basement Bathroom Rough-In Drainage and Venting

[dwipl]

Hello,

I'm hoping someone significantly more experienced with plumbing can help provide me some direction on redoing my basement bathroom plumbing. Here is the general information:

I'm in MN. I believe we use a version of UPC code here.
The existing bathroom was not installed with a permit and after some demo work we've found it isnt' to code.I'm working with city inspectors to resolve the issue. They are willing to work with me and provide direction.
My plan is to try dryfit and layout how I want the drainage and venting to be setup and have the inspector validate my configuration before I start any pvc welding / bonding.

Here is a very rough draft of what I'd like to accomplish.

You'll have to excuse my very layman understanding of plumbing and venting. The inspector suggested wet venting the WC with the lav. He informed me I'll have to use 2'' to allow the lav to server as a wet vent. The lav 2'' vent will cut across through the studs to the other 1.5'' dry vent of the shower and then I'll bring 2'' all the way back to the stack next to my washing machine.

Unfortunately after reading a lot of MN code and searching online I still feel pretty uninformed. I realize I have to be 6'' above the water spill line before I go horizontal on the vents.

Here is the existing work I need to remove still.

 

[phishfood]

I have been trying to post this since yesterday, had to email it to myself and download it.

Here is what you want to do.

 

[dwipl]

Thanks! That helps a lot. I'll probably need some clarification regarding the shower portion. I'll take some progress pictures and update my diagram to help make things clearer.

 

[dwipl]

Would this work?

 

[johnjh2o]

No, the vent for the tub is running horizontally below the flood rim of the highest fixture.

 

[Dlehrke]

Hey John. Thanks for the response, you seem to know what you're talking about. I'm a buddy of the OP and I created that last image as a better starting point. Would you mind if I pick your(and anyone else's) brain about a few things?

1. Does everything else look correct before(starting from the left) to that last(most right) 45 degree sanitary tee? I wasn't sure if that's all fine or if we should run the 3" farther before going down to the shower, or just use a reducer at the end instead of a 45 and the cap. If there's a better way to do any of it, we're all ears.

2. "the vent for the tub is running horizontally below the flood rim of the highest fixture" - could you expand on that? You're correct that it is whats happening, just to clarify, it goes over to the wall on a slight incline and then up. I'll add another image. Is this still wrong, I'm not really understanding any other way to do it... Oh, I think I might have just realized the cause of some confusion... the drain is for a shower only, not a tub. If nothing I've clarified changes anything, I'd be very grateful for any input on a correct solution.

Thanks for your time.

 

[phishfood]

The whole issue is that you need to turn up vertically directly underneath the shower vent before you run to the shower trap. This way, the horizontal section of piping will have a fixture draining water through it, keeping any debris flushed out, and that will prevent the horizontal pipe from getting clogged with said debris. The way you have it illustrated, there is a section of horizontal vent pipe that does not get washed out by the shower drainage.

You mention capping the drainage line, but in the first picture it appears as though the pipe continues, presumably picking up other fixtures?

 

[Dlehrke]

OOOOOOkkkkkay

I think I finally understand what you mean... I've created more images... so the vent pipe will actually be a above the rest of the drain by about a the height of a pipe.

The 3" does look like it continues in the first picture but it went to a clean out, it's our impression that that is not necessary.

Here's 3 options, perhaps you could let us know which is best or if it's a combination, which features work best.

 

[Dlehrke]

option 4 incase this works

 

[phishfood]

No, that still won't be to code. If you look at the drawing I posted earlier, in the little detail, you will see that the pipe is turned vertical, with a sanitary tee on the vertical pipe, then the pipe leading to the trap is attached to the side of the tee, with the vent attached to the top of the tee.

Run the pipe directly to the vent, the pipe leading to the Ptrap should not be attached to the horizontal pipe.

 

[Dlehrke]

That'll leave us with an acute angle with the drain and the Ptrap right? is that an issue?

 

[johnjh2o]

Just to try to clear things up for you. Run the waste line directly to the vent were it enters the wall. Just below the point that it enters the wall put a san.tee on the vertical line. Run the branch of the san.tee to the shower drain.

 

[Dlehrke]

Alright, thanks for the help guys. Does this look like a winner?

 

[johnjh2o]

That's it. Good job.

 

[AQualityPlumber]

Hey John. Thanks for the response, you seem to know what you're talking about. I'm a buddy of the OP and I created that last image as a better starting point. Would you mind if I pick your(and anyone else's) brain about a few things?

1. Does everything else look correct before(starting from the left) to that last(most right) 45 degree sanitary tee? I wasn't sure if that's all fine or if we should run the 3" farther before going down to the shower, or just use a reducer at the end instead of a 45 and the cap. If there's a better way to do any of it, we're all ears.

2. "the vent for the tub is running horizontally below the flood rim of the highest fixture" - could you expand on that? You're correct that it is whats happening, just to clarify, it goes over to the wall on a slight incline and then up. I'll add another image. Is this still wrong, I'm not really understanding any other way to do it... Oh, I think I might have just realized the cause of some confusion... the drain is for a shower only, not a tub. If nothing I've clarified changes anything, I'd be very grateful for any input on a correct solution.

Thanks for your time.

This is all correct. You only need to make sure that your y fitting for the 2" vent is rolled up 45 degrees that way it becomes a dry vent. This type of piping method is called horizontal wet venting. It will be the easiest, cheapest, and fasts way for you to do this. This is how I would do it anyway.

 

[johnjh2o]

This is all correct. You only need to make sure that your y fitting for the 2" vent is rolled up 45 degrees that way it becomes a dry vent. This type of piping method is called horizontal wet venting. It will be the easiest, cheapest, and fasts way for you to do this. This is how I would do it anyway.

Where do you see a dry vent? The first Y after the toilet is being washed by the shower, and the one further down the line is being washed by the lav.

 

[Dlehrke]

Awesome, again, thanks so much. I get now that the sharp angle is irrelevant because it's draining down at the tee, not turning.

 

[AQualityPlumber]

Where do you see a dry vent? The first Y after the toilet is being washed by the shower, and the one further down the line is being washed by the lav.

One of the pictures was correct but this mobile app isn't showing the pictures so just forget it.