I am currently working on expanding my basement bathroom to include a shower, and I'm trying to do most of the work myself. My existing bathroom had a toilet connecting to a 4 inch main under the concrete, and a vanity, which connected to a drain coming down from the 2nd floor from the kitchen sink.

Now I am adding the shower, and the fixtures will be located in the following order from left to right (see pic): shower, toilet, vanity, main waste line.

I can run the vanity the same way as the old setup (attaching to the kitchen drains) or I can include it with the shower and toilet in the basement underground plumbing.

Do you guys have any recommendations on how I should proceed? I am especially concerned about venting.

Would it be possible to connect the shower drain to the vanity drain where it will be wet vented? Back to you, Tom

Robjabo said,"and a vanity, which connected to a drain coming down from the 2nd floor from the kitchen sink."

He also said, "I can run the vanity the same way as the old setup (attaching to the kitchen drains) or I can include it with the shower and toilet in the basement underground plumbing"...

Here, if you want to WET VENT the toilet and shower using only the one vent then you CANNOT connect into the kitchen sink drain pipe. Here, you must run a 2" drain for the vanity and the shower and use a 2" vent to vent the whole bathroom. This vent must connect into a 2" or larger vent upstairs somewhere... ;)

Questions? Just let us know, OK?

Mark

If I keep these 3 basement fixtures as their own group, run them all underground together into the line on the right (where the toilet was located before), can I vent the system using an AAV? Or am I going to have to run a vent to the roof?

I guess what I'm asking is: Is there a way I can set these 3 fixtures up to use an aav in the vanity cabinet and that be their only source of venting?

HI RJ

If AAVs AND WET VENTING are "code legal" in your area then yeah, you can get away with the one vent/AAV for the whole bathroom group! The AAV under the sink is critical as the AAV MUST remain accessible for future swap out should the AAV fail in the future, right?

Check out the picture below. The only issue that is important in my area is that the WYE for the shower/sink/vent must roll above the centerline of the drain line for the toilet. The sink drain/vent needs to be picked up off a wye, too!

Back to you...

Mark

Mark,

I am planning on the order of the fixtures being shower, toilet, vanity. Does that pose a problem or can I rig the plumbing to make it work that way?

My township uses 2009 International Residential Building Code and it appears at first glance that the use of AAV is permitted.

http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_31_sec014.htm

This is where I am reading about the codes for anyone else that might be reading this topic.

It's definitely a lot more complicated than drawn above... may need two AAVS... ;)

I'd stick with the toilet where it is, but that is up to you, of course!


Mark

What about this layout? I could run the waste from the vanity in the wall behind and tie into the system between the shower and toilet? I could put the AAV in either spot in the diagram. Or am I totally off base with that idea?

That won't work Rob... leaves the toilet unvented.

I'll post a proper drawing in an hour or so, OK?

Sounds good. Thanks for all of the help.

See if this makes sense (see picture)... ;) You can use only one AAV, just be sure it is under the vanity!

If this seems complicated then leme know and I'll draw this up using two AAVS... but you will need an access panel for the shower AAV,OK?

Back to you (I'll check back in an hour or two).

Mark

I took another stab at it. The white outline is a wall between the shower and toilet. Was planning on adding that anyway to close off the shower a little bit. If I bring up an AAV into that wall cavity and provide an access panel to it, would that work? Of course I would still have one in the vanity as well.

I would go with Marks idea. Yours still leaves the toilet unvented. Wish I knew how to draw up diagrams, as you are pretty close, but would need to run the shower drain into a wye rolled above center on the toilet drain, which would act as your toilet vent, as well as your shower drain. Maybe Mark is thinking the same thing?

You can do it either way as presented below... either way, must connect one of the drain/vents (shower or sink) into the toilet drain. Again, the drain/vent wye must roll above the center of the toilet drain.

I like the second diagram. Mark, maybe sometime when we have actuall time, you can give me the low down on doing these drawups.

Glad to Lee... not much to it once I show you! I'll be in touch!

Sounds good.

Mark,

I think I'm going to try and set it up according to the attached picture you posted. I added some more labels to that picture... does what I added seem correct?

Make that 90 degree elbow a 45 degree fitting into the toilet elbow and you sized all perfectly! The AAV can be removed if you ever need to snake the drain line OR you could add a cleanout tee fitting under the cabinet, too (most plumbers do the cleanout tee).

Hey Mark,

I went out and picked up a bunch of fittings today. I had everything in front of me and started dry-fitting the setup. I had a physical layout idea that will work perfectly for me if it is an acceptable plumbing layout. Would you mind taking a look at it and critiquing?

-Rob

That won't fly Rob... the wye for the sink/shower drain MUST roll above the centerline of the toilet drain. It is a very specific requirement and it is why I mentioned it in post #5 and #15 and typed it out in pictures on post #12 and #19. Mygirlsdad77 even stated it in his first post (post #14), so you got to figure this is a pretty important rule... ;)

See what else you can come up with... I'm in and out all day!

When you say "roll above centerline" does that mean that the 45 degree portion of the wye needs to be perpendicular to the pipe that it is joining to (stick up like a tail fin), or can it be at less of an angle, say 45 degrees to the horizontal?

You can roll it up like a fin or just roll the wye with a street 45 in it so that the wye/45 is above the centerline... can be a bit tricky to get the wye above the centerline and still get the pipe straight so play with the wye/45 and you'll see what I mean.

Below is an image of the wye rolled up and straightened using a 45 degree fitting... See image below.