Hello! First time poster here hoping to get some insight on proper venting on a bathroom drain. I've attached an image depicting the planned piping. I know that in some cases it's possible to share a vent, but I'm not sure what the distances are. I've also read that every trap needs a vent.

Any input into where I should place traps on the planned layout would be great. I'm in NY (wet venting allowed).

Thanks!
Jim

Where to place traps in not the issue here, Jim...the entire piping layout on TWO bathrooms is the place to start (it's entirely wrong as drawn...UGH!).

Let's start by telling me what "VENT 1" is? Obviously, we have two bathrooms...try breaking them out a bit and drawing walls in to your drawing and then I'll see what I can do to help, OK?

Mark

Jim,
Massplumber is correct; the piping & labeling near the verticle stack is a
little confusing. Beyond that, shower 1 needs a vent, just be sure that you don't connect any vent horizontally below the flood level of the fixture it serves, unless it is " washed " by another fixture. Shower 2 is correctly vented via the sink 2 drain, this would not be a wet vent because the drain for the sink is one pipe size larger than the 1 1/4" sink drain...

It really is even more complicated than that Mike, but since you covered a good part of it...

How about the toilet 1...that is unvented? Here, I would suggest installing a 3"x2" wye right after the toilet 1 but before the toilet 2 branch and pick up the shower and new shower vent and wet vent the toilet 1 that way. The wet vent would need to be 2". This 3"x2" wye MUST roll above the centerline of the toilet to be considered a vent.

Now, the toilet 2 run of piping requires that the sink drain and sink vent be 2" all the way because it is WET VENTING the toilet and the shower (minimum toilet vent is 2")...branch for the sink can be 1.5". The 3"x2" wye coming off the toilet 2 run must also roll above the centerline of the drain pipe for it to be considered a vent.

Ptraps are required at all sinks and at the shower drains. the toilets have integral traps and do not require a ptrap to be piped in.

After that, as requested, we need more info. on what is happening at the stack area. Once that information is known we may have to explain another layout altogether as it could change how this all gets looked at...UGH!

Back to you Jim!

Mark

Quote:

---

Originally Posted by massplumber2008

It really is even more complicated than that Mike, but since you covered a good part of it...

How about the toilet 1...that is unvented? Here, I would suggest installing a 3"x2" wye right after the toilet 1 but before the toilet 2 branch and pick up the shower and new shower vent and wet vent the toilet 1 that way. The wet vent would need to be 2". This 3"x2" wye MUST roll above the centerline of the toilet to be considered a vent.

Now, the toilet 2 run of piping requires that the sink drain and sink vent be 2" all the way because it is WET VENTING the toilet and the shower (minimum toilet vent is 2")...branch for the sink can be 1.5". The 3"x2" wye coming off the toilet 2 run must also roll above the centerline of the drain pipe for it to be considered a vent.

Ptraps are required at all sinks and at the shower drains. the toilets have integral traps and do not require a ptrap to be piped in.

After that, as requested, we need more info. on what is happening at the stack area. Once that information is known we may have to explain another layout altogether as it could change how this all gets looked at...UGH!

Back to you Jim!

Mark

---

Thanks for the input so far! I've redone the diagram since the first one deserved to be flushed.

In addition to anything downright wrong, my main question is about proper venting (not traps, sorry I had a typo). I know to put P traps on the showers and the sinks.

This is a side profile shot vs the previous top down shot.

Thanks again for any assistance!

OK, but now, with the recommendations I suggested do you see where changes need to be made to drawing 2? The only other addition I would add now that I see drawing 2 is to add a vent to the sink that is at the stack (1.5" fine here). All vents connect at a minimum of 42" off the floor and can then run off as a single 2" vent, or you can bring the vents up and connect them in the attic/loft.

Draw it up again according to recommendations...

Quote:

---

Originally Posted by massplumber2008

OK, but now, with the recommendations I suggested do you see where changes need to be made to drawing 2? The only other addition I would add now that I see drawing 2 is to add a vent to the sink that is at the stack (1.5" fine here). All vents connect at a minimum of 42" off the floor and can then run off as a single 2" vent, or you can bring the vents up and connect them in the attic/loft.

Draw it up again according to recommendations...

---

Great, progress shown in the image attached.

1. Increased sink 2 piping to be 2" due to wet venting a toilet.
2. Added a 1.5" vent to shower 1.
3. Added a 1.5" vent to sink 1.

Toilet 1 is within 3' of the 1.5" dry vent at the top of the stack. Is it necessary to put a vent between toilet 1 and the 3" WYE for the branch going to the other bathroom?

Also, for the shower 1 vent, is it possible to vent via the 3" pipe with a second wye (3x1.5) immediately upstream from the shower?

Thanks!

This is how we install drainage and venting in my area. Good luck, Tom

It looks like I won't have enough clearance to turn the 3x2 wye at toilet 2 to be above centerline and still provide necessary grade for the 2" shower pipe upstream.

Can I instead move the shower 2 wye downstream and add a 2x3 wye (turned above centerline) between the shower 2 wye and toilet 2?

If so, would the position of this 2" vent service the shower 1 vent needed since it would be within about 2' of the shower?

I've attached an image reflecting the potential vent 3 location.

Thanks!

Closer Jim, but still not quite there...

See my image below. Here, the shower was left unvented in your drawing...I added an 1.5" vent for the shower. Toilet 1 is still unvented in your drawing. Here, add a 2" sink drain/vent (1.5" branch off for sink) via a 3"x2" wye rolled above the centerline of the drain and you will effectively wet vent the toilet 1 using the sink. Vent 1 is unnecessary, but if it is present then leave it alone.

Everything else looks great!

Quote:

---

Originally Posted by massplumber2008

Closer Jim, but still not quite there...

See my image below. Here, the shower was left unvented in your drawing...I added an 1.5" vent for the shower. Toilet 1 is still unvented in your drawing. Here, add a 2" sink drain/vent (1.5" branch off for sink) via a 3"x2" wye rolled above the centerline of the drain and you will effectively wet vent the toilet 1 using the sink. Vent 1 is unnecessary, but if it is present then leave it alone.

Everything else looks great!

---

Thanks so much, this has helped me ensure things are as they should be.

Last question: since toilet 1 has the 1.5" vent from shower 1 as well as the 2" vent before toilet two upstream, is it able to use the 3" pipe + the two vents as its vent?

I know you recommend a stand alone vent for toilet 1 but it would require quite a bit of work in my setup so I want to be 100% it's necessary with consideration to the other two upstream vents.

Thanks again!

By your drawing (and my revised drawing) toilet 1 does NOT have a stand alone vent...it now has a 2" sink drain/vent that acts to wet vent that toilet (look at my revised drawing carefully...you'll see sink tie-in in between toilet 1 and the drain for the 2nd bathroom). Unfortunately, the way venting works is such that if you don't do this as presented when you flush toilet 2 it will cause toilet 1 to burp as it doesn't have a vent when toilet 2 waste water goes by (if not piped as shown).

Does that make sense?

Quote:

---

Originally Posted by massplumber2008

By your drawing (and my revised drawing) toilet 1 does NOT have a stand alone vent...it now has a 2" sink drain/vent that acts to wet vent that toilet (look at my revised drawing carefully...you'll see sink tie-in in between toilet 1 and the drain for the 2nd bathroom). Unfortunately, the way venting works is such that if you don't do this as presented when you flush toilet 2 it will cause toilet 1 to burp as it doesn't have a vent when toilet 2 waste water goes by (if not piped as shown).

Does that make sense?

---

Yup! Makes sense, the vent for toilet 1 has to be upstream from the 3" wye going to the second toilet to keep that burping from happening.

Thanks!

Jimmer,
The State of CT has adopted the IRC, as a portion of our state building code. The IRC does not require an individual vent for any toilet that is part of a bathroom group, and a single 1.5" vent can sufficiently, and effectively vent such a group.
The purpose of a plumbing venting system is to maintain atmospheric pressure by preventing siphoning, EXCEPT in the case of a toilet - they are designed to siphon in order to promote the removal of solid waste, and they are the only fixture that has its' trap above the vent; this is allowed because it refills its' trap seal via the ballcock and refill tube

Jimmer,
There is always air available for the toilet flush in the top portion of piping in a DWV system that has a 3 " vent stack ( or stack vent ) that exits the residence, usually through the roof. The purpose of individual vents is to prevent large waste flow volume, typically from a flushed toilet, from creating a vacuum as it passes the individual fixture drainage connections...

Codes do differ from area to area, for sure!

In terms of an 1.5" vent being sufficient to vent an entire bathroom group I would have to tell you to contact your local plumbing inspector as all codes (except as mentioned by Mike) I know of require a 2" vent as a minimum for wet venting an entire bathroom group. You might also ask about rolling the wye above the centerline...don't want you to fail inspection on this as a result of an inspector disagreeing with Mike or me...;) If your inspector will allow you not to roll that wye above the centerline of the toilet drain then you could certainly do away with vent 3 here!!

Jimmer,
All New England states, except Vermont, have adopted the IRC statewide, as a portion of their residential building code. New York has also adopted the IRC, along with most northeast states. Some states are still using the 2006 edition of the IRC code book, most have adopted the 2009 edition...

Massachusetts also hasn't adopted any portion of the IRC that pertains to venting, drainage, etc...pretty sure Maine hasn't either. That is exactly why I remind Jimmer that he needs to consult with his local plumbing inspector (or a local plumber) and not entirely trust the plumbers online here or anywhere...it is, after all, his money and time that can screwed over if we are wrong!!

Mark

Mark,
I agree that Jimmer should check with his building code official. The officials in the towns that I service, keep a copy of the International Residential Code on their desks for quick reference, and they are always enthusiastic to share it during consultations; I'm sure this would be true for Jimmer in his area. He could also do a Google search for the IRC; there are several National mechanical code agencies ( IBC, IRC, IFC, IPC, IMC, etc )that publish lists with charts of the states that have adopted their codes...

Quote:

---

Originally Posted by Mike45plus

Mark,
I agree that Jimmer should check with his building code official. The officials in the towns that I service, keep a copy of the International Residential Code on their desks for quick reference, and they are always enthusiastic to share it during consultations; I'm sure this would be true for Jimmer in his area. He could also do a Google search for the IRC; there are several National mechanical code agencies ( IBC, IRC, IFC, IPC, IMC, etc )that publish lists with charts of the states that have adopted their codes...

---

and according to the International Code Councils website, Massachusetts has adopted the 2009 IRCas a part of their State code...

Read what I wrote Mike. I said, "Massachusetts also hasn't adopted any portion of the IRC that pertains to venting, drainage..."

And for the final time I'll say it again, no one can just take our word for anything when it comes to plumbing waste/vent design...they MUST ask their local plumbing inspector BEFORE proceeding to install any drain/vent system presented on line. Inspectors interpret code differently from town to town and regardless of what the code book says, if an individual tries to argue code they are only setting themselves up for trouble with that inspector for the ENTIRE JOB...simply not worth it!!!



Mark