Toilet Venting

I am doing a bathroom remodel. This is a "guest bath" which consists of a room 5' by 12.5'. The tub and toilet are in a small separate room at the end of the room. It is such a tight little room that you have to either stand on the toilet or stand in the tub to close or open the door. The toilet tissue roll is under your arm.

The outer room has a double vanity plus linen closet.

The plan is to remove the dividing wall, eliminate one of the sinks and move the toilet 12", or so, away from the tub.

The master bath is on the other side of the wall. I included a drawing (sorry about my drawing skills!).

The space below the guest and master bathrooms is my office. I have holes in the ceiling so that I can see how it is plumbed.

I opened up the dividing bathroom wall to find a vent for the toilet. This is close to where the toilet will be relocated and I don't want a wall, let alone the vent in the middle of the room. I really can't rework the vent up into the wall between the bathrooms because a 2 x 12 floor joist in the way .

The two shower/bath drains are run separately and have their own vents. (There are vents all over the roof from these two bathrooms.)

Does each toilet require a separate vent or is the existing #1 toilet vent adequate? (The #1 vent is within 6' of both toilets)

I suppose it is possible to have a small pony wall next to the toilet concealing a 2" vent connecting to the toilet #1's vent.

I poked holes into another area so that I could determine all the venting (and dimensions) for these two bathrooms. Below is an updated drawing (sorry, I've never been able to do 3D drawings). There is a 3" diameter vent when the horizontal run goes down to the sewer (as now marked). The three sinks have a 2" vent, plus that is a wet vent for the horizontal run, this 2" vent connects to the 3" vent about 5' above the floor. There is a 2" vent just downstream of the #1 toilet. Then there is a 2" vent for the #2 toilet, this goes up about 4' through the dividing wall and connects to the two shower/bath vent, the drain for the showers run separate from the sink/toilet run). (I don't understand why there are so many vents!)

I'd like to move the #2 toilet about 8" (shortening this line). If its vent is eliminated it will measure no more than 48" from the 2" vent for the #1 toilet, but the "venting" would have to go "upstream" through the Y. Not sure if this is acceptable to code. Additionally it would be no more than 64" from the new toilet #2 location to the main 3" vent. There is also a 2" wet vent no more than 48" "downstream" from the #2 toilet.

Do I have adequate venting for toilet #2 if I eliminate the existing #2 vent? I would still have 3 vents (one wet) within 6' of toilet #2.

I do want to do this right!!

Having the toilet within 4' of an existing vent ONLY works if it is an effective vent for that fixture. It would ONLY be an "effective vent" for toilet #2 if BOTH toilets connected to the drain line at the SAME location. As it is now, the flow from toilet #1 passes the connection for #2, and there is NO vent between that point and the toilet.

Thanks for the response. It certainly makes sense that the #1 vent is not effective if there is water between the toilets. But, would the 3" vent not count, it is less than 6' from the #2 toilet. (The wife doesn't understand how moving a toilet 6-8" requires so much thinking!)

Amprore -- I am only 27" from the #1 Toilet to the vent, don't think I can get much closer. I thought code was 6'

hj--

Wouldn't the 2" wet vent for the sinks work for toilet #2? Poking around this site I found the following drawing-- The one on the right is almost exactly what I have except for the #1 toilet above the Y



https://terrylove.com/forums/showthread.php?1277-Toilet-amp-Lav-Wet-Venting

Washington st. or DC,codes are different in parts of the country,under IPC you can run a closet arm 10 ft,without venting the closet but conditions apply.As in all other fixtures in the group be vent seperately.And none run past
where the closet is connected to the stack.

I guess water flows differently from state to state.

The powers that be make sure that is true.

The 3" vent would be adequate IF you did not have the #1 toilet dumping into the line between it and the #2 toilet connection. Tell your wife that moving the toilet is NOT the problem, moving the VENT is, and that is why we go to school for so many years to become plumbers, NOT handymen or DIYers. The right hand picture is fine, as long as you ELIMINATE the #1 toilet. Water flows the same way everywhere, and as long as you understand the physics of hydraulics, the BOrnelli principle, Pascal, and air movement you can do plumbing anywhere. If you do NOT understand them, then you have to do your plumbing where they have codes that are very liberal and allow almost anything you wish to do.

Thank you for your response.

Alright, #2 toilet will have its own vent. I can either go up to a 90 over connecting to the #1 vent (above toilet bowl level), enclosing this in a new pony wall, OR (the latest thought to make the wife happy), up at 45 degrees as far as I can without notching the 2 x 12 and then up 45 degrees along the wall then over at 90 to attach to the #1 vent. Most of this would not be enclosed in the wall, but I would build the cabinet with a internal "sofit" to hide the vent pipe. I've never seen this done before, it is a code problem to not enclose the vent in a wall?