# Connecting shower drain to toilet drain



## Liv

If there are any plumbing codes we should look into, let me know as well. We live in Alabama.


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## psilva8

Liv said:


> We are remodeling the master bathroom (on a concrete slab) and adding a large shower in a location far from the original shower. We want to drain this new shower through the nearby toilet drain (approx 4-5 feet away). From what I understand we'll have to raise up the shower a bit and drill an inclined path through the concrete slab to the toilet drain to allow it to drain properly. But I have a few questions about attaching this new shower drain to the toilet drain...
> 
> 1. What size pipe would we use to tie the shower drain to the toilet drain
> 2. What would be the recommended incline from the shower drain to the toilet drain?
> 3. Do we attach the new drain above or below the toilet drain?
> 3. Any other options/ suggestions for adding a new shower drainage system? Drain through sink drains instead?
> 
> And help is appreciated. We've had a bathroom remodeler tell us that's the way he wants to do it (drain shower through toilet drain). We just wanted to be sure this is a feasible option.
> Thanks for your help.


 
Drill through the concrete slab? Do you mean break out a slot trench for the new pipe? Why would you have to raise the shower unless grade is a concern?

1) 2"
2) 1/4" per foot
3) A sketch or picture would be helpful
4) Same as above

Have you thought about proper venting for the new shower? How is the toilet vented?


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## Liv

Yes, I worded that a little wrong, I did mean slotting a trench. I'm not sure what you mean by venting. I know we have a vent pipe in the bathroom that I'm assuming was used by the old shower before. We have to vent the shower separately from the toilet, correct? This the the only photo I have on me at the time, but I'm assuming we'll probably need to get a plumber out here to answer the other questions. We plan to build the shower along the back wall, the toilet room is to the left just inside the door, and the sinks run along the wall on the right. Thanks for your help!


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## M3 Pete

before you cut the slab, make sure you know what kind it is. If it is a post-tension slab, you have to be very careful to avoid cutting the tendons, which hold the slab together. 

After locating a slab leak, I had a plumber offer to immediately start jackhammering the slab. He had no idea it was a post-tension slab, and if I did not know better, he was going to blast on through.


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## Javiles

You cannot connect a shower to the toilet drain or what would be the waste arm. It needs to be piped within a properly vented branch, unless you revent the new shower line which I be leave you are under the IPC code would need to be wet vented. Which can be tricky? If not the IPC other codes may permit you to do so maybe.


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## psilva8

Javiles said:


> You cannot connect a shower to the toilet drain or what would be the waste arm. It needs to be piped within a properly vented branch, unless you revent the new shower line which I be leave you are under the IPC code would need to be wet vented. Which can be tricky? If not the IPC other codes may permit you to do so maybe.


Out of curiousity, what if the waste arm of the toilet IS the branch drain for the bathroom group? Properly vented of course.


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## homefixr

You definitely dont wanna throw a Y on the dirty arm of the toilet to drain the tub. You wanna go on the other side of the vent. But there is no problem with using the toilets waste line as the branch for the bathroom. What else would you do? Take all three fixtures all the way to the main? That can be unnessecarrily costly


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## psilva8

homefixr said:


> You definitely dont wanna throw a Y on the dirty arm of the toilet to drain the tub. You wanna go on the other side of the vent. But there is no problem with using the toilets waste line as the branch for the bathroom. What else would you do? Take all three fixtures all the way to the main? That can be unnessecarrily costly


That was kind of my point. I'm trying to learn as much as I can about plumbing. I'm finding the codes and rules vary so much from place to place.

Now what is you put a vanity on the toilet waste line, and used it to wet vent the toilet? This would be allowed correct? Or is this also depending on what code you are on?


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## JP's Dad

Following up on this thread: I have a similar issue. I have a toilet that is currently located 12" from the main stack. I am adding a tub to the bathroom and want to drain it into the toilet using a long sweep with a low-heel inlet. See below:

Tub>>> 2" drain pipe >>>>>>long sweep closet w/ heel inlet >>> 3" >>>Cast iron stack


Toilet flange will be mounted above the long sweep closet bend. Is there a problem with this? I've seen different comments on whether the toilet always has to be at the end of the branch or not. Claim seems to be that the extra air allowed into the closet bend will weaken the syphoning effect when flushing the toilet. There is not room to fit a wye between the toilet closet bend and the female connection T to the main stack. Thoughts? Thanks


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## Javiles

JP's Dad said:


> Following up on this thread: I have a similar issue. I have a toilet that is currently located 12" from the main stack. I am adding a tub to the bathroom and want to drain it into the toilet using a long sweep with a low-heel inlet. See below:
> 
> Tub>>> 2" drain pipe >>>>>>long sweep closet w/ heel inlet >>> 3" >>>Cast iron stack
> 
> 
> Toilet flange will be mounted above the long sweep closet bend. Is there a problem with this? I've seen different comments on whether the toilet always has to be at the end of the branch or not. Claim seems to be that the extra air allowed into the closet bend will weaken the syphoning effect when flushing the toilet. There is not room to fit a wye between the toilet closet bend and the female connection T to the main stack. Thoughts? Thanks



Start a new thread...


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