is this acceptable in terms of vent/connection

[wallrc]

Is this acceptable, specifically the venting situation? I am unsure if a vent has to be after the shower (or after the toilet) based on how close everything is to the stack, which is 4 inch CIP or if it's being stack vented, basically, or really, it's wet venting because each section gets bigger. The connection from the toilet to the stack can be 4 inch instead of 3 too.

This is all under a slab, so I'm trying to plan out what is possible before doing layout of the room.

 

[frodo]

I have a different idea, that will be a lot easier.

useing a 3x3x3 san tee with a 2'' side outlet. and wet vent the lav

install the tee under floor centered on the toilet, in wall, arm over to lav

and arm to tub

 

[wallrc]

I have a different idea, that will be a lot easier.

useing a 3x3x3 san tee with a 2'' side outlet. and wet vent the lav

View attachment 12328

install the tee under floor centered on the toilet, in wall, arm over to lav

and arm to tub

unfortunately everything, including the main stack, are all in a line on an exterior wall. So a Tee like that would have the outlet going the wrong direction, unless you're saying use the outlet as a vent to the exterior wall and build a new vent there. I think I was imagining a simple sanitary tee under the toilet. I will probably post a more detailed question with a larger diagram - the current issue I'm trying to figure out is if the sewer line is deep enough for these things to tap into at all and still have sufficient drop. My drawing's pretty unclear there - that intersection at the bottom of the main stack where it says "to sewer", it's actually coming straight at you from the perspective of the drawing, with the street behind you, just under the slab.

 

[frodo]

they come in left or right,

the 3'' is a simple, toilet drain, the 2'' catches the shower/tub

if you ue the correct left or right, for your situation, the outlet points straight at the tub

this is the easiest/ cheapest way. if you want to do it different fine,,,,,we can dio that also

 

[frodo]

15 3/5'' minimum center of pipe to top of tee add 5'' for opps 20'' is what you need

if you do not have that, we o something else

 

[wallrc]

Thank you for that. I appreciate the help. Let me back up to clarify, though I hadn't planned to post the whole thing here, maybe you have some thoughts that will help.

In my house (1952) they "converted" to sewer in 1966, running a line to the street under the slab of the house, which connects to the main stack. For some reason, they didn't connect more than half the fixtures to the sewer, and left them on the septic tank.
- There are 2 baths, up and down, the upstairs toilet and tub are connected to the sewer. The lav goes to the septic.
- the kitchen sinks (2) goe to septic
- Laundry goes to sewer via a standpipe that goes into the slab via what seems to be a wye to the cast iron (I can take a pic of this if needed)
- downstairs bath all fixtures go to septic
- there is one additional lav on the opposite wall of the basement bath that is pictured here - it's not important to retain, though as it shares pipes with the bath lav, it should be easy to do so.

I became aware of the situation because of an odor in the downstairs bath - I think there is a small leak in the pipe going to the septic, probably just at the top of it. I know where it is because I pumped smoke into the system and saw it come out where the slab meets wall behind the toilet. I want to fix this once and for all - the previous seller did not disclose the septic tank but it's too late to do anything about that, so I am planning to just do it properly. I scoped both parts of the system: down the cleanout next to the toilet which goes into the septic and then through the cleanout next to the HWH which goes into the sewer. After I figured out we had a septic tank which hadn't been pumped in at least 12 years (my time in the house) I dug out the tank top and had it pumped. It wasn't too bad and seems to have never backed up - scum line was fixed.

My plan:
- The upstairs sinks (bath lav, and kitchen) there is an easy fix - I can continue the pipe and Wye into the upstairs bath's drain to the stack, so that part is not really in question.

- I had planned to break up the concrete all along the back wall under the toilet/shower, lay in a new 3 inch pipe and either convert where the stand pipe adapter comes up into just a 3 or 4 inch pipe that would carry toilet/shower/lav into the sewer pipe, or if required, because of depth issues, go at a 45 degree angle and slice into the sewer approximately under where the washer is shown in this pic, and Wye into it.

- to get this done, taking down the wall between the bath/laundry is acceptable, as is moving any of the fixtures. Both washer and dryer can easily move to the far wall, allowing that space. I need to allow 24 in for hotwater heater access, which precludes putting much anything in the space occupied by the washer. Washer can easily drain into the utility sink, which can also go away as it's not used much, and the adapter on the cleanout can serve as drain for the washer. One of the possible scenarios was to move the shower to where the dryer is pictured, however I'm not sure that simplifies the main problem - cutting into the sewer in the easiest way possible.

Hopefully this is clear-er - my explanation is probably pretty muddled. I converted all supply over to pex 2 years ago so am not worried about getting it all where it needs to go.
EXISTING:

Here is one of the options, assuming that I can use the stand pipe at the base of the stack to get into the sewer
PROPOSED:

 

[frodo]

I have a few ideas, but first it is critical to know sewer debth.

your stand pipe connection , can you access the inside of the pipe ?

drop a tape measure down the pipe, till you feel the tape touch the first bend.

do a little adding/subtraction to get the number floor to invert of pipe

t
after you get that, we can figure out the plumbing

 

[frodo]

take a look at this

 

[wallrc]

Thank you. If I'm understanding your drawing correctly, you're saying:
- trench from the toilet at a 45' angle and Wye into the sewer
- trench from the shower and wye into that new line from the toilet
- either cut a small trench from the lav into the new shower line, or trench across the room and tee into the sewer approximately where the toilet is connecting

Is that right? The laundry connection, I'm not worrying about - it could go into the sink today without doing anything, the exhaust pipe can reach.

Are you suggesting that because of possible depth issues? By cutting in a few feet down the line, it might be deeper? I will work on trying to get something on the depth. The stand pipe connection I can't access, but the cleanout at the base of the stack I can.

Here are a couple of pictures of the stand pipe connection - this is looking straight down from the top of the water heater - stack to left. They grey junk everywhere is just from the dryer. That little circle is just a plastic thing that fell down, it's not part of the plumbing. Note that in the original post when I said I was thinking of using this for all the connections, I was proposing cutting out all the concrete around this, and taking out what must be a wye or adapter, and turning it into a straight 4 inch. This is what's visible. It's also possible to cut into this area below the slab from outside the house, as the floor level is appx 2 feet above the ground level and there is exposed foundation.








As always, I appreciate the time you're taking to help me.

 

[frodo]

.........................

 

[wallrc]

Yes - I think the washer drain was the one thing I didn't label - it goes along that wall, then turns left into the pictured connection that you've circled in green.

You're saying add a new toilet vent where you've noted? I'm not understanding that.

Thanks.

 

[frodo]

you have to have a vent

 

[wallrc]

Just a follow up on this - I had to fix part of the old plumbing that had rusted through at a vent. Replaced the whole thing with ABS and removed the lead interface to the CI and replaced with a donut, all seems well there.

Anyway - did a couple of measurements - although I cannot be 100% certain, I think that at the base of the main stack where it turns to become the sewer, it is 18 inches below the floor level, which is the highest point of the sewer line. I may try to measure from the roof vent to see if I can get a more accurate measure.