Sink to Toilet Drain

[ChuckA]

I am remodeling my bath and switched places with the toilet and vanity. In the below pic it is a 3" pipe that runs to the septic and the other end up through the wall and out the roof. Just above the clean out is an 1"1/2 pipe that runs to the shower and vent. That line will be replaced with 2". I feel there is not a problem with that exchange. Traveling up the 3" pipe from the clean out and above the shower drain is where the toilet drain is planned (temporary T placement), just in front of the break in pipe is a 2" T that goes into the wall to service the vanity along with a vent pipe that connects to the 3" main vent that is the 90 at the end of the run.

If I connect the two pipes will there be issues with venting or drainage or should the vanity drain be connected between the toilet drain and clean out? If pipe is connected between the two T's will the p trap water in the vanity be syphoned when the toilet is flushed? Thanks for your Help

 

[johnjh2o]

First the tee you have for the toilet should be a Y and 45 or a combo. The line going to the shower should be 2". As long as your changing it also change the t to a Y. The trap for the sink will be OK as long as it's vented. That tee should also be a Y.

 

[ChuckA]

Thanks John. I have been struggling with the correct way for about a week. Some drawings on the net show the sink or shower drain tied into the main line between the septic and the toilet, others show the toilet tied into the main line between the sink and the septic. Retired and on a fixed budget so I have no room or rather cash to redo many mistakes.

Not a problem switching out the shower line to 2" and a Wye as I already have the vent ran in that size and the 1"1/2 pipe is cut off where it is to be joined. The 1"1/2 and section tied to the clean out was already there.

Switching out the sink Tee to a Wye can be a problem to replace as I already ran that into the wall as you can see and there is no room to cut and add on. I ran the vent to the sink up and in the wall and then to the left which is then connected to the 3" vent. The 90 at the end leads to the vent going through the roof. The shower vent also ties into that vent.

The Tee for the toilet isn't glued, will exchange that for a Wye and 45 as you suggest.