Basically imagine a line a----b that is 8'. On the (a) side of the line I have my Ejector Pump with a dry vent connecting to the main stack (before the pump, not the vent for the pump itself), travelling up from that at 4' is my Tub drain and another 4' is my shower drain (b).

Now, can I wet vent this entire run? Can the Shower Share the Tub P Trap? Can the Shower and Tub both wet vent from the A side of the line near the ejector. I realize 2" is a critcal distance of 8'. Does the shower require it's own P Trap and Dry Vent?

Thank you

This is hard to picture exactly... but let me see if I can help. NO the shower cannot share the tub p trap... period. Each fixture must get its own p trap.

You could use a WET vent for say the shower and the lavatory... Here, you would install 2" wye fitting into the shower drain for vent (roll above center line to be a legal vent) and then run that vent over to the lavatory/sink and pick up the sink waste (1.5" stub out is fine)... but then you MUST continue that full size 2" to the vent stack for it to be a legitamate wet vent.

I primarily use the wet vent to wet vent lavatories using the toilet waste line vent as the waste (has to be 2" anyway... even if individual vent so if I am within 8' then I always do this).

Anyway, the tub would then need its own vent and p trap. I really needed to know where the toilet is to give you a well informed answer... but am hoping this helps a little :)

Hey, if this helped please RATE THIS ANSWER by clicking on button below. Thank you.

Thanks for your quick response MassPlumber2008,
I've included a picture of my bathroom how it looks now. I am only concerned from the ejector pump to the tub and from the tub to the shower. It's no problem to setup a P trap for the shower and the tub along a 3" drainage to the Ejector. However, the 4 way connector at the Ejector has 1.5" stub for the shower/tub (very difficult to remove), will running a 3 inch to this and then reducing it cause an issue or does it need to be a 3 inch directly into the 3 inch main drain for the bathroom, the one the toilet is on. The Tub does have it's own vent as you can see from the diagram it is 4 feet away, I would like to know if I can use this same vent for the shower it will be 8 feet away. Or do I need to tie into the old vent that was for the shower, also in the diagram. Sorry, for the long explanation, I hope I am clear, please feel free to ask questions. Thank you again.

I believe that you will need to run an individual vent for the shower for a few reasons... the most important being that 8 feet exceeds code requirements... and then tie that back into the old (existing) shower vent. You did a good job diagramatically... still hard to appreciate exactly how it is piped... how fittings roll above centerlines, etc..

OH!. and the 1.5" pipe facing toward the tub and shower...no good if I understand correctly. The shower requires a 2" minimum pipe size. I would run 2" pipe over to shower and branch off to the tub with a 2" wye fitting.

Hopefully a couple of the other plumbers here will chime in with their thoughts... this is only my opinion of your situation... and they may see something I am missing. Good luck! And do not hesitate to continue with any questions as you go... checking my posts everyday... pretty much.

Massplumber 2008,

Ok I thought it over and decided not to try to tweak things too much. I decided to leave the shower totally isolated. Pretty much like you said about the venting tieing it into the existing, and as far as the drainage, I'm going to chip up a 45 degree angle from the new shower drain to the existing 2" shower drain 5 feet away. Then everything is up to code.
I've never looked into this rolling up, when do you roll up and when do you not. If i'm coming into the 2" existing shower drain can't I just connect them with a long sweep 45?
And one last question. I'm a little confused about venting. I see in books and online people angle these at 1/4" per foot like water. Why would you angle dry vents? I would think you would angle them up since water goes down and fumes rise upwards? That brings me to venting code :) if I run my shower venting horizontal and then to the roof, can the vent angle downward and then upwards? Can you never go below the lowest point on the vent circuit? THANKS AGAIN!!

OK... rolling your vent fittings (usually a wye or a TY fitting) above center line (of the drain pipe) is done to allow air to mix with the waste as it goes down the drain... this effectively scours the pipe walls as waste goes by (if vent tied in at centerline it could potentially fill with waste and or waste could backflow up into vent thereby reducing cross sectional area of vent and therefore its contribution to self scouring the plumbing pipes. NOTE that all vents underground take off above centerline via a WYE or ty fitting, BUT the trap comes after the vent fitting within the required disatnce from the vent or less.

Also, these vents pitch 1/4" to the foot because all vents tie into vent stack that eventually ties through the roof... all vent fitttings are piped so that water will drain back INTO the drainage pipes so that any rain water will drain back into the waste system (Note... underground vents should be pitched until just before you come out of the ground.. I level the last turn before coming out of ground so that my vent pipe will be level coming out of the ground... hope that makes sense).



And all vents underground should take off above centerline of waste pipe via a wye fitting or could even use a TY fitting, but the trap comes after the vent has been cut into the waste line.

Hope this helps.. again do not hesitate to ask as you go along. We are glad to help.

Like I said, I think I'm going to use the old existing shower drain and tie into it with a 2"wye.
Question now is can I use the existing shower vent for the new shower drain. From the new shower drain to the existing is 5', the old wye is another 2' up from there. And then I would just cap off the old ptrap shower drain and bury it. Will that work?

I understand why vents connecting to stacks need to be angled down, so that water doesn't accumulate or other waste from the first floor, but a dry vent in some locations seems like air would flow better if the pipe was horizontal at minimum or angled upwards.

Another question you can see in my diagram the green vent. I have to run this up the wall around the door and then go for another 15 feet the straight up to the outside. Question is: What is the code? They must be pitched up or down? 1/8 or 1/4 a foot. I think I can pull this off by running horizontal to the outside, but would like clarification on venting the shower.

Thank you

OK.. again, if I understand correctly... the vent cannot be more than 5 feet away from the trap... that is the code... so looks like you will just need to locate the vent connection a little closer to the trap.

And the green vent should slope back toward the drain at approximately a 1/4" to the foot. Fact is, as long as it pitches back toward the drain no inspector is going to check that 1/4" to the foot (they may check the waste line pitch! ) so just pitch the vent back so any rain water will fall into (drain back into) the waste pipe underground.

Hope I was clear enough! Let me know.