Tom, Thank you for your previous reply, but unfortunately it did not solve my problem. The lay out of the bathroom is that the shower, toilet, and sink are all in a line with the toilet in the middle. The difficulty I'm having is that I have limited space below the floor and behind the wall. There is a 3" main drain line running out the basement wall horizontally approximately under where the toilet is to go.
So my first question is how can I connect the three items? I believe I can not use a cross laying on it's side? Also, how do I vent this mess. Do I need to have a vent line for each fixture?
Trying to upload image, but having trouble.
Thanks
Tim

[Update, Here is a drawing of my basement with the bathroom. Hope this helps.
Tim

Hi Tim...

Tom's not around right now so I'll pop in and try and help.

First thing is that the 3" main drain line needs a 3" main drain cleanout installed. In most areas they seem to install the cleanout outside about 18"-24" off the foundation wall, but if the cleanout isn't present outside then you will need to install one outside or could be that it will need to be installed inside and brought flush to the finish floor (cap with a decorative clean out access cover), so see if you can determine more on this for your area and let me know more about this, OK?

Next step would be to determine if WET VENTING is allowed in your area? Here, simply call a local plumbing inspector and ask him if wet venting is allowed in your area. If Wet venting is allowed it will save time and money for you so spend a few minutes and get the answer for me. If wet venting isn't allowed then all fixtures will need to be individually vented.

Finally, you are correct that you cannot use a "cross laying on its side".

Get me the answer to my question and look into the cleanout.

Back to you...

Mark

PS: I will be out most of the day working but I pop in every evening so leave your info. And check back leter tonight.

Thanks, the clean out is already installed. Have a call into the building department.

Massplumber, I finally reached the Inspection Dept. The answer is that WET Venting is allowed, but not the toilet. Also, I'm unclear where the vent for the shower needs to be in relation to the actual shower. Lastly, if it makes a difference, this bath will be in the basement directly below the bathroom above, and I can run the vent line up and tie into a vent line above (6" above the high line).

OK... what state are you in so I can confirm/consult the code?

Meanwhile, I'll try to draw something up for you but it could take a day or two, OK?

Confirm the state...

I'm in Ca.
Here is the layout. Sorry for the crudeness of the drwg. I've tried to draw a possible drain line system. I'm not clear on where the vent lines need to be and how many I need. Can the Sink be “Wet vented” through the drain from the LAV above? This is a basement space, so I'm trying not to have to fir out the walls too much to accommodate the piping. The foundation wall rises about 30” above the floor, and then the exterior wall is set back almost 6” so I have plenty of space for piping at that point.

Drawing attempt

Only the left half of the drawing showed up... what are the all the circles?

Also note, no Tee fittings on horizontal drain lines (except vent fittings)... only WYE fittings for waste. I'll explain more later on.

I'll draw something up, but give me until tomorrow AM to finish/post it, OK?

Mark

I apologize for being so inept at putting up the drawings and the delays. Here is another attempt. If it is not clearer in this drawing, the circles were to represent the different fixtures; Lav, WC, Shwr.
Thank you again.

Hi Tim:

California code appears to allow wet venting of an entire bathroom groups... read below.

Section 908.2.1

Where Permitted. Water closets, bathtubs, showers
And floor drains within one (1) or two (2) bathroom
Groups located on the same floor level and for private use
Shall be permitted to be vented by a wet vent. The wet vent
Shall be considered the vent for the fixtures and shall extend
From the connection of the dry vent along the direction of
The flow in the drain pipe to the most downstream fixture
Drain or trap arm connection to the horizontal branch drain.
Each wet-vented fixture drain or trap arm shall connect independently
To the wet-vented horizontal branch drain.
Each individual fixture drain or trap arm shall connect horizontally
To the wet-vented horizontal branch drain or shall
Be provided with a dry vent. The trap to vent distance shall
Be in accordance with Table 10-1. Only the fixtures within
The bathroom groups shall connect to the wet-vented horizontal
Branch drain. The water closet fixture drain or trap
Arm connection to the wet vent shall be downstream of any
Fixture drain or trap arm connections. Any additional fixtures
Shall discharge downstream of the wet vent system
And be conventionally vented.

For the sake of argument could you call your local inspector and see what he has to say about this section of code.

Otherwise, I'm going to consult with a local plumber from your area... our own plumbing expert, Milo Dolezal... ;) He hasn't been around much lately but he'll help me to make sure we do this once and do it right.

Check the code section above... let me know what they say!

Mark