Hello. I'm new to this site, but have "lurked" for some time. I've seen many postings that just don't quite address my problems.

I'm finishing our basement, which has the "standard" rough-in coming through the concrete floor. Basically it's all the fixtures bunched up close together - shower/bath (2" drain) joined with a wye to the lavatory (2" drain with 1 1/2" wet vent) which in turn is joined with a wye to the toilet drain (3"). I also have a floor drain which does not drain directly to this group, but is vented by the same 1 1/2" vent.

I'd like to move the fixtures by some distance (I've already busted up most of the basement floor). I've pulled the permits, but now I can't seem to find a plumber willing to "help" me with the project, as I'm trying to most of the work myself. I'm in Loudoun County, VA which, I believe, adheres to the IPC.

My first question: Is the "critical" distance for a drain measured from trap to the point at which it meets a wet vent, or the point where that vent goes vertical? To clarify, by moving the toilet, my 3" closet bend would be about 4 feet long before it meets, with a wye, the 2" drain for the lavatory. This drain is in turn about 4 feet until it goes vertical to the actual vent. Is the critical distance 3 feet or 7 feet? Is this allowed?

My second question: If the above is allowed, or if I vent the toilet separately, can I join in the shower drain downstream of the toilet and the lavatory? This would mean that the wet vent is upstream of the shower vent.

My third question: I'd also like to add a bar sink to the mess. Since I already have 4 fixtures (toilet, lavatory, shower, floor drain) going into a 1 1/2" vent, can I add a 5th fixture?

I believe that's enough for now. If I get answers to these questions, I'm sure I'll have plenty more.

Thanks in advance.

In my area we work off The Standard Plumbing Code. Unless your local code calls for a individual vent on the toilet you should be OK. We measure the distance as from the weir of the trap to where it ties to the wet vent.

You may connect the shower drain to the lavatory drain where it will be wet vented but may not connect downstream of the toilet and lavatory unless you run a separate vent on the shower.

With a 1 1/2" vent you have 10 fixture units to play with. Adding a bar sink,( 2 fixture units) to your bathroom group, (6 fixture units) gives you 8 fixture units. You're good to go. Good luck, Tom

Thanks Speedball1, that was quick! Too bad the experts on these forums don't live in my area.

OK, since it's not going to be convenient for me to connect the shower drain upstream of the toilet let me pose this as an alternative: I have a 2" floor drain that goes about 1 foot before it is vented vertically by a 1 1/2" dry vent and then continues on to the main line. Can I tie the shower drain in after the vent, or does this also have to be before the vent?

Thanks again.